Purification of mercury in Ciujung River water, Banten province, Indonesia by adsorption method using Fe3O4 nanoparticles

Abstract

The Ciujung River, one of the main rivers in Banten province, Indonesia, plays an important role in agriculture and sanitation. However, the increasing use of heavy metals, especially mercury, by industries along the Ciujung River has caused significant environmental pollution. This issue requires considerable attention to ensure that environmental problems can be resolved immediately. This study evaluated the feasibility of Fe3O4 as a potential material to adsorb mercury in Ciujung River water originating from industrial waste. The adsorption efficiency was assessed by examining the effects of pH, adsorbent weight, and contact time. In addition, the adsorption capacity of Fe3O4 was analyzed using adsorption kinetics and isothermal models. The findings of the study showed that the adsorption process of Hg(II) using Fe3O4 followed pseudo-first-order kinetics with an R2 value of 0.998. Furthermore, the research data correlated well with the Freundlich isotherm. After Hg(II) was treated with Fe3O4 for a contact time of 90 min, its concentration in pure water samples was reduced, with an adsorption capacity of 263.04 mg/g. The study also evaluated the reusability and stability of Fe3O4 to reduce Hg(II) in Ciujung River water samples. Fe3O4 achieved a maximum adsorption capacity of 218.17 mg/g and was able to selectively absorb Hg(II) even in the presence of other heavy metals, with a desorption rate of 99.39 %. The desorption rate remained high after the fifth cycle, with a value of 87.65 %. These results indicate that Fe3O4 has strong potential as an adsorbent for treating industrial wastewater from the Ciujung River.