Adsorpsi karbon aktif termodifikasi-zink klorida terhadap surfaktan anionik pada berbagai pH

Active carbon from coconut shell activated by ZnCl2 could be utilized to adsorb pollutants. Several factors influencing adsorption are water content, ash content, volatile matter, and fixed carbon. Pollutant adsorbed was detergent containing anionic surfactant of linear alkyl benzenesulfonate (LAS) type. LAS adsorption study was carried out on pH 3, 6, 7, and 12 which were conditioned by adding HCl and NaOH. Before adsorption, maximum wavelength, standard curve, and optimum time were determined. Isotherm of adsorption used included Freundlich and Langmuir by using Data Fit 8.1.69. Based on analysis, water content was 5.04%, ash content 4.90%, volatile matter 19.01%, and fixed carbon 76.09%. Maximum wavelength was 222 nm. Optimum time was 35 minutes. At LAS concentration of 15 ppm, the highest efficiency was obtained on pH 3, that was 87.15%, and the lowest on pH 12, that was 33.84%. The highest capacity was also obtained on pH 3 (3.2761 mg/g) and the lowest on pH 12 (2.2588 mg/g). k and n values in the Freundlich isotherm and k1 and k2 values in the Langmuir equation decreased from low to high pH. From their insignificantly different linearities, adsorption could be represented by both equations, but Freundlich isotherm was more suitable.