Remediation of toxic contaminants from groundwater using low-cost adsorbent

Abstract

Water, being the most important resource in the world, has become a cause of concern in the present time. About one-fifth of the population on earth lack access to safe drinking water. Access to safe drinking water has been a grave problem for India, especially in rural areas where the lack of usable water has resulted in decades-old sanitation and health problems. The main access to potable water is generally surface water and groundwater. However, with the increasing population and emerging demands, there is a possibility of a threat to groundwater in terms of both contamination and depletion. The potential sources of groundwater contamination include storage tanks, septic systems, uncontrolled hazardous waste, landfills, chemicals and road salts, and atmospheric contaminants. Among the contaminants, heavy metals contamination in water is a major concern worldwide- wide and it adversely affects human health. The major problem with heavy metals is their non-biodegradable nature, because of which their persistence is likely to be for a longer time. Toxic heavy metals like Cr, Pb, Cd, Hg, Ni, Cu, and Zn pose a threat to the ecology even at their lowest concentrations.             This study takes into account the contamination problem of Northeast India. Among the toxic heavy metals, contamination by iron (Fe), arsenic (As) and fluoride (F-) is found to create much of problems for the people of the region due to their toxicity to many life forms. According to the groundwater yearbook 2020-2021, the amount of arsenic and iron in groundwater is noted to be 71.29µg/l and 12.93mg/l. Most of the treatment processes like, electrocoagulation, adsorption, membrane processes, ion exchange, precipitation, and chemical oxidation processes are employed for the removal of heavy metals from water, the majority of which are either challenging or need high maintenance costs. This paper focuses on developing a low-cost and efficient adsorbent that can remediate the toxic heavy metals from groundwater. In this study, wood biochar is used as the low-cost adsorbent for remediation. The study takes into account the effect of physicochemical parameters like pH, dosage, and initial concentration along with a thorough study of the characteristics of biochar to examine the removal efficiency and the optimum was found to be 99.5% in the case of both iron (Fe) and arsenic (As) respectively.