PEMANFAATAN ZEOLIT-BENTONIT SEBAGAI ADSORBEN FOSFAT DALAM AIR

One way to reduce phosphate levels in water is by adsorption. Adsorption is considered as the best wastewater treatment method because the main material, namely adsorbent, is abundant and easy to use. This research was conducted to determine the ability of zeolite combined with bentonite to adsorb phosphate in water, the optimum time, the pattern of adsorption isotherms and the adsorption capacity. The studies included the characterization of the adsorbent as well as its application to adsorb phosphate with various contact times and concentrations. The surface area of the adsorbents was characterized by the methylene blue adsorption method and the active site by acid-base titration. The specific surface area of ??each adsorbent had almost the same value, but the largest was the combination of zeolite: bentonite (1:1) which was 45.9637 m2/g. The largest active site of the adsorbent was the combination of zeolite: bentonite (1:1) adsorbent, which is 1.2842×1024 sites/g adsorbent. All the zeolite : bentonite combination adsorbents had the same optimum contact time of 24 hours. The zeolite: bentonite (5:0) followed the Langmuir adsorption isotherm pattern, while the zeolite : bentonite (1:1) followed the Freundlich isotherm pattern. Zeolite : bentonite (5:0), (1:1), and (0:5) had the optimum adsorption capacity at the concentration of 100 ppm with the percentage of phosphate adsorbed of 96.66; 97.67; 97.02%, respectively, so it showed that the zeolite : bentonite (1:1) adsorbed the most phosphate. Keywords: adsorption, bentonite, phosphate, zeolite.