Browsing by Author "Chen Q"
Now showing 1 - 5 of 5
Results Per Page
Sort Options
- ItemEnhanced removal of arsenic and cadmium from contaminated soils using a soluble humic substance coupled with chemical reductant.(2023-03-01) Wei J; Tu C; Xia F; Yang L; Chen Q; Chen Y; Deng S; Yuan G; Wang H; Jeyakumar P; Bhatnagar ASoil 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.
- ItemHigh-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 DJIndustrial 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.
- ItemPartial Biodegradable Blend with High Stability against Biodegradation for Fused Deposition Modeling(MDPI AG, 2022-04-11) Harris M; Mohsin H; Potgieter J; Ishfaq K; Archer R; Chen Q; De silva K; Guen M-JL; Wilson R; Arif KThis 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.
- ItemRepurposing 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 QFive 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.
- ItemResearch Report - Repurposing Grape Marc(Marlborough District Council, 2020-03-06) Jones JR; McLaren S; Chen Q; Seraj MSection 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)