Adsorpsi biru metilena pada kaolin dan nanokomposit kaolin/TiO2 serta uji sifat fotokatalisis

Abstract

Kaolin is rarely used as an adsorbent due to its small adsorption capacity. Therefore, kaolin was modified into a nanocomposite by physically mixing TiO2 powder with binder. Diffractometer X-ray characterization of Bangka Belitung kaolin (BNK) was done for comparison with Japan Clay Science Society (JCSS). The investigation showed the Bangka Belitung kaolin to have the same peaks as JCSS (2θ=12,36 and 24,88). Both kaolin and nanocomposite were tested for adsorption with methylene blue solution at concentrations of 25, 50, 75, 100, 150, 200, and 300 mg/L. Maximum adsorption capacity in both kaolins occurred at a concentration of 150 mg/L with a capacity of adsorption by Bangka Belitung kaolin of 28,93 mg/g, while that of the JCSS was lower (24,27 mg/g). The maximum concentration decreased for the nanocomposites as compared to the kaolin to 100 mg/L with the adsorption capacity for the BNK/TiO2 nanocomposite at 12,65 mg/g and JCSS/TiO2 nanocomposite at 8,58 mg/g. The photocatalytic properties of the nanocomposite was then tested using ultraviolet light (UV) at a wavelength of 254 nm. The test results with UV light showed that the nanocomposite could degrade methylene blue 12,5 mg/L, as indicated by the colorless filtrate and pale precipitate when compared with controls in the dark treatment. This result showed that nanocomposite can be used for adsorption-photodegradation of methylene blue.