Cyclodextrin Modified Amorphous Iron Manganese Oxide Activated PMS For Degradation Of Bisphenol A

Bisphenol A(BPA),as a typical emerging contaminants(ECs),has been detected in the Taihu Lake Lake,Liaohe River and the Pearl River Basin,posing a serious threat to human health and ecological environment,and has been included in the list of key emerging contaminants under control in Shanghai and other places.BPA,as a common endocrine disruptor,is difficult to completely remove by traditional sewage treatment processes.Therefore,to solve the problem of difficult removal of trace new pollutants such as BPA in water,this paper constructs a cyclodextrin modified bimetallic oxide system and conducts research on advanced oxidation process based on peroxybisulfate(PMS)In this study,β-cyclodextrin(β-CD)modified iron and manganese bimetallic oxides were constructed.In light of the challenges faced by conventional advanced oxidation technologies,such as inadequate removal efficiency for low concentrations and interference from coexisting water matrices,bimetallic systems have been innovatively employed to facilitate metal valence cycling.Additionally,a strategy involving supramolecular enrichment of trace pollutants through cyclodextrin has been proposed to eliminate the impact of coexisting matrices.To investigate the behavior and mechanism of BPA removal through advanced oxidation based on PMS,as well as to elucidate the synergistic effect of cyclodextrin-based catalysts in enhancing endocrine pollutant removal.The primary focus of the research is outlined as follows:(1)Cyclodextrin possesses the capability to concentrate trace pollutants and polarize the local charge of the catalyst,thereby enhancing its catalytic performance.In this study,p-CD was incorporated into the preparation process of ferromanganese oxide for the first time,resulting in a cyclodextrin modified amorphous ferromanganese oxide catalyst(CDMFO)that was synthesized via a simple coprecipitation method.Studies have demonstrated that the amorphous CDMFO catalyst exhibits superior catalytic activity compared to crystalline materials,with a particle size reduction of approximately 70%,a pore volume increase of about 72 times,and a specific surface area increase of up to 225 times.This catalyst boasts more adsorption-catalytic sites than traditional iron manganese bimetallic catalysts and offers the benefits of facile synthesis and robust repeatability.(2)Based on the cyclodextrin modified iron manganese oxide catalyst mentioned above,research was conducted on the regulation of catalyst configuration and optimization of operational process parameters using bisphenol A as a model compound.The optimal Fe/Mn ratio,β-CD dosage,catalyst and PMS loading,and pH were determined.Under the conditions of Fe/Mn=2:1,0.2 mmol β-CD addition,0.4 g/L catalyst loading and 0.5 mM PMS addition,complete degradation of a 20 mg/L BPA solution was achieved within 15 minutes.(3)To investigate the catalytic oxidation mechanism of iron manganese bimetallic catalysts and the synergistic effect of cyclodextrin,experiments were conducted to capture and quench free radicals,as well as to confirm the presence of high-valence Fe(Ⅳ)and intermediate-valence Mn(III).The results suggest that active oxygen species are primarily generated on the surface of the catalyst.Firstly,the presence of Mn2+ and Fe2+ on the surface of CDMFO-2/1 activates PMS to generate S04·-.Subsequently,SO4·-reacts with other substances to produce·OH、·O2-and 1O2.During this process,the valence states of Fe2+ and Mn2+ increase to Fe4+and Mn3+,respectively.Finally,high-valent species react with each other in a valence cycle.Compared to traditional advanced oxidation systems,this catalytic oxidation system significantly reduces the formation of toxic intermediates.(4)Based on the aforementioned research,the actual water treatment potential of the CDMFO-2/1/PMS system was further validated.The CDMFO-2/1/PMS system exhibits a certain level of resistance to common anions and cations in water as well as humic acids.Even after undergoing five cycles,the CDMFO-2/1/PMS system is still capable of achieving a degradation rate exceeding 50%for 20 mg/L BPA while demonstrating high efficacy in degrading phenolic substances.A continuous flow reaction column experimental apparatus has been constructed,which can operate stably for over 12 hours under the conditions of an inlet flow rate of 180 mL/h,an inlet concentration of 5 mg/L,and a filling height of the reaction zone at 9 cm.To summarize,this paper aims to address the issue of efficiently removing trace endocrine pollutants from water by utilizing the valence cycling ability of iron-manganese bimetals and the effects of cyclodextrin pollutant recognition,enrichment,and synergistic degradation.This provides theoretical and technical support for an enhanced removal strategy for new pollutants.