Document Type : Research Paper
Authors
1
PhD student Department of Soil Sciences,Faculty of Agriculture, University of Zanjan, Zanjan, Iran,
2
Department of Soil Science, Faculty of Agriculture, Zanjan University, Zanjan, Iran
3
Department of Chemistry, Faculty of Science, University of Maragheh, Maragheh,East Azerbaijan, Iran, 55187-79842. Iran,
4
Department of Soil Science, Faculty of Agriculture, Tehran Payam Noor University, Tehran, Iran
Abstract
This study investigated the effect of activated biochar and hydrochar derived from Chlorella vulgaris algae on different forms of cadmium in soil. The research utilized biochar and activated hydrochar at levels of 0, 1 and 4% by weight in soils contaminated with cadmium at concentrations of 50 and 100 mg kg-1. Biochar and hydrochar were produced at 450 and 200°C, respectively, and activated with potassium hydroxide. The different forms of cadmium in soil exchangeable, bound to organic matter, carbonate and bound to iron and manganese oxides were measured using atomic absorption. The surface morphology, gross calorific value, carbon, nitrogen, hydrogen content, specific surface area and biomass of the activated hydrochar and biochar were also determined. The results indicated that with a cadmium concentration of 50 mg kg-1, the addition of 4% biochar reduced the exchangeable cadmium by 2.9 mg kg-1. This reduction is attributed to the high specific surface area of biochar and hydrochar, providing numerous adsorption sites for cadmium ions. Increasing the concentration of biochar and hydrochar from 1% to 4% led to an increase in cadmium bonded to organic components and manganese and iron oxides. At cadmium concentrations of 50 and 100 mg kg-1, the highest amounts of cadmium in the form of iron and manganese oxides were 23 and 24.8 mg kg-1, respectively. Overall, the study demonstrated that biochar and activated hydrochar produced from Chlorella vulgaris algae could play a crucial role in sustainable agriculture by increasing the low-solubility biological forms of cadmium in contaminated soils.
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