SEARCH CONTENT

You are looking at 1 - 10 of 1,203 items :

  • Biotechnology x
Clear All

Abstract

The method used to extract copper from its ores depends on the nature of the ore. The main process currently to separate copper from sulphide ores is the smelting process. The concentrated ore is heated strongly with silicon dioxide (silica), calcium carbonate and oxygen enriched air in a furnace or series of furnaces which is carried out using the injection of the air for oxidation the Fe and Si present in the raw material. Oxygen can be produced using several different methods. One of these methods is Air separation process, which separates atmospheric air into its primary components, typically nitrogen and oxygen, and sometimes also argon and other rare inert gases by cryogenic distillation. In this paper, simulation of air separation units (ASUs) was studied using Aspen Hysys®. The obtained simulation and model was validated with the operational data from the Oxinor I of Air Liquide S.A Plant. The ASU was divided into subsystems to perform the simulations. Each subsystem was validated separately and later on integrated into a single simulation. An absolute error of 1% and 1.5% was achieved between the simulated and observed the process variables(s). This indicated that Aspen Hysys® has the thermodynamic packages and required tools to perform simulations in cryogenic processes at industrial scale.

Abstract

Selective catalytic reduction with ammonia (NH3-SCR) is very efficient DeNOx technique. According to some problems with the commercial catalyst, novel one should be prepared. Hydrotalcites are potential precursors of the new catalysts of NH3-SCR. In this paper, several attempts to apply these materials in NH3-SCR are presented.

Abstract

This paper presents an analysis of DSC/TG/DTG thermal studies for PA6 polyamide, coal fuels and polyamide composites with these materials. The test results are aimed at comparing the thermal effects and behavior of these materials under high temperature conditions and are the basics to know of the creation and use of polymer composites with various coal fillers.

Abstract

Polymer monoliths modified by using nanoparticles (NPs) integrate high NP specific surface area with different monolith surface chemistry and high porosity. As a result, they have extensive applications within different fields, whereas nanomaterial-functionalised porous polymer monoliths have elicited considerable interest from investigators. This study is aimed at fabricating organic polymer-based monoliths from polybutyl methacrylate-co-ethylenedimethacrylate (BuMA-co-EDMA) monoliths prior to immobilization of gold or silver metal on the pore surface of the monoliths using reducing reagent (extracts of lemon peels). This was intended to denote a sustainable technique of immobilizing nanoparticles that are advantageous over physical and chemical techniques because it is safe in terms of handling, readily available, environmentally friendly, and cheap. Two different methods were used in the study to effectively immobilize nanoparticles on monolithic components. The outcomes showed that soaking the monolith rod in the prepared nano solution directly and placing it within ovens at temperatures of 80°C constituted the most effective method. Characterisation of the fabricated monolith was undertaken using SEM/EDX analysis, UV-vis. spectra analysis, and visual observation. The SEM analysis showed that nanoparticles were extensively immobilised on the surface polymers. Another peak was attained through EDX analysis, thus confirming the Au atom existence at 2.83% alongside another peak that proved the Ag atom existence at 1.92%. The fabricated components were used as sorbents for purifying protein. The ideal performance was achieved using gold nanoparticles (GNPs) immobilised organic monolith that attained a greater pepsin extraction recovery compared to silver nanoparticles (SNPs) immobilised organic monoliths alongside bare organic-based monolith.

Abstract

Yerba mate is a source of biologically active substances. The aim was to determine whether the place of origin of Yerba and the brewing method have any influence on the levels of Ca, Mg and Fe and antioxidant activity of infusions. Samples were steeped in cold water (25°C) and hot water (three consecutive infusions with 85°C water). Infusions had a high antioxidant activity and high Mg level. The levels of elements and the antioxidant activity were influenced by the brewing method. There were no significant differences in the examined parameters depending on the country of origin. The results on the levels of elements and the antioxidant activity indicate that the most efficient brewing method was infusion in hot water. The highest levels of elements were found in first infusions, with the highest antioxidant activity in the third infusions.

Abstract

This paper describes the separation of oxidation resistant components from the seeds of pomegranate (PSA), grape (GSE) and sea buckthorn (SSE). The anti-oxidation properties of the resultant extracts, used as the natural anti-oxidants for polypropylene (PP), were compared with Irganox1010. The effects of these natural antioxidants on the antioxidant levels of PP samples were estimated by thermal oxidative aging and micromixed rheology, OIT, XRD, SEM, TEM and mechanical properties tests of samples before and after aging. The results show that adding PSA, GSE and SSE can obviously increase the mechanical properties of PP. In addition, the molding stability of polypropylene raw material is prolonged and improved. Moreover, the mechanical properties of the PP samples after 240 h of thermal oxidative aging indicates that, the best results, closest to the anti-oxidation ability of Irganox1010, can be obtained when the additive amount is 0.5% (wt%) for PSE or 0.7% (wt%) for GSE.

Abstract

In this work, we have designed and synthesized the fluorescent probe 1, which was capable to selectively detect fluoride anion (F). More importantly, the probe 1 possessed near-infrared excitation and emission wavelengths (excitation at 650 nm and emission at 695), and the probe solution had changed dramatically from yellow to cyan with the addition of F. In addition, the fluorescence intensity exhibited perfectly positive correlation with concentration of F concentration from 0 to 40 μM (R2 = 0.9972), which offered the important condition for quantitative analysis. The probe 1 owned detection limit of 46 nM. Therefore, this near-infrared probe can be of great benefit for detecting F in practical application.

Abstract

Spray Drying Absorber (SDA) has been widely used for large-scale desulfurization. However, it also has some limitations. For example, the liquid absorbent easily causes scaling, which impedes the contact between the serous fluid and the flue gas and reduces the chemical reaction rate and desulfurization efficiency. This paper establishes the mathematical and physical model of gas and liquid two-phase flow and droplet evaporation and heat transfer in rotary spray desulfurization tower. To study the accumulation and distribution of chemical reaction precipitates in the desulfurization tower and analyze the removal efficiency of sulfur dioxide (SO2) in different atomization diameters, this paper establishes a simulation model concerning the coupling of desulfurization reaction and flow field calculation based on the absorption and reaction mechanism of SO2. Baffle in different widths are set to optimize the internal flow field and balance the distribution of flue gas. By setting baffles of different widths to optimize the flow field in the tower and changing the distribution of flue gas, this model reduces the scaling while ensuring the desulfurization efficiency. The results of the simulation experiment have verified that the droplet with a diameter of 50 μm is the optimal option, which can effectively remove the scaling and ensure that the desulfurizing tower runs in high efficiency and stability. When the width of baffles is 2250 mm, the efficiency of desulfurization exceeds 95%, and the amount of scaling on the desulfurization tower main wall is controlled at the minimum level, which is the optimal option for production.

Abstract

Simultaneous adsorption of heavy metals in complex multi metal system is insufficiently explored. This research gives results of key process parameters optimization for simultaneous removal of Cd(II), Co(II), Cr(III), Cu(II), Mn(II), Ni(II) and Pb(II) from aqueous solution (batch system). New lemon peel-based biomaterial was prepared and characterized by infrared spectroscopy with Fourier transformation (FTIR), scanning electron microscopy (SEM), electron dispersive spectroscopy (EDS), while the quantification of metals was made by atomic absorption spectrometry (AAS). Simultaneous removal of seven metals ions was favorable at pH 5 with 300 mg/50 mL solid-liquid phase ratio, within 60 min at room temperature with total obtained adsorption capacity of 46.77 mg g−1. Kinetic modeling showed that pseudo-second order kinetic and Weber-Morris diffusion models best describe the adsorption mechanism of all seven heavy metals onto lemon peel.