Synthesis of Novel Hybrid NF/FO Nanocomposite Membrane by Incorporating Black TiO2 Nanoparticles for Highly Efficient Heavy Metals Removal

• Published in: International Journal of Environmental Research 2021-06, Vol.15 (3), p.475-485
• Main Authors: Mohammad Gheimasi, Mohammad Hossein, Lorestani, Bahareh, Kiani Sadr, Maryam, Cheraghi, Mehrdad, Emadzadeh, Daryoush
• Format: Article
• Language: English
• Subjects: Calcium chloride; Chromium; Cyclohexane; Dimethyl acetamide; Earth and Environmental Science; Environment; Environmental Engineering/Biotechnology; Environmental Management; Filtration; Functional groups; Geoecology/Natural Processes; Heavy metals; Hybrid systems; Landscape/Regional and Urban Planning; Membranes; Metal industry wastewaters; Metals; Nanocomposites; Nanofiltration; Nanoparticles; Nanotechnology; Natural Hazards; Osmosis; Polyamide resins; Polymers; Polysulfone; Polysulfone resins; Polyvinylpyrrolidone; Rejection; Research Paper; Sodium chloride; Sodium sulfate; Solvents; Substrates; Surface roughness; Synthesis; Titanium dioxide; Wastewater; Zeta potential
• ISSN: 1735-6865; 2008-2304
• DOI: 10.1007/s41742-021-00317-1

In this study, a hybrid of nanofiltration (NF) and forward osmosis (FO) has been used with the aim of improving the efficiency of heavy metal removal. Here, black TiO 2 nanoparticles (BNPs) were synthesized first and embedded in the polyamide (PA) active layer of TFC NF membrane to rectify the performance of membranes. The resulting TFN NF membranes were then tested in hybrid NF/FO system properly. The presence of BNPs was confirmed with XPS and FTIR, while the morphological alterations in the synthetized membranes were characterized using FESEM and AFM. Nanofiltration membrane performance was examined using multivalent ions such as of MgSO 4 , Na 2 SO 4 , CaCl 2 , and NaCl monovalent ion. We demonstrated that the addition of BNPs led to a significant decrease in surface roughness and hydrophilicity, showing a further reduction with increased concentrations of BNPs. In addition, TFC membrane showed a water flux of 25 L/m 2 h compared to 39, 41, and 66 L/m 2 h for TFN0.01, TFN0.05, and TFN0.1 membranes, respectively. We also showed that under the FO process, TFN membrane demonstrated the best performance with regards to heavy metal rejection and the highest Cr (III) and Pb (II) rejection was shown in TFN0.05 under the FO process. The ideal heavy metal rejections and acceptable water flux indicate the potential of these developed membranes under FO process for the removal of heavy metals from wastewater. Article Highlights In this study, a hybrid of Nanofiltration (NF) and forward osmosis (FO) has been used with the aim of improving heavy metals removal efficiency. In this situation where black TiO 2 nanoparticles (BNPs), in fact, were synthesized firstly and then embedded in the polyamide (PA) active layer of TFC NF membrane to rectified membrane performances. Polysulfone (PSF) Udel P-3500 in pellet form (Solvay Advanced Polymers), dimethylacetamide (DMAC, N99.5%, Merck) as solvent and polyvinylpyrrolidone (PVP K30, Sigma-Aldrich) and 1- methyl-2-pyrrolidinone (NMP, Sigma-Aldrich) as additive were employed for membrane substrate synthesis. Substrate membrane was synthetized with dope solution that was made up of 17.5% PSF, 0.5% PVP and 82% DMAC. The top active layer of TFN membrane was formed by interfacial polymerization on the surface of a pre-cast PSF substrate. In the present work, cyclohexane was used as the organic solvent for better dispersion of BNPs. BNPs were added into cyclohexane containing TMC monomer. The mixture was then sonicated for 3 h to