溶液pH对纳米生物炭与针铁矿的异质团聚及左氧氟沙星吸附的影响机制  

Mechanism of Solution pH Effects on Hetero-Aggregation of Nano-Biochar and Goethite and Levofloxacin Adsorption

作　　者：马锋锋[1,2] 李庆 赵保卫 焦雅仙[1] 康宏兵 MA Fengfeng;LI Qing;ZHAO Baowei;JIAO Yaxian;KANG Hongbing(School of Environmental and Municipal Engineering,Lanzhou Jiaotong University,Lanzhou 730070,China;Ministry of Education Engineering Research Center of Water Resource Comprehensive Utilization in Cold and Arid Regions,Lanzhou Jiaotong University,Lanzhou 730070,China)

机构地区：[1]兰州交通大学环境与市政工程学院,甘肃兰州730070 [2]寒旱地区水资源综合利用教育部工程研究中心,甘肃兰州730070

出　　处：《环境科学研究》2025年第4期852-861,共10页Research of Environmental Sciences

基　　金：兰州交通大学“天佑青年托举人才计划”基金项目;兰州交通大学-天津大学联合创新基金项目(No.2022069);甘肃省自然科学基金项目(No.23JRRA874)。

摘　　要：纳米生物炭(BNPs)常与铁氧化物针铁矿(GT)共存于水环境中,其异质团聚行为显著影响左氧氟沙星(LEV)在BNPs上的吸附。溶液pH作为典型水化学条件,对BNPs与GT的异质团聚及LEV的迁移、转化和归趋起着关键调控作用。为探究溶液pH对BNPs与GT在水体中的异质团聚行为及LEV吸附性能的影响,利用XRD、FTIR、氮气吸附脱附等温线等技术表征样品的晶体结构、比表面积和表面形貌等特征,通过设计不同溶液pH条件下的团聚实验、沉降实验及吸附实验,探究溶液pH对BNPs与GT间的团聚行为及其对LEV吸附的影响。结果表明:①在酸性(pH=5~6)条件下,由于BNPs与GT表面携带相反电荷,静电引力驱动2种颗粒发生异质团聚。②在碱性(pH=8~9)条件下,BNPs+GT异质团聚体的水力学直径(D_(h))增长更快,氢键及路易斯酸碱作用成为促进异质团聚的主要作用机制,表明分子间作用力在异质团聚中占主导地位。③在吸附过程中,溶液pH通过调控BNPs+GT的表面电荷和团聚行为,显著影响着团聚体对LEV的吸附性能,氢键(普通氢键和电荷辅助氢键)、静电以及孔隙填充共同作用,BNPs与GT间的异质团聚掩蔽或占据了BNPs部分吸附位点和有效官能团,使得BNPs对LEV的吸附受到抑制。研究显示,溶液pH通过调控BNPs与GT的表面电荷和分子间作用力主导其异质团聚机制,而异质团聚行为通过掩蔽/占据吸附位点和官能团显著抑制了BNPs对LEV的吸附效能。研究结果可为解析BNPs在水环境中的迁移转化及其对抗生素归趋的影响提供一定的理论依据。Nano-biochar(BNPs)commonly coexists with the iron oxide goethite(GT)in aquatic environments,and their heteroaggregation behavior significantly affects the adsorption of levofloxacin(LEV)on BNPs.As a key water chemistry parameter,solution pH plays a crucial regulatory role in the hetero-aggregation of BNPs and GT,as well as in the migration,transformation,and fate of LEV.To investigate the impact of solution pH on the hetero-aggregation behavior of BNPs and GT in water and its effect on LEV adsorption,various characterization techniques,including X-ray diffraction(XRD),Fourier-transform infrared(FTIR)spectroscopy,and nitrogen adsorption-desorption isotherms,were used to analyze the crystal structure,specific surface area,and surface morphology of the samples.Additionally,aggregation,sedimentation,and adsorption experiments were conducted under different pH conditions to explore the effects of pH on BNPs-GT hetero-aggregation and LEV adsorption.The results revealed that:(1)Under acidic conditions(pH=5-6),BNPs and GT carried opposite surface charges,leading to hetero-aggregation driven by electrostatic attraction.(2)Under alkaline conditions(pH=8-9),the hydrodynamic diameter(D_(h))of BNPs-GT hetero-aggregates increased more rapidly,with hydrogen bonding and Lewis acid-base interactions emerging as the primary aggregation mechanisms,indicating that intermolecular forces dominated the hetero-aggregation process.(3)During the adsorption process,solution pH significantly influenced the adsorption performance of the aggregates toward LEV by regulating the surface charge and aggregation behavior of BNPs-GT.The combined effects of hydrogen bonding(both conventional and charge-assisted),electrostatic interactions,and pore filling resulted in the masking or occupation of BNPs′adsorption sites and functional groups,thereby inhibiting the adsorption of LEV on BNPs.This study demonstrates that solution pH governs the heteroaggregation mechanism of BNPs and GT by modulating surface charge and intermolecular interactions,while

关 键 词：纳米生物炭 针铁矿 异质团聚 左氧氟沙星 吸附 

分 类 号：X131.2[环境科学与工程—环境科学]