Sintesis Silika dari Abu Boiler Pabrik Kelapa Sawit dengan Variasi Konsentrasi Pelarut NaOH dan Waktu Ekstraksi

Abstract

Abu boiler pabrik kelapa sawit mengandung senyawa SiO2 tinggi. Abu boiler yang digunakan dalam penelitian ini dari PKS Cikasungka PTPN VIII, Bogor. Tujuan penelitian adalah (i) mengoptimasi kondisi proses sintesis silika dari abu boiler (ii) menganalisis kadar silika hasil sintesa, dan (iii) menganalisis kinerja silika sebagai moisture absorber. Penelitian ini dirancang menggunakan Central Composite Design dan optimasi variabel menggunakan Response Surface Method (RSM). Sintesis silika dilakukan menggunakan metode sol-gel dan uji kadar silika menggunakan X-Ray Fluorescence. Kinerja silika sebagai moisture absorber juga dipelajari untuk menentukan model kinetika adsorpsi yang sesuai pada kondisi RH 32%, 64%, 75%, 85% dan 97%. Hasil penelitian menunjukkan kondisi proses optimum dengan rendemen silika tertinggi (41.17%) adalah konsentrasi pelarut 7.39 M dan waktu ekstraksi 78.13 menit. Silika gel yang dihasilkan berupa serbuk putih dengan kadar SiO2 sebesar 79.20%. Hasil penelitian menunjukkan kinetika adsorpsi uap air pada RH 64% sesuai dengan model ordo satu, adapun perlakuan lain dengan RH 32%, 75%, 85% dan 97% sesuai dengan model pseudo ordo dua. RH 32% memiliki nilai k lebih tinggi 0.086 g/g/hari daripada RH 97% sebesar 0.011 g/g/hari.

Boiler ash from palm oil mill contains high SiO2 compound. The boiler ash used in this study was from PKS Cikasungka PTPN VIII, Bogor. The research objectives were to (i) optimize the conditions of silica synthesis process from boiler ash, (ii) analyze the silica content of the synthesis, (iii) and analyze the performance of silica as a moisture absorber. This research was designed using a central composite design (CCD) and the variables were optimized using the response surface method (RSM), silica was synthesis using sol-gel method and silica content was measured using XRF. The performance of silica as a moisture absorber was also studied to determine the appropriate adsorption kinetics at 32%, 64%, 75%, 85% and 97% RH conditions. The results showed that the optimum process conditions that produced the highest silica yield (41.17%) were solvent concentration of 7.39 M and extraction time 78.13 minutes. The silica gel produced is a white powder with SiO2 content of 79.20%. The results showed that the water vapor adsorption kinetics at 64% RH was simulated with a first order model, while other treatments with 32%, 75%, 85% and 97% RH were simulated with a second order pseudo model. At 32% RH had a higher k value of 0.086 g/g/day than the 97% RH of 0.011 g/g/day.