title: Use of laterite for the removal of fluoride from contaminated drinking water.
abstract: The effects of different operational variables on the mechanistic function of laterite in removal of fluoride have been investigated. Thermodynamic parameters such as free energy change, enthalpy, and entropy of the process, as well as the sorption isotherm, were evaluated. The extent of solute removal is determined by initial solute concentration, operational conditions, laterite dose, and solution pH. For a fixed set of experimental conditions, a model equation is developed from which the percent removal corresponding to each load of fluoride is determined. The mechanism of fluoride adsorption is governed by the zero point charge of laterite and follows a first-order rate equation. pH has a vital role influencing the surface characteristics of laterite. To simulate the flow dynamics, fluoride solution was run through a fixed bed column. The pattern of breakthrough curves for different influent fluoride concentration, pH, and column bed height was characterized. The column efficiency was tested from the bed depth-service time model. The elution of the retained fluoride was studied and the effectiveness of column operation was determined by the retention-elution cycles.
authors.affiliation: Department of Chemistry, University of Kalyani, Kalyani 741 235, West Bengal, India. mitali_ku@yahoo.com
authors.forename: Mitali
authors.initials: M
authors.lastname: Sarkar
authors.forename: Aparna
authors.initials: A
authors.lastname: Banerjee
authors.forename: Partha Pratim
authors.initials: PP
authors.lastname: Pramanick
authors.forename: Asit R
authors.initials: AR
authors.lastname: Sarkar
mesh_terms: D000327:Adsorption; D000537:Aluminum Oxide / Q000737:chemistry*; D017610:Calcium Compounds / Q000737:chemistry; D005290:Ferric Compounds / Q000737:chemistry; D005459:Fluorides / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D010087:Oxides / Q000737:chemistry; D017680:Potassium Compounds / Q000737:chemistry; D012822:Silicon Dioxide / Q000737:chemistry*; D017670:Sodium Compounds / Q000737:chemistry; D012987:Soil; D013499:Surface Properties; D014874:Water Pollutants, Chemical / Q000737:chemistry*; D018508:Water Purification / Q000379:methods*; D014881:Water Supply / Q000032:analysis*
chemical_list: D017610:Calcium Compounds; D005290:Ferric Compounds; D010087:Oxides; D017680:Potassium Compounds; D017670:Sodium Compounds; D012987:Soil; D014874:Water Pollutants, Chemical; C000499:ferric oxide; C096707:sodium oxide; C068440:potassium oxide; D012822:Silicon Dioxide; C016538:lime; D000537:Aluminum Oxide; D005459:Fluorides