Dr Madeleine Bussemaker

Ultrasound, alone or in combination with natural antimicrobials, is a novel food processing technology of interest to replace traditional food decontamination methods, as it is milder than classical sterilisation (heat treatment) and maintains desirable sensory characteristics. However, ultrasound efficacy can be affected by food structure/composition, as well as the order in which combined treatments are applied. More specifically, treatments which target different cell components could result in enhanced inactivation if applied in the appropriate order. The microbial properties i.e. Gram positive/Gram negative can also impact the treatment efficacy. This work presents a systematic study of the combined effect of ultrasound and nisin on the inactivation of the bacteria Listeria innocua (Gram positive) and Escherichia coli (Gram negative), at a range of cavitation conditions (44, 500, 1000 kHz). The order of treatment application was varied, and the impact of system structure was also investigated by varying the concentration of Xanthan gum used to create the food model systems (0 – 0.5% w/v). Microbial inactivation kinetics were monitored, and advanced microscopy and flow cytometry techniques were utilised to quantify the impact of treatment on a cellular level. Ultrasound was shown to be effective against E. coli at 500 kHz only, with L. innocua demonstrating resistance to all frequencies studied. Enhanced inactivation of E. coli was observed for the combination of nisin and ultrasound at 500 kHz, but only when nisin was applied before ultrasound treatment. The system structure negatively impacted the inactivation efficacy. The combined effect of ultrasound and nisin on E. coli was attributed to short-lived destabilisation of the outer membrane as a result of sonication, allowing nisin to penetrate the cytoplasmic membrane and facilitate cell inactivation.

•Liquid height had minimal effect on defluorination rate at constant power density.•Power density was the defining factor to increase defluorination rate.•Use of multiple reactors/transducers in parallel in a modular design demonstrated.•3 M Lightwater defluorination optimised at 20 × pre-sonolysis dilution. Sonolysis of per- and polyfluoroalkyl substances (PFAS) has recently matured to field studies, treating real world contamination. However, efficient sonolysis reactor designs are poorly researched. Moreover, the variety and complexity of PFAS pollution slows reactor optimisation and scale-up. In this work, the defluorination of 10.0 mg/L aqueous perfluorooctane sulfonic acid (PFOS) was used as a model metric for the optimisation of; reactor volume (0.6 or 1.4 L), power density (100 – 350 W L-1), number of modular reactors (1–3), and liquid height (56.7 – 340 mm). Note, the ultrasonic frequency (410 kHz) and flow rate (214.2 ml min−1) was optimised in this reactor previously. Peak PFOS defluorination rate (3.40 μmolL-1 min−1) occurred at 141.8 mm, in a 0.6 L reactor, under 200 WL–1 ultrasound. Increasing the number of transducers connected in parallel to one amplifier was able to increase treatment efficiency from 78.6 to 191.8 μmol kWh−1. The model was validated using legacy aqueous film forming foam (AFFF, 3 M FC-602 Lightwater) at different dilutions (×5, ×10, ×20 and ×100). Dilution played a role in AFFF sonolysis efficiency with optimal PFAS sonolysis rate (4.28 μmol L-1 min−1) at 20 × dilution. Overall AFFF was effectively modelled with a synthetic PFOS solution, attributed to limited matrix effects in AFFF sonolysis and high PFAS concentration (0.18–1.83 g L-1) dominated by PFOS (0.15 – 1.53 g L-1).

•Pharmaceutical removal using biological digesters, sonication and membrane filtration.•Biotransformation of pharmaceutical in biological and ultrasound treatment.•Hybrid ultrasound coupled treatment processes with biological reactor and membrane filtration. Contaminants of emerging concern (CEC) such as pharmaceuticals commonly found in urban and industrial wastewater are a potential threat to human health and have negative environmental impact. Most wastewater treatment plants cannot efficiently remove these compounds and therefore, many pharmaceuticals end up in aquatic ecosystems, inducing problems such as toxicity and antibiotic-resistance. This review reports the extent of pharmaceutical removal by individual processes such as bioreactors, advanced oxidation processes and membrane filtration systems, all of which are not 100% efficient and can lead to the direct discharge of pharmaceuticals into water bodies. Also, the importance of understanding biotransformation of pharmaceutical compounds during biological and ultrasound treatment, and its impact on treatment efficacy will be reviewed. Different combinations of the processes above, either as an integrated configuration or in series, will be discussed in terms of their degradation efficiency and scale-up capabilities. The trace quantities of pharmaceutical compounds in wastewater and scale-up issues of ultrasound highlight the importance of membrane filtration as a concentration and volume reduction treatment step for wastewater, which could subsequently be treated by ultrasound.

Current literature shows a direct correlation between the sonochemical (SC) process of iodide oxidation and the degradation of phenol solution. This implies phenol degradation occurs primarily via oxidisation at the bubble surface. There is no work at present which considers the effect of fluid flow on the degradation process. In this work, parametric analysis of the degradation of 0.1 mM phenol solution and iodide dosimetry under flow conditions was undertaken to determine the effect of flow. Frequencies of 44, 300 and 1000 kHz and flow rates of 0, 24, 228 and 626 mL / min were applied with variation of power input, air concentration, and surface stabilisation. Phenol degradation was analysed using the 4-aminoantipyrine (4-AAP) method and sonoluminescence (SL) images were evaluated for 0.1, 20 and 60 mM phenol solutions. Flow, at all frequencies under certain conditions, could augment phenol degradation. At 300 kHz there was excellent correlation between phenol degradation and dosimetry indicating a SC process, here flow acted to increase in bubble transience, fragmentation and radical transfer to solution. At 300 kHz, although oxidation is the primary phenol degradation mechanism, it is limited, attributed to degradation intermediates which reduce •OH radical availability and bubble collapse intensity. For 44 and 1000 kHz there was poor correlation between the two SC processes. At 44 kHz (0.01 mM), there was little to suggest high levels of intermediate production, therefore it was theorised that under more transient bubble conditions additional pyrolytic degradation occurs inside the bubbles via diffusion / nanodroplet injection mechanisms. At 1000 kHz, phenol degradation was maximised above all other systems attributed to increased numbers of active bubbles combined with the nature of the ultrasonic field. SL quenching by phenol was reduced in flow systems for the 20 and 60 mM phenol solutions. Here, where the standing wave field was reinforced, and bubble localisation increased, flow and the intrinsic properties of phenol acted to reduce coalescence / clustering. Further, at these higher concentrations, the accumulation of volatile phenol degradation products inside the bubbles are likely reduced in flow conditions leading to an increase SL.

The effect of flow in an ultrasonic reactor is an important consideration for practical applications and for the scale-up of ultrasonic processing. Previous literature on the influence of flow on sonochemical activity has reported conflicting results. Therefore, this work examined the effect of overhead stirring at four different frequencies, 40, 376, 995 and 1179 kHz, in two different reactor configurations. Comparable power settings were utilised to elucidate the underlying mechanisms of interactions between the flow and sonochemical activity. The sonochemical activity was determined by the yield of hydrogen peroxide, measured by iodide dosimetry, and the active region was visualised with sonochemiluminescence imaging. The overhead stirring in the low frequency reactor altered the yield of hydrogen peroxide so it produced the maximum yield out of the four frequencies. The increase in hydrogen peroxide yield was attributed to a reduction in coalescence at 40 kHz. However at the higher frequencies, coalescence was not found to be the main reason behind the observed reductions in sonochemical yield. Rather the prevention of wave propagation and the reduction of the standing wave portion of the field were considered.

The presence of ultrasound-induced cavitation in sonodynamic therapy (SDT) treatments has previously enhanced the activity and delivery of certain sonosensitisers in biological systems. The purpose of this work was to investigate the potential for two novel anti-cancer agents from natural derivatives, sanguinarine and ginger root extract (GRE), as sonosensitisers in an SDT treatment with in vitro PANC-1 cells. Both anti-cancer compounds had a dose-dependent cytotoxicity in the presence of PANC-1 cells. A range of six discreet ultrasound power-frequency configurations were tested and it was found that the cell death caused directly by ultrasound was likely due to the sonomechanical effects of cavitation. Combined treatment used dosages of 100 μM sanguinarine or 1mM of GRE with 15 s sonication at 500 kHz and 10 W. The sanguinarine-SDT and GRE-SDT treatments showed a 6% and 17% synergistic increase in observed cell death, respectively. Therefore both sangunarine and GRE were found to be effective sonosensitisers and warrant further development for SDT, with a view to maximising the magnitude of synergistic increase in toxicity.

This paper presents an intensification study of an ozonation process through an ultrasonic pre-treatment for the elimination of humic substances in water and thus, improve the quality of water treatment systems for human consumption. Humic acids were used as representative of natural organic matter in real waters which present low biodegradability and a high potential for trihalomethane formation. Ultrasonic frequency (98 kHz, 300 kHz and 1 MHz), power (10-40 W) and sonicated volume (150-400 mL) was varied to assess the efficiency of the ultrasonic pre-treatment in the subsequent ozonation process. A direct link between OH radical (●OH) formation and fluorescence reduction was observed during sonication pre-treatment, peaking at 300 kHz and maximum power density. Ultrasound, however, did not reduce total organic carbon (TOC). Injected O3 dose and reaction time were also evaluated during the ozonation treatment. With 300 kHz and 40 W ultrasonic pre-treatment and the subsequent ozonation step (7.4 mg O3/Lgas), TOC was reduced from 21 mg/L to 13.5 mg/L (36% reduction). ●OH attack seems to be the main degradation mechanism during ozonation. A strong reduction in colour (85%) and SUVA254 (70%) was also measured. Moreover, changes in the chemical structure of the macromolecule were observed that led to the formation of oxidation by-products of lower molecular weight

Sonoluminescence (SL) intensity can be increased with potassium iodide (KI) concentration, attributed to a reduction in the gas concentration of solution. However, bubble properties and active bubble distributions at different frequencies and powers also influence SL intensities. Hence, to elucidate how salt concentration affects SL intensity, a systematic study with parametric variation was undertaken. SL from KI solutions of 0.1, 1 and 2 M concentration, without flow and in the presence of flow at 24, 228 and 626 mL / min was investigated at 44, 300 and 1000 kHz. At all frequencies an increase in KI concentration caused a change in the active SL distributions. For 44 kHz, localised and standing wave field SL activity could be expanded. Flow at this frequency augmented SL and SL was maximised at the lowest power setting under stabilisation at the highest KI concentration. At 300 and 1000 kHz, attenuation of the sound field was reduced, allowing expansion of activity throughout solution. In this instance, augmentation of SL intensity was only observed under flow conditions at concentrations of 1 M (300 kHz) and 2 M (1000 kHz) under stabilisation. It was theorised that a combination of smaller bubbles at higher KI concentrations and flow effects could reduce bubble clustering and enhance field formations. This was most prevalent where the standing wave was reinforced under stabilised (44 and 300 kHz) or flow (1000 kHz) conditions, here the number of active bubbles in high pressure regions likely increases. Lastly, it was found that in KI solutions flow could localise SL activity beneath and at the flow inlet via reflection and aeration mechanisms.

Per- and poly-fluoroalkyl substances (PFAS) are xenobiotics, present at variable concentrations in soils and groundwater worldwide. Some of the current remediation techniques being researched or applied for PFAS-impacted soils involve solidification-stabilisation, soil washing, excavation and disposal to landfill, on site or in situ smouldering, thermal desorption, ball milling and incineration. Given the large volumes of soil requiring treatment, there is a need for a more environmentally friendly technique to remove and treat PFASs from soils. Sorbents such as granular/powdered activated carbon, ion exchange resins and silicas are used in water treatment to remove PFAS. In this work, PFAS adsorption mechanisms and the effect of pore size, pH and organic matter on adsorption efficacy are discussed. Then, adsorption of PFAS to soils and sorbents is considered when assessing the viability of remediation techniques. Sonication-aided treatment was predicted to be an effective removal technique for PFASs from a solid phase, and the effect of varying frequency, power and particle size on the effectiveness of the desorption process is discussed. Causes and mitigation strategies for possible cavitation-induced particle erosion during ultrasound washing are also identified. Following soil remediation, degrading the extracted PFAS using sonolysis in a water-organic solvent mixture is discussed. The implications for future soil remediation and sorbent regeneration based on the findings in this study are given.

Sonochemical (SC) processes can be increased with the application of fluid flow due to changes in bubble characteristics. In this work, a novel flow through set-up was applied to an ultrasonic horn system to investigate the effects of flow on the degradation of phenol. KI dosimetry and sonochemiluminescence (SCL) were also analysed, under the same conditions, to provide comparison of degradation to other SC processes. Further, sonoluminescence (SL) in water and different concentrations of potassium iodide (KI) and phenol solutions was studied to determine the effect of flow on processes inside the bubble that result in SL. The degradation of 0.1 mM phenol solutions, KI dosimetry and SL from phenol (0.1, 20 and 60 mM) and KI (0.1, 1 and 2 M) solutions were analysed under flow rates of 0, 24, 228 and 626 mL/min. For an ultrasonic horn system, all flow rates could augment phenol degradation beyond that of the systems without flow. At the lowest applied power, the amount of degradation was significantly increased with flow, becoming greater than degradation observed at the highest power. A strong correlation between phenol degradation and SC processes indicated that degradation followed an oxidative process. SL intensity from water, KI, and phenol solutions could also be increased with flow beyond the no flow system. For water this occurred most readily at higher powers, then for the solutes there was varied behaviour dependent upon the solute concentration. It was theorised that flow may increase the transfer of radical species to solution to enhance SC processes. An increase in SL, with flow, indicates that flow is acting to change the properties of the bubbles and/or the bubble field such that the active bubbles present collapse with greater total intensity.

Sugarcane bagasse (SCB) is an agro-industrial residue extracted during sugar processing. Sugar mills use basic process technologies for bagasse valorisation. Residues are often disposed improperly or burned inefficiently by thermal boilers causing environmental pollution. Biorefining bagasse as substrate for bio-based chemical production is superior to biomass disposal by incineration, burning and landfill. The conversion of bagasse for value-added applications may be economical with less environmental impact on humans and the ecosystem. Computer aided tools such as ontologies for knowledge modelling represent available information for bagasse feedstocks. This paper presents a reference model referred to as the SCB Ontology which is limited to a framework for the modelling of knowledge on the current utilisation of SCB feedstocks from principal sugarcane-cultivating countries. The SCB Ontology identifies opportunities for efficient bagasse valorisation by principal sugarcane producers. Potential application of the SCB Ontology for bagasse valorisation which is a circular bioeconomy initiative was also discussed.

This paper presents an expansion of an already developed ontology BiOnto (Trokanas, Bussemaker, Velliou, Tokos, & Cecelja, 2015) and processing technology eSymbiosis ontology (Raafat, Trokanas, Cecelja, & Bimi, 2013) towards valorisation of lignocellulosic biomass. The ontology provides a reference model interpretable by humans and computers by further classifying and characterizing lignocellulosic biomass (LCB) in several ways, such as: lignin, hemicellulose and cellulose content, C5 and C6 composition, elemental composition, and heat value. Similarly, LCB processing technologies are classified and characterised based on the input of LCB components, with related conversion rates of specific components. The combination of these classifications can elucidate additional information to assist in decision making for the ontology user. For example, the theoretical conversion rates of C5 and C6 polymeric sugars to ethanol are 0.5987 and 0.5679, then by employing the inference capabilities of the knowledge model, the user can gain insights into theoretical ethanol yields for various biomass types based on their C5 and C6 polymeric composition. This can also be applied to theoretical and actual yields of technologies modelled within the ontology, providing a useful reference tool for biorefinery development.

•PFAS sonolysis parameter meta-analysis.•Optimum pH, frequency and temperature derived for PFOX sonolysis.•Degradation occurs via adsorption bubble and headgroup removal.•PFOA/S sonolysis produces only CO2, H2, H+, and F-•Oxidative agents alter degradation mechanism. Human ingestion of Per- and Polyfluoroalkyl Substances (PFAS) from contaminated food and water is linked to the development of several cancers, birth defects and other illnesses. The complete mineralisation of aqueous PFAS by ultrasound (sonolysis) into harmless inorganics has been demonstrated in many studies. However, the range and interconnected nature of reaction parameters (frequency, power, temperature etc.), and variety of reaction metrics used, limits understanding of degradation mechanisms and parametric trends. This work summarises the state-of-the-art for PFAS sonolysis, considering reaction mechanisms, kinetics, intermediates, products, rate limiting steps, reactant and product measurement techniques, and effects of co-contaminants. A meta-analysis showed that mid-high frequency (100-1,000 kHz) sonolysis mechanisms are similar, regardless of reaction conditions, while the low frequency (20-100 kHz) mechanisms are specific to oxidative species added, less well understood, and generally slower than mid-high frequency mechanisms. Arguments suggest that PFAS degradation occurs via adsorption (not absorption) at the bubble interface, followed by headgroup cleavage. Further mechanistic steps toward mineralisation remain to be proven. For the first time, complete stoichiometric reaction equations are derived for PFOA and PFOS sonolysis, which add H2 as a reaction product and consider CO an intermediate. Fluorinated intermediate products are derived for common, and more novel PFAS, and a naming system proposed for novel perfluoroether carboxylates. The meta-analysis also revealed the transition between pseudo first and zero order PFOA/S kinetics commonly occurs at 15-40 µM. Optimum values of; ultrasonic frequency (300 – 500 kHz), concentration (>15-40 μM), temperature (≈20°C), and pH range (3.2 – 4) for rapid PFOX degradation are derived by evaluation of prior works, while optimum values for dilution of PFAS containing firefighting foams and applied power require further work. Rate limiting steps are debated and F- is shown to be rate enhancing, while SO42- and CO2 by products are theorised to be rate limiting. Sonolysis was compared to other PFAS destructive technologies and shown to be the only treatment which fully mineralises PFAS, degrades different PFAS in order of decreasing hydrophobicity, is parametrically well studied and has low-moderate energy requirements (several kWh g-1 PFAS). It is concluded that sonolysis of PFAS in environmental samples would be well incorporated within a treatment train for improved efficiency.

The parameters, including ultrasonic frequency, still versus stirring, biomass particle size and biomass loading were concurrently investigated for the ultrasonic treatment of wheat straw. Experiments were conducted at three different frequencies; 40, 376, and 995kHz using three different solid to liquid ratios, 1/50, 1/20, and 1/15(g/ml), with and without mechanical stirring. Additional treatments in different particle size ranges, 0-0.5, 0.5-1, and 1-2mm were performed at the solid to liquid ratio of 1/20(g/ml). Fractionation was improved at 40 and 995kHz via different mechanisms. Delignification was favored at the ultrasonic treatment frequency of 40kHz, biomass loading 1/20(g/ml) with stirring and particle size range of 0.5-1mm. However at 995kHz carbohydrate solubilization was favored, especially in the particle size range of

The effects of ultrasound (frequency and pressure amplitude) and external parameters (fluid flow rate and surface stabilisation) on active sonoluminescence (SL) and sonochemical (SC) bubbles were investigated using common characterisation techniques. The SL from water, sonochemiluminescence (SCL) from luminol solutions and iodide dosimetry were studied at flow rates of 0, 24, 228 and 626 mL / min at 44, 300 and 1000 kHz with and without surface stabilisation. An increase in flow, in general, decreased SL, SCL and dosimetry caused by a reduction in collapse intensity. However, all flow rates were also able to increase SL intensity and the highest flow rate (626 mL / min) could also increase SCL and dosimetry. For SL, augmentation with flow was attributed to a reduction in coalescence bubbles which cause growth to inactive size (44 kHz) and enhancement of the standing wave at the surface of solution (300 and 1000 kHz). Where agitation at the solution surface (44 kHz) caused aeration (without stabilisation), flow may have circulated additional cavitation nuclei, increasing SL. Increases in SCL intensity and dosimetry yields were attributed to increased bubble fragmentation which was more influential for the latter process. Disparities between SCL and dosimetry are discussed in terms of gas concentration and reaction energy requirements influenced by the transient nature of the bubbles. SL and SCL had complimentary behaviour when they were located in the same regions i.e. a reduction in SL resulted in an increase in SCL as bubbles moved from stable to transient in nature. The same was not observed when SL and SCL bubbles were located in different regions. The active region for SL / SCL could differ or overlap, depending on the standing to travelling wave proportions at each frequency effecting active regions. In some cases, increased standing wave proportions throughout the reactor (with surface stabilisation) did not facilitate an increase in SL intensity, as was expected. Here, the travelling wave without stabilisation enabled a stronger area of activity toward the surface with a localised standing wave.

In this review the phenomenon of ultrasonic cavitation and associated sonochemistry is presented through system parameters. Primary parameters are defined and considered, namely; pressure amplitude, frequency and reactor design; including transducer type, signal type, vessel-transducer ratio, liquid flow, liquid height, liquid temperature and the presence of a reflective plate. Secondary parameters are similarly characterised and involve the use of gas and liquid additives to influence the chemical and physical environments. Each of the parameters are considered in terms of their effect on bubble characteristics and subsequent impact on sonochemical activity. Evidence suggests that via parametric variation, the reaction products and efficiency may be controlled. This is hypothesised to occur through manipulation of the structural stability of the bubble.

The degradation of paracetamol, a widely found emerging pharmaceutical contaminant, was investigated under a wide range of single-frequency and dual-frequency ultrasonic irradiations. For single-frequency ultrasonic irradiation, plate transducers of 22, 98, 200, 300, 400, 500, 760, 850, 1000, and 2000 kHz were employed and for dual-frequency ultrasonic irradiation, the plate transducers were coupled with a 20 kHz ultrasonic horn in opposing configuration. The sonochemical activity was quantified using two dosimetry methods to measure the yield of HO• and H2O2 separately, as well as sonochemiluminescence measurement. Moreover, the severity of the bubble collapses as well as the spatial and size distribution of the cavitation bubbles were evaluated via sonoluminescence measurement. The paracetamol degradation rate was maximised at 850 kHz, in both single and dual frequency ultrasonic irradiation. A synergistic index higher than 1 was observed for all degrading frequencies (200–1000 kHz) under dual frequency ultrasound irradiation, showing the capability of dual frequency system for enhancing pollutant degradation. A comparison of the results of degradation, dosimetry, and sonoluminescence intensity measurement revealed the stronger dependency of the degradation on the yield of HO• for both single and dual frequency systems, which confirms degradation by HO• as the main removal mechanism. However, an enhanced degradation for frequencies higher than 500 kHz was observed despite a lower HO• yield, which could be attributed to the improved mass transfer of hydrophilic compounds at higher frequencies. The sonoluminescence intensity measurements showed that applying dual frequency ultrasonic irradiation for 200 and 400 kHz made the bubbles larger and less uniform in size, with a portion of which not contributing to the yield of reactive oxidant species, whereas for the rest of the frequencies, dual frequency ultrasound irradiation made the cavitation bubbles smaller and more uniform, resulting in a linear correlation between the overall SL intensity and the yield of ROS.

Continuous reflection and evolution of curricula in chemical engineering is beneficial for adaptation to evolving industries and technologies and for improving student experience. To this end it was necessary to develop a method to enable a holistic reflection on the curriculum and to examine potential areas of improvement and change. The curriculum was modelled using knowledge modelling through the development of an ontology, Chemical Engineering Education Ontology (ChEEdO) in the Protégé 3.5 environment. ChEEdO models topics, taught modules and the learning outcomes of the modules within the domain of chemical engineering. The learning outcomes were related to the topics using verb properties from Bloom’s taxonomy and the context of each learning outcome. The functionality of semantic reasoning via the ontology was demonstrated with a case study. The modelling results showed that the ontology could be successfully utilised for curriculum development, horizontal and vertical integration and to identify appropriate pre-requisite learning.

Continuous reflection and evolution of curricula in chemical engineering is beneficial for adaptation to evolving industry requirements, novel technologies and enhances student experience by being up to date and inclusive of effective teaching strategies. To this end it was necessary to develop a method to enable a holistic reflection on the curriculum and to examine the effect and potential areas of improvement and change. The curriculum was modelled using semantic knowledge modelling through the development of an Ontology, ChEEdO in the Protégé 3.5 environment. ChEEdo models topics within the domain of chemical engineering (Topics), modules taught in chemical engineering courses (Modules) and the learning outcomes of these modules (LearningOutcomes). The learning outcomes were related to the topics using verb properties from Bloom’s taxonomy and using the context of each learning outcome. The functionality of semantic reasoning via the ontology was demonstrated with a case study based on curriculum development. The output of the modelling results demonstrated that the ontology could be successfully utilised for this purpose and this is discussed in relation to practicality and future direction.

Conversion of lignocellulose to value-added products is normally focussed on fuel production via ethanol or heat. In this work, a techno-economic assessment of a biorefinery with three product streams, cellulose, hemicellulose and lignin is presented. Moreover, the techno-economic assessment is evaluated in the context of the supply chain through optimisation. A mixed integer linear program was developed to allow for flexible scenarios in order to determine effects of technological and pre-processing variations on the supply chain. The techno-economic and optimisation model integration was demonstrated on a case study in Scotland using woody biomass, either as sawnlogs or sawmill chips. It was established that sawmill chips is the preferred option, however sawnlogs became competitive once passive drying to 30% moisture content (wet basis) was considered. The flexibility of the modelling approach allowed for consideration of technology savings in the context of the supply chain, which can impact development choices.

This work reports the influence of ultrasound alone and combined with ozone for the treatment of real abattoir wastewater. Three different frequencies were studied (44, 300 and 1000 kHz) at an applied power of 40 W. The injected ozone dose was fixed at 71 mg/L and the treatment time varied from 1 to 60 min. Using ultrasound alone, 300 kHz was the only frequency showing a reduction in chemical oxygen demand (COD, 18% reduction) and biological oxygen demand (BOD, 50% reduction), while no diminution in microbial content was measured for any of the frequencies studied. Combining ultrasound with ozone, on the contrary, led to a significant decrease in COD (44%) and BOD (78%) removal for the three frequencies under study. A complete inactivation of total coliforms (TC) was obtained, as well as a final value of 99 CFU/mL in total viable counts (TVC, 5 log reduction). That is, the ozonation-sonication combined system was the only treatment method (compared to sonication and ozonation alone) reaching direct discharge limits, as well as meeting drinking water standards for microbial disinfection (TC and TVC).

Sonochemical activity is dependent on flow patterns within the reactor and either no affect or a decrease in activity was observed at 376, 995, and 1179 kHz from overhead stirring. The interaction of fluid flow with ultrasound was further investigated in this study with circulatory flow. The effect of fluid circulation on radical production was investigated at two circulation speeds, with and without surface stabilisation. The sonochemical activity was determined by the yield of hydrogen peroxide, measured by iodide dosimetry. The sonochemically active region was pictured using sonochemiluminescence imaging and the flow fields were visualised with dyed flow videos. At 376 and 995 kHz, an increase in sonochemical activity was observed with the slower flow rate; however at 1179 kHz, the sonochemical activity was either not affected or decreased. The observed changes in sonochemical activity were attributed to an increase in asymmetry of the bubble collapse brought about by fluid motion. © 2013 Elsevier B.V. All rights reserved.

There is a push towards sourcing chemicals and materials from renewable feedstock such as lignocellulosic biomass. Value chain assessment can be used to evaluate the feasibility of the use of a certain technology and feedstock to produce various chemical sources in a given location. In this work an optimisation model for the value chain assessment of a lignocellulosic biorefinery was developed using mixed integer linear programing. The model allows for a comparison of two product sources which undergo mechanical and/or chemical pretreatment prior to processing by the biorefinery into three product streams, delivered to the customer. Optimisation chooses the source or sources of feedstock and the locations of intermediate storages, pretreatments, biorefinery(ies) and customers with respect to maximising profit. The model was verified based on a case study detailed in Scotland. The case study evaluates the use of felled softwood and/or to the use of sawmill by-products with the production of hemicellulose, lignin and cellulose. The results and implications of the optimisation of the scenario are discussed with respect to costs of transport, processing and product values.

The human food supply chain is placing great strain upon the environment. This is compounded by the creation of wastes at all points along the supply chain. Yet many of these “wastes” are instead surplus foodstuffs that may yet have the potential to be used. Recapturing the value in these surplus foodstuffs is essential in reducing environmental impact of the food supply chain. Insect bioconversion of such surplus foodstuffs back into animal feed is one promising way of doing this. In this study an optimization-based decision support tool is developed to inform bioconversion businesses what locations to source surplus foodstuffs from, where to locate processing facilities and what business model to pursue. A case study business is presented, which utilizes Hermetia illucens (black soldier fly larvae, BSFL) in small bioconversion units which have flexible location options, i.e. close to individual sources of surplus foodstuffs. Spent brewer's grains (SBG) are used as a case study surplus foodstuff. The quantities and locations of SBG are identified within the South East UK. Three business models are evaluated, one using the live BSFL to feed local poultry and two based upon dried BSFL-meal used in aquaculture feeds. The live BSFL business model is shown to be most viable at present with the best margins, and greatest resilience to model perturbations. The novelty of this study is the application of optimization understand the reality of how insect bioconversion may operate within current supply chains, as opposed to the technical or social aspects more usually studied.

Natural antimicrobials are of interest to replace traditional food decontamination methods: they are milder and maintain desirable sensory characteristics. However, efficacy can be affected by food structure/composition, thus structural effects in a co-culture pathogen/microflora system are investigated. Listeria was grown planktonically (liquid broth) or on a biphasic viscoelastic system, in monoculture with/without artificial nisin, or in co-culture with L. lactis (nisin/non-nisin producing). Microbial growth kinetics were monitored and advanced microscopy techniques were utilised to quantify cellular interactions and spatial organisation. Microstructural effects are observed on the kinetics, with differences in monoculture/co- culture. Significant microscopic differences are observed in spatial organisation and colony size. We are the first to observe changing growth location for all species in monoculture/co- culture, with differences in colony size/organisation through stationary phase. This study provides insight into the environmental stress response/adaptation of Listeria grown on structured systems in response to L. lactis and natural antimicrobials.

Sonolysis has been proposed as a promising treatment technology to remove per- and polyfluoroalkyl substances (PFASs) from contaminated water. The mechanism of degradation is generally accepted to be high temperature pyrolysis at the bubble surface with dependency upon surface reaction site availability. However, the parametric effects of the ultrasonic system on PFAS degradation are poorly understood, making upscale challenging and leading to less than optimal use of ultrasonic energy. Hence, a thorough understanding of these parametric effects could lead to improved efficiency and commercial viability. Here, reactor characterisation was performed at 44, 400, 500 and 1000 kHz using potassium iodide (KI) dosimetry, sonochemiluminescence (SCL), and sonoluminescence (SL) in water and PFOS solution. Then the degradation of PFOS (10 mg / L in 200 mL solution) was investigated at these four frequencies. At 44 kHz, no PFOS degradation was observed. At 400, 500 and 1000 kHz the amount of degradation was 96.9, 93.8 and 91.2%, respectively, over four hours and was accompanied by stoichiometric fluoride release, indicating mineralisation of the PFOS molecule. Close correlation of PFOS degradation trends with KI dosimetry and SCL intensity was observed, which suggested degradation occurred under similar conditions to these sonochemical processes. At 1000 kHz, where the overall intensity of collapse was significantly reduced (measured by SL), PFOS degradation was not similarly decreased. Discussion is presented that suggests a solvated electron degradation mechanism for PFOS may occur in ultrasonic conditions.

There is a push towards sourcing chemicals and materials from renewable feedstock such as lignocellulosic biomass. Value chain assessment is used to evaluate the feasibility of the use of a certain technology and feedstock to produce various chemical sources in a given location. In this work an optimisation model for the value chain assessment of a lignocellulosic biorefinery was developed using mixed integer linear programing. The model allows for a comparison of two product sources which undergo mechanical and/or chemical pretreatment prior to processing by the biorefinery into three product streams, delivered to the customer. Optimisation identifies the optimal source or sources of feedstock and the locations of intermediate storages, pretreatments, biorefinery(ies) and customers with respect to maximising profit. The model was verified based on a case study detailed in Scotland. The case study evaluates the use of felled softwood and/or to the use of sawmill by-products with the production of hemicellulose, lignin and cellulose. The results and implications of the optimisation of the scenario are discussed with respect to costs of transport, processing and product values.

Remediation of per-and poly-fluoroalkyl substances (PFAS) is challenged with complexities of solutions, recalcitrance of end products and stringent, evolving regulations. Grouping, characterization and classification of PFAS compounds, environmental contaminations and treatment technologies through knowledge modelling has potential to overcome these challenges. Treatment technologies are often required to work in sequences, called treatment trains to achieve complete removal of PFAS from the environment i.e. a removal/separation stage followed by a degradation stage. Here, an ontology framework is presented to classify PFAS compounds and treatment technologies. Potential applications for the knowledge model to support decision making in environmental remediation and technology research and development is discussed.

This paper presents design and implementation of the BiOnto ontology in the domain of biorefining. The ontology models both biomass types and composition and biorefining processing technologies. The designed ontology is verified by a case study in the domain of Industrial Symbiosis.

To evaluate the feasibility and sustainability of the waste management solutions, it is necessary to assess the quantity and the flows of the waste generated. This research developed a web application which serves as a decision support system for those involved in the planning and management of municipal solid waste . In contrast to present web-based solutions, this tool provides the necessary information regarding the supply chain that is required to assess the suitability of waste valorisation in a particular location such as waste types, waste quantities and related waste contractors. Using publicly available data, a web geographic information system was designed where factors that affect the supply chain of municipal solid waste can be investigated. These include spatial and temporal variation of waste generated. The concept was demonstrated in the developed web application using publicly available data about England. Waste market opportunities were identified, for example Kent County Council and Essex County Council were identified to have the highest quantity of incinerated waste with and without energy recovery (344 and 65 kiloton) respectively. Then Staffordshire and Lancashire County Councils were identified to have the highest quantity of hazardous and non-hazardous waste being landfilled (5 and 296 kiloton) respectively. Seasonal variation was inconsistent across counties, with East Northamptonshire having little seasonal variation in household waste (

Current industrial livestock production has one of the highest consumptions of water, producing up to ten times more polluted (biological oxygen demand, BOD) wastewaters compared to domestic sewage. Additionally, livestock production grows yearly leading to an increase in the generation of wastewater that varies considerably in terms of organic content and microbial population. Therefore, suitable wastewater treatment methods are required to ensure the wastewater quality meets EU regulations before discharge. In the present study, a combined lab scale activated sludge-filtration-ozonation system was used to treat a pre-treated abattoir wastewater. A 24-h hydraulic retention time and a 13-day solid retention time were used for the activated sludge process, followed by filtration (4–7 μm) and using ozone as tertiary treatment. Average reductions of 93% and 98% were achieved for chemical oxygen demand (COD) and BOD, respectively, obtaining final values of 128 mg/L COD and 12 mg/L BOD. The total suspended solids (TSS) average reduction reached 99% in the same system, reducing the final value down to 3 mg/L. Furthermore, 98% reduction in phosphorus (P) and a complete inactivation of total coliforms (TC) was obtained after 17 min of ozonation. For total viable counts (TVC), a drastic reduction was observed after 30 min of ozonation (6 log inactivation) at an injected ozone dose of 71 mg/L. The reduction percentages reported in this study are higher than those previously reported in the literature. Overall, the combined process was sufficient to meet discharge requirements without further treatment for the measured parameters (COD, BOD, TSS, P, TC and TVC).

Continuous reflection and evolution of curricula in chemical engineering is beneficial for adaptation to evolving industry requirements, novel technologies and enhances student experience by being up to date and inclusive of effective teaching strategies. To this end it was necessary to develop a method to enable a holistic reflection on the curriculum and to examine the effect and potential areas of improvement and change. The curriculum was modelled using semantic knowledge modelling through the development of an Ontology, ChEEdO in the Protégé 3.5 environment. ChEEdo models topics within the domain of chemical engineering, modules taught in chemical engineering courses and the learning outcomes of these modules. The learning outcomes were related to the topics using verb properties from Bloom’s taxonomy and using the context of each learning outcome. The functionality of semantic reasoning via the ontology was demonstrated with a case study based on curriculum development. The output of the modelling results demonstrated that the ontology could be successfully utilised for curriculum development and this is discussed in relation to practicality and future direction.

Conversion of lignocellulose to value-added products is normally focussed on fuel production via ethanol or heat. In this work, a techno-economic assessment of a biorefinery with three product streams, cellulose, hemicellulose and lignin is presented. Moreover, the techno-economic assessment is evaluated in the context of the supply chain through optimisation. A mixed integer linear program was developed to allow for flexible scenarios in order to determine effects of technological and pre-processing variations on the supply chain. The techno-economic and optimisation model integration was demonstrated on a case study in Scotland using woody biomass, either as sawnlogs or sawmill chips. It was established that sawmill chips is the preferred option, however sawnlogs became competitive once passive drying to 30% moisture content (wet basis) was considered. The flexibility of the modelling approach allowed for consideration of technology savings in the context of the supply chain, which can impact development choices.

Matrix isolation FTIR experiments have shown that methanol is a major product when argon gas doped with water and methane is exposed to an electrical discharge and condensed to a solid matrix at 11 K. Experiments with (2)H, (17)O and (18)O-labeled isotopologues show the mechanism for the methanol production is likely to be insertion of an excited oxygen atom in the (1)D state into a C-H bond of a methane molecule. In light of these experiments, the possibility of oxygen atom insertion into methane should be considered as a possible mechanism for the production of methanol in interstellar ices.

Advances made in recent years have allowed the application of colorants obtained from natural sources into textile dyeing. The use of ultrasound in the dyeing method is reported to increase dye uptake and decrease dyeing times. The aim of this work is to further extend the knowledge of natural hair dyes considering the use of ultrasound in the dyeing method with commercially available herbal dyes and using goat hair as a model for human hair. Optimal ultrasonic parameters were selected by considering the effects of sonication times (5, 10 and 15 min), frequencies (44, 400 and 1000 kHz) and total dyeing times (30, 60 and 120 min) in the morphology of the dyed hair and the colour intensity. Damage to the hair surface was evaluated by scanning electron microscopy (SEM) images, differences in colour of the dyed hair was obtained by ImageJ analysis and quantification of dye uptake was determined by UV-visible spectroscopy. The evidence from this study suggests an increase in goat hair coloration with the use of ultrasonic energy. Optimal dyeing conditions in consideration of colouration efficacy without hair damage were identified as sonication at 400 kHz for 10 min with a total dyeing time of 60 min.

This paper reports for the first time the development in the size and shape of sodium chloride crystals during the anti-solvent crystallization in ethanol under different sonication modes. Sonication using 98 kHz and calorimetric power of 6 W was applied either continuously for a range of crystallisation times (5 – 90 s) or intermittently (5 s pulse). Under silent conditions, crystallization time of 90 s generated crystals with an average size of 73.8 ± 6.9 μm, compared to 8.7 ± 2.8 μm under 90 s of continuous sonication. However, it was observed that within the first 5 s of sonication at the beginning of the crystallization, the average crystal size was already reduced to 7.0 ± 3.3 μm. If the system was left to crystallise further to 90 s without ultrasound, the crystal size grew only slightly to 8.2 ± 1.4 μm. When 5 s burst of ultrasound was applied during the crystallization process, a bimodal distribution of small (from sonication) and large crystals (from the silent period) was obtained. These results imply that the major influence of sonication is crystal nucleation rather than fragmentation, and equilibrium is reached with 5 s sonication by precipitating most of the crystals in solution.

Carbonate-based organic electrolytes with lower flash points are widely used in commercial lithium-ion batteries, boosting the development of energy storage system. Safety problems, arising from the combustion and explosion caused by carbonate-based organic electrolytes, have become one of the bottlenecks restricting largescale application of lithium-ion batteries. In this work, flame-retardant or non-combustible electrolyte systems were investigated. Because of the excellent flame retardancy, low flammability, and high conductivity, thermal, and electrochemical stability, 1-butyl-3-menthylimidazolium-hexafluorophosphate ([Bmim]PF6) was used to generate imidazolium ionic liquids based electrolytes. The flame retardant and electrochemical performances of [Bmim]PF6-based binary electrolytes with different ionic liquid ratios, and the comparison with commercial carbonate electrolytes (CEs) were characterized. Results show that compared with commercial carbonate solvent electrolytes, battery performances, such as thermal safety and electrochemical stability of the proposed [Bmim] PF6 binary electrolyte, are superior to that of CEs when they are used in LiFePO4 electrode batteries. The binary electrolyte with 5% of [Bmim]PF6 ionic liquid possesses the best comprehensive performance. Explicitly speaking, the ionic conductivity and combustibility of the binary electrolyte are higher and significantly lower than that of CEs, respectively, thus the significantly improving the conductivity and thermal stability. Furthermore, since the battery's discharge capacity and capacity retention rate using the binary electrolyte after 100 cycles of charge and discharge at 1 C charge-discharge rate are higher than those using CEs, the [Bmim]PF6 binary electrolyte also shows good electrochemical stability.

Minimal processing for microbial decontamination, such as the use of natural antimicrobials, is gaining interest in the food industry as these methods are generally milder than conventional processing, therefore better maintaining the nutritional content and sensory characteristics of food products. The aim of this study was to quantify the impact of (i) structural composition and complexity, (ii) growth location and morphology, and (iii) the natural antimicrobial nisin, on the microbial dynamics of Listeria innocua. More specifically, viscoelastic food model systems of various compositions and internal structure were developed and characterised, i.e. monophasic Xanthan gum-based and biphasic Xanthan gum/Whey protein-based viscoelastic systems. The microbial dynamics of L. innocua at 10oC, 30oC and 37oC were monitored and compared for planktonic growth in liquid, or in/on (immersed or surface colony growth) the developed viscoelastic systems, with or without a sublethal concentration of nisin. Microscopy imaging was used to determine the bacterial colony size and spatial organisation in/on the viscoelastic systems. Selective growth of L. innocua on the protein phase of the developed biphasic system was observed for the first time. Additionally, significant differences were observed in the colony size and distribution in the monophasic Xanthan gum-based systems depending on (i) the type of growth (surface/immersed) and (ii) the Xanthan gum concentration. Furthermore, the system viscosity in monophasic Xanthan gum-based systems had a protective role against the effects of nisin for immersed growth, and a further inhibitory effect for surface growth at a suboptimal temperature (10oC). These findings give a systematic quantitative insight on the impact of nisin as an environmental challenge on the growth and spatial organisation of L. innocua, in viscoelastic food model systems of various structural compositions/complexities. This study highlights the importance of accounting for system structural composition/complexity when designing minimal food processing methods with natural antimicrobials.

The conversion of lignocellulosic biomass for biofuels and biorefinery applications is limited due to the cost of pretreatment to separate or access the biomass's three main usable components, cellulose, hemicellulose, and lignin. After pretreatment, each component may be utilized via chemical conversion, hydrolysis, and/or fermentation. In this review we aim first, to identify the current status-quo of knowledge of the parametric effects of ultrasound, second, to evaluate the potential of ultrasound as a pretreatment and fractionation method of lignocellulose, and last, to identify the challenges that this technology faces. Ultrasound produces chemical and physical effects which were both found to augment the pretreatment of lignocellulose via delignification and surface erosion. The magnitudes of these effects are altered when the ultrasonic field is influenced by parameters such as solvent, ultrasonic frequency, and reactor geometry and type. Therefore, the implementation of ultrasound for the pretreatment of lignocellulose must consider the variation of ultrasonic influences to capitalize on the key effects of ultrasound. Currently the literature is dominated by low frequency ultrasonic treatment, coupled with alkaline solutions. High frequency ultrasound, oxidizing solutions, and use of combined alternative augmentation techniques show promise for the reduction of energy consumed and synergistic enhancement of ultrasonic treatment. Furthermore, feedstock characteristics, reactor configuration, kinetics, and the ultrasonic environment should be considered. © 2013 American Chemical Society.

Undergraduate laboratory classes are being reviewed and in some cases scaled back because they are expensive to run compared to the learning outcomes for students. We believe that practical experience is essential and should remain an important part of undergraduate chemistry courses. However significant adaptations should be made to broaden the skills that students can take from these classes. We proposed to make changes which increased the value of laboratories as a tool for educating new scientists without increasing the workload for staff or students. The assessment tasks were altered to focus on learning outcomes and resources were improved and made available online and in hardcopy for students and teachers. Worksheets were introduced for each laboratory experiment and the number of full laboratory report assessments halved. The provision of worksheets placed an emphasis on the key chemical concepts and aided students in their understanding of scientific writing conventions. Students were provided with an explicit guide to writing laboratory reports and given feedback on their writing technique. The submission system was moved to the online student platform WebCT to increase flexibility and improve the quality and speed of feedback. These changes were met favorably by students, and the subsequent improvement in quality of student work was noted by the assessors. The study highlighted the importance of demonstrators as teaching staff and the need to provide them with adequate training and resources. While we acknowledge that further development is required we believe that by broadening the focus of assessment beyond chemical theory the needs of cross discipline students were met while still providing chemistry majors with a solid laboratory background.

design of InterCAPEmodel ontology, which contains a comprehensive description to represent the knowledge of models and data in the biorefining domain, is presented. Primarily, the InterCAPEmodel ontology aims at providing implicit knowledge that reflects process synthesis logic, and explicit knowledge including a complete set of input/output types and the parameters associated with each model and dataset to manage the repository. At present, the InterCAPEmodel ontology supports integration of model and/or data. To fully exploit the potential of providing the description of the model and data to sufficiently support semantic integration, the design of knowledge model is described and the use of ontology that demonstrates its functionality is presented using a case study of a lignocellulosic based biorefining models and data at supply chain level.

Sonocrystallisation is the application of ultrasound to the crystallisation process. The benefits obtained by sonication have been widely studied since the beginning of the 20th century and so far it is clear that ultrasound can be a very useful tool for enhancing crystallisation and controlling the properties of the final product. Crystal size, polymorphs, purity, process repeatability and lower induction time are only some of the advantages of sonocrystallisation. Even though the effects of sonication on crystallisation are quite clear, the physical explanation of the phenomena involved is still lacking. Is the presence of cavitation necessary for the process? Or is only the bubbles surface responsible for enhancing crystallisation? Are the strong local increases in pressure and temperature induced by cavitation the main cause of all the observed effects? Or is it the strong turbulence induced in the system, instead? Many questions still remain and can only be appreciated with an understanding of the complexity behind the individual processes of crystallisation and acoustic cavitation. Therefore, this review will first summarise the theories behind crystallisation and acoustic cavitation, followed by a description of all the current proposed sonocrystallisation mechanisms, and conclude with an overview on future prospects of sonocrystallisation applications.

This paper presents an effort to utilise semantics to improve the decision making process in biorefinery value chains. In more detail, an ontology describing biomass and biorefineries is used to facilitate the identification of the best options for the population of the optimisation problem. In addition to that, the reasoning capabilities of ontologies are used to enhance search of information. The approach has been verified with a case study for biomass available in Scotland.

Ultrasound was shown to enhance pretreatment of lignocellulose for biofuel and biorefinery applications and can augment oxidative processes, yet few studies have combined ultrasound with an oxidative environment for the pretreatment of lignocellulose. In the present contribution, pretreatment of a wheat straw using a combination of ultrasound with two oxidative pretreatments, peracetic acid and hydrogen peroxide, as well as water and acetic acid was tested. The experimentation was conducted in an ultrasonic-microwave reactor with a comparison to silent pretreatment with microwave heating alone. In addition, thermal heating was compared to microwave heating for the water pretreatment. Ultrasound produced a higher purity solid residue for all chemical pretreatments. However, ultrasound pretreatment reduced the delignification efficacy by up to 50%, attributed to lignin condensation. The chemical treatments were affected by sonolysis reactions and altered the recoverability of the solubilized carbohydrates. © 2013 American Chemical Society.

A systematic study on the sonocrystallisation of ZIF-8 (zeolitic imidazolate framework-8) in a water-based system was investigated under different mixing speeds, ultrasound frequencies, calorimetric powers and sonication time. Regardless of the synthesis technique, pure crystals of ZIF-8 with high BET (Brunauer, Emmett and Teller) specific surface area (SSA) can be obtained in water after only 5 s. Furthermore, 5 s sonication produced even smaller crystals (~ 0.08 µm). The type of technique applied for producing the ZIF-8 crystals did not have any significant impact on crystallinity, purity and yield. Crystal morphology and size were affected by the use of ultrasound and mixing, obtaining nanoparticles with a more spherical shape than in silent condition (no ultrasound and mixing). However, no specific trends were observed with varying frequency, calorimetric power and mixing speed. Ultrasound and mixing may have an effect on the nucleation step, causing the fast production of nucleation centres. Furthermore, the BET SSA increased with increasing mixing speed. With ultrasound, the BET SSA is between the values obtained under silent condition and with mixing. A competition between micromixing and shockwaves has been proposed when sonication is used for ZIF-8 production. The former increases the BET SSA, while the latter could be responsible for porosity damage, causing a decrease of the surface area.