| With economic development of China,living standards of human beings has been increased,which is accompanied with environmental pollution increase.In recent years,with the introduction of a series of environmental protection laws and regulations and a series of environmental control measures,the environmental conditions have been improved.However,there are still some water pollution problems that need to be resolved,such as antibiotic contaminated wastewater.Due to the abuse of antibiotics and the accumulation in the environment,residual antibiotics can cause harm to human health and the ecological environment,which have recently attracted widespread attention.Removing residual antibiotic pollutants in the environment have become an urgent environmental problem that need to be solved.Using the common agricultural waste-corn straw to prepare porous carbon materials and to remove pollutants from wastewater is a vivid manifestation of the idea of"treating waste with waste"and has a very broad application prospect.This study will lay a solid foundation for the resource utilization of farmland waste and the pollution control of antibiotics in wastewater.The research results and conclusions obtained from this study are as follows:1.Porous carbon material?MPC800-10?was prepared by one-step carbonization and activation,using common agricultural waste corn straw?CS?as raw material precursor,NaHCO3 and melamine as activator.SEM,BET,XRD,Raman,FTIR and elemental analysis were used to characterize the materials before and after carbonization.And its adsorption performance on tetracycline?TC?was studied.The results showed that:?1?the specific surface area of MPC800-10?1401 m2/g?was found bigger than C800?pristine biochar?and PC800?porous carbon obtained with NaHCO3 activation??498 and 1086 m2/g,respectively?with porous structure.The addition of melamine was beneficial to the formation of micropores and mesopores of carbon materials to a certain extent,enhances aromaticity,and increases the surface oxygen-containing functional groups;?2?MPC800-10 has excellent adsorption capacity for TC that can remove TC quickly,where the maximum adsorption capacity reached up to 347 mg/g;?3?The adsorption of TC by MPC800-10 was fitted well with the Pseudo-second-order kinetic model and the Freundlich isotherm adsorption model.Thermodynamic analysis showed that the adsorption of TC by MPC800-10 was a spontaneous and endothermic process.MPC800-10 had good adsorption capacity for TC under acidic and neutral conditions,and has certain anti-ion interference ability and good regeneration performance.2.CS based porous carbon was prepared by one-step phosphoric acid?H3PO4?low temperature activation.The materials were characterized by means of material characterization.And its adsorption performance on TC was studied.The results showed that:?1?H3PO4 impregnation ratio?H3PO4/CS,g/g?can greatly affect the development of pore structure,especially micropores.The ACS300-1 engineered at 300°C and the impregnation ratio of 1.0 showed the maximal specific surface area of 463.89 m2/g with total pore volume of 0.387 cm3/g.The results of XRD and Raman indicated that H3PO4 activation increased the degree of graphitization of the material.FTIR and XPS analysis indicated an increase in the oxygen-containing functional groups of ACS300-1;?2?Adsorption experiments showed that ACS300-1 had excellent TC adsorption performance under a wide range of solution pH and high ionic strength.ACS300-100-1 had a TC adsorption capacity of 227.3 mg/g at 303 K,which had comparable or even higher adsorption performance than other various carbon-containing adsorbents;?3?Adsorption data can be fitted well by the pseudo-second order kinetic model and Langmuir isotherm model.The adsorption process included both physical adsorption and chemisorption,and it was a spontaneous endothermic process.The adsorption mechanism was mainly pore filling,?-?electron donor-acceptor??-?EDA?interaction,hydrogen bonding interaction and electrostatic interaction. |
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