Multi-functional HRP@MOFs Bio-Composite For Treatment Of Harmful Pollutants

Global water pollution caused by pollutants such as heavy metals,phenols and dyes has attracted considerable attention.These harmful pollutants pose a serious threat to ecosystems and human health due to their toxicity,carcinogenicity and mutagenicity.Traditional methods such as physical adsorption,chemical oxidation,ozonation,etc.are used to remove such harmful substances from wastewater with low efficiency,high cost,and easy to form harmful by-products.Therefore,the development of an economical,efficient,and environmentally friendly treatment technology is of great significance to the sustainable development of the environment.Horseradish peroxidase?HRP?is widely used enzyme for the detection and degradation of harmful pollutants as they can oxidize a variety of compounds.However,free HRP has some drawbacks,such as poor stability,low catalytic efficiency and no recycling,which limits its practical application.Therefore,in recent years,the biomimetic mineralization method has been developed to encapsulate HRP in situ in the metal organic frameworks such as ZIF-8?HRP@ZIF-8?to improve the stability of HRP and realize its recycling.In view of the large variety and low concentration of pollutants in wastewater,this paper expands the function of HRP@ZIF-8 and realizes the synergic catalytic effect of HRP and metal organic framework for the efficient detection and degradation of pollutants in wastewater.The detailed research contents are as follows:First,coupled the zeolite imidazolate skeleton?ZIF-8?immobilized enzyme substrate function with fluorescence quenching function,the fluorescence colorimetric sensor HRP@ZIF-8/FAM-ssDNA was prepared for continuous detection of Hg²⁺and phenol.In this experiment,the biomimetic mineralization method was first used for encapsulation of HRP by ZIF-8 to prepare the HRP@ZIF-8 composite,and a high encapsulation efficiency?98.4%?was obtained,and the HRP@ZIF-8 exhibits good biocatalytic activity and stability under extreme conditions.After adding FAM-ssDNA,the HRP@ZIF-8/FAM-ssDNA fluorescence colorimetric sensor could implement rapid and highly selective fluorescence detection of Hg²⁺with detection limit as low as 0.22 nM.After fluorescence detection of Hg²⁺,the separated HRP@ZIF-8 could be continuously utilized for colorimetric detection of phenol at micromolar level.This strategy provides a convenient and effective approach for the functional integration of ZIF-8 without any complicated modification.In the field of biosensing,this discovery broadens the potential of enzyme@ZIF-8 composite for sequential detection of two pollutants.Second,the specific capture performance of the aptamer,the hybridization performance of the complementary strand and the catalytic performance of HRP are coupled to prepare the HRP@ZIF-8/P1 hybrid material.P1 self-enriching bisphenol A improves the catalytic efficiency of HRP@ZIF-8/P1,and at the same time,the hybrid magnetron complementary chain realizes the recovery and recycling of HRP@ZIF-8/P1.The effects of SA concentration,P1 concentration in hybrid materials and reaction time on the removal efficiency of BPA were investigated experimentally.Under the optimal conditions,more than 93%of BPA could be removed within 5 minutes by HRP@ZIF-8/P1.At the same time,the catalytic efficiency of hybrid materials to BPA was 5.6-fold higher than that of HRP@ZIF-8.HRP@ZIF-8/P1 showed good stability in high temperature,buffer solution?pH 7?and long-term storage conditions.More importantly,degradation efficiency of the hybrid material to BPA maintained more than64%after 5 cycles of usage.The establishment of the hybrid material has achieved high efficiency,selective removal of BPA in wastewater,and has provided a new idea for the preparation of bio-composite with high stability,high catalytic activity and recyclability.Finally,based on the inherent peroxidase activity of Fe-MIL-88A,the HRP@HKUST-1/Fe-MIL-88A composite material was prepared through surface chemical modification and bionic mineralization,and the synergistic catalysis of Fe-MIL-88A nano-enzyme and natural HRP was realized.Compared with HKUST-1/Fe-MIL-88A,free HRP,and the physical mixture of both,the HRP@HKUST-1/Fe-MIL-88A has greater catalytic activity.It not only broadens the optimal pH and temperature range of HRP,but also shows excellent stability in extreme conditions.Especially,over 97%of the initial activity was retained for HRP@HKUST-1/Fe-MIL-88A after incubating at extremely acid conditions for 2 h.What's more,the degradation rate of methyl orange by the composite can reach 98%in less than 10 minutes.In addition,the degradation efficiency of methyl orange still maintained 76%after 7 cycles.This discovery affords a solution for the inability to encapsulate enzymes during the co-precipitation process of MOFs natural nucleation.