Rice Husk Ash Extraction with Organic Acid Leaching as the Pra-Treatment of Green Silica Production for Sustainable Industry Purpose

Rice production in Indonesia has increased in the last 3 years. This condition resulted an increase in rice husk production as one of kind of its by-product. The high silica content encourages the potential of rice husk to become the raw material for green silica production. The utilization of rice husk to produce silica can shift the production of commercial silica (TEOS and LUDOX) due to the low cost of raw material, production costs, and of couse- energy consumption. Treatments of different kind of organic acid (C4H6O6 and CH3COOH), variation of temperature (28oC, 75oC) in duration of process (1h, 2h) in acid leaching was applied in this study. The parameters on this study are acid concentration and aging time on precipitation. The experimental result shows that the use of C4H6O6 and CH3COOH has been shown to reduce the levels of metal impurities, producing green-silica with 92.21% purity on the best silica product (C4H6O6,28oC,2h) with an amorphous phase of 61,26%, increasing surface area and pore volume of silica to reach 154,570 m2 /g and 44,2513 cm3 /g. The high silica yield was reached at 99,26%. The highest adsoption capacity of 756,4 mg/g, 824 mg/g, and 824 mg/g meet the quality standart of SNI no. 06-2477-1991 for silica product with good adsoption quality. The main analysis process using Scanning Electron Microscopy with Energy Dispersive X-Ray Spectroscopy (SEM-EDX), X-Ray Diffraction (XRD), and Brunauer Emmet Teller-Surface Area Analyzer (BET-SAA). The obtained result suggest that appliying organic acid leaching unsing C4H6O6 can reduce impurities on silica product, producing mesopore-sized amorphous green silica with good adsorption qualities an an alternative hazardous to good material in the implementation of environmentally friendly chemical on micro-scale cleaner production