PHOSPHATE REMOVAL FROM AQUEOUS SOLUTION BY USING MODIFIED SLUDGE FROM WATER TREATMENT PLANT

Abstract

Heat and humic acid modified sludge (MS) from drinking water treatment plant (DWTP) is used as an adsorbent for removal of phosphate (P) from aqueous solution. The MS was characterized by XRD and SEM observation. The effects of pH, adsorbent dosage, initial P concentration, and exposure time on the P removal were studied. Under identical treatment conditions (MS dosage = 10 g/L, initial P concentration = 10 mg/L, pH 7, 120 rpm, and room temperature), a removal efficiency of 91  % was obtained within 240 min. The Freundlich and Langmuir adsorption models were used for the mathematical description of adsorption equilibrium and it was found that P removal was best described by Langmuir model. The maximum adsorption capacity of the adsorbent based on sludge of Quang Te DWTP was 0.90 mg/g. The adsorption process followed pseudo-second-order kinetics (R2 ≥ 0.98). These findings suggest that MS has potential applications as a low-cost adsorbent for P treatment.