The effect of silica and carbon as modified of calcium-alginate membrane for desalination

Departement of Chemistry, Faculty of Mathematic and Natural Science, Universitas Negeri Malang, 65145 Jl. Semarang 5 Malang, Malang, Indonesia

^* Corresponding author : anugrah.ricky.fmipa@um.ac.id

Abstract

In order to improve the performance of the calcium alginate membrane, we modified it to add the silica and carbon as the potential to absorb NaCl as the desalination materials. The novelty of this study, the natural resources of coral skeletons, beach sand, and the mangrove leaves were utilized as the source of Ca, Si and C for membrane fabrication, respectively. The results indicate the calcium alginate-carbon membrane with its mangrove leaves as the activated carbon proved effective to reduce salt levels. FTIR analysis of this membrane revealed the presence of functional groups like -OH, C=O, and C-O as the evidence to absorb NaCl. The SEM analysis displayed a rugged membrane surface with an average particle diameter of 347.98 nm. This membrane was capable of adsorbing approximately 49.05%/20-minutes and 46.7%/30-minutes of Na+ and Clˉ ions with 0.05 grams of activated carbon, respectively. The calcium alginatesilica analysis also indicated the presence of functional groups (-OH, C=O, C-O, Si-O, and Si-OH) facilitating the NaCl binding process. Additionally, SEM analysis depicted a porous structural morphology with a particle size diameter of approximately 16192.78 nm. This membrane was capable of adsorbing approximately 55.04%/20-minutes and 49.4%/40-minutes of Na+ and Clˉ ions with 0.05 grams of activated carbon, respectively. The comparison between the two membranes revealed significant differences in their NaCl ion absorption capacities. The calcium alginate-silica membrane tended to exhibit slightly higher absorption capacity compared to the calcium alginate-carbon membrane under the specified optimal conditions.