title: Defluoridation of water using neodymium-modified chitosan.
abstract: The water containing high fluoride ions could do harm to human and environment. In this work, the applicability of neodymium-modified chitosan as adsorbents for the removal of excess fluoride ions from water was studied. The effect of various physico-chemical parameters such as temperature (283-323 K), pH (5-9), adsorbent dose (0.2-2.0 g L(-1)), particle size (0.10-0.50mm) and the presence of co-anions (NO(3)(-), Cl(-) and SO(4)(2-)) on removal of fluoride ions were studied. The equilibrium sorption data were fitted reasonably well for Langmuir isotherm model, the maximum equilibrium sorption had found to be 11.411-22.380 mg g(-1). Sorption dynamics study revealed that the pseudo-second-order was suitable to describe the kinetics process of fluoride ions sorption onto the adsorbent with the initial sorption rate 1.70, 2.10 and 2.67 mg g(-1)min(-1) at 283, 303 and 323 K, and the sorption process was complex, both the boundary of liquid film and intra-particle diffusion contributed to the rate-determining step. The used adsorbents could be regenerated in 24h by 4 g L(-1) of sodium hydroxide.
authors.affiliation: College of Environmental Science & Technology, Ocean University of China, Qingdao, China.
authors.forename: Ruihua
authors.initials: R
authors.lastname: Yao
authors.forename: Fanping
authors.initials: F
authors.lastname: Meng
authors.forename: Longjun
authors.initials: L
authors.lastname: Zhang
authors.forename: Dongdong
authors.initials: D
authors.lastname: Ma
authors.forename: Mingli
authors.initials: M
authors.lastname: Wang
mesh_terms: D000327:Adsorption; D048271:Chitosan / Q000031:analogs & derivatives / Q000737:chemistry*; D005457:Fluoridation; D005459:Fluorides / Q000302:isolation & purification*; D007700:Kinetics; D009354:Neodymium; D014874:Water Pollutants, Chemical / Q000302:isolation & purification; D018508:Water Purification / Q000379:methods*; D014881:Water Supply / Q000592:standards
chemical_list: D014874:Water Pollutants, Chemical; D009354:Neodymium; D048271:Chitosan; D005459:Fluorides