rGO/MUT-15 nanocomposite as a Fenton-like photocatalyst for the degradation of Acid Yellow 73 under visible light

The Fenton-like reaction is an advanced oxidation process (AOP) used to effectively eliminate organic pollutants. Fenton-like materials include metal-organic frameworks (MOFs) containing Fe, Co, Mn, and Cu metal ions. MOF-based photocatalysts with the highest performance can be designed and synthesized using these metal ions. A new Mn-based metal-organic framework with the formula of [Mn2(DClTPA)2(DMF)3] (MUT-15) containing 2,5-dichloroterephthalic acid (DClTPA) and N,N-dimethylformamide (DMF) was prepared via a solvothermal method. According to single-crystal X-ray analysis, MUT-15 (MUT = Materials from University of Tehran) has a tetragonal crystal system with the I41/a space group. A simple one-pot solvothermal method was used to prepare a rGO/MUT-15 nanocomposite. PXRD, FT-IR, TGA, FE-SEM, TEM, EDX, DRS, PL, EIS, and Mott-Schottky measurements were used to characterize the MUT-15 and rGO/MUT-15 nanocomposite. Under visible-light irradiation, MUT-15 and rGO/MUT-15 as Fenton-like photocatalysts degraded Acid Yellow 73 in only 10 min with outstanding photocatalytic activity rates of 92.39% and 96.10%, respectively. Thus, the Mn(II)-O clusters in MUT-15 significantly contributed to the degradation of Acid Yellow 73 through their Fenton-like effect.

Efficient pollutant degradation by peroxymonosulfate activated by a Co/Mn metal-organic framework

In this work, a three-dimensional bimetallic metal-organic framework (BMOF), BUC-101 (Co/Mn-H6chhc, H6chhc = cis-1,2,3,4,5,6-cyclohexane-hexacarboxylic acid, BUC = Beijing University of Civil Engineering and Architecture) was synthesized by a one-pot solvothermal method and characterized in detail by single crystal X-ray diffraction (SCXRD), Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM) element mapping analysis. BUC-101 showed excellent catalytic peroxymonosulfate (PMS) activation performance to degrade rhodamine B (RhB) without energy input. In addition, BUC-101 can maintain good stability and recyclability during the PMS activation processes, in which 99.9% RhB degradation efficiencies could be accomplished in 5 operational runs. The possible PMS activation and RhB degradation mechanisms of the BUC-101/PMS system were proposed and affirmed.

Application of Nanocatalysts in Advanced Oxidation Processes for Wastewater Purification: Challenges and Future Prospects

The increase in population demands for industrialization and urbanization which led to the introduction of novel hazardous chemicals in our environment. The most significant parts of these harmful substances found in water bodies remain in the background, causing a health risk to humans and animals. It is critical to remove these toxic chemicals from the wastewater to keep a cleaner and greener environment. Hence, wastewater treatment is a challenging area these days to manage liquid wastes effectively. Therefore, scientists are in search of novel technologies to treat and recycle wastewater, and nanotechnology is one of them, thanks to the potential of nanoparticles to effectively clean wastewater while also being ecologically benign. However, there is relatively little information about nanocatalysts’ applicability, efficacy, and challenges for future applications in wastewater purification. This review paper is designed to summarize the recent studies on applying various types of nanocatalysts for wastewater purification. This review paper highlights innovative work utilizing nanocatalysts for wastewater applications and identifies issues and challenges to overcome for the practical implementation of nanocatalysts for wastewater treatment.

The enhanced visible-light-induced photocatalytic activities of bimetallic Mn-Fe MOFs for the highly efficient reductive removal of Cr(vi)

The photocatalytic efficiencies of bimetallic MOFs, namely STA-12-Mn–Fe, for the reductive removal of Cr(vi) were explored. The best effective variable values were obtained and correlation between the response and influential variables was optimized via experimental design methodology. Complete Cr(vi) removal was achieved under natural sunlight and fluorescent 40 W lamp radiation at pH 2, with an initial Cr(vi) concentration of 20 mg L⁻¹, and 10 mg of photocatalyst within 30 min. A pseudo-first-order rate constant of 0.132 min⁻¹ at T = 298 K was obtained for the Cr(vi) reduction reaction. The title catalysts revealed high performance in the visible region based on photoefficiency measurements, while improved activity was observed compared to the corresponding single-metal MOFs under natural sunlight, highlighting the synergistic effect between the two metal ions. Trapping experiment results proved that direct electron transfer is the main pathway during the photocatalytic Cr(vi) reduction process.

The photocatalytic efficiencies of bimetallic MOFs for the reductive removal of Cr(vi) were explored. The catalysts revealed higher performance compared to the corresponding single-metal MOFs, highlighting the synergistic effect between the two metal ions.

Synthesis, structure and photocatalytic property of a novel Zn(II) coordination polymer based on in situ synthetized pyridine-3,4-dicarboxylhydrazidate ligand

One new pyridine-3,4-dicarboxylhydrazidate-coordinated compound [Zn(pdh)] 1 (pdh = pyridine-3,4-dicarboxylhydrazidate) was obtained under the hydrothermal conditions. Noteworthily, the pdh molecules in the title compound originated from the ligand in situ reaction between organic pyridine-3,4-dicarboxylic acid (pdca) and N₂H₄·H₂O. X-ray single-crystal diffraction analysis revealed that the pdh ligands exhibit a special μ₄-bridging mode in compound 1, which link Zn(II) centers into a 2D layered structure. The photocatalysis analysis indicates that it is a potential visible light catalyst. In addition, the solid photoluminescence property of compound 1 was also investigated.

3-(4-Methylthiophenyl)acetylacetone – ups and downs of flexibility in the synthesis of mixed metal–organic frameworks. Ditopic bridging of hard and soft cations and site-specific desolvation

Different Pearson-hardness of O and S donors leads to well-ordered mixed metal–organic frameworks.