Current Issue : April - June Volume : 2015 Issue Number : 2 Articles : 7 Articles
Preparation of sulfated zirconia-pillared montmorillonite was carried out in two steps; zirconia pillarization and sulfation to\nzirconia-pillared montmorillonite.The prepared materials were characterized by using X-ray diffraction (XRD), measurement of\nthe specific surface area, total pore volume and pore size distribution by the N2 adsorption method, scanning electron microscopyenergy\ndispersive X-ray (SEM-EDX), and surface acidity determination by using pyridine adsorption-FTIR analysis. The activity\nof the materials as catalysts was evaluated for a microwave-assisted conversion of citronellal. The results showed that the prepared\nmaterials had a physicochemical character that promoted high catalytic activity to convert citronellal. From varied Zr content and\nstudy of the effect of sulfation on the activity, it was found that Zr content and sulfation increase the surface acidity of the material\nas shown by the higher total conversion and tendency to produce menthol as a product of the tandem cyclization-hydrogenation\nmechanism....
Chitosan-based photocatalyst composites containing CdS nanocrystals with and without glutaraldehyde or epichlorohydrin crosslinking\ntreatments were investigated and the catalyzed photodegradation of methyl orange in aqueous solution was examined.\nIn addition, the effects of catalyst dosage, initial dye concentration, and initial pH of the dye solution on the photodegradation\nkinetics were investigated. In this study, the effect of initial solution pH was more important than other factors. The photocatalyst\ncomposite could remove 99% dye in 80 minutes at pH 4. The catalyst composite was characterized by using X-ray diffraction\n(XRD), transmission electron microscopy (TEM), thermogravimetric analysis (TGA), fourier transform infrared (FT-IR), and\nvisible reflectance spectroscopy. The dye removal mechanism of methyl orange involved an initial sorption process followed\nby photodegradation. The sorption process underwent the pseudo-second order kinetics, while photo degradation followed\nthe Langmuir-Hinshelwood kinetics. Although the glutaraldehyde cross-linked chitosan enhanced the initial dye sorption,\nthe epichlorohydrin cross-linked catalyst composite demonstrated a better overall dye removal performance, especially in the\nphotodegradation step. Both chitosan encapsulated catalyst with and without epichlorohydrin cross-linking demonstrated the same\npseudo-first order photo degradation kinetic constant of 0.026 min?1 and the same dye removal capacity. The catalyst composite\ncould be reused but the photo catalytic activity dropped successively in each cycle....
It is the need of hour to plan mining operations with sustainable development. The present work is a step in the direction to determine the magnitude of impact of mica mining on natural eco system. This study will pave the light for the mine planners and environmentalists working in mining in general and pegmatite mining in particular for eco-friendly mining....
The industrial removal process of the light hydrocarbon and water from wet natural gas can be simulated in laboratory with the\nindependently designed helically coiled tube gas-liquid separator. Experiment and numerical simulation are combined to analyze\nthe influences of various inlet velocities and gas void fractions on the gas-liquid separation efficiency and pressure-drop between\nthe inlet and outlet of the helically coiled tube. The results show that, at the inlet velocity of 4m/s to 18 m/s and the gas void fraction\nof 88% to 97% for the gas-liquid mixture, the gas-liquid separation efficiency increases at the beginning and then decreases with\nincreasing inlet velocity. Afterwards there is another increasing trend again. The gradient of pressure-drop increases slowly and\nthen fast with the increasing inlet velocity. On the other hand, the gas-liquid separation efficiency first increases with the gas void\nfraction and then shows a decreasing trend while the pressure-drop keeps falling down with the gas void fraction increasing. Above\nall the optimal operating parameters of the helically coiled tube separator are inlet velocity of 13 m/s and gas void fraction of 93%,\nand the separation efficiency and pressure-drop are 95.2% and 0.3MPa, respectively....
The hydrothermally treated sweet sorghumbagasse (SSB) powder was treated using Ca(OH)2 to extract the lignin fromit. Changes\nin chemical composition of SSB and the formation of sugars and hydrolytic products were studied.The optimum conditions of 10%\n(g/g substrate) Ca(OH)2 and 106.3 min of isothermal treatment residence time at 394K resulted in 69.67 �± 1.26% of the lignin\nextracted from the hydrothermally treated SSB powder, producing a solid residue containing 68.29 �± 0.31% residual cellulose\nand 13.26 �± 0.32% residual lignin in it. The Ca(OH)2 concentration and isothermal treatment residence time were significant in\nthe responses observed. Treatment using Ca(OH)2 is one of the potential processes for the on-farm processing of lignocellulosic\nmaterials....
A long-term test was performed in a fluid catalytic cracking (FCC) hot gas filtration facility using sintered metal candle filters.The\noperating temperature and pressure were maximum 55?C and 0.28MPa, respectively. Specific particle sampling systems were used\nto measure the particle size and concentration directly at high temperature.The range of inlet particle concentration is from 150 to\n165 mg/Nm3.The outlet particle concentration is in the range of 0.71ââ?¬â??2.77 mg/N m 3 in stable operation.The filtration efficiency is\nfrom 98.23% to 99.55%.The inlet volume median diameter and the outlet volume median diameter of the particle are about 1 ?m and\n2.2 ?m, respectively.The cake thickness is calculated based on the equation of Carman-Kozeny. The effects of operating parameters\nincluding face velocity, gas cleaning pressure, pulse duration, and maximum pressure drop were investigated.The optimal operating\nconditions and cleaning strategies were determined. The results show that sintered metal fiber filters are suitable for industrial\napplication due to the good performance and high efficiency observed....
Waste water treatment of some heavy metals was carried out by synthetic zeolite P1, which was prepared by alkaline hydro thermal\ntreatment of the pumice. Both of the pumice raw materials and synthetic zeolite were investigated for their chemical phase\ncomposition, physical properties, and micro structure.The adsorption behavior of Na-zeolite P1 with respect to Co+2, Cu+2, Fe+2,\nand Cd+2 has been studied to be applied in the industrial waste water treatment. Metal removal was investigated using synthetic\nsolutions at different ions concentrations, time, and Na-P1 zeolite doses as well as constant temperature and pH. It is concluded\nthat the optimum conditions for synthesis of highly active Na-P1 zeolite from natural pumice raw material are one molar NaOH\nconcentration, temperature at 80?C, and one week as a crystallization time. In addition to the effect of time and zeolite dose as well\nas the ion concentration of the reaction efficiency for metals removals are recorded....
Loading....