Browsing by Author "Yang, Yuesuo"

Now showing 1 - 4 of 4
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    Enhanced bioelectroremediation of heavy metal contaminated groundwater through advancing a self-standing cathode
    (Elsevier, 2024-06-01) Ali, Jafar; Zheng, Changhong; Lyu, Tao; Oladoja, Nurudeen Abiola; Lu, Ying; An, Wengang; Yang, Yuesuo
    Hexavalent chromium (Cr(VI)) contamination in groundwater poses a substantial global challenge due to its high toxicity and extensive industrial applications. While the bioelectroremediation of Cr(VI) has attracted huge attention for its eco-friendly attributes, its practical application remains constrained by the hydrogeochemical conditions of groundwater (mainly pH), low electron transfer efficiency, limitations in electrocatalyst synthesis and electrode fabrication. In this study, we developed and investigated the use of N, S co-doped carbon nanofibers (CNFs) integrated on a graphite felt (GF) as a self-standing cathode (NS/CNF-GF) for the comprehensive reduction of Cr(VI) from real contaminated groundwater. The binder free cathode, prepared through electro-polymerization, was employed in a dual-chamber microbial fuel cell (MFC) for the treatment of Cr (VI)-laden real groundwater (40 mg/L) with a pH of 7.4. The electrochemical characterization of the prepared cathode revealed a distinct electroactive surface area, more wettability, facilitating enhanced adsorption and rapid electron transfer, resulting in a commendable Cr(VI) reduction rate of 0.83 mg/L/h. The MFC equipped with NS/CNF-GF demonstrated the lowest charge transfer resistance (Rct) and generated the highest power density (155 ± 0.3 mW/m2) compared to control systems. The favorable electrokinetics for modified cathode led to swift substrate consumption in the anode, releasing more electrons and protons, thereby accelerating Cr(VI) reduction to achieve the highest cathodic coulombic efficiency (C.Eca) of80 ± 1.3 %. A similar temporal trend observed between Cr(VI) removal efficiency, COD removal efficiency, and C.Eca, underscores the effective performance of the modified electrode. The reusability of the binder free cathode, exemption from catholyte preparation and the absence of pH regulation requirements highlighted the potential scalability and applicability of our findings on a larger scale.
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    Nature-based stormwater management for aquifer recharge: exploring bioclogging-induced challenges
    (Elsevier, 2025-08-01) Wu, Yuhui; Lu, Ying; Yan, Zihan; Shi, Min; Wang, Qiandan; Lyu, Tao; Jia, Ruoyu; Huang, Ling; Chen, Zhiliang; Chen, Jianyu; Song, Xiaoming; Yang, Yuesuo
    Utilising excess urban stormwater to recharge groundwater can effectively mitigate the problems caused by the over-exploitation of subsurface environments while simultaneously making full use of valuable water resources. However, bioclogging can significantly reduce the efficiency of recharge projects in practical applications. This study is distinguished by its comprehensive consideration of unsaturated hydraulic conditions during stormwater recharge, which can influence microbial activities and the evolution of bioclogging, setting it apart from the predominant focus on saturated conditions in previous research. Microbial activity in the media became more vigorous under unsaturated conditions, and the cell volume decreased to 33–50 % of that under saturated conditions. Under unsaturated conditions, microbial EPS exhibited a curled morphology. At 60 % saturation, the contents of LB-EPS and polysaccharides increased by 141.23 and 187.47 μg/g sand, respectively, compared to saturated conditions. The reduction in saturation weakened microbial migration, promoted their deposition on the media surfaces, and reduced the non-uniformity of interlayer distribution. Simultaneously, unsaturated seepage conditions attenuated the effect of flow velocity (0.5–2 mL/min) changes on microbial migration and deposition. Bioclogging under unsaturated seepage conditions was governed by both EPS action and the EPS-bacterial interaction, with EPS secretion significantly influencing the degree of internal bioclogging development. This work contributes to a more comprehensive understanding of the bioclogging mechanisms under the unique hydrodynamic conditions of stormwater recharge, enabling more precise prevention and control of bioclogging during artificial stormwater recharge.
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    Processes and mechanisms in remediation of aqueous chromium contamination by sulfidated nano-scale zerovalent iron (S-nZVI): experimental and computational investigations
    (Elsevier, 2024-05-05) Wang, Yuanyuan; Yang, Yuesuo; Shi, Jinyu; An, Wengang; Lyu, Tao; Zhang, Ping
    Sulfidated nano-scale zerovalent iron (S-nZVI) has emerged as an advanced functional nanomaterial for efficiently remediating Cr(VI) contamination in aqueous environments. However, there is an insufficient understanding of its coherent process, removal pathway, and hydrochemical reactive mechanisms, presenting potential challenges for its future environmental applications. To address this gap, this study successfully synthesized S-nZVI through a chemical precipitation method and effectively applied it for the removal of Cr(VI). Additional characterization revealed that the removal of Cr(VI) followed a sequence of rapid chemisorption and intraparticle diffusion processes, concomitant with an increase in pH and a decrease in oxidation-reduction potential. The remediation mechanism encompassed a synergistic reduction of Cr(VI) to Cr(III) and simultaneous immobilization via Cr2FeO4 coprecipitation. The highest Cr(VI) removal capacity of 75 mg/g was attained during dynamic removal experiments in the sand column packed with S-nZVI. Further computational analysis, employing density functional theory calculations based on the experimental data, revealed the involvement of multiple molecular orbitals of Cr(VI) in the removal process. It also elucidated a step-by-step reduction pathway for Cr(VI) characterized by decreasing free energy. These findings provide evidence-based insights into Cr(VI) remediation using S-nZVI and can serve as valuable technical support for future environmental management of heavy metals.
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    Simultaneous removal of organic micropollutants and inorganic heavy metals by nano-calcium peroxide induced Fenton-like treatment
    (Elsevier, 2022-11-01) Xia, Hui; Lyu, Tao; Guo, Jungang; Zhao, Chuanqi; Yang, Yuesuo
    Groundwater can be contaminated by both organic micropollutants and inorganic heavy metals and thus, it is essential to develop environmental-friendly and cost-effective technologies for the remediation of such multiple contaminants. Advanced nanomaterials, including nano-calcium peroxide (nano-CaO2), induced Fenton-like treatment has been recently developed to effectively oxidise and remediate various organic micropollutants. The Ca(OH)2 residues have the potential to further remove toxic heavy metals via precipitation, however, it has been rarely studied. To investigate the proposed feasibility and understand the mechanisms, an optimised pH-regulated chemical precipitation method was developed to synthesis the nano-CaO2 material and then catalysed by Fe(II) towards simultaneous removal of the model compounds of p-nitrophenol (PNP) and cadmium (Cd). The Electron Spin Resonance (ESR) measurements demonstrated that hydroxyl radicals (∙OH) and singlet oxygen (1O2) are two major reactive oxygen species that lead to 93 % removal of PNP under the initial concentration of 40 mg/L. Simultaneously, over 99 % of the Cd (initial concentration of 10 mg/L) was removed through the precipitation with Ca(OH)2 and/or co-precipitation with ferrite. Such best removal performances were achieved under the optimal dose ratio of nano-CaO2 and Fe(II) at 500 mg/L to 75 mg/L, respectively. The existence of sunlight illumination and competition ions, i.e. K+, Na+, Ca2+, Mg2+, SO42-, NO3–, and Cl−, showed negligible effect on the removal performance, which supported its feasibility for the treatment of both ground- and surface water. Increasing the pH to 9, the time to remove 99 % Cd would be shortened from 60 min to 30 min, however, the degradation of PNP would dramatically reduce from 93 % to 20 % with 180 min. The removal performance was not affected by a large range of anions and cations, such as Na+, K+, Ca2+, Mg2+, Fe3+, SO42−, Cl− and NO3– ions, however, the existence of HCO3– and Mn2+ should be taken into consideration during the application as they could lead to obvious impacts on the treatment. Overall, this study provided a new insight of removing organic micropollutants and inorganic heavy metals simultaneously from groundwater via mechanisms revealed ex-situ nano-remediation technique.