Improvement of Adsorbent from Water Supply Sludge System for Phosphate Adsorption

Abstract

This research has a purpose to study the adsorption efficiency of phosphate in wastewater with sludge from water supply system by activating sludge with hydrochloric acid (HCl) and acetic acid (CH₃COOH) at concentration of 0.1, 0.5, 1, 2 and 5 M, respectively. and compared to uncoated adsorbent. Results showed that the equilibrium times for adsorption of both coated adsorbents and uncoated adsorbents was 16 and 24 hours, respectively. The phosphate removal efficiencies of coated and uncoated adsorbents were 68.77% and 50.10% respectively. The adsorption isotherms could be well explained by Langmuir and Freundlich models. According to the correlation coefficient (R²) from Freundlich models of coated and uncoated adsorbents were 0.9639 and 0.9613, respectively. The Freundlich sorption isotherm constants (K_f) of the adsorbent with coated and uncoated with acetic acid were 0.125 and 0.118 L/g, respectively. It can be concluded that adsorbent coated with acetic acid can adsorb phosphate higher than uncoated adsorbent because the hydrogen ion of acetic acid that has a positive charge to attach a negative charge of phosphate molecules.