Study On Preparation Characterization And Adsorption And Removal Of Organic Dyes Of Bamboo Shoot Based Biochar

The efficient conversion and utilization of biomass resources has been a hot topic in the field of environmental and chemical engineering.As a renewable resource in nature,biomass material has rich organic carbon content and a series of advantages such as wide sources and environmental protection.Therefore,biomass material is a kind of carbon precursor with great potential from the perspective of industrial production and preparation of porous carbon material.Biomass derived porous carbon materials have the characteristics of high specific surface area,developed pore structure and easy structure regulation.In particular,the microstructure and surface chemistry of porous carbon materials can be effectively regulated by adjusting the process flow and its parameters.In this paper,several porous carbon materials with different microstructure and surface chemical properties were prepared from bamboo and bamboo shoot shells from agricultural waste as carbon precursors,and these porous carbon materials were used as adsorbents to treat dyes in organic wastewater.The research contents of this paper are summarized as follows:First,biochar was derived from hydrochar pyrolysis at various temperatures using agricultural waste of bamboo shoot shells as the raw materials,and the microstructure of biochar varied with temperature,and the removal performance for rhodamine B(Rh B)at 0,25,and 40? were studied in detail.The results indicated that BHC-800 obtained at pyrolysis temperature of 800? showed well-developed pores with surface area of 513 m~2/g.Significantly,the maximum adsorption capacity of Rh B on BHC-800 at 25? is up to 85.8 mg/g with isotherms fitted well to Freundlich model.Adsorption kinetics indicated that the adsorption equilibrium time for Rh B on BHC-800 was of about 20 min with the data fitted better to the pseudo second order kinetics.Secondly,N-doped carbons were obtained from bamboo shoot shell via hydrothermal pretreatment under salt assistance followed by carbonization,using melamine as nitrogen source.The carbons with tubular morphology and surface areas in 406?489 m~2/g range were used as adsorbents for the removal of methyl orange(MO)and rhodamine B.Adsorption isotherms and kinetic fitting showed much better accordance with Freundlich model and pseudo second order,showing balanced capacity(q_e)of 50 mg/g for MO and 42 mg/g for Rh B on the pristine carbons(BCS-M00)at 25?.After N-doping treatment,carbons(BCS-M20)had qe of MO and Rh B up to 140 mg/g and 100 mg/g,respectively,confirming a positive effect of N-doping on the enhancement of dyes removal.Finaly,in order to explore the maximum adsorption capacity of bamboo shoot shell,we further activated bamboo shoot shell.Here we report a facile method to synthesize N-doped hierarchical carbons from hydrothermal carbonization followed by a mild KOH activation,using agricultural biowastes of bamboo shoot shells as raw materials and melamine as nitrogen source.The pore structure and surface-doping chemistry of carbons can be easily adjusted by changing activation temperature,showing surface areas of?3300 m~2/g with main mesopores centering at?2.8 nm.When the activation temperature is 800?,the adsorption capacity is extremely high adsorption performance in 40? with the adsorption capacity about 5000mg/g for Rh B,The results showed that the prepared bamboo shoot shell carbon had great potential in the adsorption of organic dyes.