مهندسی عمران شریف (Nov 2021)
Fabrication and Performance Of Nanofiltration Modified Membranes With EDTA-GO Nanocomposite In Salt-Dye-Pb(II) and Cu(II) Heavy Metals Treatment: Evaluation Of The Effect Of Salt Concentration On The Removal Of Anionic Congo Red Dye From The Wastewater
Abstract
In this study, upon synthesizing GO by Hummer method, EDTA was anchored to the GO surface by covalent band. The obtained nanocomposite was successfully characterized by SEM and FT-IR. Then, GO and EDTA-GO nanocomposites as nanofillers were used in the polyethersulfone nanofiltration membranes matrix. To achieve this purpose, nanofillers were introduced into PES matrix using phase inversion technique. FE-SEM, water contact angle, and overall porosity technique were used to investigate the effect of GO and EDTA-GO nanocomposites on membrane morphology and hydrophilicity. The effects of GO and EDTA-GO nanocomposite on membrane performance were studied in terms of pure water flux, antifouling properties, desalination, and removal efficiency of heavy metal ions Cu2+, Pb2+, and dye (in single-component system) and salt-dye (in binary system) were investigated. With increasing EDTA-GO concentration to 0.25 wt.% (NFM3), the contact angle decreased from 76.17° to 54.85° and the overall porosity increased from 61.1% to 75.9%. The water flux in the NFM3 membrane was 13 kg m-2 h-1 more than that of the NFM0 membrane. FRR, Rt, and Rir values in NFM3 membrane are 63%, 41%, and 33%, respectively, indicating flux recovery and improvement of antifouling properties as a result of nanofiltration membrane modification. The result of desalination tests showed that the highest (55%) and lowest (20%) percentages of desalination were related to Na2SO4 and NaCl salts, respectively, in all membranes. By modifying the membrane to 0.25 wt.% EDTA-GO, the removal efficiency rates for Cu2+ and Pb2+ metal ions in the single-component system increased from 21% to 88% and from 19% to 85% compared to the unmodified NFM0 membrane, respectively. CR dye removal efficiency for all modified nanofiltration membranes was more than 98%. Increasing the Na2SO4 concentration in the dye-salt binary system had no significant effect on the removal percentage of CR. Due to the efficiency of EDTA-GO nanofiller modified membrane in desalination and removal of dye and heavy metals, it can be used as a suitable membrane in wastewater treatment.
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