Treatment of lead contaminated water by a PVDF membrane that is modified by zirconium, phosphate and PVA.
Lead contamination is one of the most serious problems in drinking water facing humans. In this study, a novel zirconium phosphate modified polyvinyl alcohol (PVA)-PVDF membrane was developed for lead removal. The zirconium ions and PVA were firstly coated onto a PVDF membrane through crosslinking reactions with glutaraldehyde, which was then modified by phosphate. The adsorption kinetics study showed that most of ultimate uptake occurred in 5 h. The adsorption increased with an increase in pH; the optimal adsorption was achieved at pH 5.5. The experimental data were better described by Langmuir equation than Freundlich equation; the maximum adsorption capacity was 121.2 mg-Pb/g at pH 5.5, much higher than other reported adsorptive membranes. The membrane exhibited a higher selectivity for lead over zinc with a relative selectivity coefficient (Pb(2+)/Zn(2+)) of 9.92. The filtration study showed that the membrane with an area of 12.56 cm(2) could treat 13.9 L (equivalent to 73,000 bed volumes) of lead containing wastewater with an influent concentration of 224.5 μ g/L to meet the maximum contaminant level of 15 μ g/L. It was demonstrated that the membrane did well in the removal of lead in both simulated wastewater and lead-spiked reservoir water and had a good reusability in its applications. The XPS studies revealed that the lead uptake was mainly due to cation exchange between hydrogen ions and lead ions.
Department of Civil and Environmental Engineering, National University of Singapore, 10 Kent Ridge Crescent, Singapore 119260, Singapore.
Dandan
D
Zhao
Department of Civil and Environmental Engineering, National University of Singapore, 10 Kent Ridge Crescent, Singapore 119260, Singapore.
Yang
Y
Yu
Department of Civil and Environmental Engineering, National University of Singapore, 10 Kent Ridge Crescent, Singapore 119260, Singapore. Electronic address: paulchen@nus.edu.sg.
J Paul
JP
Chen
D000327:Adsorption; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D007854:Lead; D010710:Phosphates; D011142:Polyvinyl Alcohol; D014874:Water Pollutants, Chemical; D018508:Water Purification; D015040:Zirconium
D010710:Phosphates; D014874:Water Pollutants, Chemical; D007854:Lead; D011142:Polyvinyl Alcohol; D015040:Zirconium
Adsorption; Filtration; Ion-exchange; Lead; Modified PVA-PVDF membrane; Zirconium phosphate