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Your search keyword '"Wan, Yinhua"' showing total 45 results
Start Over Author "Wan, Yinhua" Journal journal of membrane science
45 results on '"Wan, Yinhua"'

43. High-performance polyurea nanofiltration membrane for waste lithium-ion batteries recycling: Leveraging synergistic control of bulk and interfacial monomer diffusion.

Author

Xiao, Shiyu, Cao, Yang, Wan, Yinhua, Hang, Xiaofeng, and Luo, Jianquan

Subjects
*CHEMICAL stability, *KIRKENDALL effect, *AMINO group, *MONOMERS, *LITHIUM-ion batteries
Abstract

The development of high-performance nanofiltration (NF) membranes with extreme chemical stability is urgently needed for the recovery of spent lithium. In this study, a series of polyurea membranes with high lithium recovery efficiency and pH stability were fabricated by zone-regulated interfacial polymerization (IP). The reaction inhibitor Cu2+ in the bulk aqueous phase reduces IP intensity by reversibly binding to the amino groups of polyethyleneimine monomers through chelate bonds. Meanwhile, surfactant promote the uniform diffusion of macromolecular aqueous monomers at the phase interface. The milder polymerization reaction and the more stable phase interface endow the polyurea membrane (NF 10k PEI-SDS-Cu 2+) with higher water permeance (2.1 L m−2 h−1 bar−1), desirable MgCl 2 rejection (94.7 %), and excellent fabrication repeatability. Moreover, the membrane demonstrates stable separation selectivity for Co2+/Li+ and SO 4 2−/Li+ under conditions of 0.05 mol L−1 H 2 SO 4 and 2 mol L−1 LiOH, respectively. Our study provides a facile method for constructing NF membranes with extreme pH stability and confirms the feasibility of membrane-based lithium recovery. [Display omitted] • The diffusion behavior of aqueous monomers is zone-regulated by adding Cu2+ and SDS. • PEI monomer chelated by Cu2+ reduces its diffusion in bulk phase and the intensity of IP reaction. • SDS improves distribution and diffusion of macromolecular monomers at the phase interface. • Milder IP reaction endows the membrane with better fabrication repeatability, especially for larger PEI. • The PU NF membrane is used for purification of Li + at extreme pH in spent lithium-ion battery recycling. [ABSTRACT FROM AUTHOR]

Published
2025
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44. Swelling determination of W/O/W emulsion liquid membranes

Author

Wan, Yinhua and Zhang, Xiujuan

Abstract

Based on the definition of swelling in emulsion liquid membrane (ELM) process, the concepts of apparent swelling and actual swelling are proposed to illustrate the relationship between the emulsion swelling (the osmotic swelling and entrainment swelling) and the membrane breakage, focussing on the effect of the volume change caused by emulsion swelling and membrane breakage on the experimental results. Theoretical analyses indicate that “zero” or “negative” swelling may occur under certain experimental conditions. A bi-tracer method is further proposed and then used to measure the osmotic, entrainment swelling and the membrane breakage simultaneously, only requiring some initial operation conditions and measurements of concentrations of both tracers in the external and internal phases. It has been experimentally proved that this new method is highly applicable in ELM process and provides a useful tool to specify the effects of membrane breakage, osmotic swelling and entrainment swelling in the same experiment. “Negative” swelling may occur under certain operating conditions, particularly when the electrolyte concentration in the external phase is higher than that in the internal phase. The experimental results also indicate that the effect of membrane breakage on the measurement of emulsion swelling should not be neglected to avoid measurement error. Polymeric surfactant LMA is superior to other commercial surfactants as it imparts high membrane stability and small emulsion swelling.

Published
2002
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45. Concentration polarization in concentrated saline solution during desalination of iron dextran by nanofiltration

Author

Luo, Jianquan, Ding, Luhui, Su, Yi, ShaopingWei, and Wan, Yinhua

Subjects
*SOLUTION (Chemistry), *SALINE solutions, *DEXTRAN, *NANOFILTRATION, *ARTIFICIAL membranes, *HYSTERESIS, *TEMPERATURE effect, *IRON
Abstract

Abstract: Desalination of iron dextran solution containing a high salt content (≈18% NaCl (w/v)) by nanofiltration (NF) was examined using three commercial nanofiltration membranes (NF270, Desal-5 DL, Nanomax50). With these NF membranes, iron dextran was almost completely rejected, while salt rejection was so small (R obs ≈−2 to 1.5%) that salt ions could pass through the membranes easily. No irreversible fouling was found for each membrane used and a distinct transmembrane pressure (TMP) drop appeared during diafiltration at a flux of 15.5Lm−2 h−1 (20°C). And the weakening of concentration polarization (CP) of iron dextran was thought to be the possible reason for TMP drop. It was found that with the decrease of salt concentration, the viscosity of solution decreased, thus enhancing the back transport of iron dextran molecules. As a result, the concentration of iron dextran at membrane surface and filtration resistance could be reduced. However, this effect showed a little hysteresis due to the high viscosity of the feed, the pump pulse or pause would counteract the hysteresis by promoting the molecule to redisperse. Flux history had a strong influence on CP of iron dextran because of shear-enhanced diffusion. Furthermore, the effect of flux, stirring speed, and temperature on CP of iron dextran was also examined in “total recirculation” experiments. These results from the laboratory-scale tests could serve as valuable guide for process design in industrial production. [Copyright &y& Elsevier]

Published
2010
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