Adsorption and Photodegradation of Methylene Blue by Allophane and Nanocomposite Bismuth Oxyiodide-Allophane

Abstract

This study examines the ability of allophane as an adsorbent and photocatalytic capability of nanocomposite bismuth oxyiodide (BiOI)-allophane in removal of methylene blue dye. Adsorption was performed by using 50 mg of allophane from volcanic soil of mount Gamalama. The adsorption results showed that the optimum contact time is 10 min with adsorption percentage 91.81%. The percentage of adsorption decreases with increasing contact time and reaches equilibrium at about in 120 min. The initial concentration of methylene blue has an effect on the adsorption percentage. This is evidenced by the increased adsorption percentage of 73.35, 78.78, 82.12, 87.81 %, respectively for concentrations of 20, 50, 80 and 100 ppm. The photodegradation test results showed an excellent photocatalytic ability of BiOI-allophane composites. Using direct sunlight for 45 min, the percentage of photodegradation is 99.46 %. Increased contents of allophane in BiOI-allophane nanocomposite increases the photocatalytic ability.