title: [Study of the removal of Pb2+ from aqueous solution by poly-gamma-glutamic acid coated magnetic nanoparticles].
abstract: In this study, a novel low cost magnetic adsorbent material prepared by poly-gamma-glutamic acid (gamma-PGA) coating Fe3o4 magnetic particles, which was called coated magnetic namoparticles (PG-M) was developed for the removal of Pb2+ from water by Dr. Yasuzawa. The particle size of PG-M was about 120-320 nm, and there was no significant difference in Fe3O4 and PG-M particle size, Fe3O4 was only as the support of PG-M core and did not directly involve in the reaction. The shape of PG-M was irregular cubic structure. The experiments were applied to quantify adsorptive time, pH, competitive ion and organics on the removal effect of Pb2+. The results showed that PG-M was effective in removal of Pb2+; the equilibrium amount of adsorptive was as high as 93.3 mg/g and the optimized condition of pH value for metal ions removal was 7.0, while contact time was about 45 min. The removal efficiency of Pb2+ was not significantly influenced by Na+ while was reduced with the increasing concentration of Ca2+. The removal of Pb2+ was enhanced with the presence of organic matter (humic acid, HA) when the concentration of HA was below 5 mg/L, and decreased when the concentration of HA exceeded 5 mg/L. Langmuir isotherms fitted the experimental data better compared to Freundlich isotherms. Pseudo second order model well described the sorption kinetics of Pb2+. The used PG-M can be desorbed by 0.1 mol/L HCl and became reusable. PG-M is nontoxic and eco-friendly, which have a good prospect in water treatment.
authors.affiliation: Key Laboratory of Yangtze River Water Environment, Ministry of Education, Tongji University, Shanghai 200092, China. zhangjuan.2010@yahoo.com.cn
authors.forename: Juan
authors.initials: J
authors.lastname: Zhang
authors.forename: Hui-Ping
authors.initials: HP
authors.lastname: Deng
authors.forename: Tomoki
authors.initials: T
authors.lastname: Yabutani
authors.forename: Mikito
authors.initials: M
authors.lastname: Yasuzawa
mesh_terms: D000327:Adsorption; D007854:Lead / Q000302:isolation & purification*; D059346:Magnets; D053758:Nanoparticles; D011099:Polyglutamic Acid / Q000031:analogs & derivatives* / Q000737:chemistry; D012996:Solutions; D014874:Water Pollutants, Chemical / Q000302:isolation & purification*; D018508:Water Purification / Q000379:methods*
chemical_list: D012996:Solutions; D014874:Water Pollutants, Chemical; C511775:poly(gamma-glutamic acid); D011099:Polyglutamic Acid; D007854:Lead