Zn-Fe双金属/生物炭复合催化剂活化过硫酸盐降解污染物的机制  

The mechanism of Zn-Fe bimetal/biochar composite catalyst for the activation of persulfate in pollutant degradation

作　　者：潘斌锋 朱枫 李渊 吴礼光[1] 王挺[1] PAN Binfeng;ZHU Feng;LI Yuan;WU Liguang;WANG Ting(School of Environmental Science and Engineering,Zhejiang Gongshang University,Hangzhou 310012;School of Tourism and Urban Planning,Zhejiang Gongshang University,Hangzhou 310012)

机构地区：[1]浙江工商大学,环境科学与工程学院,杭州310012 [2]浙江工商大学,旅游与城乡规划学院,杭州310012

出　　处：《环境科学学报》2025年第2期45-58,共14页Acta Scientiae Circumstantiae

基　　金：国家自然科学基金(No.22078291);浙江工商大学“数字+”项目(No.SZJ2022B014)。

摘　　要：以新型生物炭为载体构建用于活化过硫酸盐(PDS)降解污染物的复合催化剂,不仅有助于废弃物质的资源化利用,在水环境深度治理方面也有广阔的应用前景.本研究以坚果类代表废弃物—核桃壳为原料制备生物炭,而后采用微乳液合成Zn-Fe双金属纳米粒子,将其负载在生物炭中构建Zn-Fe双金属/生物炭复合催化剂.通过活化PDS降解四环素(TC)和罗丹明B(RhB)评价复合催化剂的催化性能.同时,利用XRD、XPS、TEM和ESR等分析表征复合催化剂的形貌结构,并结合降解中间产物分析,探明复合催化剂对TC和RhB的吸附和降解机制.研究发现,生物炭载体表面呈负电性,其对带正电荷的RhB吸附能力较强,难以吸附带负电荷的TC分子.微乳液法制备的Zn-Fe双金属纳米粒子带正电荷,致使Zn-Fe双金属/生物炭复合催化剂整体呈正电荷,其对TC的吸附能力较生物炭大幅增加.另外,Zn-Fe双金属纳米粒子负载并未改变生物炭的表面及其形貌特性,复合催化剂对RhB仍具有较强的吸附能力.Zn-Fe双金属/生物炭复合催化剂能高效活化PDS,产生以羟基自由基为主的活性物种,5 h后催化剂对TC和RhB的去除率分别达到了96%和100%,且污染物降解过程的中间产物毒性较TC和RhB均显著降低.结果表明,基于Zn-Fe双金属/生物炭复合催化剂可高效活化PDS降解有机污染物,能显著降低水环境中潜在的安全风险.The utilization of new biomass as a carrier to fabricate composite catalysts for activated persulfate(PDS)to degrade pollutants does not only contribute to the resource utilization of waste materials,but also holds promising prospects for the deep treatment for pollutant in water.In this study,walnut shell,a representative waste material from nuts,was utilized as raw material to prepare biochar.Subsequently,Zn-Fe bimetallic nanoparticles synthesized via microemulsion were loaded onto biochar to construct a Zn-Fe bimetallic/biochar composite catalyst.The catalytic performance of this composite catalyst was evaluated by activating PDS for the degradation of tetracycline(TC)and Rhodamine B(RhB).The microstructures of the composite catalyst were characterized using XRD,XPS,and TEM techniques.Additionally,the adsorption and degradation mechanisms of TC and RhB were investigated by ESR analysis and analyzing the degradation intermediates.The Zn-Fe bimetallic nanoparticles,prepared using the microemulsion method,possess a positive charge which contributes to the overall positive charge of the Zn-Fe bimetallic/biochar composite catalyst.Consequently,its adsorption capacity for TC with positive charge is significantly enhanced compared to that of biochar alone.Moreover,the incorporation of Zn-Fe bimetallic nanoparticles does not alter the surface and morphology of biochar while maintaining a substantial adsorption capacity for RhB with negative charge.Zn-Fe bimetallic/biochar composite catalyst effectively activates PDS and generates hydroxyl free radicals as dominant active species.After 5 hours,TC and RhB removal rates reached 96%and 100%,respectively;furthermore,intermediate products formed during pollutant degradation exhibited reduced toxicity compared to TC and RhB themselves.These findings demonstrate that the Zn-Fe bimetallic/biochar composite catalyst efficiently activates PDS for organic pollutant degradation while significantly reducing potential safety risks in water environments.

关 键 词：生物炭 双金属复合催化剂 过硫酸盐活化 污染物降解路径 

分 类 号：X703[环境科学与工程—环境工程]