Selective Fenton-like oxidation of methylene blue on modified Fe-zeolites prepared via molecular imprinting technique

Abstract

A facile strategy to increase the selectivity of heterogeneous Fenton oxidation is investigated. The increase was reached by increasing selective adsorption of heterogeneous Fenton catalyst to a target pollutant. The heterogeneous Fenton catalyst was prepared by a two-step process. First, zeolite particles were imprinted by the target pollutant, methylene blue (MB), in their aggregations, and second, iron ions were loaded on the zeolite aggregations to form the molecule imprinted Fe-zeolites (MI-FZ) Fenton catalyst. Its adsorption amount for MB reached as high as 44.6 mg g while the adsorption amount of un-imprinted Fe-zeolites (FZ) is only 15.6 mg g. Fenton removal efficiency of MI-FZ for MB was 87.7%, being 33.9% higher than that of FZ. The selective Fenton oxidation of MI-FZ for MB was further confirmed by its removal performance for the mixed MB and bisphenol A (BPA) in solution. The removal efficiency of MB was 44.7% while that of BPA was only 14.9%. This fact shows that molecular imprinting is suitable to prepare the Fe-zeolites (FZ)-based Fenton catalyst with high selectivity for removal of target pollutants, at least MB.

Construction of a 3D Metal–Organic Framework and Its Composite for Water Remediation via Selective Adsorption and Photocatalytic Degradation of Hazardous Dye

“… 83 − 85 Upon irradiation of sunlight, the organic linkers act as an electron-releasing agent via a conjugation system to metal ions. 86 The hopping of electrons from one place to another place triggers the redox mechanism. Herein, we assume that under the illumination of sunlight, the excited electrons from the ligand system could react with molecular oxygen, forming reactive oxygen species (ROS).…”

“…MOFs as a semiconducting catalyst can absorb photons and generate electron–hole pairs in conduction and valance bands. − Upon irradiation of sunlight, the organic linkers act as an electron-releasing agent via a conjugation system to metal ions . The hopping of electrons from one place to another place triggers the redox mechanism.…”

“…Herein, we assume that under the illumination of sunlight, the excited electrons from the ligand system could react with molecular oxygen, forming reactive oxygen species (ROS). Similarly, water molecules and their hydroxyl ions react with the holes and form reactive hydroxyl radicals (OH • ). − Therefore, ROS and OH · radicals play a central role in the degradation of MB dye molecules (Figure ). According to some recent reports, − presumably, the lower band gap energy of ZnO@ 1 could facilitate the electron excitation at a lower energy and hence fast production of ROS and OH • radicals, which results in an enhanced rate of photodegradation of MB dye molecules. , …”

Optimization and Modelling Using the Response Surface Methodology for Methylene Blue Removal by Electrocoagulation/Hazelnut Shell Adsorption Coupling in a Batch System

“…For this current density, current and voltage values were 0.468 A and 7.5 V, respectively. Based on these values, the energy consumption (ENC) can be estimated by the following equation: ENC = (UIt)/v (9) …where U, I, t and v are the voltage (V), current (A), reaction time (h) and effluent volume (m 3 ), for the EC process. Based on the China market in 2018, the electricity cost was $0.049/kwh.…”

Decomposition of the Methylene Blue Dye Using Layered Manganese Oxide Materials Synthesized by Solid State Reactions

“…Oxidative degradation of organic compounds, especially methylene blue, has been reported as a surface reaction that generates reactive oxygen species [45,46]. e oxidation of methylene blue through Fenton-type reactions involves the generation of free radicals from an oxidizing substance and from a material that can potentially provide electrons [45,47]. In this case, hydrogen peroxide is decomposed by the manganese oxide to generate highly reactive oxygen species [18,19,45,48].…”