Current issue of "International Review of Chemical Engineering

International Review of
Chemical Engineering
Rapid Communications (IRECHE)
January 2014 (Vol. 6 N. 1)

of IRECHE:

Immobilization of Recombinant CGTase JCGT8-5 on Magnetically-Modified Silicates and Natural Supports

by V. Ivanova, K. Petrov, M. Safarikova, I. Safarik, P. Petrova, A. Tonkova, N. Delchev

Abstract - Recombinant cyclodextrin glucanotransferase JCGT8-5 (CGTase, EC 2.4.1.19) was effectively immobilized by adsorption on magnetically-modified particles. Silicates (montmorillonite and halloysite), natural supports (oat straw, wheat bran, banana peel, sawdust, hazelnut and peanut shell, coffee beans, tea leaves, algae Chlorella vulgaris) and activated carbon were engaged as carriers, as the most of them were used for the first time for enzyme adsorption. The immobilization capacities of the carriers entrapping ultra-concentrate or purified enzyme were determined. Binding yields reached from 50% to 90% of the initial enzyme quantity. The analysis of the formed cyclodextrins (CDs) revealed that the highest amount of total CDs was obtained by the use of halloysite particles (10.1 mg/ml), followed by sawdust (8.6 mg/ml), algae (8.6 mg/ml) and peanut shell (8.2 mg/ml). A high degree of starch conversion into CDs, ranging from 21 to 25% was achieved for 20 min starch hydrolysis. Variations in γ-CD: α-CD: β-CD ratios due to the immobilization on the different carriers were observed. The six-fold reuse of the magnetic biocatalysts containing purified recombinant CGTase bound to halloysite, washed algae or sawdust provided 29-36 mg/ml CD yield without presence of α-CD for 120 min starch hydrolysis.

Keywords: Immobilization, Recombinant CGTase, Magnetic Carriers, CDs Production .

Production of Saturated Esters from Hydrolysis and Hydrogenation Simultaneous Process

by Carla C. C. M. da Silva, Ana Paula da Silva, Luzineide W.Tinoco, Isabelle Cândido de Freitas, Jussara Gonçalvez, Neyda Om Tapañes, Mariana M.V. M. Souza, Donato A. G. Aranda

Abstract - Hydrolysis reactions are of major importance to the oleochemical industry in the production of fatty acids and their derivates. During the hydrolysis of Castor oil using nickel catalysts it was verified that the glycerol produced worked as hydrogen donor, allowing the hydrogenation of unsaturated ester produced. Maximum conversion was achieved in 3 hours, using 25% NiO/CeO₂/Al₂O₃ catalyst, temperature of 250°C and 280°C.

Keywords: Hydrolysis, Castor Oil, Hydrogenation, Saturated Fatty Acid.

Closed-Loop Identification and Performance Indexes of an Industrial Paperboard Machine

by A. M. Almeida, G. S. Silva, I. Neitzel, M. K. Lenzi

Abstract - A closed-loop identification technique was applied to the pH control loop of the headbox of an industrial paperboard machine. A first-order-plus-time-delay process model was inserted into the closed-loop transfer function. The ISE index and its uncertainty were determined, leading the Kahn and Lehman rule to present the best performance and to the lowest ISE uncertainty. A novel index, IEP (integral of the error propagation), was also proposed to investigate the accuracy of the controlled variable predictions. The IEP index also led to the choice of the Brambilla et al tuning rule as the best choice, as it presented the lowest value.

Keywords: pH, Closed-Loop, Uncertainty, Performance Index, Industrial Data, Paper Machine .

Bimetallic Platinum Catalysts for Paraffin Dehydrogenation

by S. B. Kogan

Abstract - Promoting action of elements of Cu, Zn, Ga, Ge, Bi, S subgroups and of Re on platinum catalysts in paraffins dehydrogenation is considered. The mechanism of influence on activity, selectivity and stability (coke tolerance effect) is discussed. It was demonstrated the prevailing role of geometric (ensemble) factor.

Keywords: Paraffins Dehydrogenation, Bimetallic Platinum Catalysts, Coke Tolerance Effect.

Comparative Analysis of Investments for Biodiesel Production with Help of Excel Spreadsheet

by Paulo Roberto Cisneiros Vieira, Valdemir Alexandre dos Santos

Abstract - Was developed a computational method in Excel® spreadsheet to compare investments with application in the production of biodiesel. Biodiesel can replace all or part of the diesel oil in automotive diesel engines. Its use on a large scale will allow the economy to foreign exchange to import diesel oil, and expected reduction of environmental pollution. The methodology applied to assess the economic viability of a production process used the simultaneous employment of technical calculations of Net Present Value (NPV) and Internal Rate of Return (IRR). A value of IRR in the NPV calculation expression replacing the Minimum Rate of Attractiveness (MRA) and leads to an iterative calculation whose result cancels the NPV value. For a quick and efficient choice of investment more attractive the spreadsheet was developed using the Excel 2007® Solver function. This tool is available and easily accessible to investors. It is established that presented method for calculating those economic parameters requires minimal efforts from the users.

Keywords: Biodiesel Fuel Production, Waste Cooking Oils, NPV, IRR, MRA.

Spectroscopic Studies on the Degradation of Methylene Blue by Using TiO₂ and TiO₂ - (x) ZnFe₂O₄

by Violeta Dimitrova Kassabova-Zhetcheva, Lilyana Parvanova Pavlova

Abstract - Titanium dioxide (TiO₂) and nanocomposites of TiO₂ – (x) Zinc Ferrite (ZnFe₂O₄); (x = 0.01, 0.04 and 0.06 mole fractions) have been synthesized by complex polymerization process involving peroxy species. The used nanometric ZnFe₂O₄ was previously prepared. The materials have been characterized through X-ray diffraction (XRD) and Electron Paramagnetic Resonance (EPR). Photo-catalytic action of synthesized materials has been evaluated by the Ultraviolet - Visible (UV-Vis) spectroscopy through degradation of pollution model Methylene Blue (MB). Optical thresholds have been measured by applying Ultraviolet - Visible Diffuse Reflectance Spectroscopy (UV-Vis DRS). The addition of previously synthesized ZnFe₂O₄ contributes to the extension of photo-response in the visible range of light but this phenomenon differs from previous studies because it does not cause higher photo-catalytic action compared to TiO₂ derived by the same method. UV-Vis DRS studies give reason to assume that the enhanced photo-catalytic action of ТiO₂ - (X) ZnFe₂O₄ composites compared to that of TiO₂ is probably due to the accidental inclusions of ferric ions in the lattice of TiO2, rather than charge transfer due to heterojunction band alignment, which was claimed in prior studies. The basis for this assumption is the appearance of absorption threshold of all composite materials around 450 nm, which is not typical, neither for Zn-ferrite nor for TiO₂.

Keywords: Titanium Dioxide, Nanocomposites, Visible Light-Activated Catalysis, Zinc Ferrite, Methylene Blue.

Macro-Molecules as a Source of Levulinic Acid

by Johan Ahlkvist, Päivi Mäki-Arvela, Jyri-Pekka Mikkola

Abstract - The production of levulinic acid from biomass and macromolecules has been reviewed. It was concluded that the most important parameters in the one-pot hydrolysis of biomass, also including dehydration of glucose to hydroxymethylfurfural as well as its further rehydration to formic and levulinic acids, respectively, are the reaction temperature, initial reactant concentration, acid type as well as the raw material applied. The theoretical maximum yield can hardly be obtained due to formation of humins.Further, the optimum reaction conditions as well as the influence of the catalyst and biomass type are also discussed.

Keywords: Biomass, Acid Catalysts, Levulinic Acid.

Vegetable Oils for Biodiesel Production as Friendly Energetic Alternative: The Case of Mexico

by D. Alvarez-Barrera, G. Segovia-Hernández, A.J. Castro-Montoya, R. Maya-Yescas, M.C. Chávez-Parga

Abstract - Among the current cited biofuels, biodiesel production using vegetable oils as raw materials exhibits technical, social and economic advantages. Some crops exhibit untapped potential as source-alternatives for satisfying the increasing energy demand; therefore, it is important to study the feasible reaction routes to transform triglycerides, mainly, into biodiesel. Mexico has been taken into account as case of study, in order to estimate the potential utility and economic impact of vegetable oils in its development. It is noticed that about 90% of the Mexican territory exhibits favorable climatic characteristics to crops able to produce vegetable oils useful in biodiesel production.

Keywords: Biodiesel, Energy Alternative, Mexico, Vegetable Oils.

Special Section on 5^th CEAM 2013 - Virtual Forum

Experimental Investigation of Equilibrium Adsorption for Pure Propylene on 13X and Li- modified 13X Zeolites

by F. Rahiminejad, M. Soleimani, A. Kargari, M. TakhtRavanchi, M.Songolzadeh

Abstract - Propylene is one of the most commonly used materials in petrochemical industries. In most methods for producing propylene, a mixture of propylene and propane is achieved. In recent decades, among various separation methods for these mixtures, adsorption process have been concerned as a preferred one due to features such as low operating cost, simplicity and low energy consumption. In this work, the equilibrium adsorption of pure propylene over two commercial zeolite types (13X and Li-modified 13X) has been investigated. The experiments have been performed using static volumetric method at 293, 303 and 323 K and the pressure up to 2.5 bar. The results indicated that the equilibrium adsorption capacity of 13X is greater than Li-modified 13X (about 10 to 30%) at these operating conditions. Four Equilibrium isotherm models, namely, Freundlich, Langmuir, Toth and Sips have been implemented to analyze the equilibrium data. Equilibrium results were in good agreement with Toth and Sips isotherms for propylene adsorption over 13X. However, the results of equilibrium isotherm of propylene over Li-13X indicated that none of these models fit the experimental data correctly. This phenomenon may be due to the chemical adsorption.

Keywords: Propylene, Adsorption, Zeolites, Volumetric, Equilibrium Isotherm.

Immobilization of Beta-Cyclodextrin on to the Activated Carbon

by Mohammad Hassan Mahaninia, Tahereh Kaghazchi, Mansooreh Soleimani

Abstract - In present work, immobilization of activated carbon with Beta-Cyclodextrin have been carried out. Both activated carbon and Beta-Cyclodextrin have adsorption properties but Beta-Cyclodextrin is soluble in water thus it needs a base substance for anchoring. In order to immobilization of Beta-Cyclodextrin on activated carbon, a straightforward strategy has been applied in this study. First, activated carbon has found suitable surface functional groups by means of a series of chemical reaction. These groups have capability to connect with Beta-Cyclodextrin hydroxyl group. Then, activated carbon and Beta-Cyclodextrin bounded together. Finally, the structural properties of resulting composite were characterized by means of main analyzing methods such as N2 adsorption/desorption, Fourier transform infrared (FT-IR), thermogravimetric analysis (TGA), elemental Analysis, and SEM observation to indicate which immobilization has occurred. Our results demonstrate that connection between activated carbon and Beta-Cyclodextrin has occurred both physically and chemically.

Keywords: Activated Carbon, Beta- Cyclodextrin, Immobilization, Characterization.

Characterization of Polyethylene Decomposition Reactions Using the TG Curve

by D. Lázaro, E. Puente, M. Lázaro, D. Alvear

Abstract - Pyrolysis models represent the fundamental mechanism of fire spread modelling, and are also important tools for assessing the flammability properties of materials. Within these models the reaction rates of materials can be characterized by a set of parameters such as the pre-exponential factor (A), the energy of activation (E) and the reaction mechanism f(α). To obtain automatically a reaction scheme we use in this paper the change in mass loss rate during pyrolysis. This is possible by hypothesizing that the polymer mass loss rate is a chain of stable successive processes characterized by a constant mass loss rate. Once the reaction scheme is fixed, we suppose Arrhenius-like behaviour obtaining the kinetic triplet for each reaction step; the apparent activation energy, the pre-exponential factor and the global reaction mechanism. The interpretation was applied to thermo-oxidation and decomposition of lineal low-density polyethylene performed by simultaneous thermal analysis.

Keywords: Pyrolysis, Thermal Analysis, Lineal Low-Density Polyethylene, Kinetic Mechanism.