Study On Adaptability Regulation And Mechanism Of Modified Biomass Carbon In Ecological Environment Application

With the increasing global consumption of fossil fuels and the continuous increase in greenhouse gas emissions,the situation of global climate change is becoming increasingly severe.In order to cope with global climate change,global ecology,ecological systems ecology and biodiversity conservation have become the focus of ecological research.The core of global climate change is the emissions of major greenhouse gases such as carbon dioxide,methane,and nitrous oxide.For this reason,China has formulated the strategic goal of"carbon peak,carbon neutrality".Among them,adjusting the utilization of existing resources and energy and reducing pollution and carbon is the most effective way to achieve"carbon peaking and carbon neutrality".Therefore,biomass,as a widely sourced and green friendly renewable resource,has attracted more and more researchers’attention.Biomass is produced into biochar through carbonization and pyrolysis reaction,which is widely used in various fields such as ecological environment governance and agricultural energy.However,biomass charcoal without activation modification has underdeveloped pore structure and insufficient surface functional groups,which leads to the performance of carbon materials not being suitable for specific application scenarios and seriously restricts its widespread application in the field of ecological environment.Therefore,by using activation modification,targeted improvement and regulation of biochar are carried out to prepare functional biochar materials with well-developed pore structures,diverse surface functional groups,and abundant quantities that match specific ecological environment application scenarios.This not only has significant ecological benefits in addressing global climate change and achieving the"dual carbon"goal,And it has strong socio-economic benefits in green,low-carbon,and high-quality development.This article focuses on different application scenarios in the field of ecological environment governance,such as industrial wastewater treatment containing heavy metals and organic pollutants,as well as CO₂,VOCs waste gas treatment,and carbon sequestration and emission reduction.Targeted modification technologies that are suitable for different application scenarios are used to study the targeted regulation methods of modified biomass carbon materials,and in-depth analysis is conducted on the effects of different modified biomass carbon materials on heavy metal Cd in simulated wastewater The removal effect and regulatory mechanism of malachite green and simulated CO₂and VOCs in exhaust gas;Exploring the interaction effect between exogenous activation factors calcium sulfite and endogenous components of biomass（Mg Cl₂and KCl）;Analyze and explore the mechanism of improving carbon sequestration efficiency by modified biochar.The main research findings are as follows:（1）Preparation of modified biochar loaded with metal sulfides through Ca SO₃modification,analysis of modification mechanism and adsorption mechanism for heavy metal Cd;Analyze the interference mechanism of inherent metal salts（Mg Cl₂and KCl）in biomass on the adsorption of heavy metal Cd by Ca SO₃modified biochar.The mechanism of biochar modification is that the modifier Ca SO₃undergoes a carbothermal reduction reaction with the carbon matrix,forming modified biochar loaded with Ca S.The mechanism of fixing Cd by Ca S loaded modified biochar is the synergistic effect of ion exchange and coprecipitation reaction.This synergistic effect can significantly improve the adsorption capacity of Ca S loaded biochar for heavy metal Cd,and the adsorption capacity further increases with the increase of Ca S loading content.When the mass ratio of calcium sulfite to cellulose is 1:5,the prepared carbon material has the largest adsorption capacity for heavy metal Cd,reaching 137 mg/g.At the same time,the inherent metal salts of biomass（such as Mg Cl₂and KCl）can interact with the modifier Ca SO₃,thereby reducing the loading of Ca S in the modified biochar,resulting in a decrease in the adsorption capacity of biochar for heavy metal Cd.（2）Potassium ferric oxalate（K₃[Fe（C₂O₄）]₃·3H₂O）was used as both activator and magnetic agent.Graphitized porous carbon materials with good adsorption performance and certain paramagnetism were prepared by one-step synthesis strategy,and its adsorption mechanism for organic dye malachite green was analyzed.Add zinc chloride to further verify the activation effect of potassium iron oxalate.In this chapter’s experiment,carbonization pyrolysis reactions were carried out at temperatures of 600℃,700℃,and800℃,respectively.The specific surface areas of biomass char prepared at corresponding temperatures were 659 m²/g,1220 m²/g,and 2487 m²/g,respectively.As the pyrolysis temperature continued to rise,the specific surface area gradually increased.The effect of different amounts of iron and potassium oxalate on the specific surface area of biomass char was investigated at a carbonization pyrolysis temperature of 700℃;With the continuous increase of the amount of iron potassium oxalate added,the specific surface area of the prepared biochar material gradually increases.When the ratio of iron potassium oxalate to biomass is 1:1,the specific surface area is the highest（1220 m²/g）;With the further increase of potassium iron oxalate addition,when the ratio of potassium iron oxalate to biomass is 2:1,the specific surface area does not increase but decreases,only732 m²/g.At a carbonization pyrolysis temperature of 700℃,the added zinc chloride can react with the activator potassium iron oxalate,inhibiting the pore forming function of potassium iron oxalate;As the amount of zinc chloride added increases,when the mass ratio of potassium iron oxalate to zinc chloride is 1:2,the excess zinc chloride exerts its pore forming function again,with a specific surface area and adsorption capacity of 1178m²/g and 688.5 mg/g,respectively.The results indicate that the added potassium iron oxalate generates potassium carbonate（pore forming）and elemental iron（magnetized）during the pyrolysis process,which is crucial for improving the adsorption capacity of peacock green and the recovery of carbon materials.（3）By co activation of K₂CO₃and urea,a porous biochar material with both ultra microporous structure and N atoms was constructed,and its adsorption performance for CO₂,benzene,and toluene was analyzed.The synergistic co activation of K₂CO₃and urea can significantly increase the specific surface area of biochar materials.When the carbonization pyrolysis temperature is 700℃and the mass ratio of K₂CO₃and urea is 1:2,the specific surface area is the highest,reaching 2943 m²/g.At the same time,N-containing functional groups are introduced into the biochar materials,resulting in a high adsorption capacity for CO₂,reaching 95.7 mg/g;At the same time,it has good selective adsorption performance and low-temperature adsorption performance for CO₂,and improves the cycling stability of CO₂adsorption.After co activation with K₂CO₃and urea,the modified biochar material has a high nitrogen content and narrow microporous distribution,and its adsorption capacity for benzene and toluene increases to 781.3 mg/g and 746.3 mg/g,respectively.Due to the fact that the kinetic diameter of toluene（0.67 nm）is larger than that of benzene（0.58 nm）,the pore size of K₂CO₃and urea co activated biochar materials is more suitable for benzene,resulting in higher adsorption capacity and faster adsorption rate for benzene.The penetration experiments of benzene and water vapor,as well as toluene and water vapor,indicate that the modified biochar material co activated by K₂CO₃and urea has excellent selective adsorption ability for benzene and toluene compared to adsorbed water vapor.（4）Five metal salts,Fe Cl₃·6H₂O,KCl,Mg Cl₂,K₂CO₃,and Mg CO₃,were selected as modifiers to study the effects of different modifiers and their addition levels on the carbon sequestration ability of biomass charcoal.Compared with the other four groups of modified biochar,Fe Cl₃·6H₂O modified biochar has the highest carbon retention and strongest thermal stability.This is mainly because Fe₃O₄in Fe Cl₃modified biochar fixes the carbon containing functional groups containing C=O and C-O,which inhibits the conversion of carbon containing substances to biogas and bio oil,thus improving the carbon retention.And when the highest amount of Fe Cl₃·6H₂O was added（2.5 mmol）,the carbon retention reached 76.2%.The results indicate that adding metal salts can achieve the goal of improving the carbon sequestration capacity of biomass charcoal.The directional modification and regulation of biochar can provide important theoretical basis for the adsorption of heavy metals,organic compounds in the aqueous phase,as well as CO₂and VOCs in the gas phase;The study on the adaptability of modified biochar in carbon fixation and emission reduction can provide broad application prospects for biochar in the field of ecological environment protection.