Iron-based metal organic frameworks have been verified to be efficient heterogeneous Fenton catalysts due to their open pore channels and highly uniform distribution of metallic centers.In these catalysts,however,the ...Iron-based metal organic frameworks have been verified to be efficient heterogeneous Fenton catalysts due to their open pore channels and highly uniform distribution of metallic centers.In these catalysts,however,the iron element is mainly in the form of Fe(III),which results in a process required to reduce Fe(III)to Fe(II)to initiate Fenton reaction.To address this problem,carbon nanotubes(CNTs)with electron-rich oxygen-functional groups on the surface were incorporated into the metal organic frameworks(MIL-88B-Fe)to improve Fe(II)content for an enhanced Fenton-like performance.The prepared CNT@MIL-88B-Fe(C@M)showed much stronger catalytic ability toward H2O2 than MIL-88B-Fe.The pseudo-first-order kinetic constant for phenol degradation by C@M(0.32 min–1)was about 7 times that of MIL-88B-Fe,and even higher than or comparable to the values of reported heterogeneous Fenton-like catalysts.Moreover,the Fenton-like system could effectively degrade various kinds of refractory organic pollutants and exhibited excellent catalytic activity over a wide pH range(4–9).XPS analysis confirmed that Fe(II)content of the catalyst gradually increased with CNT loadings.Electron spin resonance analysis showed that the signal intensity(?OH)of C@M was much higher than MIL-88B-Fe,which was consistent with the degradation efficiency of pollutants.Furthermore,the Fe(II)content of the catalyst gradually increased along with the oxygen-functional group content of CNTs.The result demonstrated that oxygen-containing functional groups of CNTs have a significant impact on the enhanced catalytic performance of C@M.This study provides a new insight to enhance Fenton reaction by using nanocarbon materials.展开更多
Monotonic pore size and particles inseparability of metal-organic frameworks(MOFs)caused serious effects on its light absorption ability and charge separation,restricting its application for antibiotic such as levoflo...Monotonic pore size and particles inseparability of metal-organic frameworks(MOFs)caused serious effects on its light absorption ability and charge separation,restricting its application for antibiotic such as levofloxacin(LEV)degradation in water.In this study,a magnetically detachable nano-photocatalyst(ZnFe_(2)O_(4)@MIL-88A(Fe))was synthesized using a simple two-step hydrothermal technique.The morphology and microstructure analyses showed that n-type ZnFe_(2)O_(4)catalyst particleswere efficiently assembled onto the surface of MIL-88A(Fe)crystal.Photocatalytic activity studies indicated that the ZnFe_(2)O_(4)@MIL-88A(Fe)plus H_(2)O_(2)exhibiting a significantly boosted photo-Fenton activity toward LEV at visible light irradiation,compared to the pure ZnFe_(2)O_(4)and MIL-88A(Fe),the degradation efficiency accordingly reached up to nearly 82%and 25%within 60 min.This excellent photocatalytic performance was ascribed to the synergistic effects of the heterogeneous structure of ZnFe_(2)O_(4)and MIL-88A(Fe),whereby the efficient separation of charge carriers in the catalytic system is mutually reinforced with the efficient reduction of Fe^(3+)and Fe^(2+).Meanwhile,the degradationmechanism and intermediates of LEV during the photo-Fenton reaction process were also studied in depth through free radical burst,electron paramagnetic resonance,and mass spectrometry analyses,etc.Additionally,the ZnFe_(2)O_(4)@MIL-88A(Fe)composite catalyst displayed significant stability and ease of separation,indicating potential for the photooxidative degradation of organic pollutants.展开更多
The photo-assisted Fenton-like method is an effective and sustainable way to remove organic pollutants from water.Herein,a series of three-dimensional composites containing MIL-88A(Fe)-derived α-Fe_(2)O_(3)and graphe...The photo-assisted Fenton-like method is an effective and sustainable way to remove organic pollutants from water.Herein,a series of three-dimensional composites containing MIL-88A(Fe)-derived α-Fe_(2)O_(3)and graphene aerogel(GA-Fe-X)were designed and used as catalysts to degrade ciprofloxacin(CIP)by peroxymonosulfate(PMS)activated photo-Fenton-like technology.The as-prepared GA-Fe-1 displayed remarkable enhancement with a CIP degradation rate constant(0.017 min^(-1))higher than that of graphene aerogel(0.0031 min^(-1))and MIL-88A(Fe)(0.0039 min^(-1)).Experimental results demonstrated that the combination of MIL-88A(Fe)-derived α-Fe_(2)O_(3)and graphene aerogel forming GA-Fe-X enhanced the separation efficiency of electron-hole pairs,activating PMS to produce SO_(4)^(·-),^(·)OH and ^(1)O_(2) for enhanced CIP degradation through radical and non-radical pathways.The factors affecting CIP degradation during the photoFenton-like process were thoroughly investigated.The possible CIP degradation pathways and ecotoxicity of the intermediates were also analyzed.This work enhances our understanding of the photo-Fenton-like effect in three-dimensional graphene aerogel composites.展开更多
随着新型冠状病毒肺炎(COVID-19)在全球的流行,主要成分为苯扎氯铵的消毒剂大量使用对环境带来威胁.本研究通过水热法成功制备了铁基金属有机骨架MIL-88A,将其作为光催化剂成功实现了苯扎氯铵在可见光下的高效降解.通过SEM、XRD、XPS以...随着新型冠状病毒肺炎(COVID-19)在全球的流行,主要成分为苯扎氯铵的消毒剂大量使用对环境带来威胁.本研究通过水热法成功制备了铁基金属有机骨架MIL-88A,将其作为光催化剂成功实现了苯扎氯铵在可见光下的高效降解.通过SEM、XRD、XPS以及UV-visDRS等表征方法研究了MIL-88A的形貌、结构以及光催化性能.为了达到光催化降解苯扎氯铵的最佳效率,探究了MIL-88A在不同条件下的光催化降解性能.结果表明,MIL-88A在pH=5,H2O2投加量为0.9 mL·L^(-1),MIL-88A剂量为0.25 g·L^(-1)时,降解效果最好,35 min DDBAC降解效率达到100%.采用UHPLC-Q-TOF-MS确定了降解中间产物,分析了苯扎氯铵可能的降解途径.此外,基于分子轨道理论和自由基淬灭实验证明了氧化降解苯扎氯铵过程中羟基自由基是主要贡献者.通过发光细菌法对DDBAC及其中间体的毒性进行了评估,结果表明,MIL-88A可见光光芬顿工艺能够实现溶液脱毒.光催化降解循环实验以及对催化剂反应前后的表征证明了MIL-88A具有较高的稳定性.展开更多
MIL-88A(Fe)@sponge(MS) was synthesized by a dip-coating method, which displayed efficient photocatalytic Cr(Ⅵ) reduction efficiency under both low power LED UV light and real solar light irradiation. It was observed ...MIL-88A(Fe)@sponge(MS) was synthesized by a dip-coating method, which displayed efficient photocatalytic Cr(Ⅵ) reduction efficiency under both low power LED UV light and real solar light irradiation. It was observed that MS(0.2 g/L) could remove 100% Cr(Ⅵ)(10 mg/L) by adding 0.4 mmol/L tartaric acid(TA) without adjusting pH(pH 5.05) within 6.0 min and 3.0 min under UV light and real solar light irradiation, respectively. Besides, the photo-induced e-and radicals(O_(2)^(·-) and CO_(2)^(·-)) were found to play the momentous roles in the MS/TA/UVL/Cr(Ⅵ) system by the scavenger experiments and electron spin resonance(ESR) tests. MS was also filled into a fixed-bed reactor to test the possibility of long-term Cr(Ⅵ)reduction operation in TA/UVL system. As expected, the results revealed that MS could still maintain 100% activity up to 60 h. These results demonstrated that MIL-88A(Fe) might be the potentially efficient catalyst for large-scale wastewater treatment in the near future.展开更多
基金National Natural Science Foundation of China(Grant No.51478075)Department of Science & Technology of Dalian(No.2018J11CY012)+1 种基金the Program of Introducing Talents of Discipline to Universities(No.B13012)programme for Changjiang Scholars and Innovative Research Team in University(No.IRT_13R05).
文摘Iron-based metal organic frameworks have been verified to be efficient heterogeneous Fenton catalysts due to their open pore channels and highly uniform distribution of metallic centers.In these catalysts,however,the iron element is mainly in the form of Fe(III),which results in a process required to reduce Fe(III)to Fe(II)to initiate Fenton reaction.To address this problem,carbon nanotubes(CNTs)with electron-rich oxygen-functional groups on the surface were incorporated into the metal organic frameworks(MIL-88B-Fe)to improve Fe(II)content for an enhanced Fenton-like performance.The prepared CNT@MIL-88B-Fe(C@M)showed much stronger catalytic ability toward H2O2 than MIL-88B-Fe.The pseudo-first-order kinetic constant for phenol degradation by C@M(0.32 min–1)was about 7 times that of MIL-88B-Fe,and even higher than or comparable to the values of reported heterogeneous Fenton-like catalysts.Moreover,the Fenton-like system could effectively degrade various kinds of refractory organic pollutants and exhibited excellent catalytic activity over a wide pH range(4–9).XPS analysis confirmed that Fe(II)content of the catalyst gradually increased with CNT loadings.Electron spin resonance analysis showed that the signal intensity(?OH)of C@M was much higher than MIL-88B-Fe,which was consistent with the degradation efficiency of pollutants.Furthermore,the Fe(II)content of the catalyst gradually increased along with the oxygen-functional group content of CNTs.The result demonstrated that oxygen-containing functional groups of CNTs have a significant impact on the enhanced catalytic performance of C@M.This study provides a new insight to enhance Fenton reaction by using nanocarbon materials.
基金supported by the National Natural Science Foundation of China(No.22178325)Jinhua Science and Technology Plan Project.
文摘Monotonic pore size and particles inseparability of metal-organic frameworks(MOFs)caused serious effects on its light absorption ability and charge separation,restricting its application for antibiotic such as levofloxacin(LEV)degradation in water.In this study,a magnetically detachable nano-photocatalyst(ZnFe_(2)O_(4)@MIL-88A(Fe))was synthesized using a simple two-step hydrothermal technique.The morphology and microstructure analyses showed that n-type ZnFe_(2)O_(4)catalyst particleswere efficiently assembled onto the surface of MIL-88A(Fe)crystal.Photocatalytic activity studies indicated that the ZnFe_(2)O_(4)@MIL-88A(Fe)plus H_(2)O_(2)exhibiting a significantly boosted photo-Fenton activity toward LEV at visible light irradiation,compared to the pure ZnFe_(2)O_(4)and MIL-88A(Fe),the degradation efficiency accordingly reached up to nearly 82%and 25%within 60 min.This excellent photocatalytic performance was ascribed to the synergistic effects of the heterogeneous structure of ZnFe_(2)O_(4)and MIL-88A(Fe),whereby the efficient separation of charge carriers in the catalytic system is mutually reinforced with the efficient reduction of Fe^(3+)and Fe^(2+).Meanwhile,the degradationmechanism and intermediates of LEV during the photo-Fenton reaction process were also studied in depth through free radical burst,electron paramagnetic resonance,and mass spectrometry analyses,etc.Additionally,the ZnFe_(2)O_(4)@MIL-88A(Fe)composite catalyst displayed significant stability and ease of separation,indicating potential for the photooxidative degradation of organic pollutants.
基金National Natural Science Foundation of China(Nos.12075152,42177405,12075147)for the financial support。
文摘The photo-assisted Fenton-like method is an effective and sustainable way to remove organic pollutants from water.Herein,a series of three-dimensional composites containing MIL-88A(Fe)-derived α-Fe_(2)O_(3)and graphene aerogel(GA-Fe-X)were designed and used as catalysts to degrade ciprofloxacin(CIP)by peroxymonosulfate(PMS)activated photo-Fenton-like technology.The as-prepared GA-Fe-1 displayed remarkable enhancement with a CIP degradation rate constant(0.017 min^(-1))higher than that of graphene aerogel(0.0031 min^(-1))and MIL-88A(Fe)(0.0039 min^(-1)).Experimental results demonstrated that the combination of MIL-88A(Fe)-derived α-Fe_(2)O_(3)and graphene aerogel forming GA-Fe-X enhanced the separation efficiency of electron-hole pairs,activating PMS to produce SO_(4)^(·-),^(·)OH and ^(1)O_(2) for enhanced CIP degradation through radical and non-radical pathways.The factors affecting CIP degradation during the photoFenton-like process were thoroughly investigated.The possible CIP degradation pathways and ecotoxicity of the intermediates were also analyzed.This work enhances our understanding of the photo-Fenton-like effect in three-dimensional graphene aerogel composites.
文摘随着新型冠状病毒肺炎(COVID-19)在全球的流行,主要成分为苯扎氯铵的消毒剂大量使用对环境带来威胁.本研究通过水热法成功制备了铁基金属有机骨架MIL-88A,将其作为光催化剂成功实现了苯扎氯铵在可见光下的高效降解.通过SEM、XRD、XPS以及UV-visDRS等表征方法研究了MIL-88A的形貌、结构以及光催化性能.为了达到光催化降解苯扎氯铵的最佳效率,探究了MIL-88A在不同条件下的光催化降解性能.结果表明,MIL-88A在pH=5,H2O2投加量为0.9 mL·L^(-1),MIL-88A剂量为0.25 g·L^(-1)时,降解效果最好,35 min DDBAC降解效率达到100%.采用UHPLC-Q-TOF-MS确定了降解中间产物,分析了苯扎氯铵可能的降解途径.此外,基于分子轨道理论和自由基淬灭实验证明了氧化降解苯扎氯铵过程中羟基自由基是主要贡献者.通过发光细菌法对DDBAC及其中间体的毒性进行了评估,结果表明,MIL-88A可见光光芬顿工艺能够实现溶液脱毒.光催化降解循环实验以及对催化剂反应前后的表征证明了MIL-88A具有较高的稳定性.
基金supported by National Natural Science Foundation of China (Nos. 22176012, 51878023)Beijing Natural Science Foundation (No. 8202016)+1 种基金Beijing Talent Project (No. 2020A27)BUCEA Doctor Graduate Scientific Research Ability Improvement Project (No. DG2021004)。
文摘MIL-88A(Fe)@sponge(MS) was synthesized by a dip-coating method, which displayed efficient photocatalytic Cr(Ⅵ) reduction efficiency under both low power LED UV light and real solar light irradiation. It was observed that MS(0.2 g/L) could remove 100% Cr(Ⅵ)(10 mg/L) by adding 0.4 mmol/L tartaric acid(TA) without adjusting pH(pH 5.05) within 6.0 min and 3.0 min under UV light and real solar light irradiation, respectively. Besides, the photo-induced e-and radicals(O_(2)^(·-) and CO_(2)^(·-)) were found to play the momentous roles in the MS/TA/UVL/Cr(Ⅵ) system by the scavenger experiments and electron spin resonance(ESR) tests. MS was also filled into a fixed-bed reactor to test the possibility of long-term Cr(Ⅵ)reduction operation in TA/UVL system. As expected, the results revealed that MS could still maintain 100% activity up to 60 h. These results demonstrated that MIL-88A(Fe) might be the potentially efficient catalyst for large-scale wastewater treatment in the near future.
