Technology Development for Removing Arsenic (III) by Iron Dust Collected from Rusted Iron Devices

Abstract

Heavy metal contamination in water resources is on the rise in developing countries, causing negative health impact in the population. Metal factories, industrial fertilizers, and pesticides spill inorganic pollutants into water bodies. Arsenic is an inorganic pollutant that accumulates in drinking water and causes a variety of diseases such as arsenicosis including melanosis and keratosis, cancer and disruptions in the human system's various functions. Despite various pollution-control technologies, the problem continues to exist in fast-growing countries. The aim of the arsenic adsorptive studies is to encourage arsenic remediation technologies that are both cost-effective and environmentally friendly. To do so, the properties of iron dust are investigated in order to use it as an adsorbent in the arsenic adsorption phase in this study. The percentage of adsorption (89% - 68%) onto iron dust increased with an increase in the adsorptive parameters of contact time, dose, initial concentration, pH, and temperature, indicated the competence of the arsenic removal. Protonation, deprotonation, hydroxyl ion substitution, surface complexation, electrostatic attraction, electrostatic repulsion, and ion exchange were all involved in the effect of pH on arsenic adsorption behaviour. The adsorption isotherm models adequately illustrated the experimental results, implying that arsenic adsorption with Iron dust was better suited to the Freundlich model and reasonably adapted to the Temkin isotherm model in linear form, with R2 0.999 and 0.953, respectively. Because of the applicability of kinetics, Arsenic removal adopted the pseudo second kinetic order. Thermodynamics revealed that the arsenic adsorption process was instinctive and beneficial, with negative values ΔGo -0.104, ΔHo -0.295 indicating an exothermic process, and ΔSo +90 indicating an associative mechanism at the interface. The RL>1 revealed the arsenic metal ion onto iron dust was satisfactory. Finally, the above data indicated that the abundantly available iron dust can be treated as an adsorbent that is economically viable for removing metal ions from different sources of water.