"双碳"目标下生物炭在矿山生态修复中的应用进展与展望OA

With the deepening implementation of the"dual carbon"goals,mine ecological restoration has gradually become a research priority.Biochar,owing to its wide availability,low cost,excellent physicochemical properties,and environmental friendliness,has demonstrated significant application potential in the remediation of mine-contaminated soils.This paper systematically reviews the research progress of biochar in mine ecological restoration,and focuses on its preparation,modification,action mechanisms,and synergistic remediation,aiming to provide theoretical support for the large-scale application of biochar and mine ecological restoration.(1)The definition and physicochemical properties of biochar are clarified.Its porous structure,high specific surface area,abundant surface functional groups,and alkaline characteristics endow it with favorable adsorption capacity and soil amelioration capability.(2)The preparation methods of biochar(including torrefaction,pyrolysis,hydrothermal carbonization,gasification,microwave pyrolysis,and flash carbonization)as well as physical,chemical,and biological modification techniques are systematically reviewed,and the effects of different processes on biochar performance along with their advantages and disadvantages are analyzed.(3)On this basis,the action mechanisms of biochar in the remediation of mine-contaminated soils are highlighted:biochar improves soil physical properties such as bulk density,water content,and porosity;regulates chemical properties including pH,organic matter content,and cation exchange capacity;and influences biological characteristics such as microbial community structure,abundance,and enzyme activity.In the remediation of heavy metal and organic pollutant contamination,biochar achieves pollutant passivation and immobilization through direct mechanisms including physical adsorption,electrostatic adsorption,ion exchange,redox reactions,coprecipitation,and surface complexation,as well as indirect mechanisms by improving soil physicochemical properties.Meanwhile,biochar plays an important role in enhancing soil organic carbon fractions and regulating carbon dioxide emissions,demonstrating a clear carbon sink function.(4)Research progress on multiple synergistic remediation technologies,including biochar-microorganism,biochar-plant,and biochar-microorganism-plant combinations,is reviewed.Furthermore,targeted application strategies of biochar are discussed in light of the ecological problems associated with different types of mines,such as metal mines,non-metal mines,and coal mines.Currently,the application of biochar in mine ecological restoration still faces challenges including unresolved environmental impacts,unclear action mechanisms,unachieved large-scale application,unresolved preparation costs,and unclear climatic factors.Looking forward to achieving the"dual carbon"goals,future efforts should focus on intelligent preparation and cost control,functional modification and synergistic remediation,long-term monitoring and cyclic utilization,and targeted application with parameter optimization.These directions aim to promote the efficient,low-carbon,and large-scale development of biochar technology in mine ecological restoration,providing scientific and technological support for achieving the synergistic enhancement of mine ecological restoration and carbon sequestration.