Iron-Manganese Bimetallic-Organic Framework as A Photocatalyst for Degradation of Rhodamine B Organic Dye Under Visible Light

In recent years, there have been many research works on use of different methods to treat textile dyeing wastewater such as mechanical, biological and chemical methods (using oxidizing agents, such as: H2O2, O3, and H2O2/O3). However, some traditional textile dyeing wastewater treatment methods such as mechanical and biological methods have limitations in treating these pollutants thoroughly. To enhance the treatment efficiency, the use of photocatalysts combination with strong oxidizing agents, such as H2O2, has been extensively developed in recent years. In this study, the iron-centred bimetallic organic framework Fe-MOF has been synthesized by partial replacement of Fe3+ ions with Mn metal ions by solvent-thermal method. The analytical methods used to evaluate the structural characterization of the as-synthesized materials including Scanning Electron Microscope (SEM), Brunaurer-Emmett-Teller (BET), X-ray Diffraction (XRD), Fourier Transform Infra Red (FT-IR), and UV-Vis Diffuse Reflectance Spectroscopy (DRS). The experiments on the decomposition of organic pigment Rhodamine B were performed under varying conditions of pH, catalyst mass and RhB colorant concentration. Experiments with different electron capturers indicate that h+ plays a major role in the photochemical degradation of RhB. The stability and durability of the 0.1 Mn/Fe-MOF catalyst were evaluated through the leaching and recycle experiments, showing that the RhB degradation efficiency of the photocatalyst decreased modestly after five repetitions. Copyright © 2021 by Authors, Published by BCREC Group. This is an open access article under the CC BY-SA License (https://creativecommons.org/licenses/by-sa/4.0).

Orange-derived and lemon-derived adsorbents with controlled grain for an efficient elimination of some cationic and anionic dyes

Purpose This study aims to demonstrate that orange-derived and lemon-derived systems can be used in continuous processes as efficient adsorbents to the entrapment of some anionic and cationic dyes in the textile dyeing wastewater effluents. Design/methodology/approach Physically and chemically modified orange and lemon mesocarps are used as natural adsorbents for the cationic dyes Basic Blue 3, Basic Yellow 21, Basic Red 18 and Basic Green 4 and the anionic dyes Acid Blue 264, Acid Yellow 49 and Acid Red 337, all commonly used in the textile dyeing industry. Adsorption capacities of the orange-derived and lemon-derived adsorbents on the dyes are studied simulating a batch and continuous industrial processes. Findings Results demonstrate that treated orange mesocarp (orange-derived adsorbent) can adsorb up to 97% of cationic Basic Green 4 in 30 min, whereas the lemon mesocarp (lemon-derived adsorbent) can retain up to 88% within the same time. In the case of anionic, 91% Acid Blue 264 is adsorbed by the orange mesocarp in 15 min, whereas 92% is adsorbed by the lemon homologue within the same time. Originality/value As far as the authors know, physically and chemically modified orange and lemon mesocarps have not been used on the removal of cationic (Basic Blue 3, Basic Yellow 21, Basic Red 18 and Basic Green 4) and anioinic (Acid Blue 264, Acid Yellow 49 and Acid Red 337) dyes of textile dyeing wastewater industry. It is a costless and efficient treatment that supposes, on the one hand, an eco-friendly and feasible process for discolouration of wastewater and, on the other, a valorisation (upcycling) of orange and lemon peels, which are not currently used.

Enhanced Photo–Fenton Removal Efficiency with Core-Shell Magnetic Resin Catalyst for Textile Dyeing Wastewater Treatment

Heterogeneous photo–Fenton reactions have been regarded as important technologies for the treatment of textile dyeing wastewaters. In this work, an efficient core-shell magnetic anion exchange resin (MAER) was prepared through in situ polymerization and used to remove reactive brilliant red (X-3B) in a UV–Fenton system. The MAER exhibited satisfactory removal efficiency for X-3B because of its highly effective catalytic activity. More than 99% of the X-3B (50 mg/L) was removed within 20 min in the UV–Fenton reaction. This is because the uniformly dispersed core-shell magnetic microsphere resin could suppress the aggregation of Fe3O4 nanoparticles and, thus, enhance the exposure of Fe reaction sites for catalytic reaction with H2O2. The good adsorption capacity of MAER also played an important role in promoting contact between X-3B and reactive radicals during the reaction. Mechanism research showed that hydroxyl radical (•OH) was the main reactive radicals for the removal of X-3B in the MAER UV–Fenton system. The MAER can be easily separated by a magnet after catalytic reactions. Moreover, the matrix effects of different substrates (Cl−, NO3−, SO42−, and humic acid) were investigated. The results showed that SO42− could be beneficial to improve the removal of X-3B but that the others decrease the removal. The MAER UV–Fenton also removed significant amounts of total organic carbon (TOC) for the X-3B solution and an actual textile dyeing industrial wastewater. The heterogeneous oxidation system established in this work may suggest prospects for practical applications in the treatment of textile dyeing wastewater.