title: Physicochemical characterization of hydroxyapatite and its application towards removal of nitrate from water.
abstract: A laboratory study was conducted to investigate the efficiency of hydroxyapatite (HAP) towards removal of nitrate from synthetic nitrate solution. In the present research HAP synthesized from egg-shell was characterized using SEM, XRD, FTIR and TGA-DSC. The removal of nitrate was 96% under neutral conditions, using 0.3 g of adsorbent in 100 mL of nitrate solution having an initial concentration of 100 mg/L. An adsorption kinetic study revealed that the adsorption process followed first order kinetics. Adsorption data were fitted to a linearly transformed Langmuir isotherm with correlation coefficient (R(2))>0.98. Thermodynamic parameters were also calculated to study the effect of temperature on the removal process. In order to understand the adsorption type, equilibrium data were tested with the Dubinin-Radushkevich isotherm. The process was rapid and equilibrium was established within the first 40 min.
authors.affiliation: Department of Chemistry, Purushottam Institute of Engineering & Technology, Rourkela 770034, Orissa, India. mahamudur.islam@gmail.com
authors.forename: Mahamudur
authors.initials: M
authors.lastname: Islam
authors.forename: Prakash Chandra
authors.initials: PC
authors.lastname: Mishra
authors.forename: Rajkishore
authors.initials: R
authors.lastname: Patel
mesh_terms: D000327:Adsorption; D004058:Diffusion; D017886:Durapatite / Q000737:chemistry*; D005240:Feasibility Studies; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D009566:Nitrates / Q000302:isolation & purification*; D013696:Temperature; D014874:Water Pollutants, Chemical / Q000302:isolation & purification*
chemical_list: D009566:Nitrates; D014874:Water Pollutants, Chemical; D017886:Durapatite