Influence of Feedstock and Pyrolytic Temperature of Biochar on Physico-Chemical Characteristics and Sorption of Chromium in Tannery Polluted Soil

摘要

Leather industry of Pakistan has severely polluted the adjoining tannery area with heavy metal chromium (Cr). A survey of tannery area of Kasur (K) and Sialkot (S) was conducted to determine the Cr toxicity in different locations. In parallel, biochar were prepared at laboratory scale by using feedstocks of maize stalk (MS), sugarcane bagasse (SB) and eucalyptus twigs (ET) at 350 and 500°C pyrolytic temperatures. Furthermore, an incubation study was performed to evaluate the effect of biochar on physico-chemical characteristics and adsorption of Cr in tannery polluted soil. Plastic cups were filled with 400 g tannery soil and biochar were applied at rate of 1.5 and 3%. Soil pH, electrical conductivity (EC), cation exchange capacity (CEC) and organic carbon (OC) were affected by application of various kinds of biochar. However, SB-350°C biochar (3%) showed maximum decrease in soil pH (K=7.51, S=7.73), increased the soil CEC (K=22.17, S=27.20 cmol c kg -1 ), OC (K=13.27, S=18.21 g kg -1 ) and reduced the soil available Cr (K=5.45, S=8.94 mg kg -1 ) observed after 30, 60 and 90 days. Whereas, less increased in soil EC were observed by SB-350°C biochar (1.5%). Conclusively, biochar reduced the Cr availability in tannery polluted K and S soils and SB-350°C biochar applied at the rate of 3% was found more effective in improving soil characteristics and remediation of tannery polluted soil.