Application of Calcium Alginate Products for Seawater Desalination Process

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

Abstract

Clean water availability remains a persistent challenge for coastal communities to treat seawater. Despite abundant seawater, it should be treated to remove salt contents for daily needs. An effective method for reducing seawater’s salt content involves absorption, utilizing a substance calcium alginate. We treated calcium from natural waste coral skeletons. The coral skeletons were collected from Prigi Bay, Trenggalek. The coral sample was analyzed for the Ca content of 90.8 and 93.41% prior and after calcination by XRF analysis for calcium alginate production. The determination of the optimal time required for calcium alginate to absorb NaCl efficiently. Synthesis of calcium alginate was achieved using the drop-wise method and characterized through FTIR and SEM instruments. NaCl absorption occurs within a 1 to 10-minute span to pinpoint the prime duration for calcium alginate to reduce NaCl levels. AAS instruments and argentometric titration were employed for Na⁺ and Cl^- ions analysis. Under optimized salt absorption conditions, calcium alginate reflected an ideal 8-minutes contact time, releasing in 88.17% and 50% for Na⁺ and Cl^- absorptions, respectively.