Fabrication of pollution-free coal gangue-based catalytic material utilizing ferrous chloride as activator for efficient peroxymonosulfate activation

Novel coal gangue-based persulfate catalyst(CG-FeCl_(2))was successfully synthesized by the means of calcinating under nitrogen atmosphere with the addition of ferrous chloride tetrahydrate(FeCl_(2)·_(4)H_(2)O).The phase transformation of the prepared materials and gas products during the heating process are thoroughly investigated.It is suggested that ferrous chloride participated in the phase transformation and formed Si-O-Fe bonds.And the main gaseous products are H_(2)O,H_(2),and HCl during the heating process.Besides,the ability of CG-FeCl_(2) to activate peroxymonosulfate(PMS)for catalytic degradation of polycyclic aromatic hydrocarbons(PAHs)and phenol was deeply studied.More than 95%of naphthyl,phenanthrene and phenol were removed under optimizied conditions.In addition,1O_(2),·OH,and SO_(4)·−were involved in the CG-FeCl_(2)/PMS system from the free radical scavenging experiment,where 1O_(2) played a major role during the oxidation process.Furthermore,CG-FeCl_(2)/PMS system exhibited superior stability in a relatively wide pH range and the presence of common anion from related degradation experiments.Overall,the novel CG-FeCl_(2) is an efficient and environmentally friendly catalyst,displaying potential application prospect in the field of PAHs and phenol-contaminated wastewater treatment.

Research progress of CO_(2) capture and mineralization based on natural minerals

Natural minerals,such as kaolinite,halloysite,montmorillonite,attapulgite,bentonite,sepiolite,forsterite,and wollastonite,have considerable potential for use in CO_(2) capture and mineralization due to their abundant reserves,low cost,excellent mechanical prop-erties,and chemical stability.Over the past decades,various methods,such as those involving heat,acid,alkali,organic amine,amino sil-ane,and ionic liquid,have been employed to enhance the CO_(2) capture performance of natural minerals to attain high specific surface area,a large number of pore structures,and rich active sites.Future research on CO_(2) capture by natural minerals will focus on the full utiliza-tion of the properties of natural minerals,adoption of suitable modification methods,and preparation of composite materials with high specific surface area and rich active sites.In addition,we provide a summary of the principle and technical route of direct and indirect mineralization of CO_(2) by natural minerals.This process uses minerals with high calcium and magnesium contents,such as forsterite(Mg_(2)SiO_(4)),serpentine[Mg_(3)Si_(2)O(OH)_(4)],and wollastonite(CaSiO_(3)).The research status of indirect mineralization of CO_(2) using hydro-chloric acid,acetic acid,molten salt,and ammonium salt as media is also introduced in detail.The recovery of additives and high-value-added products during the mineralization process to increase economic benefits is another focus of future research on CO_(2) mineralization by natural minerals.

Fabrication of graphene modified CeO_(2)/g-C_(3)N_(4)heterostructures for photocatalytic degradation of organic pollutants

A specific type S-scheme photocatalyst CeO_(2)@N-GO/g-C_(3)N_(4)was successfully synthesized,resulting in a 2-mer-captobenzothiazole(MBT)degradation rate of 100%,which is more than twice that of g-C_(3)N_(4)and CeO_(2).The improved degradation performance can be attributed to the introduction of N-graphene oxide(N-GO),which facilitates the electron transfer.Additionally,the unique Ce^(4+)→Ce^(3+)conversion property enhances the charge carrier utilization,and thereby the photocatalytic activity.Furthermore,theoretical calculations suggest the formation of an interfacial internal electric field(IEF)formed between CeO_(2)(the(200)and(311)planes)and g-C_(3)N_(4)(the(002)plane)to enhance the delocalization of the charge carriers.Moreover,various photo-electrochemical analyses are employed for the in-depth mechanism on MBT degradation and IEF-induced S-scheme over CeO_(2)@N-GO/g-C_(3)N_(4),where the differential charge proves the electron transfer path from CeO_(2)to g-C_(3)N_(4)that significantly prolongs its lifetime.The radical capture and electron spin resonance(ESR)results proved the existence of the active species of·OH,·O_(2)^(-),and h^(+)in the S-scheme photocatalytic system.