Preparation Of Activated Carbon With Silage Stalks And Its Adsorption Of Two Kinds Of Antibiotics

In this paper,activated carbon was prepared by H₃PO₄ activation and corn stalks as raw materials.In order to improve the adsorption performance of activated carbon from corn stalks,the preparation of activated carbon from silage modified stalk was studied.The adsorption of ciprofloxacin and amoxicillin in wastewater was studied.In this paper,five kinds of activated carbon were studied.Activated carbon by corn stalks?AC-1,AC-2?,activated carbon by silage corn stalks?AC-S1,AC-S2?and activated carbon with succinic acid modified were studied.In the preparation process,AC-1 and AC-S1 were prepared from the raw material and phosphoric acid impregnation ratio at 1:2,activation time of 10 h,carbonization temperature of 450 ?,carbonization time of 1h.Based on response surface method?RSM?design,AC-2,AC-S2 and AC-SA were optimized scheme for carbonization temperature at 584 ?,raw material and phosphoric acid impregnation ratio at 1:1.9,modifier of succinic acid dosage of 0.005 mol/g,carbonization time of 1h.The specific surface area and pore size of the prepared activated carbon were analyzed,and the specific surface area of AC-1 was 1091.22m²/g,AC-S1 was 741.63m²/g,AC-1 contained both microporous and mesoporous,and AC-S1 contained most of the microporous.The specific surface area of AC-2 was 1455 m²/g,the specific surface area of AC-S2 was about 1521 m²/g,the AC-SA was about 1347 m²/g.The three kinds of activated carbon have micropores and mesopores.Scanning electron microscopy?SEM?analysis of activated carbon showed that the surface of AC-1 was smooth,the pore size was larger,the AC-S1 was rough,and the acidic functional groups were attached.Compared with AC-S2,AC-SA and AC-2,the surface of AC-SA contained more attachments,and the reason is that the surface of the activated carbon was residual succinic acid.Bohem titration and infrared spectroscopy?FTIR?analysis showed that the surface of activated carbon contained carboxyl,lactone,phenolic hydroxyl and carbonyl groups.The content of acidic functional groups of AC-1 is much lower than AC-S1,and the content of acidic functional groups around three activated carbon was AC-SA> AC-2>AC-S2,which is consistent with the results of FTIR analysis.AC-1 and AC-S1 can effectively remove the ciprofloxacin in wastewater,and the removal effect of AC-S1 was better.The adsorption capacity was 323.70 mg/g and 407.75 mg/g,the removal rate was up to 63.85% and 80.58%,respectively.The adsorption process was mainly chemical adsorption and reached the equilibrium around after 12 h,AC-1 and AC-S1 were in accordance with pseudo-two-order kinetic adsorption model.The Langmuir model was more suitable for the analysis of adsorption thermodynamics,and the two kinds of activated carbon are mainly monolayer adsorption.The pH value has a great influence on the adsorption effect,and the adsorption effect was better at pH= 5-7.It is found that electrostatic interaction,cation exchange and ?-?EDA may be involved in the adsorption process.AC-2,AC-S2 and AC-SA can effectively remove amoxicillin in wastewater,the removal effect of AC-SA was better,the adsorption capacity was 45.60 mg/g,the removal rate was up to 90.96%.The adsorption effect of AC-2 was similar to that of AC-S2,the adsorption amount was 38.84 mg/g and 39.69 mg/g,the removal rate was up to 77.99% and 78.36%,respectively.The adsorption process was mainly chemical adsorption and reached the equilibrium around after 6h.Three activated carbons were in accordance with pseudo-two-order kinetic adsorption model.Adsorption isotherm was more suitable for Langmuir model.Activated carbon was mainly adsorbed by single molecule layer,in which AC-SA has partial adsorption of multi molecular layer.The pH value has a great influence on the adsorption effect,and the adsorption effect is better under acidic conditions.It was found that electrostatic interaction,cation exchange and?-? EDA may be involved in the adsorption process.