Current Issue : January - March Volume : 2019 Issue Number : 1 Articles : 6 Articles
This work evaluates the use of a synthetic NaP1 zeolite obtained from a hazardous Al-containing waste for the removal of ammonium\n(NH4\n+) from aqueous solutions by batch experiments. Experimental parameters, such as pH (6â??8), contact time (1â??360 min),\nadsorbent dose (1â??15 g/L), and initial NH4\n+ concentration (10â??1500 mg/L), were evaluated. Adsorption kinetic models and\nequilibrium isotherms were determined by using nonlinear regression. The kinetic was studied by applying both the pseudo-firstorder\nand pseudo-second-order models. The equilibrium isotherms were analyzed according to two-parameter equations\n(Freundlich, Langmuir, and Temkin) and three-parameter equations (Redlichâ??Peterson, Sips, and Toth). The results showed that the\nNH4\n+ uptake on NaP1 was fast (15 min) leading to a high experimental sorption capacity (37.9 mg/g). The NH4\n+ removal on NaP1\nwas a favorable process that followed the pseudo-first-order kinetic model. The NH4\n+ adsorption was better described by the Sips\n(54.2 mg/g) and Toth (58.5 mg/g) models. NaP1 zeolite from Al-waste showed good NH4\n+ sorption properties, becoming a potential\nadsorbent to be used in the treatment of contaminated aqueous effluents. Thus, a synergic effect on the environmental protection can\nbe achieved: the end of waste condition of a hazardous waste and the water decontamination....
The aim of this study is to determine favorable process conditions for the coating of placebo tablets. Tablets made of microcrystalline\ncellulose are coated with hydroxypropyl cellulose polymer and Advantiaâ?¢ Prime polymeric mixture film in lab-scale\nfluid-bed environment with a Wurster tube. In order to determine favorable process conditions (concentration, Wurster tube\nposition, inlet air temperature, and atomization pressure), evaluation factors expressing process efficiency were calculated.\nStereomicroscopy analysis provided good results with respect to the coating layer adherence and consistency. Results showed that\nthe increased number of the coating cycles contributes to the desired featureless film morphology, when sufficiently high\ntemperature and pressure are applied, thus resulting in high intra- and intertablet uniformity. Additionally, this paper analyzes the\ncoating process from a mechanistic perspective of the underlying phenomena occurring on a tablet surface. Provided diagrams\ncan help efficiently in detecting proper conditions that will result in coated tablets with strictly defined aimed properties. Process\nand formulation properties synergically result in a preferential occurrence of a deposition mechanism for all experiments\nconducted. Moreover, collision is found as a prevalent impact regime for the coating process studied. Finally, our intention here is\nto correlate hydrodynamic conditions and droplet breakup occurrence with a droplet diameter....
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Over the years, the oil industries have avoided aromatic, naphthenic, and paraffinic oils as drilling mud base fluids principally\nbecause of their detrimental environmental issues on pelagic and benthic marine ecosystems as a result of their toxicity and\nnonbiodegradability coupled with the possible deterioration of the oil itself and the rubber parts of the drilling equipment because\nthe aromatic hydrocarbons present in the oil have a tendency to dissolve/damage elastomers present in rubber. Hence, possible\ninsights into how to chemically and/or physically produce synthetic base drilling fluids whose cuttings are nontoxic, readily\nbiodegradable, environmentally friendly, and of nonpetroleum source become imperative. In this study, enzymatic interesterification\nof canola oil was done with ethanol by using enzyme lipase as catalyst under optimum conditions of temperature and\npressure and the physicochemical properties of the produced ester were evaluated and compared with that of diesel and a synthetic\nhydrocarbon base fluid (SHBF). Results show that the specific gravity, kinematic viscosity, dynamic viscosity, and surface tension\nof canola oil were reduced by 5.50%, 94.74%, 95.03%, and 9.38%, respectively, upon enzymatic interesterification to conform to\nstandard requirements. Similarly, increased |mud ability to pump fluids and possibility of cold temperature environment can be\nachieved with the reduction in pour point and cloud point, respectively, of the produced canola oil ester. Finally, the produced\nester showed no aromatic content as confirmed from its FTIR analysis which indicates its nontoxicity, biodegradability, and\nenvironmental friendliness....
In this work, the production of Syngas (H2/CO) from oxidative reforming of methane (ORM) and partial oxidation of methane\n(POM) over NiO/Y2O3/ZrO2 catalysts was studied. The nickel concentration was varied (ranging from 0 to 40 wt.%) aiming to\noptimize the performance in ORM and POM reactions; these reactions were carried out at 750 C and 1 atm for 6 hours. The\ncatalysts were prepared by the one-step polymerization method (OSP) and characterized by different techniques. This method led\nto production of materials of smaller crystallite size than others of similar composition prepared under other methods; the\ncatalysts presented good nickel dispersion, well-defined crystalline structure, and well-defined geometrical morphology. Additionally,\nthe OSP method was advantageous because it was carried out in a single calcination step. The catalyst containing 20%\nwt. of nickel (20Ni20YZ sample) showed the highest methane conversion, high selectivity to H2 and CO, low carbon deposition\nrates, and, curiously, the best geometric morphology. The results of this paper also demonstrated that the nickel concentration in\nthe mixture strongly influenced the morphology of the catalysts; therefore, the morphology also influenced the catalytic performances\nduring the Syngas production reactions....
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