Study On Preparation Of Reed Biochar And Its Adsorption Performance Of New Pollutants

In this study,tetracycline?TC?and bisphenol A?BPA?were selected as research objectsto find out adsorpton performance of reed biochar under the increasingly serious pollution of new pollutants.The properties of biochar materials prepared by different methods and the adsorption performance of different materials for TC and BPA were discussed.The properties of biochar materials prepared by different preparation methods were discussed.The suitable materials were selected to investigate their adsorption properties for TC and BPA.Specific research content is as follows.?1?Typical artificial wetland plant-reed was used as the research object to prepare reed biochar,by direct carbonization?named 4B,6B?,KOH activation?named4K,6K?,450?and 650?are selected and by CO₂ activation methods?named 7C,8C and 9C?,700?,800?and 900?are selected.The physical and chemical characteristics of the surface and pores of biochar were analyzed by Scanning electron microscopy?SEM?,BET?measurement of specific surface area?and Fourier Transform infrared spectroscopy?FTIR?.The effect of preparation method on the adsorption performance of biochar was studied by using reed biochar to absorb methylene blue?MB?,and the application prospect of biochar was evaluated by the capacity of adsorption and removal rate of pollutants.The results showed that the adsorption rate of biochar increased with the increase of pyrolysis temperature,and the adsorption amount is directly related to the preparation method,direct carbonization<KOH activation<CO2.The adsorption property is consistent with the physical and chemical properties of the adsorption material.The adsorption of TC and BPA by the same biochar also showed different characteristics,and the specific performance was that the adsorption effect of TC was better than that of BPA under the same conditions.?2?In this paper,4B,6B,4K and 6K were selected for further study.The results show that the removal effect of TC is affected by temperature,adsorption time,initial concentration and pH value of the solution.But the removal effect of BPA was not significantly affected by temperature and pH value of the solution.Under the comprehensive consideration,the best condition for BPA to removal is:15±1?,pH not adjustment,set 6K as adsorbent,amount adsorbent is 15 mg,Amount f solution is 10mL,time adsorption equilibrium is 1 h;The best condition to removing TC is:40±1?,pH=6,set 6 K as adsorbent,amount adsorbent is 15 mg,Amount of solution is 10 mL,time adsorption equilibrium is 2 h;Under the best conditions,the removal rate of BPA?140mg/L?and TC?100 mg/L?could reach 95.64%and 61.32%,respectively.?3?The kinetics of TC and BPA adsorbed by 4B,6B,4K and 6K can be characterized by quasi-second order kinetic model and modified intra-particle diffusion model.The adsorption capacity can be characterized by Freundlich and Langmuir model at equilibrium concentration.Adsorption thermodynamics and kinetics study shows that four kinds of biochar,isothermal adsorption process of TC and BPA can be fitted much better by the Freundlich modlle at different temperature.And the adsorption dynamics which conform to the secondary dynamics equation,adsorption process is a process dominated by chemical adsorption.