Adsorption Behavior Of Antimony In Water By Modified Biochar

In order to find more effective sorbents to remove antimony in water,the adsorption of biochar?BC?and its modified products[trivalent aluminum modified biochar?Al-BC?and potassium permanganate modified biochar?KMnO₄-BC?]for Sb?V?and Sb?III?in water were studied by changing the experimental conditions such as the amount of sorbent added,reaction time,initial concentration of adsorbate,and reaction pH.Combined with BET surface area analysis,SEM scanning electron microscopy and FTIR infrared spectroscopy,the results of isothermal adsorption experiments and adsorption kinetics experiments were to characterize the biochar and its modified products.The adsorption rule and adsorption mechanism of the biochar and its modified products for Sb?V?and Sb?III?in water were primarily investigated.The main conclusions are as follows:?1?At 25°C,the ratio of solid to liquid was 2.5g·L^-1,reaction time was 4 h,pH was 2.0,the maximum adsorption capacity of BC,Al-BC and KMnO₄-BC to Sb?V?was4.41,10.48 and 30.06 mg·g^-1 respectively.The adsorption capacity for Sb?V?decreased gradually with the increase of pH.At 25°C,when the solid-liquid ratio was 2.5 g·L^-1,reaction time was 4 h,and pH was 4.0,the maximum adsorption capacity of BC,Al-BC and KMnO₄-BC to Sb?III?was 10.56,81.21 and 14.88 mg·g^-1 respectively.Biochar had better adsorption for Sb?III?under acidic conditions.?2?The isothermal adsorption curves of three biochars for Sb?V?conformed to the Langmuir isotherm model.The adsorption kinetics of BC and KMnO₄-BC for Sb?V?followed a pseudo-second order kinetics equation,and Al-BC adsorption for Sb?V?conformed to the pseudo first-order kinetic equation.The adsorption process of biochar on Sb?V?was a physical-chemical compounding process based on physical adsorption behavior.The adsorption mechanisms for Sb?III?of Al-BC and KMnO₄-BC were different.The isothermal adsorption curve for Sb?III?on KMnO₄-BC conformed to the Langmuir isotherm model.And the kinetics of adsorption followed the pseudo-second order kinetic equation.However,Freundlich and the first-order kinetic equation were more in line with the adsorption process for Sb?III?by Al-BC.The biosorption of Sb?III?by three kinds of biochar were mainly based on physical adsorption,and there were also the participation of chemical adsorption.?3?The characterization experiment results showed that the large adsorption capacity of Al-BC was mainly due to the increase of its specific surface area and pore volume.And the crystal attached to the surface of KMnO₄-BC improved its adsorption capacity.The surface functional groups of biochar before and after modification did not change much.