Development And Analysis Of Hydrotalcite-Modified Porous Membranes For Carbon Dioxide Separation

The emission of carbon dioxide (CO2) has become one of the most serious environmental problems since the industrial revolution. Today, reducing CO2 emissions is considered extremely important in order to abate the global climate change and global warming. For this purpose, CO2 separations from gas mixtures have been actively researched. The main objective of this research is to separate CO2 from the synthetically produced gas stream containing binary gas mixtures using inorganic membrane technology. The research focused on the synthesis and development of different porous inorganic membranes modified with hydrotalcite (HT) to facilitate the separation of CO2. Hydrotalcite material was incorporated to improve the CO2 affinity and the thermal stability of the inorganic membranes for CO2 gas separation. The crack free mesoporous HT-alumina (~10 μm) and microporous HT-silica (~200 nm) porous membranes were successfully synthesized on top of γ-Al2O3 layer supported by a α-Al2O3 disc support using the sol-gel and dip-coating techniques. The effect of different parameters on the membrane performance, the structure and permeation properties relationships and the transport mechanism were studied by varying hydrotalcite compositions and sintering temperatures. The unsupported membranes were characterized for the presence of HT, surface functional groups, surface topography and morphology, surface area, pore size, CO2 adsorption and desorption capacity

Vanadium oxide supported on porous clay heterostructure for the partial oxidation of hydrogen sulphide to sulfur

Vanadium oxide supported on porous clay heterostructures (PCH) catalysts have been synthesized, characterized and evaluated in the selective oxidation of H2S to elemental sulfur. The catalysts were characterized by XRD, adsorption-desorption of N-2 at -196 degrees C, diffuse reflectance UV-vis, H-2-TPR, Raman spectroscopy and XPS. The catalysts with higher vanadium content are more active and selective, exhibiting a H2S conversion close to 70% after 360h on stream with a high selectivity toward elemental sulfur and a low formation of undesired SO2. The catalysts with V2O5 crystallites have shown a higher activity and resistance to the deactivation. The analysis of the spent catalyst has revealed the formation of V4O9 crystals during the catalytic test, which has been reported as the active phase in the selective oxidation of the H2S. (C) 2015 Elsevier B.V. All rights reserved.The authors would like to thank the DGICYT in Spain (Projects CTQ2012-37925-C03-01, CTQ2012-37925-C03-03 and FEDER funds, and MAT2010-19837-C06-05) and project of Excellence of Junta de Andalucia (project P12-RNM-1565) for financial support. A. Natoli thanks to SECAT (Spain) for a grant.Soriano Rodríguez, MD.; Cecilia, JA.; Natoli, A.; Jimenez-Jimenez, J.; López Nieto, JM.; Rodriguez Castellon, E. (2015). Vanadium oxide supported on porous clay heterostructure for the partial oxidation of hydrogen sulphide to sulfur. Catalysis Today. 254:36-42. https://doi.org/10.1016/j.cattod.2014.12.022S364225

Electrolytic Production of Potassium bromate Using Graphite Substrate Lead dioxide (GSLD) Anode

Graphite substrate lead dioxide (GSLD) was used to make a suitable anode for the production of potassium bromate from potassium bromide. This anode has been used successfully in the presence of certain addition agents (like potassium dichromate) as a replacement for graphite anode. A laboratory electrolytic cell was designed to produce of potassium bromate. A solution of potassium bromide (240 g/l) and potassium bromate (20 g/l) is electrolyzed in batch wise. The effect of anodic current density, temperature, and starting PH of electrolyte on the current efficiency of bromate formation was studied. High current efficiency of about 92 – 94 % was obtained by using (GSLD)

Wastewater Treatment Using Modified Alumina

Alumina surface was modified by adsorption of an anionic surfactant, sodium sulfate (S.S). Typical S-shaped isotherm of surfactant on alumina was observed. The adsorption of herbicide on alumina and surfactant treated alumina has been investigated.The enhancement in adsorption of herbicide on surfactant treated alumina is observed, which may be attributed to the solubilization of herbicide on surfactant aggregates formed at solid/liquid interface. The effect of pH on adsorption has been studied. The adsorption is greatly influenced by pH of the medium. The applicability of Freundlich equation was tested for equilibrium data. The influence of various factors such as initial concentration, and mass of adsorbent on adsorption was also studied. The batch kinetics has been tested to pseudo second order reaction and rate constants were calculated

Kinetic Study of Carbon Dioxide Reaction with Binding Organic Liquids

Binding organic liquids are strong base of amidine have been used for CO2 capture. Up to now, there is no known datum on the reaction kinetics of CO2 with 1.5-Diazabicyclo [4.3.0] non-5-ene (DBN). In this paper, Kinetics of reaction between CO2 and DBN/MDEA in 1-Pentanol was performed utilizing the stirred cell reactor with DBN concentration (2 – 2.9 M) and at room temperature. The reaction path was qualified using zwitterion and the termolecular mechanism. From the kinetic datum with DBN concentrations (2 - 2.9 M), it was found that the capturing process happened in a fast reaction system with a second-order reaction kinetics of DBN/MDEA and first order with CO2. In addition, CO2 absorption was achieved using gas-liquid contact system. CO2 absorption rate was (2×10−5−2.8 × 10−5kmol⁄m2.sec) at DBN concentration (2 – 2.9 M). Finally, it is known that DBN/MDEA/1-Pentanol/CO2 system is easily switchable and can be used both CO2 capture and for other applications that require rapid change of medium from nonionic to ionic liquid

Estimating Of Etchant Copper Concentration In The Electrolytic Cell Using Artificial Neural Networks

In  this paper, Artificial Neural Networks (ANN), which are known for their ability to model nonlinear systems, provide accurate approximations of system behavior and are typically much more computationally efficient than phenomenological models  are used to predict the etchant copper concentration in the electrolytic cell in terms of electric potential, operating time, temperature of the electrolytic cell , ratio of surface area of poles per unit volume of solution  and the distance between poles. In this paper 350 sets of data are used to trained and test the network.. The best results were achieved using a model based on a feedforword Artificial Neural Network (ANN) with one hidden layer and fifteen neurons in the hidden layer gives a very close prediction of the copper concentration in the electrolytic cell.</p

Commercial CaO Catalyzed Biodiesel Production Process

Biodiesel produced from vegetable oils is a good alternative clean diesel. The present study was conducted because there are some variations or contradictions in literature on the use of CaO heterogeneous catalyst. In this study, biodiesel was produced from sunflower vegetable oil and methanol in presence of commercial calcium oxide catalyst in batch mechanical stirrer reactor. The effect of three operating conditions, methanol mole ratio (4-12), reaction time (0.5-2.5 h) and catalyst amount (2-10 %), on the yield of biodiesel was studied at constant reaction temperature of 60 oC. Response surface methodology (RSM) was used with central composite design (CCD) of experiments. Polynomial correlation was found for the dependent variable of the process (yield of biodiesel), satisfactorily predicted at 95% confidence level. The optimum yield biodiesel was about 98% and at operating condition of methanol ratio 10, reaction time 2 h and catalyst amount 8 %. The reaction time was found to be the most effective operating condition. Kinetics study of the process showed that first order reaction with triglyceride concentration and zero order with methanol concentration gave best fit with the experimental data, triglyceride with a reaction rate constant k= 1.53 h-1