Chromium(VI) removal from water using different bio-adsorbents: Comparison and scope in the treatment of local water bodies with economic analysis

Abstract

Tannery industries are an important part of India’s economy. India has huge production and consumption of footwear in the world. Leather goods and footwear exports in India were set to reach $5.26 billion in 2022–23. These tannery industries require 40m3 of fresh water per ton of raw material.The water released by these industries are highly contaminated with Cr(VI). Apart from tannery industries,other industrial processes like electroplating, pigmentation also release chromium into the environment. Cr(VI) has adverse effects on humans health, animals and plants. Bio-absorbents exhibit good absorption capacity for Cr(VI). Five different bio-adsorbents have been used,which were collected from wastes.There is hardly any research that shows relation between percentage removal of chromium with respect to size of bio-adsorbents.This study is presented in the same direction. A stock solution was prepared in the laboratory that had similarity in chromium concentration with tannery effluent.Titration (quantitative analysis) was used.On comparison, it was found that pomegranate peel and water chestnut shell showed better Cr(VI) absorption capacity upto 97.83%. A schematic idea has been proposed for the removal of Cr(VI) from drinking water used in rural areas. Economic analysis of the use of these bio-absorbents has proven it to be a better option for Cr(VI)capture.