锰氧化物改性生物炭对水中四环素的强化吸附

Enhanced adsorption activity of manganese oxide-modified biochar for the removal of tetracycline from aqueous solution

以MnCl2为改性剂,制备锰氧化物改性生物炭(MBC),用于强化生物炭对水中四环素的吸附。采用比表面积法(BET)、X射线衍射(XRD)和红外光谱(FTIR)等手段表征其微观结构,并通过单因素试验研究改性前后生物炭对四环素的吸附行为和影响因素。结果表明,Langmuir模型计算的MBC最大吸附量为736 mg·g^-1,较原始生物炭提高了15倍。吸附符合准二级动力学模型,受物理化学过程控制,是一个自发的吸热过程。溶液pH、二价阳离子对吸附影响较大,而一价阳离子和共存腐植酸对吸附影响微弱。MBC吸附水中四环素主要是通过氢键作用、静电作用及锰与四环素之间的配位作用,吸附效果较BC显著提高,且环境适应能力更强,对去除水环境中的抗生素具有较好的应用前景。

In this study,manganese oxide modified biochar(MBC)was synthesized using MnCl2 as a modifier to enhance the adsorption capacity of biochar for tetracycline in water.The specific surface area method(BET),X-Ray diffraction(XRD),and Fourier transform infrared spectroscopy(FTIR)were used to characterize the microstructure of the modified and pristine biochar.The influencing factors and adsorption behavior of biochar were investigated using the batch technique.The results showed that the maximum adsorption capacity of MBC calculated by the Langmuir model was 736 mg·g^-1,which was 15 times higher than the adsorption by the raw biochar.In this study,the adsorption process was a spontaneous and endothermic reaction,which fit the pseudo-second-order kinetic model and was controlled by both physical and chemical processes.pH value and divalent cations in solution were both important factors for the adsorption of MBC,whereas the monovalent cation and humic acid had only a slight effect.The hydrogen bonding,electrostatic interaction,and complexation between manganese ion and tetracycline were the main mechanisms for the removal of tetracycline through MBC adsorption.All the results showed that compared with the pristine biochar,the adsorption capacity of MBC was significantly improved,which indicated that MBC had a wider range of application and a good application prospect for the removal of antibiotics in water.