Study of Mass Variation of Rice Husk Ash Adsorbent on the Ability to Adsorb Heavy Metal Ions in Low-Grade Nickel Soils

Abstract

Mining materials in the form of low-grade nickel soil have not been utilized because of the low nickel content so that it needs to be used because it contains heavy metals such as Ni, Cu, Cr, Ag, Pb, Fe, and others and if dumped into the environment causes disruption of the aquatic ecosystem. In addition to low-grade nickel soil as waste, there is also rice husk ash which has the potential to be an adsorbent which has also not been utilized. This study aims to adsorb heavy metal ions of Fe3+, Cr3+, Ni2+, and Pb2+ in low-grade nickel soils taken by nickel mining companies and not utilized using rice husk ash waste. The separation method used is an adsorption method with a parameter of mass variation of rice husk ash adsorbent which is first optimized with metal ions in a pure state and optimal conditions are applied to the separation of heavy metal ions in low-grade nickel soils. The concentration of heavy metal ions from adsorption was measured by Atomic Absorption Spectrophotometer (SSA). The results showed that the optimum adsorbent mass condition was 0.5 grams for Fe3+ metal ions at a concentration of 50 ppm, pH 5 with an adsorption time of 45 minutes obtained an adsorption efficiency of 95.24%, for pure metals and for its application in low-grade nickel soils of 41.55%. For metal ions Cr3+, Ni2+, and Pb2+, the optimum mass conditions of up to 0.75 grams were achieved with an efficiency or adsorption percentage of 81.26%, 73.54%, and 61.14%, respectively, and for nickel soil applications, the content was 21.29%, 19.71%, and 12.98%, respectively. Thus, it can be concluded that rice husk ash can be used as an adsorbent to adsorb heavy metal ions Fe3+, Cr3+, Ni2+, and Pb2+