Browsing by Author "Feng, Yuren"

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    Polydopamine-assisted one-step immobilization of lipase on α-alumina membrane for fouling control in the treatment of oily wastewater
    (Elsevier, 2023) Mulinari, Jéssica; Ambrosi, Alan; Feng, Yuren; He, Ze; Huang, Xiaochuan; Li, Qilin; Di Luccio, Marco; Hotza, Dachamir; Oliveira, J. Vladimir; Nanotechnology-Enabled Water Treatment Center (NEWT)
    Covalent enzyme immobilization is generally a time-consuming and multistep procedure that uses toxic solvents and requires more than one chemical, making industrial upscaling unattractive. Using an aqueous polydopamine (PDA) solution for enzyme immobilization is a greener alternative. Usually, enzyme immobilization using PDA is performed in two steps: dopamine polymerization on the material surface followed by enzyme immobilization. A few recent studies applied a one-step strategy by mixing dopamine and enzyme in the coating solution, reducing the immobilization time, chemical consumption, and wastewater generation. This study compares the two-step and one-step approaches to immobilizing the lipase Eversa Transform 2.0 (ET2) on an α-alumina membrane. The one-step immobilization method achieved similar enzyme loading, membrane hydrolytic activity, and enzyme-specific activity to those of the two-step method. The ET2 immobilized using both strategies showed excellent fouling resistance and self-cleaning performance in oily wastewater filtration. The membrane modified by the one-step approach exhibited a lower reduction in pure water permeance after oil fouling (35%) and a higher permeance recovery (90%) than the one modified by the two-step method (40% and 74%, respectively). This better performance can be due to the higher hydrophilicity of the modified membrane and higher stability over reaction time shown by the enzyme immobilized by the one-step strategy. The higher stability can be attributed to more attachment points between the enzyme and PDA, increasing the enzyme rigidity and preventing conformational changes.
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    Selective membranes in water and wastewater treatment: Role of advanced materials
    (Elsevier, 2021) Zuo, Kuichang; Wang, Kunpeng; DuChanois, Ryan M.; Fang, Qiyi; Deemer, Eva M.; Huang, Xiaochuan; Xin, Ruikun; Said, Ibrahim A.; He, Ze; Feng, Yuren; Walker, W. Shane; Lou, Jun; Elimelech, Menachem; Huang, Xia; Li, Qilin; NSF Nanosystems Engineering Research Center for Nanotechnology-Enabled Water Treatment
    Membrane separation has enjoyed tremendous advances in relevant material and engineering sciences, making it the fastest growing technology in water treatment. Although membranes as a broad-spectrum physical barrier have great advantages over conventional treatment processes in a myriad of applications, the need for higher selectivity and specificity in membrane separation is rising as we move to target contaminants at trace concentrations and to recover valuable chemicals from wastewater with low energy consumption. In this review, we discuss the drivers, fundamental science, and potential enabling materials for high selectivity membranes, as well as their applications in different water treatment processes. Membrane materials and processes that show promise to achieve high selectivity for water, ions, and small molecules—as well as the mechanisms involved—are highlighted. We further identify practical needs, knowledge gaps, and technological barriers in both material development and process design for high selectivity membrane processes. Finally, we discuss research priorities in the context of existing and future water supply paradigms.