The Adsorption Performance Of Manganese-rich Pokeweed Biochar To Pb²⁺、 Cd²⁺ And Cu²⁺ In Wastewater

Recently,manganese-modified biochar prepared by manganese modification technology has been widely used in the treatment of heavy metal pollution in water.Pokeweed is a super-enriched plant for manganese,and it has got rid of the biological disadvantages of many super-enriched plants.At the same time,it has many advantages such as good adaptability,strong fecundity and wide geographical distribution.It is widely used as an ideal plant in remediation of soil in manganese mining area.Manganese-rich pokeweed plants were prepareds in 300℃,400℃and 500℃manganese-rich pokeweed biochar through high-temperature pyrolysis,and through comparative experiments,static adsorption experiments,cyclic experiments,and simulation of the ternary system competitive adsorption experiment and actual electrolytic zinc wastewater experiment and potential risk analysis experiment,as well as fourier infrared spectroscopy（FTIR）,scanning electron microscopy-energy spectroscopy（SEM-EDS）,specific surface area and aperture（BET）,elemental analysis,X-ray Diffraction（XRD）and X-ray photoelectron spectroscopy（XPS）characterization analysis,this paper studied the adsorption performance and adsorption mechanism of manganese-rich pokeweed biochar for heavy metals Pb²⁺,Cd²⁺and Cu²⁺,and potential environmental pollution risks.it could provide data support and theoretical basis for the research and development of new environmentally friendly biochar materials,at the same time can provide a model for the scientific treatment and disposal of heavy metal-containing biomass and the resource utilization of biochar.（1）Through the characterization and analysis,it can be seen that the manganese-rich pokeweed biochar has a rod-like structure with particles on the surface;its structure has not changed before and after adsorption,but after adsorption of Pb²⁺and Cd²⁺,Pb₃（CO₃）₂（OH）₂is produced respectively Pb CO₃and Cd CO₃compounds precipitate;they have abundant functional groups;since the pyrolysis temperature rises,their specific surface area,pore size,carbonization degree and aromaticity all increase accordingly;it also proves that the Mn element in the manganese-rich pokeweed biochar is mainly Mn O₂mainly and successfully adsorbed heavy metals.（2）Through a series of experiments,it can be known that the optimal adsorption parameters,maximum adsorption capacity and recyclability of manganese-rich pokeweed biochar;at the same time,it is proved that manganese-rich pokeweed biochar not only has higher adsorption of Pb²⁺,Cd²⁺and Cu²⁺Adsorption capacity,also has a certain adsorption capacity for Zn and Mn;and also proved that after converting manganese-rich pokeweed into biochar,the potential pollution risk to the environment will continue to decrease as the pyrolysis temperature rises,especially BC500 drop to a low pollution level.（3）Through mechanism analysis,it can be known that the adsorption mechanism of manganese-rich pokeweed biochar to heavy metals Pb²⁺,Cd²⁺and Cu²⁺includes electrostatic attraction,complex adsorption,chemical adsorption and precipitation adsorption.In general,manganese-rich pokeweed biochar has the characteristics of simple preparation,low cost,high adsorption capacity,recyclability and low risk of potential environmental pollution.