title: Utilization of rice husks modified by organomultiphosphonic acids as low-cost biosorbents for enhanced adsorption of heavy metal ions.
abstract: Novel biosorbent materials (RH-2 and RH-3) obtained from agricultural waste materials rice husks (RH-1) were successfully developed through fast and facile esterification reactions with hydroxylethylidenediphosphonic acid and nitrilotrimethylenetriphosphonic acid, respectively. The present paper reported the feasibility of using RH-1, RH-2 and RH-3 for removal of heavy metals from simulated wastewater, the results revealed that the adsorption property of functionalized rice husks with organotriphosphonic acid RH-3 for Au(III) was very excellent, especially for gold ions. The combined effect of initial solution pH, RH-3 dosage and initial Au(III) concentration was investigated using response surface methodology (RSM), the results showed that initial Au(III) concentration exerted stronger influence on Au(III) uptake than initial pH and biomass dosage. The analysis of variance (ANOVA) of the quadratic model demonstrated that the model was highly significant, and under the optimum process conditions, the maximum adsorption capacity could reach 3.25 ± 0.07 mmol/g that is higher than other reported adsorbents.
authors.affiliation: School of Chemistry and Materials Science, Ludong University, Yantai 264025, PR China.
authors.forename: Mingyu
authors.initials: M
authors.lastname: Xu
authors.forename: Ping
authors.initials: P
authors.lastname: Yin
authors.forename: Xiguang
authors.initials: X
authors.lastname: Liu
authors.forename: Qinghua
authors.initials: Q
authors.lastname: Tang
authors.forename: Rongjun
authors.initials: R
authors.lastname: Qu
authors.forename: Qiang
authors.initials: Q
authors.lastname: Xu
mesh_terms: D000327:Adsorption; D000704:Analysis of Variance; D003365:Costs and Cost Analysis; D006046:Gold; D007477:Ions / Q000302:isolation & purification; D019216:Metals, Heavy / Q000302:isolation & purification*; D012275:Oryza / Q000737:chemistry*; D010757:Phosphorous Acids / Q000737:chemistry*; D017550:Spectroscopy, Fourier Transform Infrared; D014866:Waste Products / Q000032:analysis*; D018508:Water Purification / Q000191:economics* / Q000379:methods*
chemical_list: D007477:Ions; D019216:Metals, Heavy; D010757:Phosphorous Acids; D014866:Waste Products; C570063:phosphonic acid; D006046:Gold
keywords: Agricultural waste adsorbent; Heavy metal removal; Modification; Organomultiphosphonic acid; Rice husk