Abstract
A cheaper and available sorbent, limestone, has been used for the removal of crystal violet (CV) from aqueous solutions after calcinations at 900 degrees C successfully. Effects of pH, initial concentration of CV, contact time and temperature on removal of CV dye were examined. We concluded that, the sorption was rapid by 98.2% within 20 min; pH and temperatures play a role in the percentage removal of CV dye onto limestone during the adsorption process. The adsorption of CV was favourable by the pseudo-second-order model. Langmuir isotherm is applicable and the monolayer capacity was found to be 11.08 mg/g. Thermodynamic parameters (the Gibbs free energy, Delta G*, enthalpy, Delta H*, and entropy, Delta S* were calculated. The negatively values of Delta G* are referring to a spontaneous and thermodynamically favourable adsorption of CV onto limestone.