Study On The Preparation Of Jujube Branch Biochar And Its Adsorption Characteristics And Mechanism For Nitrate And Ammonium

According to the survey,the rapid development of jujube and its related industries will produce more biomass wastes.How to efficiently and comprehensively utilize jujube biomass resources is to deal with scientific issues between economic development and the ecological environment,and it is also a current resource for exploration.Research hotspots using new approaches.In this paper,the high-temperature pyrolysis method is used to prepare high-performance carbon materials and by-products of potential utilization value by using waste jujube biomass resources in an anaerobic environment.Mainly by controlling the pyrolysis temperature and constant temperature time,and then performing physical activation,ten kinds of jujube branch biochar（JB）with different carbonization processes were prepared,and by-products such as bio-oil and synthesis gas were also obtained.And with the help of advanced material characterization methods,the SEM,XPS,XRD,FTIR,TGA,BET specific surface area and pore size analysis,Zeta potential,element analysis and other physical and chemical properties of biochar were analyzed,and PYGC-MS was used to analyze the pyrolysis process.The chemical composition of by-products.Finally,8 isothermal adsorption and adsorption kinetic models were used to simulate the adsorption process of nitrate nitrogen and ammonium nitrogen by biochar to clarify the adsorption mechanism.The main conclusions of this research are as follows:（1）The physical and chemical properties of JB and bio-oil were systematically characterized in the article.The results proved that as the pyrolysis temperature increased from 300°C to 700°C,the carbon content of JB increased,the p H value increased,and oxygen and nitrogen The content decreases;the specific surface area(S_BET)and the content of basic functional groups both increase;while the content of total functional groups gradually decreases.The zeta potential and yield of jujube branch biochar gradually decrease with the increase of pyrolysis temperature.The pyrolysis temperature of jujube branch biochar has a greater impact on the performance of biochar than the pyrolysis constant temperature time.（2）The adsorption characteristics of jujube branch biochar to nitrate nitrogen and ammonium nitrogen were studied experimentally,and its pyrolysis and adsorption mechanism was discussed.The optimal preparation process of jujube branch biochar is pyrolysis temperature 600℃,pyrolysis constant temperature time 2h,and its adsorption capacity for nitrate nitrogen and ammonium nitrogen is the highest,which are 21.17 mg·g^-1and 30.57 mg·g^-1,respectively..The studies on isothermal adsorption and kinetic adsorption of jujube branch biochar were described by Langmuir model and pseudo-second-order kinetic model,respectively.The NO₃^--N and NH₄⁺-N adsorption mechanisms of jujube branch biochar include surface adsorption,intra-particle diffusion,electrostatic interaction and ion exchange.In addition,the adsorption of NH₄⁺-N is also related toπ-πinteraction and surface complexation.（3）The main by-product of pyrolysis is bio-oil,which contains chemical substances such as maltol,guaiacol,apigenin,allopurinol,pyridine and furan.This research result enables the effective use of jujube tree biomass,turning waste into treasure;providing a theoretical and practical basis for future research on biochar and bio-oil,and promoting the utilization of eco-friendly resources and the prevention and control of nitrogen pollution in water bodies.