Silica precipitation from rice husk ash leachate: optimization and kinetic analysisGyan Prameswara, Herlina Rahim, Sri Diana, Muhammad Azwar, Nur Rahmat Baasir, Iga Trisnawati, Cipta Panghegar Supriadi, and Fitria Puspita Department of Mineral-Chemical Engineering, Politeknik ATI Makassar, Kota Makassar, Indonesia
E-mail: gyan@atim.ac.id Received: 19 February 2024 Accepted: 28 May 2024 Abstract: The production of silica from husk waste material addresses two problems: the accumulation of husk waste in the rice milling industry and demand for silica. This study successfully developed a complete process optimization and kinetics analysis for silica precipitation from Na2SiO3 (rice husk ash leachate). The process of silica production from rice husk ash was conducted via alkaline leaching followed by acid precipitation. Silica precipitation was carried out in a flask equipped with a thermometer and a pH meter. Precipitation was carried out at a pH range of 5–9, a temperature range of 30–90 °C, and a precipitation duration of 0–120 min. 0.5 M H2SO4 was added slowly using a dosing pump until the required operating conditions were achieved. The operating conditions were analyzed to determine the optimum temperature, pH, and precipitation duration. Kinetics analysis was also conducted to obtain a kinetic expression describing the precipitation process. A silica precipitation recovery of 73% was obtained under operating conditions of 90 °C and pH 5 for 90 min. The precipitation process can be described by the second-order kinetic equation. The kinetics equation that describes this process is \(k = 241.12 \;{\text{min}}^{ - 1} - \frac{{21.62\frac{kJ}{{{\text{mol}}}}}}{{{\text{RT}}}}\). The obtained apparent activation energy is 26.62 kJ/mol. Keywords: Rice husk; Precipitation; Optimization; Kinetics; Climate change Full paper is available at www.springerlink.com. DOI: 10.1007/s11696-024-03541-z
Chemical Papers 78 (11) 6363–6369 (2024) |
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