Catalyst For Reduction Of Dyes Research Articles

Synthesis and characterization of polyaniline/nickel oxide composites for fuel additive and dyes reduction

Polyaniline (PANI) and Polyaniline/Nickel oxide (PANI/NiO) composites are prepared to use as a potential catalyst, by Chemical oxidation method using ammonium persulfate (NH4)2S2O8)) as an oxidant. Nickel oxide (NiO) nanopartiles are prepared by Sol-gel method. The synthesized products were characterized by Scanning Electron Microscopy (SEM), Energy Dispersive X-ray analysis (EDX), Fourier Transform Infrared Spectroscopy (FTIR) and X-ray Diffraction technique (XRD). The prepared PANI/NiO composites are used as additive with different concentrations in diesel to investigate their efficiency as fuel additive. The catalytic properties are studied by using the synthesized products as catalyst for reduction of dyes in aqueous media. Sodium borohydride (NaBH4) is used as reducing agent. Linear relationships are obtained between time and ln(A0/At) for Methyl orange and Methylene blue. Kapp values were obtained for three catalysts showed the increasing trend of reduction for both dyes as, PANI < NiO < PANI/NiO composites. Experimental data analysis proved PANI/NiO composites to be efficient catalysts and fuel additive as compared to PANI and NiO.

Nanocomposite of functionalized halloysite and Ag(0) decorated magnetic carbon dots as a reusable catalyst for reduction of dyes in water

A new magnetic, catalytic nanocomposite of Hal-MT-Cys-Ag/MNCD was fabricated and utilized for catalyzing reductive de-colorization of methyl orange and rhodamin B in aqueous media at room temperature. To prepare this material, Cl-functionalized halloysite nanoclay was successively reacted with melamine and 2,4,6-trichloro-1,3,5-triazine to furnish multi-nitrogen containing ligand on halloysite surface. Then, magnetic carbon dots were crafted through a facile method and decorated with Ag nanoparticles and cysteine to furnish Cys-Ag/MNCD species. The final nanocomposite was obtained via incorporation of this latter species onto functionalized halloysite. This new composite was characterized through the XRD, TEM, BET, FTIR, TGA, EDX, and mapping analyses. The catalytic experiments confirmed that low loadings of the Hal-MT-Cys-Ag/MNCD composite reduction of both dyes were performed in ~1 min. This material could also be readily collected from the reaction media magnetically and displayed excellent recyclability with a slight decrease in its activity of at most ~6% up to 8 cycles. The kinetic and thermodynamic study of de-colorization reactions emphasized high catalytic performances of the synthesized nanocomposite. More precisely, activation energy, enthalpy, and entropy were determined to be 48.15 kJ mol−1, 45.65 kJ mol−1, and -124.61 J mol−1 K−1; respectively for the methyl orange while the corresponding values for the rhodamine B were found to be 11.03 kJ mol−1, 8.53 kJ mol−1, and -249.93 J mol−1. K−1.

Silver nanoparticles anchored TiO2 nanotubes prepared using saponin extract as heterogeneous and recyclable catalysts for reduction of dyes

In the present study, we made an effort to synthesize silver nanoparticles anchored onto TiO2 nanotubes using saponin extracted from Simarouba glauca oil seed meal. Obtained silver anchored TiO2 nanotubes (Ag-TiO2) were characterized using spectroscopic, microscopic and X‐ray diffraction techniques and used as catalysts for reduction of nitrophenol (NP), Methylene blue (MB), Methyl orange (MO) and Congo red (CR). The reduction reactions were carried out in aqueous medium in presence of NaBH4 at room temperature. Progress of the catalytic reaction was observed by decolorization of the dye solution and monitored by recording UV–Vis spectra. It was observed that Ag-TiO2 nanotubes emerged as an effective catalyst in reducing the dyes in the time range of 2–7 min with pseudo first-order kinetics and also effective in the simultaneous reduction of all dyes in 12 min. In addition, the catalyst showed a good recovery yield with unaffected catalytic efficiency up to ten cycles.

Green synthesis of Ag NPs on magnetic polyallylamine decorated g-C3N4 by Heracleum persicum extract: efficient catalyst for reduction of dyes

Silver nanoparticles were immobilized on magnetic polyallylamine (PAA) decorated g-C3N4 by using Heracleum persicum extract as a biological reducing and stabilizing agent. The resulting nanocomposite, Fe3O4-g-C3N4-TCT-PAA-Ag, was then characterized using BET, VSM, XRD, TGA, FTIR, TEM, EDS and ICP. The catalytic performance of the synthesized nanocatalyst was considered in the reduction of rhodamine B, and methyl orange in the presence of sodium borohydride in the aqueous medium at room temperature. The results showed that Fe3O4-g-C3N4-TCT-PAA-Ag nanocomposite could promote both reduction reactions efficiently in very short reaction times (70–100 s). In addition, Fe3O4-g-C3N4-TCT-PAA-Ag could be magnetically recovered and recycled for several cycles with no significant decrease in its catalytic performance. Using the experimental results, the rate constant, enthalpy, and entropy of the reduction reactions of both dyes were estimated.

Magnetic GO‐PANI decorated with Au NPs: A highly efficient and reusable catalyst for reduction of dyes and nitro aromatic compounds

Due to the high activity of Au nanoparticles (NPs) for various reactions, many researchers have tried to develop heterogeneous catalysts in order to prevent irreversible agglomeration of Au NPs. Herein, magnetic graphene oxide modified with polyaniline (PANI) was used as a support for Au NPs that brings together advantages including: uniform dispersal of the catalyst in water,alarge surface area related to the graphene oxide; easy electron transfer in chemical reactions and good attachment of Au NPs to the support associated with PANI; and finally facile recovery in the presence of a magnetic field. Catalytic reduction of different analytes (Congo red, methylene blue, rhodamine B and 4‐nitro phenol) was evaluated in the presence of NaBH4 and the results show high catalytic activity of the catalyst. The catalyst was thoroughly characterized using various methods including FTIR, XRD, XPS, FE‐SEM and HRTEM analyses while its catalytic activity was evaluated via reduction of different analytes.

Goldcore–polyanilineshell composite nanowires as a substrate for surface enhanced Raman scattering and catalyst for dye reduction

The unique morphology of the nanocomposite is due to the confinement, typical diffusion path and the interaction between PANI and Au-nanoparticles.