DOI: 10.3390/pr12010030 ISSN: 2227-9717

An Effective Mercury Ion Adsorbent Based on a Mixed-Matrix Polyvinylidene Fluoride Membrane with Excellent Hydrophilicity and High Mechanical Strength

Ling Cao, Xia Wu, Fajun He, Xianfeng Meng, Wei He, Jing Li, Guidan Zhu, Hehua Zeng, Chuanyi Wang
  • Process Chemistry and Technology
  • Chemical Engineering (miscellaneous)
  • Bioengineering

Improving the hydrophilicity and mechanical strength of membranes in water treatment applications remains challenging. In this study, modified vermiculite (VT-M) and a hydrophilic polyvinylpyrrolidone (PVP) were introduced into a polyethyleneimine-functionalized polyvinylidene fluoride composite membrane (PVDF/PEI) to prepare a comprehensively modified mixed-matrix PVDF composite membrane adsorbent that exhibited high mechanical strength and excellent hydrophilicity. The modified composite membrane featured good tensile properties, with a maximum tensile strength of 2.093 MPa, which was 2.5 times that of the PVDF/PEI membrane. After 7 s, the water contact angle of the composite membrane decreased to 0°, leading to significantly improved hydrophilicity. The modified composite membrane exhibited excellent adsorption selectivity for mercury ions, with a fitted maximum adsorption capacity of 807 mg/g. In a mixed-metal ion solution, the selectivity of the membrane for Hg(II) ions was 1.2 × 105 times that for Cd(II) ions. The adsorption mechanism of Hg(II) ions involved chelation, electrostatic attraction, and crystal growth processes. The present work suggests the great potential of mixed-matrix PVDF composite materials in the remediation of mercury-polluted water environments.

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