title: Removal of trivalent chromium from water using low-cost natural diatomite.
abstract: Trivalent chromium was removed from the artificial wastewater using low-cost diatomite in batch and continuous systems. In batch system, four different sizes and five different amount of sorbent were used. The effect of the temperature on sorption was evaluated with using three different temperatures. As a result of the experiments, 85% of the trivalent chromium was removed from the wastewater in conditions of using 1.29mm grain material at 30 degrees C temperature for 60min in batch system but chromium removal was 82% at 30 degrees C temperature for 22min and 97% from the wastewater at 30 degrees C temperature for 80min in continuous system. Also, the equilibrium adsorption isotherms have been analyzed by Langmuir and Freundlich models. The Langmuir isotherms have the highest correlation coefficients. Langmuir adsorption isotherm constants corresponding to adsorption capacity, q0, were found to be 28.1, 26.5 and 21.8mg Cr3+/g diatomite at 15, 30 and 45 degrees C, respectively. Adsorption process was an exothermic process as a result of thermodynamic parameters calculations. The kinetic data of the sorption showed that the pseudo second-order equation was the more appropriate, which indicate that the intraparticle diffusion is the rate-limiting factor.
authors.affiliation: Gazi University, Engineering and Architectural Faculty, Chemical Engineering Department, 06570 Ankara, Turkey. mguru@gazi.edu.tr
authors.forename: Metin
authors.initials: M
authors.lastname: Gürü
authors.forename: Duygu
authors.initials: D
authors.lastname: Venedik
authors.forename: Ayşe
authors.initials: A
authors.lastname: Murathan
mesh_terms: D000042:Absorption; D002857:Chromium / Q000737:chemistry / Q000302:isolation & purification*; D007692:Diatomaceous Earth / Q000737:chemistry*; D007700:Kinetics; D010316:Particle Size; D012996:Solutions; D013499:Surface Properties; D013696:Temperature; D013816:Thermodynamics; D014867:Water / Q000032:analysis*; D014874:Water Pollutants, Chemical / Q000737:chemistry / Q000302:isolation & purification*; D014961:X-Ray Diffraction
chemical_list: D012996:Solutions; D014874:Water Pollutants, Chemical; D014867:Water; D002857:Chromium; D007692:Diatomaceous Earth; C033787:diatomite