Adsorption Of Sb(Ⅲ)in Water By Modified Rice Straw Biochar

In order to improve the adsorption performance of the biochar adsorbent to antimony,rice straw biochar modified by Mn and Fe-Mn were marked as Mn-BC,Fe-Mn-BC respectively,which were used as absorbents to remove Sb（Ⅲ）and Sb（Ⅴ）from water.The adsorption performance of the adsorbent was explored by carrying out dynamic and static adsorption experiments.First,determine the optimal dosage and p H value for static adsorption experiments,and then carry out isothermal adsorption,kinetic adsorption,and system coexisting anion effects experiments on this basis.At the same time,explore the regenerative adsorption capacity of Mn-BC and Fe-Mn-BC,and then the three dynamic adsorption experiments on antimony solutions with different concentrations and flow rates were investigated.Finally,SEM,BET,FT-IR,and XPS were used to explore the surface properties of the adsorbent and its mechanism of action.Draw the following main conclusions:（1）At 25℃,the Solid-liquid ratio is 2.5 g/L,and the maximum adsorption capacity of BC,Mn-BC and Fe-Mn-BC for Sb（Ⅲ）under the conditions of p H 2.0,4.0,4.0 are 5.08,11.45,29.45 mg/g;the maximum adsorption capacity of Sb（Ⅴ）under the condition of p H 2.0 is 7.79,21.41,35.62 mg/g,respectively.The adsorption of Sb（Ⅲ）and Sb（Ⅴ）by Mn-BC and Fe-Mn-BC is mainly chemical adsorption,accompanied by physical adsorption,and adsorption is easy to occur.（2）The adsorption of Sb（Ⅲ）and Sb（Ⅴ）by Mn-BC is greatly affected by different concentrations of F^-,HCO₃^-and H₂PO₄^-;while the adsorption of Sb（Ⅲ）by Fe-Mn-BC is only affected by HCO₃^-And the weak influence of H₂PO₄^-,the adsorption of Sb（Ⅴ）is only weakly affected by F^-,but is basically not affected by the ionic strength.Compared with Mn-BC,Fe-Mn-BC has better adsorption and regeneration capacity for Sb（Ⅲ）and Sb（Ⅴ）;compared with BC,Mn-BC,Fe-Mn-BC has better Sb concentration and flow rate.The dynamic adsorption performance of（Ⅲ）and Sb（Ⅴ）has been improved,but the regularity is not obvious.（3）Compared with BC,Mn-BC and Fe-Mn-BC have larger specific surface area and total pore volume,but the type of surface functional groups have not changed significantly.（4）Mn-BC and Fe-Mn-BC have oxidation effect on the adsorption of Sb（Ⅲ）,The products may be Sb（Ⅴ）-based complexes.In the adsorption process,protonation,electrostatic interaction,and complexation under acidic conditions are the most important mechanisms in the adsorption process.