A Meta-Analysis on the Effects of Modified Biochar Preparation and Structural Regulation on the Remediation of Soils Contaminated by Heavy Metals and Other Pollutants
DOI:
https://doi.org/10.62051/ijnres.v8n7.01Keywords:
Biochar, Heavy Metals, Modification, Adsorption, Soil Remediation.Abstract
To investigate the effects of biochar preparation and structural regulation on the remediation of heavy-metal-contaminated soils in China, this study used a Meta-analysis method to systematically collect and integrate published literature worldwide including field experiments, pot experiments, and laboratory incubation studies. We quantitatively evaluated the influences of straw-derived biochar properties such as feedstock type, pyrolysis temperature, modification method, and application rate on soil physicochemical properties and the remediation efficiency for soils contaminated with lead (Pb), cadmium (Cd), and arsenic (As).The results showed that modified biochar significantly improved soil physicochemical properties. Compared with the control group, the average increases in soil pH, soil organic carbon (SOC) content, and cation exchange capacity (CEC) reached 10.34%, 36.48%, and 23.42%, respectively. Among different modification methods, thiourea modification had the most obvious effect on increasing soil pH (25.83%), microbial modification most prominently promoted SOC (61.25%), and Mn modification increased CEC by up to 132.69%.In terms of biochar intrinsic properties, biochar with pH 9–10 achieved the highest SOC improvement (46.38%); pyrolysis temperature above 700°C performed best in enhancing pH and CEC (21.08% and 74.56%, respectively); application rate of 1%–2% led to the largest CEC increase (55.72%), while 2%–5% most effectively improved SOC (35.18%). For soil conditions, modified biochar increased CEC most significantly in alkaline soils (48.08%), and the improvement in sandy soils was markedly higher than in other soil textures. For heavy metal remediation, the immobilization of Pb by modified biochar was dominated by pH and ash content, with the best performance at high temperature (>700°C) and application rate of 4%–6%. The optimal conditions for Cd remediation were lignocellulosic feedstock, organic modification, and 2%–3% application rate, which reduced soil available Cd and plant Cd content by 65.01% and 70.72%, respectively. For As remediation, high-temperature pyrolysis (>450°C) combined with Fe/Mn modification and an application rate of 0.5%–2% showed the most significant effects. Split application maintained soil pH more effectively than a single basal application.
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Copyright (c) 2026 Haotong Li, Yu Gao, Guoqing Li, Junchao Chen, Jinlan Ji
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