Preparation Of Modified Tobacco Powder Biomass Adsorbent And Removal Of Nitrate From Wastewater

Industrial and agricultural production activities make the nitrate pollution of the water environment increasingly severe.The traditional nitrate treatment method has incomplete conversion,the electrode material is easy to corrode and passivate,the economic benefit is low,and the processing conditions are severe.It is very urgent to develop a cost-effective biomass adsorption material for nitrate and to clarify its adsorption mechanism.China's tobacco production and planting area are among the highest in the world,and a large amount of discarded tobacco powder are produced in cigarette production,causing a serious load on the cost and ecological environment of enterprises.The waste tobacco powder has excellent pore structure and high cellulose content.It is of great significance to preparation of biomass adsorbent using waste tobacco powder as raw material for treating nitrate in water to alleviate environmental pollution,realize the green development concept of“treating waste by waste”,and broaden the utilization of waste tobacco.It also inspired the development of Chinese biomass adsorbents.Using waste tobacco powder as raw materials to react with epichlorohydrin in DMF.Under the catalytic conditions of pyridine,modification of cellulose in tobacco by triethylamine as amine introduction group to prepare modified tobacco powder biomass adsorbent?MTPBA?.Through the single factor experiment,the influence of main parameter conditions in the preparation process of MTPBA was studied,and determined the best conditions for the preparation of MTPBA.The physicochemical characteristics of tobacco powder before and after modification were characterized by SEM,EDX,FTIR,XRD etc.The results show that the optimum condition for preparing MTPBA is NaOH concentration of 1.5mol/L during strong alkali pretreatment;the temperature of the crosslinking reaction is80?;the dosage of the crosslinking agent is 5mL/g;the temperature of the quaternization reaction is 80?.The formed MTPBA has uniform morphology,increased crystallinity,a large number of fine pores on the surface,and the successful introduction of tertiary amine group and chloroalkyl groups.The results indicate that MTPBA has a better pore structure than the original tobacco powder,and the introduction of tertiary amine groups,chloroalkyl groups and surface zeta potential changes are favorable for adsorption of NO₃^-.Through the static adsorption experiment method,the adsorption effect of MTPBA on the nitrate in the simulated wastewater of KNO₃ solution was studied,determined the optimal adsorption conditions.SEM,EDX and FTIR were used to characterize MTPBA in order to study its adsorption performance and mechanism.The results showed that the optimal conditions for the adsorption of nitrate were MTPBA dosage 4.0g/L,solution pH=6.68,adsorption time 30min,applicable concentration 2⁵0mg/L.The adsorption process is well fitted to the pseudo second order kinetic model?R²>0.99?.The experimental data fit well with the Langmuir and Freundlich isothermal model?R²>0.92?.The adsorption capacity of MTPBA for NO₃^-was Q_max=28.46 mg/g.The results indicate that MTPBA has better adsorption properties.The adsorption mechanism is mainly related to the tertiary amine group and the porous structure.