β-环糊精改性猪粪生物炭对水中四环素的吸附特性及机制

Adsorption characteristics and mechanism of tetracycline in water by swine manure biochar modified with β-cyclodextrin

为了从源头控制抗生素污染以及达到“以废治废”的目的,以猪粪为原料制备猪粪生物炭(SMBC),以β-环糊精(β-CD)为改性剂制得改性猪粪生物炭(β-SMBC)。通过元素分析、比表面积分析、SEM和FTIR等对SMBC和β-SMBC的组成、形貌和结构进行表征。以四环素(TC)为目标污染物,考察了溶液pH、吸附剂投加量和温度对其吸附TC的影响,研究了SMBC和β-SMBC对水中TC的吸附特性及机制。结果表明:溶液pH对SMBC和β-SMBC吸附TC的影响较大,在酸性条件下更有利于TC的吸附。SMBC和β-SMBC对TC的吸附动力学均能被准二级动力学方程很好地描述,吸附过程主要包括液膜扩散和颗粒内扩散两个阶段。同时,Freundlich模型能更好的描述TC在SMBC和β-SMBC上的吸附行为,最大吸附量分别为35.050和53.503 mg·g^(-1)。与SMBC相比,β-SMBC对TC的吸附效果更好,且主要的吸附机制为静电作用、氢键作用和π-π相互作用。热力学结果表明,SMBC和β-SMBC对TC的吸附是一个自发的吸热过程。上述结果表明,β-SMBC对TC具有较强的吸附性能且其重复利用性好,是一种在抗生素废水处理领域具有应用前景的高效、可再生吸附材料。

In order to control antibiotic pollution from the source and achieve the purpose of"treating waste with waste",swine manure biochar(SMBC)was prepared from swine manure,andβ-cyclodextrin(β-CD)was used as modifier to prepare modified swine manure biochar(β-SMBC).The composition,morphology,and structure of SMBC andβ-SMBC were characterized by elemental analysis,specific surface area analysis,SEM,and FTIR.Taking tetracycline(TC)as the target pollutant,the effects of solution pH,adsorbent dosage,and temperature on TC adsorption by SMBC andβ-SMBC were investigated,and the adsorption characteristics and mechanisms of SMBC andβ-SMBC on TC in water were studied.The results showed that the pH of the solution had a greater effect on TC adsorption by SMBC andβ-SMBC,and TC adsorption was more favorable under acidic conditions.The adsorption kinetics of SMBC andβ-SMBC toward TC could be well described by the pseudo-second-order equation,and the adsorption process was mainly divided into two stages:liquid film diffusion and internal particle diffusion.Meanwhile,the Freundlich models could better describe the adsorption behavior of TC on SMBC andβ-SMBC with maximum adsorption of 35.050 and 53.503 mg·g^(-1),respectively,and TC removal byβ-SMBC was better than SMBC.The main adsorption mechanisms are electrostatic interaction,hydrogen bonding,andπ-πinteraction.The thermodynamic results indicated that the adsorption of TC by SMBC andβ-SMBC was a spontaneous endothermic process.In conclusion,β-SMBC had a strong performance on TC adsorption and its reusability was excellent.Therefore,β-SMBC is a highly efficient and regenerable adsorbent material with application prospects in the field of antibiotic wastewater treatment.