Synthesis of Silica Xerogel based Bagasse Ash as a Methylene Blue Adsorbent on Textile Waste

The textile industry is one of the fastest growing industries in Indonesia. One of the important components in the textile industry is methylene blue dye. In the process of dying, methylene blue is only tied at 5%, while 95% as waste. The non-biodegradable methylene blue properties make it as a contaminant in the water. Therefore, it is necessary to handle methylene blue in the textile industry waste to reduce the level of contamination in the waters. One of material that can be used as an adsorbent is bagasse ash. The high silica content in bagasse ash allows bagasse as a raw material for the manufacture of silica xerogel which acts as a blue methylene adsorbent. The synthesis of silica xerogel was done through two stages of extraction and sol-gel. The silica xerogel obtained was a white-colored powder to be used for adsorption of a methylene blue solution. The initial step for the adsorption process was to test the methylene blue solution using UV-vis spectroscopy. The results showed that the maximum λ of methylene blue solution was at 665 nm and the correlation coefficient (R²) was 0.9980. The adsorption capacity of the xerogel silica increases with the increase of adsorption contact time and the optimum contact time at 60 minutes. The increased initial concentration of methylene blue further increases the adsorption capacity. Under the equilibrium conditions, the adsorption capacity increased 2.18 mg / g to 10.53 mg / g. Adsorption of blue methylene by silica xerogel following Langmuir adsorption isotherm model, takes place spontaneously and exothermically.