Construction Of ZIF-67-based Derivative Nanomaterials And Analysis Of Pollutant Degradation By Fenton-like Reactio

In recent years,the growing production and consumption of organic compounds,especially the widespread use of antibiotics,has significantly improved the progress and development of human health and contributed to the development and progress of society.However,the residues and difficult degradation of some organic antibiotics have led to serious pollution of the aquatic environment.Therefore,it has become urgent to design and construct an efficient catalyst that can deal with refractory antibiotic-based organic pollutants.In this paper,high catalytic activity and low metal leaching were achieved by constructing ZIF-67-based derived catalysts for antibiotic degradation in a Fenton-like reaction.Details of the study are as follows:(1)Firstly,ZIF-67@Co2SiO4/SiO2 yolk/shell structure was prepared in one-step at room temperature,in which ZIF-67 was served as the hard-template,H2O was served as etchant and tetraethyl orthosilicate(TEOS)was served as the raw material for Co2SiO4/SiO2.After calcination,the non-typical CoxOy@Co2SiO4/SiO2 yolk/shell nanoreactor with Co2SiO4/SiO2 dual-shells and CoxOy multiple-cores was obtained.On the one hand,more active sites were exposed on multiple-cores surface and better protection were provided by dual-shells.On the other hand,the sheet-like Co2SiO4 inner shell not only extended the travel path and retention time of pollutants trapped in cavity,but also separated the multiple-cores from aggregation.Therefore,the nanoreactor displayed the outstanding catalytic activity and recyclability in Fenton-like reaction.Metronidazole(20 mg/L)was completely degraded after 30 min.The catalytic mechanism suggests the following contribution of the various active species:1O2>SO4·->·O2->·OH.This chapter presented a simple method for non-typical yolk/shell nanoreactor.(2)A Mott-Schottky heterojunction is reported to boost the peroxymonosulfate(PMS)activation in Fenton-like reaction through a non-radical path.The heterojunction with Co nanoparticles(Co NPs)encapsulated by nitrogen-doped graphitized carbon(NGC)shell was synthesized via pyrolysis of ZIF67@ZIF8 and subsequent acidic treatment.Benefiting from Mott-Schottky effect,the electrons were transferred from Co nanoparticles to the N-GC shell,leading to the rearranged electron density on NGC surface and improvement of the PMS activation.The PMS utilization efficiency of heterojunction(86.0%)was much higher than the reference catalyst without MottSchottky effect(35.3%),and even comparable to Co2+(86.2%).85.0%of tetracycline removal efficiency was realized in only 10 s.Moreover,the intrinsic advantages of nonradical path were well inherited by Mott-Schottky heterojunction,including high antiinterfere property toward various anions,cations and organics,high catalytic activity in a wide pH range,low metal leaching,and high magnetic recyclability.