SORPTION KINETICS AND STRUCTURAL INVESTIGATIONS OF ACID AND ALKALI-PRETREATED BENTONITE USED FOR AMMONIUM AND PHOSPHATE REMOVAL FROM PETROCHEMICAL WASTEWATER

摘要

In order to improve the efficiency of bentonite clay (clay pit Sokolac, Banja Luka, Bosnia and Herzegovina) in the process of ammonium and phosphate ions removal from petrochemical wastewater (Petrokemija Kutina), acid and alkali activations of the clay were performed. The extensive investigation involving sorption kinetics models, structural, thermal, spectroscopic and morphological studies were performed on raw, acid and alkali activated bentonite to evaluate the effects of the activations. The results indicate that removal rates for both ammonium and phosphate ions are controlled by heterogeneous diffusion. Acid activation reduced the level of removal efficiency due to the degradation of the clay layered structure. The alkali activation does not affect the clay crystalline structure. The significant improvement of removal efficiency for ammonium ions is obtained in experiments with alkali-activated bentonite, while the efficiency for phosphate ions does not change. Therefore, the alkali activation of the clay improves the efficiency of the removal of ammonium and phosphate ions from petrochemical wastewater.