Reaction Kinetics, Mechanisms and Catalysis 

About: Reaction Kinetics, Mechanisms and Catalysis is an academic journal published by Springer Science+Business Media. The journal publishes majorly in the area(s): Catalysis & Photocatalysis. It has an ISSN identifier of 1878-5190. Over the lifetime, 2310 publications have been published receiving 18292 citations.

Adsorption kinetics and isotherm of methylene blue and its removal from aqueous solution using bone charcoal

Abstract: This study aims at describing the removal of methylene blue (MB) from aqueous solution using bone charcoal (BC) as an adsorbent material. The effects of dye concentration, pH, contact time and the adsorbent dose were investigated. The chemical composition and solid structure of BC were analyzed using X-ray diffraction (XRD) and scanning electronic microscopy (SEM). The surface area was measured via the Brunauer–Emmett–Teller (BET) isotherm. The experimental data were analyzed with Langmuir, Freundlich and Temkin isotherm models. The results show that the main component of BC is calcium hydroxylapatite (Ca5(PO4)3OH). The BETSuface area of BC is approximately 100 m2/g. The experimental adsorption isotherm complies with Langmuir equation model (R 2 = 0.99) and the maximum amount of adsorption (q max) was 5 mg/g. The elevation of BC dose led to a decrease in q max, however, increasing the pH led to the elevation of dye adsorption. The kinetic studies revealed that the adsorption of MB is rapid and complies with the pseudo second-order kinetic (R 2 > 0.99). Apart from R 2, four error functions have been used for the validation of data. Analysis of data with Dubinin–Radushkevich isotherm showed that the energy of MB adsorption process onto BC was 2.65 kJ/mol, which implies that the adsorption of MB with BC is a physical adsorption.

Enhanced CO oxidation and toluene oxidation on CuCeZr catalysts derived from UiO-66 metal organic frameworks

Abstract: In this work, several MxOy-supported ZrO2 (MxOy = CuO, CeO2, CuO-CeO2) catalysts were prepared through the direct decomposition of metal organic frameworks UiO-66 in air. The catalysts were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), N2 adsorption–desorption isotherms and H2-temperature programmed reduction (H2-TPR). The catalytic performance for CO oxidation and toluene oxidation over Zr based catalysts was investigated. Amongst the prepared catalysts, CuCeZr catalyst displayed excellent CO oxidation and toluene oxidation performance. The addition of Cu was favorable to the enhancement of catalytic performance. Importantly, the addition of cerium led to the formation of easily reducible surface copper species, consequently improving the CO oxidation and toluene oxidation performance.

Methanol synthesis from CO2 hydrogenation over copper based catalysts

Abstract: A series of Cu–ZnO/Al2O3 catalysts prepared by coprecipitation were used for methanol synthesis by CO2 hydrogenation in a fixed bed reactor system. The effect of the catalysts composition and the reaction temperature on the catalytic activity was investigated. The main results show that the highest CO2 conversion and the best yield of methanol are obtained with the catalyst containing 51 wt% Cu and 22 wt% Zn. This result is assigned to the highest metallic copper surface area and to the interaction between copper and zinc oxide. However, the reaction temperature increase is disadvantageous for the methanol synthesis reaction.

A novel Ag/BiOBr nanoplate catalyst with high photocatalytic activity in the decomposition of dyes

Abstract: A novel Ag/BiOBr composite catalyst has been synthesized by a solution combination with photodeposited method. The as-synthesized catalysts were characterized by powder X-ray diffraction, scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy, and UV–Vis diffuse reflectance spectra. The photocatalytic reaction tests in the degradation of the dyes of acid orange II, rhodamine B and methyl orange showed that the deposition of optimal amount of 1–2 wt% Ag could bring about a big increase in the activity under visible light irradiation. The high photocatalytic performance could be attributed to the strong visible light absorption and low recombination rate of the e−/h+ pairs resulted in by the presence of metal silver nanoparticles.

The influence of different agitation techniques on the adsorption kinetics of 4-chlorophenol on granular activated carbon

Abstract: The influence of different agitation techniques on the adsorption of organic compounds, represented by 4-chlorophenol, onto granular activated carbon was investigated. The effect of the flask type and the type of agitator, including a laboratory shaker, mechanical agitator, magnetic stirrer as well as mixing with gas bubbles, was studied. The results of adsorption kinetics demonstrate that the adsorption process of 4-chlorophenol on the activated carbon follows a pseudo-second order kinetic model closely. The adsorption equilibrium was reached faster in the Erlenmeyer flask than in the round-bottomed flask. At the same agitation speed (200 rpm), the better adsorption rate and adsorption efficiency were observed using the mechanical and magnetic stirrers than the laboratory shaker. At the gas flow rate of 1.5 dm3 min−1, the mixing with the air or nitrogen bubbles was comparable with the agitation when using mechanical and magnetic stirrers at 200 rpm. The effect of the agitation speed on the adsorption of the 4-chlorophenol by the activated carbon was also tested. The kinetic experiments were carried out at 100, 200, 300 and 500 rpm and it was found that the adsorption rate increases with the increase in the agitation speed. As the stirring rate increased from 100 to 500 rpm, the adsorption rate constants increased from 0.577 to 1.264 g mmol−1 h−1 (mechanical agitator) and from 0.560 to 1.231 g mmol−1 h−1 (magnetic stirrer), respectively. The experimental results demonstrate that the agitation affects the adsorption kinetics significantly as well as the adsorption equilibrium of the organic compounds on the activated carbon, and should be taken into account in such studies.