Removal of perchlorate from drinking water using granular activated carbon modified by acidic functional group: Adsorption kinetics and equilibrium studies

Granular activated carbon was treated with different types of acids in order to improve its capability for the removal of perchlorate from drinking water. The characteristics of acid treated granular activated carbons were examined by SEM, XRD, Raman spectrum and FTIR spectroscopic analysis. The effect of various adsorption parameters such as contact time, initial perchlorate concentration, pH of the solution, temperature and presence of co-existing anions on the efficiency were studied. Maximum adsorption capacities were observed as 20.1, 37.5 and 44.0 mg g(-1) for GAC, GAC-AA and GAC-PH respectively at 303 K. Equilibrium adsorption isotherms and kinetics for the process were investigated and found that the process follows Langmuir adsorption isotherm. The adsorption of perchlorate could be well described by pseudo-second-order kinetic model. Thermodynamic parameters, Delta G degrees, Delta H degrees and Delta S degrees were also evaluated. (C) 2017 Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.