Three-Dimensional Welded Mn_(1) Site Catalysts with nearly 100% Singlet Oxygen Fabrication for Contaminant Elimination

Reactive oxygen species(ROS)have a significant part in the elimination of recalcitrant organic pollutants and commonly coexist in one advanced oxidation system.It is difficult for us to make clear the effect of the co-instantaneous generation of radicals and nonradicals,which would cover and obscure the transformation pathway.Herein,a coordinate welding process is presented for fabricating accessible Mn1 site catalysts(Mn SSCs)in order to clarify the nonradical(singlet oxygen/^(1)O_(2))generated pathway and transformation in oxidative removal of contaminants.The Mn SSCs achieve nearly 100%^(1)O_(2) fabrication by activating peroxymonosulfate,which displays an excellent sulfamethoxazole elimination performance,super anti-anion interference,and extraordinary stability.As revealed by density functional theory calculations,the Mn SSCs with a special welded three-dimensional nanostructure could significantly boost the activation process by oxidizing the peroxymonosulfate at the interlayer of Mn SSCs and reducing dissolved oxygen on the surface of Mn SSCs.This design of Mn SSCs with a three-dimensional welded nanostructure might offer a potential approach for employing single site catalysts for environmental remediation.

Different non-radical oxidation processes of persulfate and peroxymonosulfate activation by nitrogen-doped mesoporous carbon

Activated persulfate oxidation is an emerging advanced oxidation process for organic pollutant degradation.Own to different molecular structures and oxidation potentials,persulfate(PDS)and peroxymonosulfate(PMS)may show different degradation performances due to various catalytic mechanisms even by the same catalysts.In this study,the nitrogen-doped mesoporous carbon(N-OMC)was applied to activate PDS and PMS for degrading a model organic pollutant phenol to reveal their activation mechanisms.Re sults show that both PDS and PMS could be efficiently activated by N-OMC.The degradation of phenol fitted well with pseudo-first-order kinetics,whose kinetic constants increased with the increase of pH,PDS/PMS dosage,and N-OMC dosage.Based on quenching experiments and electron spin resonance spin-trapping technique,the N-OMC was found to activate PDS and PMS via nonradical process of electron transfer and singlet oxygen formation,respectively,instead of the commonly observed radical process.This wo rk will be useful to understand the activation processes of PDS and PMS,and benefit for the development of catalysts for pollutant degradation.

Probing the redox process of p-benzoquinone in dimethyl sulphoxide by using fluorescence spectroelectrochemistry

Quinones are common organic compounds frequently used as model dissolved organic matters in water, and their redox properties are usually characterized by either electrochemical or spectroscopic methods separately. In this work, electrochemical methodology was combined with two fluorescence spectroelectrochemical techniques, cyclic voltafluorescence spectrometry （CVF） and derivative cyclic voltafluorescence spectrometry （DCVF）, to determine the electrochemical properties of p-benzoQuinone in dimethvl sulfoxide, an aprotic solution. The CVF results show that the electrochemical reduction ofp-benzoquinone resulted in the formation of radical anion and dianion, which exhibited a lower fluorescence intensity and red-shift of the emission spectra compared to that of p-benzoauinone. The fluorescence intensity was found to vary along with the electrochemical oxidation and reduction ofp-benzoquinone. The CVF and DCVF results were in good consistence. Thus, the combined method offers a powerful tool to investigate the electrochemical process of p-benzoquinone and other natural organic compounds.