Heterogeneous degradation of toxic organic pollutants by hydrophobic copper Schiff-base complex under visible irradiation

Synthesis of UiO-66-Sal-Cu(OH)2 by a Simple and Novel Method: MOF-Based Metal Thin Film as a Heterogeneous Catalyst for Olefin Oxidation

Metal-organic frameworks (MOFs), particularly UiO-66-NH₂, are employed as a catalyst in many industrial catalyst applications. As converting catalysts into thin film significantly increases their catalytic properties for the epoxidation of olefins, we report a general approach to synthesizing MOF thin films (UiO-66-Sal-Cu(OH)₂). Using the postsynthesis method (PSM), UiO-66-NH₂ was functionalized with salicylaldehyde and entrapped on copper hydroxide nanoparticle surfaces using a modern strategy (MOF thin film). We used field-emission scanning electron microscopy (FE-SEM), EDX (energy-dispersive X-ray analysis), XRD (X-ray diffraction), FT-IR (Fourier transform infrared), BET (Brunauer-Emmett-Teller), TGA (thermogravimetric analysis), XPS (X-ray photoelectron spectroscopy), and ICP-MS (inductively coupled plasma mass spectrometry) to determine the structure and morphology of the synthesized UiO-66-Sal-Cu(OH)₂. The oxidation of cyclooctene by the UiO-66-Sal-Cu(OH)₂ thin film was studied. Due to its advantages, such as being environmentally friendly (base metal-loaded catalyst, room temperature, solvent-free reaction), reusability, and high yield, this compound can be an appropriate catalyst for the oxidation of olefins.

Oxidative degradation of toxic organic pollutants by water soluble nonheme iron(iv)-oxo complexes of polydentate nitrogen donor ligands

The ability of four mononuclear nonheme iron(iv)-oxo complexes supported by polydentate nitrogen donor ligands to degrade organic pollutants has been investigated. The water soluble iron(ii) complexes upon treatment with ceric ammonium nitrate (CAN) in aqueous solution are converted into the corresponding iron(iv)-oxo complexes. The hydrogen atom transfer (HAT) ability of iron(iv)-oxo species has been exploited for the oxidation of halogenated phenols and other toxic pollutants with weak X-H (X = C, O, S, etc.) bonds. The iron-oxo oxidants can oxidize chloro- and fluorophenols with moderate to high yields under stoichiometric as well as catalytic conditions. Furthermore, these oxidants perform selective oxidative degradation of several persistent organic pollutants (POPs) such as bisphenol A, nonylphenol, 2,4-D (2,4-dichlorophenoxyacetic acid) and gammaxene. This work demonstrates the utility of water soluble iron(iv)-oxo complexes as potential catalysts for the oxidative degradation of a wide range of toxic pollutants, and these oxidants could be considered as an alternative to conventional oxidation methods.

Photodegradation of microcystin-LR by pyridyl iron porphyrin immobilized on NaY zeolite

A novel photocatalyst, FeTPyPY, was prepared by immobilizing water-soluble tetra(4-pyridyl)phenyl iron-porphyrin (FeTPyP) on NaY zeolite to degrade microcystin-LR (MC-LR), one of the most toxic microcystins (MCs). UV-Vis analysis, UV-Vis diffuse reflectance spectroscopy, infrared spectroscopy, cyclic voltammetry and transmission electron microscopy were employed to characterize immobilized FeTPyPY. Under visible light (λ ≥ 420 nm), MC-LR was degraded utilizing immobilized FeTPyPY by activating molecular oxygen. The results showed that 85% of MC-LR was efficiently degraded by FeTPyPY with loading amount 100:1 (m_NaY:m_FeTPyP) after 300 min of visible light illumination. Moreover, FeTPyPY was stable in the degradation system with pH 7.0. The degradation mechanism was evaluated using electron spin resonance, and the results demonstrated that highly reactive oxygen species (^•OH radical) were generated in the system to degrade MC-LR. Therefore, immobilized FeTPyPY was available to break down the toxic groups within MC-LR by utilizing environmental ^•OH radical under circumneutral condition.

Co(II/III) Complexes with Benzoxazole and Benzothiazole Ligands as Efficient Heterogenous Photocatalysts for Organic Dyes Degradation

The problem of pollution in the current world is growing, however people’s awareness of environmental protection and ecology is also increasing. The aim of the study is to present three new Schiff base compounds with Co(II/III) ions and to assess their photocatalytic activity. The study was supported by cyclic voltammetry technique. In due course the complex 2 revealed as the most effective in AR18 degradation, even more than commercially available TiO2. The search for new photocatalysts able to decompose harmful organic dyes into environmentally friendly basic substances is becoming a new trend in the area of chemistry development.

Heterogeneous Fenton-like activity of novel metallosalophen magnetic nanocomposites: significant anchoring group effect

Novel magnetically recoverable Fe(iii)- and Mn(iii)salophen complexes were designed for the effective degradation of hazardous organic dyes using a heterogeneous advanced oxidation process.