Capture And Visible-Light-Triggered Release Of Sulfonamides In MOF/Ag-Based Nanoparticle Composites:Performance And Mechanism

With the large-scale development of the pharmaceutical and washing and chemical industry,the pharmaceutical and personal care products?abbreviated as PPCPs?as pseudo persistent organic pollutants are continuously imported into the environment,leading to the extensive residue,which exert serious threats to the ecological environment and even human health.The antibacterial sulfonamides?SAs?are widely selected in human and veterinary pharmaceuticals to inhibit/kill bacteria,to diminish inflammation,and to boost livestock growth,which resulted in their wide distribution in the environment annually.Various methods including coagulation-flocculation,biodegradation,chlorination,advanced oxidation processes,ozonation and adsorption,have been adopted to eliminate PPCPs from the drinking water or wastewater.It is difficult for conventional adsorbents to realize desorption,which might result in secondary pollution and massive energy consumption.Functional materials,which can be structurally switchable by light,have attracted wide interest,since light,especially concentrated sunlight,possessed several advantages such as no byproducts,environmental friendliness,and nearly zero energy input.Hence,visible-light-triggered desorption is highly preferred in the wide research fields ranging from environmental chemistry,materials science,and biology.In view of energy shortages,difficulties in material desorption,and unclear targeting in conventional drug treatment,metal-organic frameworks?MOFs?as substrates combine with light-sensitive Ag-based compounds to fabricate a series of MOFs/Ag-NPs composites with outstanding adsorption and visible-light-triggered desorption performance toward SAs,along with that the influencing factor and possible mechanism have been studied in this work.These results were briefly described as follows:? he light-responsive materials are attracting increasing amount of attention and have great potential in many research fields in environmental chemistry,materials science,biology,and nanotechnology.In this work,UiO-66-NH₂/Ag₃PO₄?UAP-X?composites with remarkable adsorption performance toward sulfamethoxazole?SMX?were reported.In addition,visible light-triggered release of SMX in the UAP-X composites was reported for the first time.It is believed that the light-triggered desorption of SMX is due to the transformation from Ag⁺to Ag⁰ in Ag₃PO₄ nanoparticles?NPs?of the composites.The SMX release performance of UAP-X can be tuned by the size of Ag₃PO₄ NPs distributed on the UiO-66-NH₂.Specifically,the smaller crystal size of Ag₃PO₄ NPs,which can facilitate the reduction of Ag⁺to Ag⁰,can be achieved with an increase in relative iO-66-NH₂ content in the composites.In addition,the higher UiO-66-NH₂ content of the omposite could provide more deposition area to minimize the aggregation of Ag₃PO₄, hich could further enhance the reduction of Ag⁺.The light triggered desorption provides ew possibility to achieve pollution-free and low-cost recyclability of adsorbents.? he visible light-responsive materials sparked wide interests due to that visible light ossess some merits like no by-product formation,environmental friendliness,and nearly ero energy consumption.In this work,UiO-66-NH₂/Ag₂CO₃?UAC-X?composites with utstanding adsorption and visible light-triggered desorption performances toward SAs like ulfamethoxazole,sulfisoxazole?SIX?and sulfamethazine?SMT?were reported.It was elieved that the interactions between-NH₂ from SAs and Ag⁺of Ag₂CO₃ and UAC-X anoparticles contributed to the outstanding adsorption performance toward the SAs.The onversion from Ag⁺to Ag⁰ of the photosensitive Ag₂CO₃ NPs in the UAC-X composites ed to the controlled diliver of SAs,in which the release performance could be tuned by the iO-66-NH₂ proportion in UAC-X.Additionally,the DFT calculation results demonstrated hat the binding energy of Ag⁺-NH₂?BE=-0.925 eV?is lower than the band gap of g₂CO₃?BE=2.3 eV?,implying that the conversion from Ag⁺to Ag⁰ contributed to the As desorption.The light-induced desorption will provide new strategies to realize nvironment friendly and inexpensive regeneration of adsorbents.? onsidering that UiO-66-NH₂/Ag-NPs composites could achieve visible-light-triggered dsorption-desorption toward SAs,Ag₃PO₄ NPs were dispersed onto various MOFs ubstrates to investigate the selectivity of Ag-NPs toward MOFs as templates for tunable isible-light-triggered desorption of SAs.Four MOF/Ag₃PO₄ NPs composites with ifferent ligands and metals were fabricated and SMX,SIX,and SMT were chosen as argets.The results showed that all of the four MOFs/Ag-NPs composites possess isible-light-triggered desorption activity of SAs,and the adsorption-desorption erformance toward SAs could be tuned via changing the proportion of MOFs in the omposites.Whereas,the regulation degree of various MOFs substrates on SAs adsorption nd visible-light-triggered desorption performance was different.