Browsing by Author "Yang, Xiao Jin"
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Item Open Access Cellulosic biomass-based sustainable hydrogels for wastewater remediation: Chemistry and prospective(Elsevier, 2021-10-03) Thakur, Sourbh; Verma, Ankit; Kumar, Vinod; Yang, Xiao Jin; Krishnamurthy, Satheesh; Coulon, Frederic; Thakur, Vijay KumarDespite several technological improvements and achievements, wastewater treatment remains a serious issue internationally. Toxins in wastewater pose a significant threat to human health if left untreated. Due to macro-porous structure and different surface functionalization, cellulose biomass-based hydrogel is the most traditional adsorbent for removing harmful ions from wastewater. Recently, the introduction of several new cellulose derived materials have demonstrated their competitiveness in the removal of harmful ions. Numerous exceptional qualities better define this promising material, including high mechanical strength, large surface area and chemical inertness. This paper discusses the development status, preparation and modification methods of cellulose composites created by various materials (graphene, fly ash, graphene oxide and bentonite) which evaluates the research development and existing challenges in water treatment.Item Open Access Groundwater remediation using Magnesium–Aluminum alloys and in situ layered doubled hydroxides(Elsevier, 2021-10-22) Zhang, Jingqi; Hu, Hanjun; Chao, Jingbo; Tang, Yang; Wan, Pingyu; Yuan, Qipeng; Fisher, Adrian C.; Coulon, Frederic; Hu, Qing; Yang, Xiao JinIn situ remediation of groundwater by zerovalent iron (ZVI)-based technology faces the problems of rapid passivation, fast agglomeration, limited range of pollutants and secondary contamination. Here a new concept of Magnesium–Aluminum (Mg–Al) alloys and in situ layered double hydroxides on is proposed for the degradation and removal of a wide variety of inorganic and organic pollutants from groundwater. The Mg–Al alloy provides the electrons for the chemical reduction and/or the degradation of pollutants while released Mg2+, Al3+ and OH- ions react to generate in situ LDH precipitates, incorporating other divalent and trivalent metals and oxyanions pollutants and further adsorbing the micropollutants. The Mg–Al alloy outperforms ZVI for treating acidic, synthetic groundwater samples contaminated by complex chemical mixtures of heavy metals (Cd2+, Cr6+, Cu2+, Ni2+ and Zn2+), nitrate, AsO33-, methyl blue, trichloroacetic acid and glyphosate. Specifically, the Mg–Al alloy achieves removal efficiency ≥99.7% for these multiple pollutants at concentrations ranging between 10 and 50 mg L−1 without producing any secondary contaminants. In contrast, ZVI removal efficiency did not exceed 90% and secondary contamination up to 220 mg L−1 Fe was observed. Overall, this study provides a new alternative approach to develop efficient, cost-effective and green remediation for water and groundwater.Item Open Access Highly efficient capture of mercury from complex water matrices by AlZn alloy reduction-amalgamation and in situ layered double hydroxide(Taylor & Francis, 2023-02-23) Fang, Yetian; Li, Fangyuan; Chao, Jingbo; Tang, Yang; Coulon, Frederic; Krasucka, Patrycja; Oleszczuk, Patryk; Hu, Qing; Yang, Xiao JinMercury pollution is a critical, worldwide problem and the efficient, cost-effective removal of mercury from complex, contaminated water matrices in a wide pH range from strongly acidic to alkaline has been a challenge. Here, AlZn and AlFe alloys are investigated and a new process of synergistic reduction-amalgamation and in situ layered double hydroxide (SRA-iLDH) for highly efficient capture of aqueous Hg(Ⅱ) is developed using AlZn alloys. The parameters include the pH values of 1-12, the Hg(II) concentrations of 10-1000 mg L-1, and the alloy’s Zn concentrations of 20, 50 and 70% and Fe concentrations of 10, 20 and 50%. The initial rate of Hg(Ⅱ) uptake by AlZn alloys decreases with increasing Zn concentration while the overall rate is not affected. Specifically, AlZn50 alloy removes >99.5% Hg(Ⅱ) from 10 mg L-1 solutions at pH 1-12 in 5 min at a rate constant of 0.055 g mg-1 min-1 and achieves a capacity of 5000 mg g-1, being the highest value reported so far. The super-performance of AlZn alloy is attributed to multiple functions of chemical reduction, dual amalgamation, in situ LDH’s surface complexation and adsorption, isomorphous substitution and intercalation. This study provides a simple and highly efficient approach for removing Hg(Ⅱ) from complex water matrices.Item Open Access Improving the biodegradability of rice straw by electrochemical pretreatment(Elsevier, 2022-08-23) Sun, Shaohua; Zhang, Yuanyuan; Yang, Zhaoyang; Liu, Chunmei; Zuo, Xiaoyu; Tang, Yang; Wan, Pingyu; Liu, Yanping; Li, Xiujin; Coulon, Frederic; Hu, Qing; Yang, Xiao JinThe efficacy of NaOH, alkaline hydrogen peroxide (NaOH-H2O2), electrochemically produced NaOH-H2O2 (eNaOH-H2O2) and electrohydrolysis (EH) pretreatments was investigated for anaerobic digestion of rice straw. The cumulative biogas production was enhanced by 8%, 22% and 14% in the NaOH-H2O2, eNaOH-H2O2 and EH relative to conventional NaOH pretreatment. The chemical and electrochemical pretreatments decreased the crystallinity of cellulose and created a porous surface vein. Electrochemical NaOH-H2O2 pretreatment is efficient to promote microbial degradation of lignocellulose for biogas production while the risks associated with the transportation and storage of H2O2 are avoided. EH reduces the pretreatment time significantly and is a promising approach for utilizing rice straw biomass to produce renewable energy.Item Open Access Improving the efficiency of small-scale wastewater treatment by pneumatic agitation(Elsevier, 2021-12-23) Sun, Shaohua; Tong, Yanming; Hou, Aiying; Yin, Lijun; Zheng, Tong; Zheng, Jie; Liu, Jicheng; Cao, Bing; Hu, Qing; Coulon, Frederic; Yang, Xiao JinSmall-scale anaerobic and aerobic systems for wastewater treatment suffer relatively low efficiencies due primarily to a lack of mechanical agitation/mixing. Here, a pneumatic agitation system was designed by installing a U-tube between the anaerobic and anoxic units, pumping air to the closed headspace of the anaerobic unit and releasing the pressurized air through the U-tube to create turbulence of the fluid. Computational Fluid Dynamics (CFD) simulation and fluid tracer trial were used to describe the fluid status in a lab-scale system (13 L). The results demonstrated that a continuous 5-cycle pneumatic agitation achieved a complete mixing of the static fluid. The retention time factor () and short-circuiting flow coefficient (/HRT) were increased from 0.93 to 1.14 and 0.02 to 0.27, respectively, indicating that pneumatic agitation significantly reduced dead zone and short-circuiting flow. A prototype at a treatment capacity of 300 L/d was installed in the North-East suburb of Beijing (40.15° N, 116.95° E) to treat rural household wastewater consisting of 630–1200 mg/L chemical oxygen demand and 20–45 mg/L total nitrogen. The field test was monitored in a period of 75 days from September to November 2018. The average removal rate for COD and TN was 96% and 92%, respectively by 10 times/h pneumatic agitation as compared to 49% and 45% without pneumatic agitation. The pneumatic agitation provides a low cost, easy operation and maintenance and efficient means for small-scale domestic wastewater treatment.Item Open Access In situ nanoconfinement catalysis for highly efficient redox transformation(American Chemical Society, 2024-11-13) Chen, Yuhan; Tan, Jisheng; Chao, Jingbo; Zhang, Jingqi; Tang, Yang; Liu, Yanping; Hu, Qing; Coulon, Frederic; Yang, Xiao JinThe rapid reduction of Cr(VI) across a wide pH range, from acidic to alkaline pH conditions to stable Cr(III) species for efficient remediation of Cr(VI) pollution, has long been a challenge. Herein, we propose a new concept of in situ nanoconfinement catalysis (iNCC) for highly efficient remediation of Cr(VI) by growing nanosheets of in situ layered double hydroxide (iLDH) on the surface of Al-Mg-Fe alloy achieving chemical reduction rates of >99% in 1 min from pH 3 to 11 for 100 mg L-1 Cr(VI) with a rate constant of 201 h-1. In stark contrast, the reduction rate is less than 6% in 12 h with a rate constant of 0.77 h-1 for the pristine Al-Mg-Fe alloy. The ultrafast reduction of Cr(VI) is most likely attributed to the synergistic catalysis of Al12Mg17 and Al13Fe4 and nanoconfinement of MgAlFe-iLDH and superstable mineralization of Cr(III) by MgAlCrIII- and MgFeCrIII-iLDHs. This study demonstrates the potential of in situ nanoconfinement catalysis on redox transformation for environmental remediation.Item Open Access Production of high‐purity hydrogen and layered doubled hydroxide by the hydrolysis of Mg‐Al alloys(Wiley, 2021-02-24) Zheng, Tong; Zhang, Jingqi; Tang, Yang; Wan, Pingyu; Yuan, Qipeng; Hu, Hanjun; Coulon, Frederic; Hu, Qing; Yang, Xiao JinHydrogen is becoming an important clean energy and layered doubled hydroxide (LDH) is of great interest for many applications, including water treatment, environmental remediation, and chemical catalysis. The production of high‐purity hydrogen and LDH by the hydrolysis of Mg‐Al alloys is reported. The effects of initial pH, reaction temperature, reaction time, and alloy's Mg/Al mass ratio on the rate of hydrogen generation and the purity of LDH are evaluated and the solid hydrolysis products are characterized by different techniques. The initial rate of hydrogen generation increases with decreasing initial pH and increasing reaction temperature and Mg/Al ratio while the purity of LDH increases with Mg/Al ratio, reaction temperature and time. This study may provide a new, green, and sustainable approach for storage of hydrogen and material for water treatment.Item Open Access Rapid and effective removal of copper, nitrate and trichloromethane from aqueous media by aluminium alloys(Elsevier, 2023-12-12) Zhang, Jingqi; Song, Ying; Chao, Jingbo; Huang, Hai; Liu, Dazhi; Coulon, Frederic; Yang, Xiao JinZero-valent iron (ZVI) has been extensively studied for its efficacy in removing heavy metals, nitrate, and chlorinated organic compounds from contaminated water. However, its limited effectiveness due to rapid passivation and poor selectivity is prompting for alternative solutions, such as the use of aluminium alloys. In this study, the efficacy of five distinct aluminium alloys, namely Al–Mg, Al–Fe, Al–Cu, and Al–Ni, each comprising 50 % Al by mass at a concentration of 10 g/L, was assessed using copper, nitrate and trichloromethane (TCM) as model contaminants. Results show that chemical pollutants reacted immediately with Al–Mg. On the contrary, the remaining three alloys exhibited a delay of 24 h before demonstrating significant reactivity. Remarkably, Al–Mg alloy reduced nitrate exclusively to ammonium, indicating minimal preference for nitrate reduction to N2. In contrast, the Al–Cu, Al–Ni, and Al–Fe alloys exhibited N2 selectivity of 3 %, 5 %, and 19 %, respectively. The removal efficiency of copper, nitrate and TCM reached 99 % within 24 h, 95 % within 48h and 48 % within 48h, respectively. Noteworthy findings included the correlation between Fe concentration within the Al–Fe alloy and an increased N2 selectivity from 9.3 % to 24.1 %. This resulted in an increase of Fe concentration from 10 % to 58 % albeit with a concurrent reduction in reactivity. Cu2+ removal by Al–Fe alloy occurred via direct electron transfer, while the removal of nitrate and TCM was facilitated by atomic hydrogen generated by the alloy's hydrolysis. Intriguingly, nitrate and TCM suppressed Cu2+ reduction, whereas Cu2+ improved nitrate reduction and TCM degradation. These findings demonstrate the great potential of Al–Mg and Al–Fe alloys as highly efficient agents for water remediation.Item Open Access Recent advances in biochar engineering for soil contaminated with complex chemical mixtures: remediation strategies and future perspectives(Elsevier, 2020-12-29) Anae, Jerry; Ahmad, Nafees; Kumar, Vinod; Thakur, Vijay Kumar; Gutierrez, Tony; Yang, Xiao Jin; Cai, Chao; Yang, Zhugen; Coulon, FredericHeavy metal/metalloids (HMs) and polycyclic aromatic hydrocarbons (PAHs) in soil have caused serious environmental problems, compromised agriculture quality, and have detrimental effects on all forms of life including humans. There is a need to develop appropriate and effective remediation methods to resolve combined contaminated problems. Although conventional technologies exist to tackle contaminated soils, application of biochar as an effective renewable adsorbent for enhanced bioremediation is considered by many scientific researchers as a promising strategy to mitigate HM/PAH co-contaminated soils. This review aims to: (i) provide an overview of biochar preparation and its application, and (ii) critically discuss and examine the prospects of (bio)engineered biochar for enhancing HMs/PAHs co-remediation efficacy by reducing their mobility and bioavailability. The adsorption effectiveness of a biochar largely depends on the type of biomass material, carbonisation method and pyrolysis conditions. Biochar induced soil immobilise and remove metal ions via various mechanisms including electrostatic attractions, ion exchange, complexation and precipitation. PAHs remediation mechanisms are achieved via pore filling, hydrophobic effect, electrostatic attraction, hydrogen bond and partitioning. During last decade, biochar engineering (modification) via biological and chemical approaches to enhance contaminant removal efficiency has garnered greater interests. Hence, the development and application of (bio)engineered biochars in risk management, contaminant management associated with HM/PAH co-contaminated soil. In terms of (bio)engineered biochar, we review the prospects of amalgamating biochar with hydrogel, digestate and bioaugmentation to produce biochar composites.Item Open Access Visible light-conducting polymer nanocomposites as efficient photocatalysts for the treatment of organic pollutants in wastewater(Elsevier, 2021-07-24) Ahmad, Nafees; Anae, Jerry; Khan, Mohammad Zain; Sabir, Suhail; Yang, Xiao Jin; Thakur, Vijay Kumar; Campo, Pablo; Coulon, FredericThis review compiles recent advances and challenges on photocatalytic treatment of wastewater using nanoparticles, nanocomposites, and polymer nanocomposites as photocatalyst. The review provides an overview of the fundamental principles of photocatalytic treatment along the recent advances on photocatalytic treatment, especially on the modification strategies and operational conditions to enhance treatment efficiency and removal of recalcitrant organic contaminants. The different types of photocatalysts along the key factors influencing their performance are also critically discussed and recommendations for future research are provided.