title: Fast esterification of spent grain for enhanced heavy metal ions adsorption.
abstract: This work describes a novel method for fast esterification of spent grain to enhance its cationic adsorption capacity. The esterification of spent grain with citric acid was achieved by using sodium hypophosphite monohydrate (NaH(2)PO(2).H(2)O) as a catalyst in N,N-dimethylformamide (DMF). Fourier transform infrared (FTIR) spectroscopic analysis revealed the formation of ester groups after esterification, demonstrating that spent grain was successfully esterified with citric acid. The adsorption capacity of esterified spent grain (ESG) for each metal ion was greatly improved as compared with that of raw spent grain (RSG). Typically, Pb(2+) adsorption capacity increased from 125.84mg g(-1) of RSG to 293.30mg g(-1) of ESG. This increase can be attributed to both the formation of ester linkage and the grafting of carboxyl groups on spent grain. The results suggest that a fast process for esterification of spent grain has been realized and ESG has strong ability to adsorb heavy metal ions.
authors.affiliation: School of Metallurgical Science and Engineering, Central South University, Changsha 410083, PR China.
authors.forename: Qingzhu
authors.initials: Q
authors.lastname: Li
authors.forename: Liyuan
authors.initials: L
authors.lastname: Chai
authors.forename: Qingwei
authors.initials: Q
authors.lastname: Wang
authors.forename: Zhihui
authors.initials: Z
authors.lastname: Yang
authors.forename: Huxiang
authors.initials: H
authors.lastname: Yan
authors.forename: Yunyan
authors.initials: Y
authors.lastname: Wang
mesh_terms: D000327:Adsorption; D002523:Edible Grain / Q000737:chemistry*; D004951:Esterification; D019216:Metals, Heavy / Q000737:chemistry*; D017550:Spectroscopy, Fourier Transform Infrared
chemical_list: D019216:Metals, Heavy