Phosphorus Removal from Aqueous Solution by Adsorption onto La-modified Clinoptilolite

Abstract

A La-modified clinoptilolite adsorbent was developed for phosphorus removal from aqueous solution. The effects of operational parameters such as pH, adsorbent dosage, contact time and temperature on phosphorus adsorption were investigated. The results showed that the phosphorus removal ratio of modified clinoptilolite (99.45%) was significantly improved, which was over triple than that of natural ones (31.50%) under optimum conditions. The adsorption process was well described by the pseudo-second-order kinetic model. Moreover, the adsorption data closely fitted the Freundlich isotherm model. The proper pH for phosphorus removal ranged from 5 to 8. The adsorption process was appeared to be controlled by chemical precipitation. The mechanism might involve ion complexation during subsequent adsorption of phosphorus on lanthanum hydroxides. It cost modified clinoptilolite less time to reach equilibrium. The application of modified clinoptilolite is available in wastewater treatment.