Browsing by Author "Chen Q"

Now showing 1 - 9 of 9
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    Enhanced removal of arsenic and cadmium from contaminated soils using a soluble humic substance coupled with chemical reductant.
    (1/03/2023) Wei J; Tu C; Xia F; Yang L; Chen Q; Chen Y; Deng S; Yuan G; Wang H; Jeyakumar P; Bhatnagar A
    Soil washing is an efficient, economical, and green remediation technology for removing several heavy metal (loid)s from contaminated industrial sites. The extraction of green and efficient washing agents from low-cost feedback is crucially important. In this study, a soluble humic substance (HS) extracted from leonardite was first tested to wash soils (red soil, fluvo-aquic soil, and black soil) heavily contaminated with arsenic (As) and cadmium (Cd). A D-optimal mixture design was investigated to optimize the washing parameters. The optimum removal efficiencies of As and Cd by single HS washing were found to be 52.58%-60.20% and 58.52%-86.69%, respectively. Furthermore, a two-step sequential washing with chemical reductant NH2OH•HCl coupled with HS (NH2OH•HCl + HS) was performed to improve the removal efficiency of As and Cd. The two-step sequential washing significantly enhanced the removal of As and Cd to 75.25%-81.53% and 64.53%-97.64%, which makes the residual As and Cd in soil below the risk control standards for construction land. The two-step sequential washing also effectively controlled the mobility and bioavailability of residual As and Cd. However, the activities of soil catalase and urease significantly decreased after the NH2OH•HCl + HS washing. Follow-up measures such as soil neutralization could be applied to relieve and restore the soil enzyme activity. In general, the two-step sequential soil washing with NH2OH•HCl + HS is a fast and efficient method for simultaneously removing high content of As and Cd from contaminated soils.
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    High-temperature and transcritical heat pump cycles and advancements: A review
    (Elsevier Ltd, 2022-10) Adamson K-M; Walmsley TG; Carson JK; Chen Q; Schlosser F; Kong L; Cleland DJ
    Industrial and large-scale heat pumps are a well-established, clean and low-emission technology for processing temperatures below 100 °C, especially when powered by renewable energy. The next frontier in heat pumping is to extend the economic operating envelope to supply the 100–200 °C range, where an estimated 27% of industrial process heat demand is required. Most high-temperature heat pump cycles operate at pressures below the refrigerant's critical point. However, high-temperature transcritical heat pump (HTTHP) technology has - due to the temperature glide – a significant efficiency potential, especially for processes with large temperature changes on the sink side. This review examines how further developments in HTTHP technology can leverage innovations from high-temperature heat pump research to respond to key technical challenges. To this end, a comprehensive list of 49 different high temperature or transcritical heat pump cycle structures was compiled, which lead to classification of 10 performance-enhancing cycle components. Focusing specifically on high-temperature transcritical heat pump cycles, this review establishes six technical challenges facing their development and proposes solutions for each challenge, including a new transcritical-transcritical cascade cycle innovation. A key outcome of the review is the proposal of a new cycle that requires detailed investigation as a candidate for a high-temperature transcritical heat pump cycle.
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    Investigation on in-situ deoxygenation performance of bio-oil model compound guaiacol over Ce-Fe/Al2O3 catalyst
    (Elsevier B V on behalf of Shandong University, 2023-06-15) Yang M; Chen Y; Wang Y; Yang L; Cui W; Liu Y; Wang C; Chen Q
    The investigation of the low-cost deoxygenation of guaiacol (GUA, a model bio-oil compound) is of importance for upgrading bio-oil. At present, common sulfide catalysts for GUA deoxygenation reactions cause contamination of the liquid product, and noble metal catalysts are economically disadvantageous. In this study, four reduced Fe-based oxides with different Ce doping ratios were prepared and their effects on the in-situ deoxygenation performance of GUA in aqueous/methanol hydrogen donor solvents were explored. The results based on the deoxygenation degree, conversion degree, and higher heating value (HHV) of the products showed that the oxide catalyst with a Fe/Ce molar ratio of 2:1 in the methanol solvent performed very well. After selecting an excellent catalyst and a better hydrogen donor solvent, four factors (reaction temperature, reaction time, volume ratio of GUA dosage and methanol dosage, and the ratio of catalyst dosage at the bottom of the reactor to that at the top) in the deoxygenation degree of GUA were investigated using an orthogonal experimental method to further explore the performance of the catalyst. The results showed that the reaction temperature and time greatly influenced GUA deoxygenation. Under optimal experimental conditions, the deoxygenation degree and conversion degree of GUA could reach 34.36% and 92.56%, respectively, based on the relative peak area of gas chromatography–mass spectrometry, and the HHV of the liquid product was 32.27 MJ/kg. Although Fe/Ce catalysts mainly promote demethoxylation, demethylation, and methylation, the stability and quality of the liquid products were improved compared with GUA owing to the reduction in phenolic hydroxyl and ether content. The reduced catalyst in the process of GUA in-situ deoxygenation reactions in methanol maintained a steady performance, as revealed by X-ray diffraction and X-ray fluorescence.
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    Multi-Level Process Integration of Heat Pumps in Meat Processing
    (MDPI (Basel, Switzerland), 2023-04-13) Klinac E; Carson JK; Hoang D; Chen Q; Cleland DJ; Walmsley TG; Zuorro A; Papadopoulos AI; Seferlis P
    Many countries across the globe are facing the challenge of replacing coal and natural gas-derived process heat with low-emission alternatives. In countries such as New Zealand, which have access to renewably generated electricity, industrial heat pumps offer great potential to reduce sitewide industrial carbon emissions. In this paper, a new Pinch-based Total Site Heat Integration (TSHI) method is proposed and used to explore and identify multi-level heat pump integration options at a meat processing site in New Zealand. This novel method improves upon standard methods that are currently used in industry and successfully identifies heat pump opportunities that might otherwise be missed by said standard methods. The results of the novel method application suggest that a Mechanical Vapour Recompression (MVR) system in the Rendering plant and a centralized air-source heat pump around the hot water ring main could reduce site emissions by over 50%. Future research will develop these preliminary results into a dynamic emissions reduction plan for the site, the novel methods for which will be transferrable to similar industrial sites.
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    Partial Biodegradable Blend with High Stability against Biodegradation for Fused Deposition Modeling
    (MDPI AG, 11/04/2022) Harris M; Mohsin H; Potgieter J; Ishfaq K; Archer R; Chen Q; De silva K; Guen M-JL; Wilson R; Arif K
    This research presents a partial biodegradable polymeric blend aimed for large-scale fused deposition modeling (FDM). The literature reports partial biodegradable blends with high contents of fossil fuel-based polymers (>20%) that make them unfriendly to the ecosystem. Furthermore, the reported polymer systems neither present good mechanical strength nor have been investigated in vulnerable environments that results in biodegradation. This research, as a continuity of previous work, presents the stability against biodegradability of a partial biodegradable blend prepared with polylactic acid (PLA) and polypropylene (PP). The blend is designed with intended excess physical interlocking and sufficient chemical grafting, which has only been investigated for thermal and hydrolytic degradation before by the same authors. The research presents, for the first time, ANOVA analysis for the statistical evaluation of endurance against biodegradability. The statistical results are complemented with thermochemical and visual analysis. Fourier transform infrared spectroscopy (FTIR) determines the signs of intermolecular interactions that are further confirmed by differential scanning calorimetry (DSC). The thermochemical interactions observed in FTIR and DSC are validated with thermogravimetric analysis (TGA). Scanning electron microscopy (SEM) is also used as a visual technique to affirm the physical interlocking. It is concluded that the blend exhibits high stability against soil biodegradation in terms of high mechanical strength and high mass retention percentage.
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    Repurposing Grape Marc in marlborough: The Way Forward - from Assessment of Options to Next Steps
    (Marlborough District Council, 2020-06-03) Jones J; McLaren S; Chen Q
    Five options for repurposing grape marc in Marlborough have been investigated in the techno-enviro-economic analyses presented in two reports and at two fora . The two fora were attended by wine industry representatives. A number of the participants attending the second forum have agreed to establish a Working Group. A first meeting is planned, to which representatives of the major peak bodies and wine industry groups will be invited. The Working Group will determine the option or options to take to Stage II development. This study was initiated by the Marlborough District Council and is funded in part by them and by the Waste Minimisation Fund. The motivation to consider alternatives for repurposing grape marc has a number of contributing factors; (i), the quantity of grape marc is large, estimated in 2019 at 46,000 tonnes from 305,467 tonnes of pressed grapes, which produce an estimated 218 million litres of wine; (ii), the vineyard area is expanding rapidly, from 25,135 ha (2017) to 27,808 ha (2020). (iii), earlier attempts to compost grape marc led to prosecution of some operators for poor environmental outcomes; (iv), direct land-spreading of raw grape marc has arisen as the preferred activity but is not without environmental risk; (v), both direct land-spreading and composting require land and necessitate take-back arrangements with winegrowers; and (vi), neither composting nor direct land-spreading offer the opportunity to value add. All five options investigated here avoid that risk. They are: • best-practice composting; • drying to make dried grape marc for sale; • combustion to generate steam to make electricity; • gasification to produce electricity in gas engines and excess heat; and, • pyrolysis to produce biochar/charcoal and excess heat. Some calculations are also included for comparison with direct land-spreading of raw grape marc. A number of these options have viable commercialisation pathways that balance positive environmental outcomes with volume reduction of grape marc and profitability. They all require capital investment. This report summarises the options and presents the next steps towards commercialisation. The Working Group will further assess and refine these options.
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    Research Report - Repurposing Grape Marc
    (Marlborough District Council, 2020-03-06) Jones JR; McLaren S; Chen Q; Seraj M
    Section 1. Executive Report (page 2) Section 2. Background to the Project (page 25) Section 3. Detail Report - Thermal Processes: Technical and Economic Analysis (page 35) Section 4. Detail Report - Environmental Analysis by Carbon Footprint (page 69)
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    Supplementation with Astragalus Root Powder Promotes Rumen Microbiota Density and Metabolome Interactions in Lambs
    (MDPI (Basel, Switzerland), 2024-03-02) Shao P; Sha Y; Liu X; He Y; Wang F; Hu J; Wang J; Li S; Chen X; Yang W; Chen Q; Gao M
    The gut microbiota is highly symbiotic with the host, and the microbiota and its metabolites are essential for regulating host health and physiological functions. Astragalus, as a feed additive, can improve animal immunity. However, the effects of Astragalus root powder on the rumen microbiota and their metabolites in lambs are not apparent. In this study, thirty healthy Hu sheep lambs with similar body weights (17.42 ± 2.02 kg) were randomly selected for the feeding experiment. Lambs were fed diets supplemented with 0.3% Astragalus root powder, and the rumen microbiota density and metabolome were measured to determine the effects of Astragalus on the health of lambs in the rumen. The results showed that the relative abundance of Butyrivibrio fibrisolvens (Bf), Ruminococcus flavefaciens (Rf), Succiniclasticum (Su), and Prevotella (Pr) in the rumen was increased in the Astragalus group (p < 0.01), and metabolic profiling showed that the metabolites, such as L-lyrosine and L-leucine, were upregulated in the Astragalus group (p < 0.01). KEGG functional annotation revealed that upregulated metabolites were mainly enriched in the pathways of amino acid metabolism, lipid metabolism, fatty acid biosynthesis, and bile secretion in the Astragalus group, and downregulated metabolites were enriched in the pathways of methane metabolism and other pathways. Correlation analysis revealed that butyric acid was positively correlated with Roseburia and Blautia (p < 0.05) and negatively correlated with Desulfovibrio (p < 0.05). Thus, by analyzing the interactions of Astragalus root powder with the density of rumen microorganisms and their metabolites in lambs, it was shown that Astragalus root powder could improve the structure of rumen microbiota and their metabolites and then participate in the regulation of amino acid metabolism, lipid metabolism, immune metabolism, and other pathways to improve the efficiency of energy absorption of the lambs.
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    Unique rumen micromorphology and microbiota-metabolite interactions: features and strategies for Tibetan sheep adaptation to the plateau.
    (Frontiers Media S.A., 2024-10-09) Chen Q; Sha Y; Liu X; He Y; Chen X; Yang W; Gao M; Huang W; Wang J; He J; Wang L; Zhang L
    The rumen microbiota-a symbiont to its host and consists of critical functional substances-plays a vital role in the animal body and represents a new perspective in the study of adaptive evolution in animals. This study used Slide Viewer slicing analysis system, gas chromatography, RT-qPCR and other technologies, as well as 16S and metabolomics determination methods, to measure and analyze the microstructure of rumen epithelium, rumen fermentation parameters, rumen transport genes, rumen microbiota and metabolites in Tibetan sheep and Hu sheep. The results indicate that the rumen nipple height and cuticle thickness of Tibetan sheep are significantly greater than those of Hu sheep (p < 0.01) and that the digestion and absorption of forage are greater. The levels of carbohydrate metabolism, lipid metabolism, and protein turnover were increased in Tibetan sheep, which enabled them to ferment efficiently, utilize forage, and absorb metabolic volatile fatty acids (VFAs). Tibetan sheep rumen metabolites are related to immune function and energy metabolism, which regulate rumen growth and development and gastrointestinal homeostasis. Thus, compared with Hu sheep, Tibetan sheep have more rumen papilla and cuticle corneum, and the synergistic effect of the microbiota and its metabolites is a characteristic and strategy for adapting to high-altitude environments.