scholarly journals Poly(N-isopropylacrylamide-co-methacrylic acid) microgel stabilized copper nanoparticles for catalytic reduction of nitrobenzene

2015 ◽  
Vol 33 (3) ◽  
pp. 627-634 ◽  
Author(s):  
Zahoor H. Farooqi ◽  
Zonarah Butt ◽  
Robina Begum ◽  
Shanza Rhauf Khan ◽  
Ahsan Sharif ◽  
...  
Keyword(s):  
Copper Nanoparticles ◽  
Methacrylic Acid ◽  
Catalytic Reduction ◽  
Aqueous Media ◽  
Activation Parameters ◽  
Reducing Agent ◽  
Different Temperatures ◽  
Entropy Of Activation ◽  
Micro Reactors

Abstract Poly(N-isopropylacrylamide-co-methacrylic acid) microgels [p(NIPAM-co-MAAc)] were synthesized by precipitation polymerization of N-isopropylacrylamide and methacrylic acid in aqueous medium. These microgels were characterized by dynamic light scattering and Fourier transform infrared spectroscopy. These microgels were used as micro-reactors for in situ synthesis of copper nanoparticles using sodium borohydride (NaBH4) as reducing agent. The hybrid microgels were used as catalysts for the reduction of nitrobenzene in aqueous media. The reaction was performed with different concentrations of cat­alyst and reducing agent. A linear relationship was found between apparent rate constant (kapp) and amount of catalyst. When the amount of catalyst was increased from 0.13 to 0.76 mg/mL then kapp was increased from 0.03 to 0.14 min-1. Activation parameters were also determined by performing reaction at two different temperatures. The catalytic process has been discussed in terms of energy of activation, enthalpy of activation and entropy of activation. The synthesized particles were found to be stable even after 14 weeks and showed catalytic activity for the reduction of nitrobenzene.

In-situ stabilization of silver nanoparticles in polymer hydrogels for enhanced catalytic reduction of macro and micro pollutants

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Luqman Ali Shah ◽  
Rida Javed ◽  
Mohammad Siddiq ◽  
Iram BiBi ◽  
Ishrat Jamil ◽  
...  
Keyword(s):  
Catalytic Reduction ◽  
Thermo Gravimetric Analysis ◽  
Activation Parameters ◽  
Reduction Reaction ◽  
Gravimetric Analysis ◽  
X Ray Diffraction ◽  
In Situ Stabilization ◽  
Hybrid Hydrogels ◽  
Kinetics Of

AbstractThe in-situ stabilization of Ag nanoparticles is carried out by the use of reducing agent and synthesized three different types of hydrogen (anionic, cationic, and neutral) template. The morphology, constitution and thermal stability of the synthesized pure and Ag-entrapped hybrid hydrogels were efficiently confirmed using scanning electron microscopy (SEM), Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD) and thermo gravimetric analysis (TGA). The prepared hybrid hydrogels were used in the decolorization of methylene blue (MB) and azo dyes congo red (CR), methyl Orange (MO), and reduction of 4-nitrophenol (4-NP) and nitrobenzene (NB) by an electron donor NaBH4. The kinetics of the reduction reaction was also assessed to determine the activation parameters. The hybrid hydrogen catalysts were recovered by filtration and used continuously up to six times with 98% conversion of pollutants without substantial loss in catalytic activity. It was observed that these types of hydrogel systems can be used for the conversion of pollutants from waste water into useful products.

Oxidation of secondary alcohols by sodium N-chlorobenzenesulphonamide in aqueous solution. A kinetic study

1991 ◽  
Vol 56 (8) ◽  
pp. 1671-1679 ◽  
Author(s):  
Chirchingi K. Mythily ◽  
Dandinasivara S. Mahadevappa ◽  
Kanchugarakoppal S. Rangappa
Keyword(s):  
Isotope Effects ◽  
Activation Parameters ◽  
Secondary Alcohols ◽  
Energy Relation ◽  
Linear Free Energy ◽  
Rate Limiting Step ◽  
Different Temperatures ◽  
Entropy Of Activation ◽  
Free Energy Relation ◽  
Solvent Isotope

The kinetics of oxidation of five secondary alcohols by sodium N-chlorobenzenesulphonamide (chloramine-B) has been studied in acid medium at 40°C. The reaction is first order with respect to the oxidant and alcohol and fractional order in [H+]. The influence of added halide ions and of reaction product and the effects of varying ionic strength and dielectric constant of the medium have also been studied. The solvent isotope effects k’(H2O)/k’(D2O) were determined. The rates were studied at four different temperatures and the activation parameters were evaluated. Attempts have been made to arrive at a linear free energy relation through the Taft treatment. An isokinetic relation is observed with β = 248 K, indicating the entropy of activation as the rate controlling factor. Protonated chloramine-T (monochloramine-T) has been postulated as the reactive oxidizing species, the main product of oxidation being the corresponding ketone. A mechanism involving the interaction of protonated haloamine species and the alcohol in a rate limiting step has been proposed.

Preparation and properties of cotton nanocomposite fabrics with in situ generated copper nanoparticles using Red sanders powder extract as a reducing agent

2019 ◽  
Vol 49 (10) ◽  
pp. 343-348 ◽  
Author(s):  
Venkateswara Rao Amara ◽  
Ashok Basa ◽  
Uma Mahesh Mallavarapu ◽  
Chandrasekhar Vatti ◽  
Subbareddy V. Gopireddy ◽  
...  
Keyword(s):  
Copper Nanoparticles ◽  
Reducing Agent ◽  
Red Sanders ◽  
Powder Extract

In situ generated nickel on cerium oxide nanoparticle for efficient catalytic reduction of 4-nitrophenol

RSC Advances ◽  
2016 ◽  
Vol 6 (51) ◽  
pp. 45947-45956 ◽  
Author(s):  
S. Vivek ◽  
P. Arunkumar ◽  
K. Suresh Babu
Keyword(s):  
Cerium Oxide ◽  
Absorption Spectra ◽  
Catalytic Reduction ◽  
Reduction Process ◽  
Reducing Agent ◽  
Oxide Nanoparticle ◽  
Uv Visible ◽  
P Absorption

Absorption spectra recorded using UV-visible spectrometer during the reduction process of 4-nitrophenol to 4-aminophenol in the presence of reducing agent (NaBH4) and catalyst (Ni(NO3)2/CeO2).

scholarly journals Synthesis, characterization and fabrication of copper nanoparticles in N-isopropylacrylamide based co-polymer microgels for degradation of p-nitrophenol

2015 ◽  
Vol 33 (1) ◽  
pp. 185-192 ◽  
Author(s):  
Zahoor H. Farooqi ◽  
Tanzila Sakhawat ◽  
Shanza Rauf Khan ◽  
Farah Kanwal ◽  
Muhammad Usman ◽  
...  
Keyword(s):  
Acrylic Acid ◽  
Aqueous Medium ◽  
Copper Nanoparticles ◽  
Catalytic Reduction ◽  
Copper Ions ◽  
Effect Of Temperature ◽  
Ft Ir ◽  
Catalyst Dosage ◽  
Hybrid Microgels

AbstractPoly(N-isopropylacrylamide-co-acrylic acid) [P(NIPAM-co-AAc)] microgels were synthesized by precipitation polymerization. Copper nanoparticles were successfully fabricated inside the microgels by in-situ reduction of copper ions in an aqueous medium. The microgels were characterized by Fourier Transform Infrared Spectroscopy (FT-IR) and Dynamic Light Scattering (DLS). Hydrodynamic radius of P(NIPAM-co-AAc) microgel particles increased with an increase in pH in aqueous medium at 25 °C. Copper-poly(N-isopropylacrylamide-co-acrylic acid) [Cu-P(NIPAM-co-AAc)] hybrid microgels were used as a catalyst for the reduction of 4-nitrophenol (4-NP). Effect of temperature, concentration of sodium borohydride (NaBH4) and catalyst dosage on the value of apparent rate constant (kapp) for catalytic reduction of 4-NP in the presence of Cu-P(NIPAM-co-AAc) hybrid microgels were investigated by UV-Vis spectrophotometry. It was found that the value of kapp for catalytic reduction of 4-NP in the presence of Cu-P(NIPAM-co-AAc) hybrid microgel catalyst increased with an increase in catalyst dosage, temperature and concentration of NaBH4 in aqueous medium. The results were discussed in terms of diffusion of reactants towards catalyst surface and swelling-deswelling of hybrid microgels.

scholarly journals Palladium nanoparticles supported on activated carbon (C) for the catalytic hexavalent chromium reduction

2021 ◽  
Author(s):  
İbrahim Gözeten ◽  
Mehmet Tunç
Keyword(s):  
Activated Carbon ◽  
Formic Acid ◽  
Acid Medium ◽  
Hexavalent Chromium ◽  
Catalytic Reduction ◽  
Activation Parameters ◽  
Trivalent Chromium ◽  
Reducing Agent ◽  
Chromium Reduction ◽  
Mild Conditions

Abstract Hexavalent chromium is widely used in industry and causes human health and environmental problems due to its extremely toxic properties. On the contrary, trivalent chromium is necessary for living ecosystems. Therefore, it is best idea to detoxicate hexavalent chromium by reducing hexavalent chromium to trivalent chromium.. Pd(0)@C catalyst was prepared in solution under mild conditions by a simple impregnation-reduction method and was identified by XPS, XRD, TEM, TEM-EDX, HR-TEM, ICP-OES analyses. TEM results showed that very well dispersed Pd nanoparticles were formed on the C surface (mean particle sizes 3.98 ± 0.24 nm). The catalytic activity of Pd(0)NPs impregnated on C was tested in hexavalent chromium reduction in the reducing agent formic acid medium. The activated carbon supported Pd(0)@C nanoclusters were used as heterogeneous nanocatalysts in the catalytic reduction of Hexavalent chromium in formic acid medium, which is a good reducing agent under mild conditions. It was determined that the formed Pd(0) nanoclusters could successfully reduce Cr(VI) to Cr(III) by high selectivity (~ 97%). It was observed that the Pd(0)@C catalyst retained a significant (> 75%) initial activity even after the 5th use. In addition, for the kinetic data of the catalytic reduction reaction of Cr(VI) catalyzed by Pd(0)@C, the rate equation and activation parameters were derived depending on the [Cr2O72−], [Pd(0)@C], [HCOONa], [HCOOH]concentrations and temperature.

In situ green synthesis of Au nanoparticles onto polydopamine-functionalized graphene for catalytic reduction of nitrophenol

RSC Advances ◽  
2014 ◽  
Vol 4 (110) ◽  
pp. 64816-64824 ◽  
Author(s):  
Jing Luo ◽  
Nan Zhang ◽  
Ren Liu ◽  
Xiaoya Liu
Keyword(s):  
Catalytic Activity ◽  
Green Synthesis ◽  
Au Nanoparticles ◽  
Catalytic Reduction ◽  
Reducing Agent ◽  
Functionalized Graphene ◽  
Au Nps ◽  
Surface Modifier ◽  
Green Route

A simple and green route was demonstrated to prepare graphene/Au NPs nanocomposite using polydopamine as surface modifier, reducing agent and stabilizer simultaneously, which exhibits remarkable catalytic activity for the reduction of 4-nitrophenol.

scholarly journals A Superhydrophobic, Antibacterial, and Durable Surface of Poplar Wood

Nanomaterials ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 1885
Author(s):  
Xinyu Wu ◽  
Feng Yang ◽  
Jian Gan ◽  
Zhangqian Kong ◽  
Yan Wu
Keyword(s):  
Stearic Acid ◽  
Antibacterial Properties ◽  
Alkali Resistance ◽  
Poplar Wood ◽  
X Ray Diffraction ◽  
X Ray ◽  
Different Temperatures ◽  
Acid And Alkali Resistance ◽  
The Stability

The silver particles were grown in situ on the surface of wood by the silver mirror method and modified with stearic acid to acquire a surface with superhydrophobic and antibacterial properties. Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and X-ray energy spectroscopy (XPS) were used to analyze the reaction mechanism of the modification process. Scanning electron microscopy (SEM) and contact angle tests were used to characterize the wettability and surface morphology. A coating with a micro rough structure was successfully constructed by the modification of stearic acid, which imparted superhydrophobicity and antibacterial activity to poplar wood. The stability tests were performed to discuss the stability of its hydrophobic performance. The results showed that it has good mechanical properties, acid and alkali resistance, and UV stability. The durability tests demonstrated that the coating has the function of water resistance and fouling resistance and can maintain the stability of its hydrophobic properties under different temperatures of heat treatment.

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