Preparation and application of a molecularly imprinted polymer for determination of glibenclamide residues

The performance of a molecularly imprinted polymer (MIP) as selective packing material for solid-phase extraction (SPE) of residual glibenclamide in an industrial process was investigated. MIP was prepared using 4-vinylpyridine as monomer, ethylenedimethacrylate as cross linker, 2,2’-azobis-2-methylpropionitrile as initiator and dimethyl formamide as porogen. Use of acetonitrile as a rebinding solvent allows good recognition of the glibenclamide template. It was found that this polymer can be used for determination of trace levels of glibenclamide with a recovery percentage that could reach 87.1 %. Furthermore, the synthesized MIP showed higher selectivity towards glibenclamide than other compounds such as glimepiride and metformine. The synthesized MIP enabled direct determination of the target contaminant after an enrichment step that allowed quantification of a low glibenclamide concentration as low as 0.016 mg L–1. Combination of high performance liquid chromatography with MIP-SPE could be successfully used for quality control of pharmaceuticals during the cleaning process in the production of dry drug forms

Magnetic TiO2/Fe3O4-chitosan beads: a highly efficient and reusable catalyst for photo-electro-fenton process

Heterogeneous photo-electro-Fenton process is an attractive technology for the removal of recalcitrant pollutants. To better exploit the presence of an irradiation source, a bifunctional catalyst with TiO2 nanoparticles embedded into an iron–chitosan matrix was developed. The catalytic activity of the catalyst was improved by the optimization of the loaded TiO2content. The prepared composite catalysts based on TiO2, Fe3O4 and chitosan were called TiO2/Fe3O4-CS beads. The best catalyst with an optimal ratio TiO2/Fe = 2 exhibited a high efficiency inthe degradation and mineralization of chlordimeform (CDM) insecticide. Under the optimum conditions (concentration of catalyst equal to 1 g L−1 and applied current intensity equal to 70 mA), a real effluent doped with 30 mg L−1 of CDM was efficiently treated, leading to 80.8 ± 1.9% TOC reduction after 6 h of treatment, with total removal of CDM after only 1 h.The generated carboxylic acids and minerals wereidentified and quantified. Furthermore, the stability and reusability of the developed catalyst was examined, and an insignificant reduction in catalytic activity was noticed forfour consecutive cycles of the photo-electro-Fenton process. Analyses using SEM, XRD and VSM showed a good stability of the physicochemical properties of the catalyst after use.Xunta de Galicia | Ref. ED481B 2019/091Ministerio de Ciencia e Innovación | Ref. PID2020-113667GB-I00 464Universidad de Kairouan, Túnez | Ref. UR16ES0

Magnetic TiO₂/Fe₃O₄-Chitosan Beads: A Highly Efficient and Reusable Catalyst for Photo-Electro-Fenton Process

Heterogeneous photo-electro-Fenton process is an attractive technology for the removal of recalcitrant pollutants. To better exploit the presence of an irradiation source, a bifunctional catalyst with TiO2 nanoparticles embedded into an iron–chitosan matrix was developed. The catalytic activity of the catalyst was improved by the optimization of the loaded TiO2 content. The prepared composite catalysts based on TiO2, Fe3O4 and chitosan were called TiO2/Fe3O4-CS beads. The best catalyst with an optimal ratio TiO2/Fe = 2 exhibited a high efficiency in the degradation and mineralization of chlordimeform (CDM) insecticide. Under the optimum conditions (concentration of catalyst equal to 1 g L−1 and applied current intensity equal to 70 mA), a real effluent doped with 30 mg L−1 of CDM was efficiently treated, leading to 80.8 ± 1.9% TOC reduction after 6 h of treatment, with total removal of CDM after only 1 h.The generated carboxylic acids and minerals were identified and quantified. Furthermore, the stability and reusability of the developed catalyst was examined, and an insignificant reduction in catalytic activity was noticed for four consecutive cycles of the photo-electro-Fenton process. Analyses using SEM, XRD and VSM showed a good stability of the physicochemical properties of the catalyst after use

Magnetic TiO2/Fe3O4-Chitosan Beads: A Highly Efficient and Reusable Catalyst for Photo-Electro-Fenton Process

Heterogeneous photo-electro-Fenton process is an attractive technology for the removal of recalcitrant pollutants. To better exploit the presence of an irradiation source, a bifunctional catalyst with TiO2 nanoparticles embedded into an iron–chitosan matrix was developed. The catalytic activity of the catalyst was improved by the optimization of the loaded TiO2 content. The prepared composite catalysts based on TiO2, Fe3O4 and chitosan were called TiO2/Fe3O4-CS beads. The best catalyst with an optimal ratio TiO2/Fe = 2 exhibited a high efficiency in the degradation and mineralization of chlordimeform (CDM) insecticide. Under the optimum conditions (concentration of catalyst equal to 1 g L−1 and applied current intensity equal to 70 mA), a real effluent doped with 30 mg L−1 of CDM was efficiently treated, leading to 80.8 ± 1.9% TOC reduction after 6 h of treatment, with total removal of CDM after only 1 h.The generated carboxylic acids and minerals were identified and quantified. Furthermore, the stability and reusability of the developed catalyst was examined, and an insignificant reduction in catalytic activity was noticed for four consecutive cycles of the photo-electro-Fenton process. Analyses using SEM, XRD and VSM showed a good stability of the physicochemical properties of the catalyst after use

Removal of Amitraz insecticide by heterogeneous UV-Fenton process using metals supported on chitosan beads as a catalyst

International audiencePhotocatalytic degradation of Amitraz insecticide in a heterogeneous phase was studied at neutral pH using several types of metals supported on chitosan beads (Fe-CS, Fe3O4-CS, Mn-CS, MnO2-CS, and TiO2-CS). Scanning Electron Microscopy (SEM), X-Ray Diffraction (XRD), Fourier Transform Infrared (FTIR), and Brunauer Emmett Teller (BET) analysis were used to characterize the prepared catalysts. Parameters, including the type of catalyst, UV irradiation, the method of hydrogen peroxide addition, and the presence of dissolved oxygen were investigated in order to evaluate the performance of the heterogeneous Fenton process. The optimal conditions were achieved when using 1 g L−1 of Fe3O4-CS catalyst under UV irradiation with the sequential addition of 12 mM of H2O2 and a continuous bubbling of air in the reactional medium. The degradation of the pollutant follows a pseudo-first-order kinetic. The catalyst stability was evaluated and confirmed in four repeated runs with a control of the amount of leached iron in the aqueous solution. © 2020 American Institute of Chemical Engineer