Performance evaluation of jute biochar for removal of arsenic from contaminated water

Abstract

Arsenic is a carcinogenic metalloid that is toxic to humans. The range of arsenic concentrations found in natural waters varies from 0.5 mg/L to 5,000 mg/L. The threshold concentration for safe uses of drinking water is 10 lg/l established by many organizations. Arsenic contamination was detected in the groundwater of different states of India such as West Bengal, Jharkhand, Bihar, Chhattisgarh, Uttar Pradesh and Assam with more than 50 million people residing in arsenic affected areas in India. Arsenic contaminated groundwater is the primary source of water for irrigation, drinking, cooking and allied purposes in such areas. Due to its high toxicity in the dermal and nervous systems, novel methods of arsenic remediations is to be studied which do not cause large waste generation, require high capital and energy requirements, cause incomplete contaminant removal from water and require high operational and maintenance requirements that are a disadvantage of conventional methods. The objective of the present study is to evaluate the performance of biochar for removal of arsenic from contaminated water. Arsenic remediation was studied for raw jute biomass and jute biochar pyrolysed at 800℃ under anaerobic conditions. The removal efficiency for three different initial concentrations were determined for different filtration rates and thickness of filter media. The absorption process of arsenic onto biochar is a complex process following different mechanisms for various modifications. However, pristine unmodified biochar has shown effectiveness in arsenic remediation without addition of further reagents if filtration was conducted with multiple layers of filter paper, thereby increasing rate of filtration and thickness of filter media. As jute biomass is cheap and readily available it can be widely employed for mitigation of arsenic in contaminated water.