摘要
随着人们生活需求的发展与改变,因人类活动而排入地表水中的污染物种类也日益增多.类芬顿技术是解决水污染问题的有效途径之一.多相催化剂的空位在类芬顿技术中的作用引起广泛地关注,空位可以有效地改变材料的电荷分布,改善类芬顿反应中电子转移和活性位点失活等问题.同时,空位也加强了催化剂表面对反应物的吸附能,降低反应能垒,促进了氧化剂的活化和污染物的降解.到目前为止,还缺少材料空位在类芬顿技术中的作用的综述报道.本文系统地综述了空位的种类、构建方法、表征技术、作用机理以及在类芬顿技术中去除不同类型污染物的应用,并展望了空位工程在类芬顿技术中的发展前景.本文可为空位的可控合成、类芬顿技术中氧化剂的活化机理和去除污染物的应用提供参考.
Abstract
With the evolution of human living standards and changing needs,the types of pollutants released into surface water due to human activities have increased.Most of these pollutants are chemically persistent,difficult to remove and tend to accumulate in living organisms,posing threats to ecosystems and human health.Fenton-like technology,a widely used advanced oxidation method,has gained much attention owing to its exceptional oxidation capabilities.Typical Fenton-like technologies include hydrogen peroxide-based,persulfate-based,photo-Fenton and electric Fenton systems.By activating oxidants,such as peroxymonosulfate(PMS)and H2O2,to generate active species via oxidation,the process decomposes pollutants within the solution.However,the multi-phase Fenton technology developed in recent years faces challenges such as metal ion leakage,low electron transfer rates and easy inactivation of active site.Therefore,it is vital to identify suitable modification methods to enhance the Fenton-like characteristics of the catalyst.Material vacancies are common structural defects that effectively regulate the structure and catalytic performance of catalysts.During Fenton-like reactions,these vacancies influence the overall charge distribution of the material.Electrons present in the vacancy can participate in the redox reaction,effectively addressing issues related to electron transfer and active site inactivation.Moreover,vacancies enhance the adsorption energy of reactants on the catalyst surface,reducing the reaction energy barrier and facilitating the activation of oxidants and the degradation of pollutants.In recent years,researchers have investigated the creation of diverse vacancy defects and their interaction mechanisms with Fenton reaction oxidants such as persulfate(PS)and H2O2.However,the role of material vacancies in Fenton-like reactions remains under-reviewed.In this study,we offer a comprehensive review of vacancy types,construction methods,characterisation techniques and mechanisms affecting Fenton-like technology.Common methods for fabricating vacancies include heat treatment,doping strategies,intercalation stripping and surface chemical etching.The suitability of construction techniques varies with the material structure;for instance,laminated materials are best suited for the intercalation-peeling method.In addition,we highlight the existing vacancy characterisation methods and discuss their respective advantages,disadvantages and applicability.We also summarise the different mechanisms by which material vacancies impact the material itself,oxidant and contaminant.Such vacancies can modify the structure of the catalyst,such as through the controlled construction of active sites and efficient separation of charges.They can also alter the adsorption energy of the oxidant on the catalyst surface,the bond length of the oxidant's O-O bond and the activation path of the oxidant.Furthermore,vacancies affect electron transfer between the catalyst and reactants,generating double reaction centres and influencing the Fenton-like reaction process.In addition,we review the use of vacancy constructs in Fenton-like technology to remove various contaminants,such as antibiotics and endocrine disruptors,and for bacterial inactivation.Finally,we discuss potential advancements in vacancy engineering within Fenton-like technology.This review offers valuable insights into pollutant elimination,oxidant activation mechanisms in Fenton-like technology and the standard synthesis of vacancies.
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