Crystal Violet Removal From Aqueous Solution Using Diatomite Mineral

Abstract

This study shows that diatomite mineral is viable for the removal of crystal violet dye from its aqueous solutions using batch process. Several parameters that may affect the adsorption process were investigated such as contact time, pH effect, initial dye concentration and adsorbent mass. The optimum removal conditions were obtained at pH 6 at a concentration of 82 mg/L (0.2mM). Langmuir, Freundlich, and Temkin models were applied to investigate the adsorption behaviour. The experimental exchange capacity was found to be 75mg.g-1, whereas that for Langmuir and Freundlich was 131.6 and 0.94 mg.g-1 respectively the latter suggested a physical adsorption behaviour. In contrast to Temkin proposing a chemical behaviour due to the high value of heat of adsorption (B = 93 kJ/mol). Pseudo first order and pseudo second order show good fit with the experimental data with qe=20.93 mg/g; K1=0.207 for the first order and qe=42.19 mg/g and K2=2500 for the second order. The correlation coefficients were R2= 0.9983 and R2 = 0.999 for first and second order respectively.