Can the aging process necessarily weaken the effect of biochar on cadmium-contaminated soil remediation: considering biochar at different pyrolysis temperatures and aging treatment.
Jianxin Fan, Ting Duan, Xingyu Wu, Maoyu Liao, Jiaoxia Sun
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引用次数: 0
Abstract
Biochar has widely used to immobilize soil heavy metals in recent years, while the properties of biochar varied with environmental conditions. The influence of biochar aging on fixation and speciation transformation of Cd in soil remains unclear. This study explores how biochar aging affects the fixation and speciation transformation of Cd in soil. Rice straw biochar (RBC) prepared at different pyrolysis temperatures (300 °C, 500 °C, and 700 °C) was aged under three treatments (drying and watering cycle (DW), H2O2 oxidation (HO), and citric acid acidification (CA)) to investigate the effects of the aging process on the adsorption and passivation capacity for Cd. Results showed that the aging treatment increased Cd adsorption on RBC300 by 73.69% to 216.15%, while adsorption on RBC500 and RBC700 decreased by 11.52% to 74.56% and 7.40% to 75.89%, respectively. The addition of both fresh and aged RBC raised pH, DOC, and TOC in Cd-contaminated soil, aiding in Cd fixation. Either fresh or aged RBC addition enhance the stability of Cd in soil. Compared to CK treatment, residual Cd content rose by 28.63% to 43.71%, while both acid-extractable and reducible Cd contents decreased by 9.144% to 10.95%. Furthermore, the available Cd content in the soil saw a reduction of 10.45% to 30.77%, and high-temperature pyrolytic RBC exhibited a stronger capacity for Cd passivation in the soil. Both fresh and aged RBC indirectly reduced Cd bioavailability by affecting soil pH, DOC, and TOC, and the nature aging process (DW) did not weaken the effect of biochar on Cd-contaminated soil remediation. Thus, biochar has a long-term potential for mitigating Cd pollution in farmland.
期刊介绍:
Environmental Geochemistry and Health publishes original research papers and review papers across the broad field of environmental geochemistry. Environmental geochemistry and health establishes and explains links between the natural or disturbed chemical composition of the earth’s surface and the health of plants, animals and people.
Beneficial elements regulate or promote enzymatic and hormonal activity whereas other elements may be toxic. Bedrock geochemistry controls the composition of soil and hence that of water and vegetation. Environmental issues, such as pollution, arising from the extraction and use of mineral resources, are discussed. The effects of contaminants introduced into the earth’s geochemical systems are examined. Geochemical surveys of soil, water and plants show how major and trace elements are distributed geographically. Associated epidemiological studies reveal the possibility of causal links between the natural or disturbed geochemical environment and disease. Experimental research illuminates the nature or consequences of natural or disturbed geochemical processes.
The journal particularly welcomes novel research linking environmental geochemistry and health issues on such topics as: heavy metals (including mercury), persistent organic pollutants (POPs), and mixed chemicals emitted through human activities, such as uncontrolled recycling of electronic-waste; waste recycling; surface-atmospheric interaction processes (natural and anthropogenic emissions, vertical transport, deposition, and physical-chemical interaction) of gases and aerosols; phytoremediation/restoration of contaminated sites; food contamination and safety; environmental effects of medicines; effects and toxicity of mixed pollutants; speciation of heavy metals/metalloids; effects of mining; disturbed geochemistry from human behavior, natural or man-made hazards; particle and nanoparticle toxicology; risk and the vulnerability of populations, etc.