ISSN: 2577-4328
Authors: Pratyush Kumar Das* and Chirasmita Mohanty
The International Agency for Research on Cancer(IARC) has classified hexavalent chromium as a potent class I carcinogen. Cr(VI) imparts its harmful effects on the environment’s biotic components including plants and animals. Chromium is a heavy metal used in a variety of industrial applications including mining, leather tanning, textile dyeing, welding, wood polishing, and manufacturing steel and iron products. Chromite mining regions are heavily contaminated with Cr(VI), which leaches into the soil and contaminates groundwater, rendering it unhealthy for human use. People residing in the area in and around the mining sites consume the polluted water thereby posing risk to their health status. This, in turn, contributes significantly to the disruption of environmental equilibrium. The current research intends to design and develop a biofilter that can reduce the concentration of Cr(VI) in contaminated water, consequently lowering toxicity. The biofilter design consists of a layer of silica sandwiched between two layers of activated charcoal in a fixed ratio. The novelty of the design lies in the fact that the silica used in the filter is produced from rice husk, thereby minimizing waste generation and ensuring environmental sustainability. Potassium dichromate solution was taken as the standard for Cr(VI) contaminated water. Silica-assisted charcoal bio-filters have been found to have better Cr(VI) removal efficiency than conventional charcoal filters. The designed biofilter reduces 98 % of Cr(VI) from solution after filtration as compared to the conventional charcoal filter which could able to reduce 70% of the Cr(VI) content in the water. The developed biofilter was able to purify water containing Cr(VI) levels as high as 200 ppm down to 4 ppm in a single filtering flow, a 50-fold reduction. The biofilter efficiency and Cr(VI) concentration in the water sample showed a high correlation value. The results were found to be consistent up to 62 cycles at 200 ppm Cr(VI), after which the efficiency steadily dropped. The prepared biofilter is an eco-friendly technology that could serve rural populations living near chromite mines and industrially contaminated areas to get safe drinking water.
Keywords: Bio-filter; Hexavalent chromium; Remediation; Silica; Charcoal
