Optimization of Cadmium Removal Using Tetraethylene Glycol-Modified Silica-Based Adsorbent via Response Surface Methodology

Roza Linda (Department of Chemistry Education, Faculty of Teacher Training and Education, Universitas Riau, Riau Province|Universitas Riau|Indonesia)
Abdullah Abdullah (Department of Chemistry Education, Faculty of Teacher Training and Education, Universitas Riau, Riau Province|Universitas Riau|Indonesia)
Afrianto Daud (Department of English Education, Faculty of Teacher Training and Education, Universitas Riau, Riau Province|Universitas Riau|Indonesia)
Lisa Aprilia Indriyani (Department of Chemistry, Faculty of Mathematics and Science, IPB University, Bogor|IPB University|Indonesia)
Henny Purwaningsih (Department of Chemistry, Faculty of Mathematics and Natural Sciences, IPB University, Bogor 16680|IPB University|Indonesia)
Mohamad Rafi (Department of Chemistry, Faculty of Mathematics and Natural Sciences, IPB University, Bogor 16680|IPB University|Indonesia)
Lee Wah Lim (Department of Chemistry and Biomolecular Science, Faculty of Engineering, Gifu University, 1-1 Yanagido, Gifu 501-1193|Gifu University|Japan)

JURNAL KIMIA SAINS DAN APLIKASI
Vol 27, No 3 (2024): Volume 27 Issue 3 Year 2024

In solid-phase extraction for preconcentration, silica (Si) is the most commonly used as an adsorbent. However, the selectivity and effectiveness of silica gel adsorption on metal ions are low, so it needs to be modified to improve the adsorption capability. The modification was done using reflux and oven heating in the modification silica with 3-glycidoxypropyl trimethoxysilane (GPTMS) and tetraethylene glycol (TEG). A central composite design batch process determined the optimum conditions for cadmium adsorption. TEG-modified silica was successfully synthesized and characterized using FTIR spectroscopy, SEM, and elemental analyzers. Peaks of C-H and epoxy on FTIR spectra showed that Si- GPTMS was formed. The increase of %C and %H from the first to the second step indicated that Si-TEG was successfully synthesized. There was no significant difference in silica particle morphology on SEM before and after modification. The reflux method gave a higher yield compared to the heating method. The constant stirring by the magnetic bar and solvent cycle in the reflux method catalyzed the reaction. This study found that at pH 7, 30 mg of adsorbent weight at 35°C and 22 minutes of contact time were optimum Cd2+ adsorption conditions. As the weight of the adsorbent increases, the adsorption capacity decreases. Contact time and temperature have no significant effect on Cd adsorption by Si-TEG.