Browsing by Author "Jiang, Ying"

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    Ag/Ag2O confined visible-light driven catalyst for highly efficient selective hydrogenation of nitroarenes in pure water medium at room temperature
    (Elsevier, 2020-04-10) Yin, Zhengliang; Xie, Liangxu; Cao, Shunsheng; Xiao, Yingguan; Chen, Gang; Jiang, Ying; Wei, Wenxian; Wu, Limin
    Although photocatalysis has attracted tremendous research interest, there still remains critical challenges (e.g., low visible-light quantum efficiency, organic media, etc.), especially for selective hydrogenation of nitroarenes. Herein, we design and synthesize the first confined photocatalyst by introducing the nanospace of double-shelled hollow silica sphere as a photocatalytic nanoreactor to promote the hydrogenation reaction with the fast reaction kinetics. This photocatalyst exhibits excellent activity, selectivity, and recyclability. Especially, superior selectivity (>99%) is achieved when used for the hydrogenation of nitroarenes under visible-light irradiation in pure water medium. Both experimental and theoretical simulation results indicate that the Ag/Ag2O structure and confined nanospace of the photocatalyst greatly increase the contact probability between photogenerated atomic hydrogen and nitroarenes. Additionally, corresponding anilines are obtained almost quantitatively towards the hydrogenation of nitroarenes in pure water medium at room temperature. Therefore, this work provides a rational design concept of highly efficient visible-light photocatalyst for green chemistry industry.
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    Ammonia inhibition and toxicity in anaerobic digestion: a critical review
    (Elsevier, 2019-07-20) Jiang, Ying; McAdam, Ewan; Zhang, Yue; Heaven, Sonia; Banks, Charles J.; Longhurst, Philip
    As a waste management technology which offers environmental benefit and renewable energy production, anaerobic digestion (AD) has become the preferred technology for the treatment of organic waste. However, in such waste streams nitrogen contents are likely to be high. There is prevailing literature evidence suggests that high ammonia concentration especially its free molecular form (NH3), derived from nitrogen content in substrates is the cause of inhibition and sudden failure of the AD process. This paper comprehensively reviews previous knowledge from digestion studies using high nitrogen waste streams as feedstocks and critically analysed the considerable variations in the inhibition/toxicity levels reported for ammonia. Literature evidences suggest methanogens, particularly acetoclastic methanogens are most susceptible to ammonia toxicity, and therefore this review has a particular focus on the mechanism of the ‘selective’ inhibition to methanogens and the impact of ammonia toxicity to the overall methanogen population in an AD digester. This population change explains in many reported cases that sufficient acclimatisation can significantly alleviate the phenomenon of inhibition and specific requirement of certain trace nutrients. Currently available mitigation strategies for high nitrogen content feedstock digestion are reviewed and discussed in relation to the population change and trace nutrient requirements.
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    Arsenic transformation behaviour during thermal decomposition of P. vittata, an arsenic hyperaccumulator
    (Elsevier, 2017-01-22) Duan, Lunbo; Li, Xiaole; Jiang, Ying; Lei, Mei; Dong, Ziping; Longhurst, Philip J.
    Thermal treatment of P. vittata, an arsenic hyperaccumulator harvested from contaminated land is a promising method of achieving volume reduction, energy production and arsenic (As) recovery simultaneously. In this paper, the arsenic transformation characteristics of field-harvested P. vittata were investigated during its pyrolysis and gasification process. The produced solid residue and flue gas were analysed by a high performance liquid chromatography coupled with inductively coupled plasma mass spectrometry (HPLC-ICP-MS) to determine both the arsenic concentration and speciation. Moreover, the occurrence of arsenic in the solid residues was further identified as soluble and insoluble, which can feed information to the next arsenic recovery step. Results show that the fuel arsenic into gas phase increases firstly from 400 °C to 600 °C, but then drops from 600 °C to 800 °C, probably due to the self-retention of arsenic by CaO enriched in this P. vittata. Further increasing temperature to 900 °C will result in fast arsenic release. Gasification results in slightly higher arsenic release into the gas phase compared with pyrolysis
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    The behaviour of metal(oid)s contaminants in woody biomass during advanced thermal conversion processes.
    (Cranfield University, 2019-05) Al-Badri, Shurooq Badri; Wagland, Stuart; Jiang, Ying
    A remarkable proportion (about 64%) of renewable biomass energy is produced from woody biomass (wood and its wastes). However, waste wood (WW) often exhibits a high level of chemical contaminants, likely due to the presence of metal(loid) elements in preservatives, paintings, coatings, and other related activities. By thermally treating WW, the metal(loid)s will end up in the bottom ash and/or be emitted into the atmosphere, causing severe environmental concerns and technical damages (e.g. slagging and corrosion). Thus, it is necessary to understand the behaviour of metal(loid)s during the woody biomass thermal conversion process, specifically gasification and pyrolysis. While a great deal of knowledge is available on this matter, there is still uncertainty surrounding the identification and characterisation of metal(loid) elements in relation to woody biomass utilisation, as well as the influences of reaction atmosphere composition in terms of interactions and interferences. In addition to that, knowledge is needed on partitioning profiles of the key metal(loid) elements during the gasification and pyrolysis of WW in order to evaluate the emission potential of these elements. This thesis firstly provides a highly informative dataset that contains comprehensive details about the characterisation and elemental composition of key metal(loid) elements (As, B, Co, Cr, Cu, Fe, Ni, Pb, Mn, Hg and Ti) that are regularly present in woody biomass. Moreover, chemical equilibrium calculations were performed to predict elemental phase transformation and speciation formation under given gasification and pyrolysis operation conditions. Among the results, it was found that Ni-As interactions form the dominant species As₂Ni₅ and As₈Ni₁₁, which increase the solid-gaseous phase transformation of As. In addition, the Ca-Cr interaction forms C₃Cr₇; meanwhile, the absence of Ca creates instability in the Cr phase transformation due to the generation of the species Cr₂Na₂O₄. Subsequently, a set of experiments were conducted using a TGA analyser with different heating rates to understand the thermal behaviour of woody biomass and define the operational conditions of the pyrolysis process. Tube furnace experiments were also conducted to investigate the distributions of Al, As, Ca, Cd, Co, Cr, Cu, Fe, Hg, K, Na, Mn, Mo, Ni, Pb, Si, Ti, V, and, Zn during the operation of pyrolysis. Experimental results indicated that Cd and Hg are exceedingly volatile elements, whereas Al, Co, Cr, Cu Fe, Mo, Ni, Si, Ti, and V are non-volatile elements. The elements As, Mn, Pb, and Zn exhibited differences in partitioning across all experiments. Importantly, this study provides unique insight into the behaviour of As in terms of As-Ni interaction. That is, the presence of Ni should be regarded in combination with its associated concentration profile. Finally, the experimental data and the calculation results are complementary rather than competitive. Overall, the experimental results are within acceptable validation limits.
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    China's soil and groundwater management challenges: Lessons from the UK's experience and opportunities for China
    (Elseveir, 2016-03-10) Coulon, Frederic; Jones, Kevin; Li, Hong; Hu, Qing; Gao, Jingyang; Li, Fasheng; Chen, Mengfang; Zhu, Yong-Guan; Liu, Rongxia; Liu, Ming; Canning, Kate; Harries, Nicola; Bardos, Paul; Nathanail, C. Paul; Sweeney, Rob; Middleton, David; Charnley, Maggie; Randall, Jeremy; Richell, Martin; Howard, Trevor; Martin, Ian; Spooner, Simon; Weeks, Jason; Cave, Mark; Yu, Fang; Zhang, Fang; Jiang, Ying; Longhurst, Philip J.; Prpich, George; Bewley, Richard; Abra, Jonathan; Pollard, Simon J. T.
    There are a number of specific opportunities for UK and China to work together on contaminated land management issues as China lacks comprehensive and systematic planning for sustainable risk based land management, encompassing both contaminated soil and groundwater and recycling and reuse of soil. It also lacks comprehensive risk assessment systems, structures to support risk management decision making, processes for verification of remediation outcome, systems for record keeping and preservation and integration of contamination issues into land use planning, along with procedures for ensuring effective health and safety considerations during remediation projects, and effective evaluation of costs versus benefits and overall sustainability. A consequence of the absence of these overarching frameworks has been that remediation takes place on an ad hoc basis. At a specific site management level, China lacks capabilities in site investigation and consequent risk assessment systems, in particular related to conceptual modelling and risk evaluation. There is also a lack of shared experience of practical deployment of remediation technologies in China, analogous to the situation before the establishment of the independent, non-profit organisation CL:AIRE (Contaminated Land: Applications In Real Environments) in 1999 in the UK. Many local technology developments are at lab-scale or pilot-scale stage without being widely put into use. Therefore, a shared endeavour is needed to promote the development of technically and scientifically sound land management as well as soil and human health protection to improve the sustainability of the rapid urbanisation in China.
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    Chlorine removal from the pyrolysis of urban polyolefinic waste in a semi-batch reactor
    (Elsevier, 2020-12-11) Torres, Daniel; Jiang, Ying; Sanchez Monsalve, D. A.; Leeke, Gary
    The pyrolysis of urban chlorine-containing polyolefinic plastic waste with simultaneous retention of HCl is investigated. Different chemical removers based on sodium, calcium and zinc bases, and different adsorbents based on alumina or zeolites were used inside the reactor or in downstream hot filters, respectively, for chlorine removal and upgrading of pyrolysis oils. Initially, polyolefin waste (POW, containing a 98.5 wt% polyolefins) was thermogravimetrically pyrolyzed to determine its thermal behaviour. Subsequently, chemical removers were mixed with the POW which was pyrolyzed at 480 °C in a semi-batch reactor. The adsorbents were tested separately in hot filters (300 ± 20 °C) downstream of the pyrolysis reactor. After the pyrolysis, the resulting char containing the chemical removers and the absorbents in the hot filters were analysed by FTIR, CHN elemental analysis and ESEM-EDS to determine their respective chlorine contents. The highest chlorine retention was 23.8 wt% for chemical remover when used in direct contact with POW, while a zeolite used in the hot filter (gas streams) gave a chlorine retention of 65.6 wt%. The pyrolytic liquids consisted of mixtures of C7-C40 hydrocarbons made up of olefinic and aliphatic hydrocarbons with a very low presence of aromatics (estimated to be below 3 wt% by HPLC). In most cases, the chlorine removal processes resulted in waxier pyrolytic oils and with a higher degree of branching
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    Conceptual environmental impact assessment of a novel self-sustained sanitation system incorporating a Quantitative Microbial Risk Assessment approach
    (Elsevier, 2018-05-26) Anastasopoulou, Aikaterini; Kolios, Athanasios; Somorin, Tosin; Sowale, Ayodeji; Jiang, Ying; Fidalgo, Beatriz; Parker, Alison; Williams, Leon; Collins, Matt; McAdam, Ewan; Tyrrel, Sean
    In many developing countries, including South Africa, water scarcity has resulted in poor sanitation practices. The majority of the sanitation infrastructures in those regions fail to meet basic hygienic standards. This along with the lack of proper sewage/wastewater infrastructure creates significant environmental and public health concerns. A self-sustained, waterless “Nano Membrane Toilet” (NMT) design was proposed as a result of the “Reinvent the Toilet Challenge” funded by the Bill and Melinda Gates Foundation. A “cradle-to-grave” life cycle assessment (LCA) approach was adopted to study the use of NMT in comparison with conventional pour flush toilet (PFT) and urine-diverting dry toilet (UDDT). All three scenarios were applied in the context of South Africa. In addition, a Quantitative Microbial Risk Assessment (QMRA) was used to reflect the impact of the pathogen risk on human health. LCA study showed that UDDT had the best environmental performance, followed by NMT and PFT systems for all impact categories investigated including human health, resource and ecosystem. This was mainly due to the environmental credits associated with the use of urine and compost as fertilizers. However, with the incorporation of the pathogen impact into the human health impact category, the NMT had a significant better performance than the PFT and UDDT systems, which exhibited an impact category value 4E + 04 and 4E + 03 times higher, respectively. Sensitivity analysis identified that the use of ash as fertilizer, electricity generation and the reduction of NOx emissions were the key areas that influenced significantly the environmental performance of the NMT system.
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    Data supporting: 'Evaluating Different Soil Amendments as Bioremediation Strategy for Wetland Soil Contaminated by Crude Oil'
    (Cranfield University, 2023-02-01 17:33) Jumbo, Raphael; Coulon, Frederic; Cowley, Tamazon; ndubuisi Azuazu, Ikeabiama; Atai, Emmanuel; Bortone, Imma; Jiang, Ying
    This study evaluated the efficacy of using Tween 80 surfactant (TW80) and food-waste anaerobic digestate fibre (FWAD) as soil amendments for the remediation of wetlands contaminated by crude oil. A 112-day mesocosms experiment was carried out to simulate hydrocarbon degradation under typical acidified wetland conditions. Soil was spiked with 50,000 mg kgˆ’1 crude oil and TW80 and FWAD were added to mesocosms at 10%, 20% and 30% w/w. The soil basal respiration, microbial community dynamics, environmental stress, alkanes, and PAHs degradation were monitored throughout the mesocosm experiment. Amending the mesocosms with FWAD and TW80 enabled the recovery of the soil microbial activities. This was evidenced by soil basal respiration which was the highest in the 30% FWAD and 30% TW80 mesocosms and translated into increased degradation rate of 32% and 23% for alkanes, and 33% and 26% for PAHs compared to natural attenuation, respectively. Efficient total hydrocarbon degradation was achieved in soil mesocosms with 30% FWAD and 30% TW80 at 90% and 86.8%, respectively after 49 days. Maize seed germination results showed significant improvement from 29% to over 90% following the FWAD and TW80 treatment.
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    Diagnostic features emerging in near-infrared reflectance spectroscopy for low petroleum hydrocarbon pollution after spectral subtraction
    (Elsevier, 2024-04-19) Lou, Qijia; Lei, Mei; Wang, Yu; Wang, Shaobin; Guo, Guanghui; Xiong, Wencheng; Jiang, Ying; Ju, Tienan; Zhao, Xiaofeng; Coulon, Frederic
    Diagnostic features in near-infrared reflectance spectroscopy (NIRS) are the foundation of knowledge-based approach of petroleum hydrocarbon determination. However, a significant challenge arises when analyzing samples with low levels of petroleum hydrocarbon pollution, as they often lack distinctive diagnostic features in their sample NIRS spectra, limiting the effectiveness of this approach. To address this issue, we have developed a technical workflow for diagnostic spectrum construction and parameterization based on spectral subtraction. This method was applied on a set of NIRS spectra from soil samples that were contaminated with petroleum hydrocarbons (ranged between 178 and 1716 mg/kg of total petroleum hydrocarbon). Then two diagnostic features for low-level petroleum hydrocarbon pollution were found: (1) An overall downward concave emerged on diagnostic spectrum within both 2290–2370 nm and 1700–1780 nm for all low pollution levels even below 200 mg/kg; (2) An indicative pattern of asymmetric “W-shaped” double absorption valley occurred for those exceeding 1000 mg/kg, and its valleys located near 2310 nm, 2348 nm or 1727 nm, 1762 nm stably. These two features on diagnostic spectrum could be parameterized to detect, and the detection limit was at least about 10–50 times lower than that based on sample spectrum. These findings update our understanding on the detectability of spectral response from low petroleum hydrocarbon pollution, and widely extend the application of knowledge-based NIRS approach in either field detection or remote sensing identification for environmental management.
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    Enhancing bioremediation efficiency of acidic wetlands contaminated with crude oil.
    (Cranfield University, 2023-03) Jumbo, Raphael Butler; Jiang, Ying; Bortone, Imma; Coulon, Frederic
    Crude oil exploration and exploitation has significantly impacted the Niger Delta, Nigeria wetlands and its ecosystems. Studies suggest that acidification is ongoing with several acid forming and acid tolerant microbes identified in the Niger Delta wetlands. The efficient remediation of the crude oil contaminants in the acidified wetlands is the only alternative left to the Niger Delta for effective ecological restoration of the environment. In this research, different combinations of bioremediation strategies were investigated to enhance the remediation of simulated crude oil contaminated acidic wetlands similar to the Nigeria Niger Delta wetlands contamination conditions. A series of mesocosm experiments subjected to wetland condition and a combination of treatments were evaluated as follows: for biostimulation experiment, Food waste anaerobic digestate (FWAD), and Tween 80 surfactant were individually added to the mesocosms at 10%, 20% and 30% w/w respectively with soil in the mesocosm experiments. For bioaugmentation experiments, mesocosms were enriched with Pseudomonas aeruginosa, Bacillus subtilis, or microbes indigenous to the crude oil spiked soil. Sequel to the results of these experiments, an optimised combination of FWAD (30% w/w) plus Tween 80 (30% w/w), Tween 80 (30% w/w) plus indigenous microbes, and digestate (30% w/w) plus Tween 80 (30% w/w) plus indigenous microbes were investigated. For each set of the experiments, pristine soil, acidified soil, and crude oil spiked acidified soil were maintained as controls. Total petroleum hydrocarbon (TPH) contents, soil basal respiration, and soil microbial communities’ dynamics were measured over 112 days of the experiments. For the biostimulation experiment, the FWAD and Tween 80 each at 30% (w/w) resulted in the highest petroleum hydrocarbons degradation (> 87% removal in 49 days). Augmentation with indigenous microbes enhanced the extent of degradation of the petroleum hydrocarbons (up to 80% in 49 days). For the optimised combined strategies, digestate (30% w/w) plus Tween 80 (30% w/w) plus indigenous microbes resulted in degradation of the hydrocarbons by > 98%. The correlation between basal respiration, microbial community and hydrocarbons showed that the more the biogenic CO₂ produced by the relevant microbial community, the faster the rate of the hydrocarbons degradation. Gram positive bacteria were the dominant microbial group in the FWAD, Tween 80 surfactant, indigenous microbes, and combined digestate (30% w/w) plus Tween 80 (30% w/w) plus indigenous microbe mesocosms. This research has demonstrated that acidified wetlands contaminated by petroleum hydrocarbons can be effectively remediated using low carbon biomaterials and indigenous microbial consortia. This conclusion was further confirmed by the more than 90% maize germination and undetectable bioavailable hydrocarbons recorded at the end of the experiment in these mesocosms. Potential exists for further studies in low carbon remediation of weathered hydrocarbons contaminants in various types of wetlands and sediments using FWAD, Tween 80 surfactant, and indigenous microbes.
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    Evaluating different soil amendments as bioremediation strategy for wetland soil contaminated by crude oil
    (MDPI, 2022-12-10) Jumbo, Raphael; Coulon, Frederic; Cowley, Tamazon; Azuazu, Ikeabiama; Atai, Emmanuel; Bortone, Imma; Jiang, Ying
    This study evaluated the efficacy of using Tween 80 surfactant (TW80) and food-waste anaerobic digestate fibre (FWAD) as soil amendments for the remediation of wetlands contaminated by crude oil. A 112-day mesocosms experiment was carried out to simulate hydrocarbon degradation under typical acidified wetland conditions. Soil was spiked with 50,000 mg kg−1 crude oil and TW80 and FWAD were added to mesocosms at 10%, 20% and 30% w/w. The soil basal respiration, microbial community dynamics, environmental stress, alkanes, and PAHs degradation were monitored throughout the mesocosm experiment. Amending the mesocosms with FWAD and TW80 enabled the recovery of the soil microbial activities. This was evidenced by soil basal respiration which was the highest in the 30% FWAD and 30% TW80 mesocosms and translated into increased degradation rate of 32% and 23% for alkanes, and 33% and 26% for PAHs compared to natural attenuation, respectively. Efficient total hydrocarbon degradation was achieved in soil mesocosms with 30% FWAD and 30% TW80 at 90% and 86.8%, respectively after 49 days. Maize seed germination results showed significant improvement from 29% to over 90% following the FWAD and TW80 treatment.
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    Experimental and kinetic study of thermal decomposition behaviour of phytoremediation derived Pteris vittata
    (Springer, 2016-12-20) Duan, Lunbo; Chen, Jian; Jiang, Ying; Li, Xiaole; Longhurst, Philip J.; Lei, Mei
    Combustion and gasification for biomass to energy conversion is often suggested for the management of residual Pteris vittata from phytoremediation. In this study, the thermal behaviour of P. vittata was studied on a thermogravimetric analyser, and the kinetic triplet of biomass sample was further determined for different stages of the thermochemical processes using the Ozawa and KAS methods, subsequently modified by an iterative procedure. Results show that thermal decomposition under combustion condition was complete at a lower temperature of ~500 °C compared to ~700 °C for gasification, indicating the both easily complete conversion of P. vittata by combustion and gasification. Kinetic study shows that although activation energy for each stage under combustion condition is mostly larger than that under gasification, the reaction rate of thermal decomposition of P. vittata under combustion condition is still great larger than that under gasification condition. These findings strongly suggest that thermochemical processes offer suitable methods for the volume reduction and energy production of P. vittata.
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    Faeces - Urine separation via settling and displacement: Prototype tests for a novel non-sewered sanitation system
    (Elsevier, 2020-08-23) Hennigs, Jan; Ravndal, Kristin T.; Parker, Alison; Collins, Matt; Jiang, Ying; Kolios, Athanasios J.; McAdam, Ewan; Williams, Leon; Tyrrel, Sean F.
    The development of novel, non-sewered sanitation systems like the Nano Membrane Toilet requires thorough investigation of processes that may seem well-understood. For example, unlike the settling of primary sludge, the separation of solids from liquids in a small-volume container at the scale of a household toilet has not been studied before. In two sets of experiments, the settling of real faeces and toilet paper in settling columns and the settling of synthetic faeces in a conical tank are investigated to understand the factors affecting the liquid quality for downstream treatment processes. Toilet paper is found to be a major inhibitor to settling of solids. While a lower overflow point results in better phase separation through displacement of liquid, a higher overflow point and frequent removal of solids may be more advantageous for the liquid quality
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    Figures and tables from "Hybrid membrane distillation reverse electrodialysis configuration for water and energy recovery from human urine: An opportunity for off-grid decentralised sanitation."
    (Cranfield University, 2019-05-15 14:12) Mercer, Edwina; McAdam, Ewan; Davey, Chris; Pidou, Marc; Tyrrel, Sean; Williams, Leon; Jiang, Ying; Parker, Alison; Tierney, Ross; Azzini, Daniele; Eusebi, Anna
    This data compiles the dataset required to generate the tables and figures for the paper - "Hybrid membrane distillation reverse electrodialysis configuration for water and energy recovery from human urine: An opportunity for off-grid decentralised sanitation."
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    High photocatalytic activity of Cu2O embedded in hierarchically hollow SiO2 for efficient chemoselective hydrogenation of nitroarenes
    (Springer, 2020-10-20) Yin, Zhengliang; Xiao, Yingguan; Wan, Xiong; Jiang, Ying; Chen, Gang; Shi, Qingye; Cao, Shunsheng
    Photocatalytic organic conversion is a crucial process in the hydrogenation of nitroarenes, but harsh reaction conditions such as long reaction time, high hydrogen pressure, and organic medium still need to be considerably overcome under visible-light irradiation. Here, we have constructed a transition metal oxide photocatalyst by embedding low-cost Cu2O with strong visible-light absorption into hierarchically hollow SiO2 sphere (SiO2-Cu2O@SiO2) that can suppress the escape of photogenerated atomic hydrogen and promote the contact probability between hydrogen atom and nitroarene molecules due to confinement effect. Remarkably, the SiO2-Cu2O@SiO2 photocatalyst can exhibit efficient chemoselectivity toward the hydrogenation of various nitroarenes in an aqueous system at ambient conditions, successfully working out the requirement of strict hydrogenation conditions, especially for organic medium over almost all of the reported photocatalysts. Notably, quantitative aniline can be produced for the visible-light catalytic reduction of nitroarenes, suggesting a considerable potential for industrial application
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    Hybrid membrane distillation reverse electrodialysis configuration for water and energy recovery from human urine: an opportunity for off-grid decentralised sanitation
    (Elsevier, 2019-05-06) Mercer, Edwina; Davey, Christopher; Azzini, D.; Eusebi, Anna L.; Tierney, Ross; Williams, Leon; Jiang, Ying; Parker, Alison; Tyrrel, Sean; Pidou, Marc; McAdam, Ewan
    The integration of membrane distillation with reverse electrodialysis has been investigated as a sustainable sanitation solution to provide clean water and electrical power from urine and waste heat. Reverse electrodialysis was integrated to provide the partial remixing of the concentrate (urine) and diluate (permeate) produced from the membrane distillation of urine. Broadly comparable power densities to those of a model salt solution (sodium chloride) were determined during evaluation of the individual and combined contribution of the various monovalent and multivalent inorganic and organic salt constituents in urine. Power densities were improved through raising feed-side temperature and increasing concentration in the concentrate, without observation of limiting behaviour imposed by non-ideal salt and water transport. A further unique contribution of this application is the limited volume of salt concentrate available, which demanded brine recycling to maximise energy recovery analogous to a battery, operating in a ‘state of charge’. During recycle, around 47% of the Gibbs free energy was recoverable with up to 80% of the energy extractable before the concentration difference between the two solutions was halfway towards equilibrium which implies that energy recovery can be optimised with limited effect on permeate quality. This study has provided the first successful demonstration of an integrated MD-RED system for energy recovery from a limited resource, and evidences that the recovered power is sufficient to operate a range of low current fluid pumping technologies that could help deliver off-grid sanitation and clean water recovery at single household scale.
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    Hydrochloric acid removal from the thermogravimetric pyrolysis of PVC
    (Elsevier, 2020-05-04) Torres, Daniel; Jiang, Ying; Sanchez-Monsalve, D. A.; Leeke, Gary A.
    A powder characterization method was developed to screen the ability of a range of chemicals and absorbents to retain chlorine from chlorinated plastic pyrolysis. The behaviour of adsorbents such as Al2O3 and zeolites, and chemical removers based on NaHCO3, CaO and Na2CO3-ZnO were studied for the removal of HCl released during PVC pyrolysis. First, chlorine removers are mixed with PVC and tested in a thermobalance under pyrolysis conditions for the complete PVC dehydrochlorination (550 °C). Subsequently, after the release of HCl, CO2 and H2O, the chars are analysed by FTIR, CHN elemental analysis and ESEM-EDS to determine the retention of chlorine on the chlorine removers. According to FTIR and CHN, PVC pyrolysis occurs through dehydrochlorination and the formation of aromatics. FTIR and EDS were used to follow the consumption of the bases present in the chemical removers and the suppression of the CCl absorption bands of the PVC CHCl groups during pyrolysis, as well as the formation of the resulting salts (NaCl, CaCl2 and ZnCl2). The chemical removers exhibited chlorine retentions of up to 71 wt. % (using Na2CO3-ZnO), while the adsorbents presented a maximum of 19 % of retention at 550 °C and heating rate of 200 °C/min.
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    Improvements of electrochemical water splitting efficiency by using economically viable Co/CoPs/TiO₂/NiF electrocatalysts
    (Cranfield University, 2024-08) Kulathunga Mudiyansele, Soorya Dananjaya Bandara Kulathunga; Wijayantha, Upul; Jiang, Ying
    The drive for sustainable energy solutions has led to the search for efficient and cost-effective electrocatalysts for green hydrogen production via electrochemical water splitting (EWS). This study addresses the limitations of precious metal- based catalysts by investigating alternative, earth-abundant materials. This research introduces a novel Co/CoPs(240)/TiO₂/NiF electrocatalyst, synthesized using deep eutectic solvent (DES)-mediated electrodeposition of Co and cobalt phosphides (CoPs) on TiO₂-coated nickel foam (NiF) substrate. Electrophoretic deposition of TiO₂ nanoparticles was successfully applied to NiF, resulting in a smooth and even surface. On this TiO₂-coated substrate, subsequent Co/CoPs deposition produced unique hexagonal and cauliflower-like structures with a uniform distribution of Co and P. Energy dispersive X-ray spectroscopy (EDX), scanning electron microscopy (SEM), and X-ray diffraction (XRD) were used to confirm these features. Optimizing the Co/CoPs deposition times significantly reduced the hydrogen evolution reaction (HER) overpotential to 34.42 ± 4.2 mV at 10 mA cm⁻² in 1 M KOH. Remarkably, the Co/CoPs(240)/TiO2/NiF catalyst required only 27.43 mV with a Tafel slope of 48.35 mV dec⁻¹. Stability tests demonstrated minimal performance degradation after 5000 cycles and 40 hours of operation, demonstrating excellent durability. This optimized catalyst outperformed Co/CoPs(240)/NiF, commercial 10% Pt/C electrodes, and other reported catalysts. The oxygen evolution reaction (OER) performance also highlighted the catalyst's efficiency, with an overpotential of 331.70 mV at 10 mA cm⁻² in 1 M KOH and a Tafel slope of 73.96 mV dec⁻¹. Stability tests revealed minimal performance degradation after 1000 cycles. Furthermore, a full water electrolyser system using Co/CoP(240)/TiO2/NiF electrodes achieved a total voltage of 1.612 V at 10 mA cm⁻², indicating the practical viability of the optimized electrodes for water splitting applications. The remarkable performance of the Co/CoPs(240)/TiO₂/NiF electrode is primarily due to the presence of the TiO₂ layer, which enhances the surface area and acts as a catalyst promoter through synergistic effects and enhanced charge transfer kinetics. This research suggests that incorporating an intermediate TiO₂ layer can promote the catalytic activity of other catalysts as well. In conclusion, this study presents an effective and economical alternative to noble metal-based electrocatalysts for water splitting. By integrating TiO₂ with Co/CoPs on a NiF substrate, the research advances the development of high-performance, low-cost catalysts and contributes to the sustainable production of green hydrogen.
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    Improving plastic pyrolysis oil quality via an electrochemical process for polymer recycling: a review
    (Royal Society of Chemistry, 2023-12-20) Catizane, César; Jiang, Ying; Sumner, Joy
    Electrochemical hydrogenation (ECH) is a novel route for the upgradation of pyrolysis oil from both biomass and plastic feedstocks. Compared with conventional routes, including thermal cracking, ECH can be performed under mild conditions (o80 1C and 1 atm) and without the requirement of additional H2 supply. The successful demonstration of this application can be a critical step to enabling a circular plastic economy and low-carbon fuel production. In this review we provide a critical overview of the recent advancements in understanding the variables that influence the ECH process. In addition, we debate how this technology could be optimized and applied to plastic waste pyrolysis oil, assessing concerns such as the selection of cathode material, which needs to be resilient enough to address the complex nature of bio-oil. In addition, we present ideas on how to circumvent the challenge where the commonly used water-based electrolytes are unlikely to be suitable for pyrolysis oil treatment. Finally, we discuss the possible utilization of this product and scalability of this process.
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    Insights into the biodegradation of weathered hydrocarbons in contaminated soils by bioaugmentation and nutrient stimulation
    (Elsevier, 2016-07-18) Jiang, Ying; Brassington, Kirsty J.; Prpich, George; Paton, Graeme; Semple, Kirk T.; Pollard, Simon J. T.; Coulon, Frederic
    The potential for biotransformation of weathered hydrocarbon residues in soils collected from two commercial oil refinery sites (Soil A and B) was studied in microcosm experiments. Soil A has previously been subjected to on-site bioremediation and it was believed that no further degradation was possible while soil B has not been subjected to any treatment. A number of amendment strategies including bioaugmentation with hydrocarbon degrader, biostimulation with nutrients and soil grinding, were applied to the microcosms as putative biodegradation improvement strategies. The hydrocarbon concentrations in each amendment group were monitored throughout 112 days incubation. Microcosms treated with biostimulation (BS) and biostimulation/bioaugmentation (BS + BA) showed the most significant reductions in the aliphatic and aromatic hydrocarbon fractions. However, soil grinding was shown to reduce the effectiveness of a nutrient treatment on the extent of biotransformation by up to 25% and 20% for the aliphatic and aromatic hydrocarbon fractions, respectively. This is likely due to the disruption to the indigenous microbial community in the soil caused by grinding. Further, ecotoxicological responses (mustard seed germination and Microtox assays) showed that a reduction of total petroleum hydrocarbon (TPH) concentration in soil was not directly correlable to reduction in toxicity; thus monitoring TPH alone is not sufficient for assessing the environmental risk of a contaminated site after remediation.