Study On Preparation Of Porous Carbon And Its Adsorption Performance By Biomass As Carbon Source

In the study, corn starch and shaddock peel were utilized to prepare the carbon materials. The method of pyrolysis carbonization was adopted in the study for its easy operation and causing little pollution. And the researches about using starch-based carbon and shaddock peel-based carbon to remove heavy metal ions pollutants including Cu2+, Pb2+ and Cd2+ from simulated wastewater were carried out preliminarily.The as-prepared carbon materials were characterized by using scanning electron microscope, X-ray power diffractometer and Fourier transforming infrared spectrum. It was found that the microstructure and surface functional groups of the biomass carbon were changed with the synthesizing conditions. A large number of pores in the biomass carbon and some oxygen functional groups can contribute to the adsorption performances.The structures and the adsorption performance for as-prepared carbon at different synthesizing conditions were explored, such as the concentration of starch, the content of epoxy chloropropane, the reaction time and the maximum carbonization temperature. High carbonization temperature and moderate content of epoxy chloropropane can improve pollutant removal capability for the biomass carbon. The optimal preparation conditions of starch-based carbon were that the concentration of starch was 3%, the content of epoxy chloropropane was 20%, the reaction time was 16 h and the maximum carbonization temperature was 800℃. The optimal preparation condition of shaddock peel-based carbon was that the maximum carbonization temperature was 800℃.The influences of several experimental parameters including initial pH, the mass of biomass carbon, adsorption time and initial concentration of heavy metal ion on the removal of Cu2+, Pb2+ and Cd2+ from simulated wastewater by the biomass carbon were studied. The results showed that the optimal initial pH value for removing Cu2+ Pb2+ and Cd2+ with starch-based carbon were 7.0,6.0 and 8.0, respectively. And the optimal initial pH values for removing Cu2+, Pb2+ and Cd2+ with shaddock peel -based carbon were 6.0. The adsorption equilibrium was reached in 4 h. The absorption efficiency for Cu2+ was better than for Pb2+ and Cd2+, and the absorption efficiency for Cd2+ was the worst among Cu2+, Pb2+ and Cd2+. The results showed that the adsorption capacity of the starch-based carbon for Cu2+, Pb2+ and Cd2+ can reach 163, 128 and 83 mg/g, respectively, and the adsorption efficiency was 81.5%,64% and 41.5%, respectively. The adsorption capacity of the shaddock peel-based carbon for Cu2+, Pb2+ and Cd2+ can reach 181,145 and 102 mg/g, respectively, and the adsorption efficiency was 90.5%,72.5% and 50.8%, respectively.The adsorption kinetics and isotherms of Cu2+, Pb2+ and Cd2+ were investigated. The results showed that the pseudo-second-order kinetics models for Cu2+, Pb2+ and Cd2+ were confirmed by absorptive data fitted. And the Freundlich isotherm models fitted very well with the experimental data for the removal of Cu2+, Pb2+ and Cd2+.