Treatment of textile effluent containing recalcitrant dyes using MOF derived Fe-ZSM-5 heterogeneous catalyst

Abstract

Iron based heterogeneous catalysts are widely used in many industrial applications includingFenton Oxidation Processes (FOPs) to treat the effluents containing recalcitrant contaminants such as dyes. In this work, Metal Organic Framework (MOF) derived iron nano oxide particles supported on ZSM-5 Zeolite were synthesized under the optimized experimental conditions. Central Composite Design (CCD) method was employed to optimize the yield of the catalyst. The catalyst was then characterized using EDX, SEM, HRTEM, FTIR, STA and BET. Subsequently, the catalytic activity of the catalyst in Fenton Oxidation process was evaluated based on the degradation of the model azo dyes, Acid Blue 113, Methyl Orange, and Reactive Black. The optimized experimental yield was 81.5%, which was in agreement with the CCD predicted. Apart from high catalyst's yield, excellent mineralization efficiency was obtained where 77%, 71 % and 68% of Total Organic Carbon (TOC) removal were achieved for Acid Blue 113, Methyl Orange, and Reactive Black 5, respectively. Based on the yield and activity, it was concluded that the synthesized Fe-ZSM-5 is a promising catalyst for Fenton oxidation process.The specific surface area of the support and catalyst (in m2/g) was determined by measuring the volume of N 2 gas, using the BET (Brunauer-Emmett-Teller) method. Table S3 shows the specific surface areas, pore width, and pore volume. Presence of nano sized iron particles reduced the specific surface area of ZSM-5 from 297 to 241m 2 /g. Similarly, the pore volume was also changed from 0.17 to 0.11cm 3 /g. BET analysis confirmed the filling of iron oxide particles in the pores of ZSM-5 matrix 28 . Synthesized Fe-ZSM-5 had greater pore size (2.66 nm) than the parent ZSM-5 (2.45 nm).This may be attributed to multilayer formation of nano sized particles on ZSM-5 support, which can be seen FESEM images (Fig. 2). Changes in the pore size, and surface area were well supported by the literature 7, 28, 42 .Comparison Plot for Fe-MOFs.The optimization of the results obtained through experiments was carried out using Response Surface Methodology (RSM). Responses were kept within the desired ranges while the maximum yield was targeted. The suggested optimized values of temperature (33 o C), time (4 h) and stirrer speed (245 rpm) were validated through the experiment. The approximate yield of the Fe-complexes was 81.5%. There was a good agreement between the predicted and experimental results under optimized environment.Furthermore, in the impregnation step, 82-84% yield of Fe-ZSM-5 was observed. The yield can be further increased up to 90% with an efficient filtration system. Efficiency and Stability Evaluation of the Fe-ZSM-5 catalystExperiments exhibiting Fenton oxidation were carried out to degrade and decolorize three selected dyes. In order to examine the adsorption, the preliminary study was conducted with 100 mg/L of dye concentration. After four hours, percentage of adsorbed Acid Blue 113,

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Synthesis and Characterization of an Iron(II) Bipyridine Redox-Active Polymer

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