Photocatalytic performance of carbon nanotubes/activated carbon composite carrier carrying cadmium sulfide

The in-situ reaction process was used to prepare composite materials loaded with cadmium sulfide, which were respectively loaded by carbon nanotubes, activated carbon, and carbon nanotube/activated carbon composites for the study of photocatalytic degradation of methyl orange. The results show that when carbon nanotubes and activated carbon are used as carriers, the photocatalytic degradation reaction rate constants are 3.6 times and 8.8 times higher than those without a carrier. The photocatalytic performance of the carbon nanotube/activated carbon composite carrier with a mass ratio of 20: 80 to support cadmium sulfide is significantly higher than that of cadmium sulfide supported by carbon nanotubes and activated carbon respectively, and its photocatalytic degradation reaction rate constant is 30% – 40% higher than that under the condition of activated carbon alone as carrier. It shows that when the modified activated carbon is used as a photocatalyst carrier, carbon nanotubes have a significant effect in improving the efficiency of degrading organic matter.

Photocatalytic Degradation of 4,4′-Isopropylidenebis(2,6-Dibromophenol) on Sulfur-Doped Nano TiO2

In present work, we examine the photocatalytic properties of S-doped TiO2 (S1, S2) compared to bare TiO2 (S0) in present work. The photocatalytic tests were performed in alkaline aqueous solutions (pH = 10) of three differently substituted phenols (phenol (I), 4,4′-isopropylidenebisphenol (II), and 4,4′-isopropylidenebis(2,6-dibromophenol) (III)). The activity of the catalysts was evaluated by monitoring I, II, III degradation in the reaction mixture. The physicochemical properties (particle size, ζ-potential, Ebg, Eu, E0cb, E0vb, σo, KL) of the catalysts were established, and we demonstrated their influence on degradation reaction kinetics. Substrate degradation rates are consistent with first-order kinetics. The apparent conversion constants of the tested compounds (kapp) in all cases reveal the sulfur-loaded catalyst S2 to show the best photocatalytic activity (for compound I and II S1 and S2 are similarly effective). The different efficiency of photocatalytic degradation I, II and III can be explained by the interactions between the catalyst and the substrate solution. The presence of bromine substituents in the benzene ring additionally allows reduction reactions. The yield of bromide ion release in the degradation reaction III corresponds to the Langmuir constant. The mixed oxidation-reduction degradation mechanism results in higher degradation efficiency. In general, the presence of sulfur atoms in the catalyst network improves the degradation efficiency, but too much sulfur is not desired for the reduction pathway.

Efficient degradation of methyl orange and methylene blue in aqueous solution using a novel Fenton-like catalyst of CuCo-ZIFs

In this study, the synthesized CuCo-zeolitic imidazolate framework (ZIF) catalyst was used to degrade methyl orange (MO) and methylene blue (MB) in water via a novel Fenton-like catalytic reaction. Effects of catalyst dosage, H2O2 concentration, initial concentration of the contaminants, and reaction time were evaluated. The results showed that MO and MB decomposition efficiencies were highly influenced by CuCo-ZIF concentration. The presence of H2O2 accelerated the degradation reaction of both MO and MB. Although it took 100 min to complete the removal of MB, it was 60 min for MO. At concentrations of MO and MB lower than 40 mg·L−1, the catalyst showed an almost complete degradation. The CuCo-ZIF catalyst presented a good recyclability with more than 90% removal of MO and MB after four times and five times reuse, respectively. These results demonstrated that MO and MB were efficiently degraded by a Fenton-like catalyst of CuCo-ZIFs and its potential in industrial wastewater treatment.

Zeolite-X Encapsulated Ni(II) and Co(II) Complexes with 2,6-Pyridine Dicarboxylic Acid as Catalysts for Oxidative Degradation of Atenolol in an Aqueous Solution

Complexes of Co (II) and Ni (II) with dipicolinic acid, 2,6-pyridine dicarboxylic acid (PydcH2) have been synthesized in the NaX (zeolite-X) nanopores. The formation of zeolite X encapsulated Co(II) and Ni(II) complexes ([M(pydcH)2]-NaX, where M = Co(II) and Ni(II]) were confirmed using spectroscopic methods of FT-IR, elemental analysis, XRD, FE-SEM, and TEM. It was affirmed that the encapsulation of complexes in NaX pores was performed without changes in the structure and shape of the zeolite. The oxidative degradation reaction of atenolol with hydrogen peroxide as an oxidant was performed in the presence of synthesized [M(pydcH)2]-NaX nanocomposites to study their catalytic activity. Therefore, oxidation of atenolol was performed under different conditions of catalyst, temperature, and time. Under optimal conditions, catalysts [Co(pydcH)2]-NaX and [Ni(pydcH)2]-NaX showed 82.3% and 71.1% activity of atenolol oxidation, respectively. These catalysts were stable after recovery and were used three more times. The results showed that these catalysts were reusable and had a reduction in the catalytic activity of less than ten percent.

Environmentally Benign Organic Dye Conversion under UV Light through TiO2-ZnO Nanocomposite

In this work, we developed a very simple and novel approach for synthesizing TiO2-ZnO nanocomposites via the urea-assisted thermal decomposition of titanium oxysulphate and zinc acetate at different weight ratios. The synthesized nanocomposite samples were studied by means of HR-TEM, XRD, STEM, UV–Vis DRS, PL and EDS. The observed results demonstrate that the TiO2-ZnO nanocomposite consists of an anatase crystal phase of TiO2 with a crystallite size of 10–15 nm. Combined characterization, including UV–Vis DRS, STEM, EDS and HR-TEM, revealed the successful formation of a heterojunction between TiO2 and ZnO and an improvement in UV spectrum absorption. The photocatalytic activity was explored using MO degradation under ultraviolet light illumination. The results of the optimized TiO2-ZnO nanocomposite show excellent photocatalytic activity and photostability over a number of degradation reaction cycles. In addition, the current approach has immense potential to be used as a proficient method for synthesizing mixed metal oxide nanocomposites.

Synthesis, characterization and Stydy thermal stabilization effect of calcium complex of anthocyanin on the poly (vinyl chloride)

In this study, calcium complex of anthocyanin was synthesized from anthocyanin, a flavonoid type natural phenolic product, which was extracted from eggplant peel. The structure of Ca-anthocyanin was characterized by FTIR spectroscopy. Its efficiency as bio-based thermal stabilizer to stabilize poly (vinyl chloride) was investigated and compared to that of Reapak B-NT/7060, a Ca/Zn-based commercial stabilizer. The influence of Ca-anthocyanin complex on the thermal degradation reaction of PVC was monitored by differential scanning calorimetry (DSC). The results indicated that the Ca-anthocyanin complex is an efficient thermal stabilizer and it reduces the rate of dehydrochlorination reaction of PVC already at a concentration as small as 2 phr, part per hundred of PVC resin. The thermal degradation reaction of PVC through the first degradation stage is clearly limited by the addition of Ca-anthocyanin complex as single (primary) stabilizer. Its efficiency is similar to that of Reapak B-NT/7060 used as reference stabilizer and it can enhance the performance of commercial stabilizer when used as co-stabilizer at mixing ratio (1:1). This study has allowed verifying and validating the usefulness of environmental friendly thermal stabilizer for PVC with very evident stabilization effect.

Functioned catalysts with magnetic core applied in the ibuprofen degradation

In the present work, the performance of Ag/ZnO/CoFe2O4 magnetic photocatalysts in the photocatalytic degradation of Ibuprofen (IBP) was evaluated. This study considered the use of pure Ag/ZnO (5% Ag) and also use the Ag/ZnO/CoFe2O4 magnetic catalysts containing different amounts (5, 10 and 15% wt) of cobalt ferrite (CoFe2O4). The catalysts were characterized by Scanning Electron Microscopy (SEM), X-ray diffraction (XRD) and photoacoustic Spectroscopy. To carried the photocatalytic degradation reaction, different concentrations of the ibuprofen contaminant solution (10, 20 and 30 ppm) and different concentrations of photocatalyst were tested (0.3 gL−1, 0.5 gL−1 and 1.0 gL−1). The reaction parameters studied were: IBP concentration, catalyst concentration, adsorption and photolysis, influence of the matrix, radiation source (solar and artificial) and the effect of organic additive. At the end of the photocatalytic tests, the best operation conditions were defined. Considering the obtained results of degradation efficiency and magnetic separation, the optimal parameters selected to proceed with the other tests of the study were: ibuprofen solution concentration 10 ppm, Ag/ZnO/CoFe2O4(5%) catalyst at a concentration of 0.3 g L−1 and pH 4.5 of the reaction medium. The results indicated the feasibility of magnetic separation of the synthesized catalysts. A long duration test indicated that the catalyst exhibits stability throughout the degradation reaction, as more than 80% of ibuprofen was degraded after 300 minutes. The photocatalytic activity was directly affected by the ferrite load. The higher the nominal load of ferrite, the lower the performance in ibuprofen degrading. It was also observed that the smallest amount of ferrite studied was enough for the catalyst to be recovered and reused. The adsorption and photolysis tests did not show significant results in the IBP degradation. In addition, it was possible to verify that the aqueous matrix, the use of solar radiation and the addition of additive (acid formic) interfered direct in the process. The catalyst reuse tests indicated that it can be recovered and reused at least three times without considerable catalytic activity loss.

Kinetic, Thermodynamic Studies for Photo Degradation of Glibinclamide Drug

In this work the photo degradation of glibinclamide is studied by UV light and different concentrations using solvents (water and ethanol) and different times. The reaction kinetic is studied and found that the photo degradation reaction of glibinclamide is (first-order) reaction and the thermodynamic properties (ΔHo, ΔSo and ΔGo) for glibinclamide were calculated and it was found to be (endothermic and spontaneous reaction).