Experimental Study and Mathematical Modeling of NO Removal Using the UV/H2O2 Advanced Oxidation Process

An experimental study on NO removal via UV/H₂O₂ process was conducted in a semi‐continuous bubble‐column reactor and the effect of some operation parameters including NO initial concentration and gas flow rates on removal efficiency was investigated. Applying UV light increased the efficiency significantly. The steady‐state removal efficiency was found to be higher at the lower gas flow rates. The bubble size as an important factor in mass transfer calculations and modeling procedure was determined at different gas flow rates using bubble photographs and image processing technique. In the ranges of flow rates studied here, the gas flow rate had no significant effect on the bubble diameter. A mathematical model was developed to describe the NO removal process. The model predictions were compared with existing experimental data, confirming a good agreement of the data.     

Investigation on the morphological and mechanical properties of (polyamide 6)/(poly[styrene‐co‐acrylonitrile])/(poly[styrene‐b‐{ethylene‐co‐butylene}‐b‐styrene]) ternary blends

In this work, ternary polymer blends based on (polyamide 6)/(poly[styrene‐co‐acrylonitrile])/(poly[styrene‐b‐{ethylene‐co‐butylene}‐b‐styrene]) (SEBS) triblock copolymer and a varying concentration of the reactive (maleic anhydride)‐grafted SEBS were prepared by using a melt‐blending process. The effects of the material parameters (composition of ternary blends and SEBS/[{maleic anhydride}‐grafted SEBS] concentration ratio) and blending sequence on the morphological and mechanical properties of ternary blends were studied. Taguchi experimental design methodology was employed to design the experiments and select the material and processing parameters for the optimized mechanical properties. Tensile properties (Young's modulus and yield stress) and impact strength were considered as the response variables. It was demonstrated that there is a meaningful relationship between the composition of blends, processing parameters, observed phase structure, and obtained mechanical properties. The mechanical tests showed that the highest impact strength was achieved as the dispersion of the rubbery phase achieved an optimum size of about 1 μm. J. VINYL ADDIT. TECHNOL., 23:329–337, 2017. © 2015 Society of Plastics Engineers     

Adsorptive removal of refractory sulfur compounds by tantalum oxide modified activated carbons

Adsorptive desulfurization of a model diesel fuel consisting of dibenzothiophene (DBT) or 4,6‐dimethyldibenzothiophene(4,6‐DMDBT) in hexadecane was performed over activated carbons and tantalum oxide modified (Ta‐x/ACC, x= 2, 5 or 10 wt % Ta, Activated Carbon Centaur) activated carbons at 50°C. The adsorption isotherm for ACC followed the Langmuir model while the adsorption on Ta‐5/ACC fitted the Sips equation indicating more than one type of adsorption sites. Characterization studies indicated new types of adsorption site resulting from the incorporation of Ta oxide into the porous structure of the ACC. XPS data suggested interaction of Ta with the S atom in DBT. The heats of adsorption in the liquid phase determined from micro flow calorimetry for DBT in C16 confirmed the interaction of Ta with DBT. Ta‐5/ACC exhibited the highest adsorption capacity for 4,6‐DMDBT compared to literature reports. Competitive adsorption experiments showed the adsorption capacity as follows: quinoline> DBT? naphthalene. © 2017 American Institute of Chemical Engineers AIChE J, 2017     

Theoretical modeling of thermal stress imposed by selective permeation membranes reinforced with graphene oxide

The main purpose of the present work is to study the thermal stress imposed by selective permeation hydrogel‐filled nonwoven membranes (SPHM) in various environmental conditions, including cold, moderate and hot, in view of high and low wearer activity levels. In addition, graphene oxide (GO) has been used in the matrix structure of SPHM to reduce thermal stress. Hence, a mathematical model is proposed to study one‐dimensional heat transfer through SPHM reinforced with GO. Heat transfer equation was solved using the differential quadrature method and the resulting model was verified by experiments using a dynamic heat transfer simulation apparatus. It was observed that SPHM causes a significant thermal stress, especially in hot environments, and high activity level due to the low thermal conductivity of hydrogels. The results also showed that an increase in the GO content from 0.1% up to 0.5% leads to an increase in thermal conductivity up to 85% of blank SPHM without GO. Therefore, SPHM reinforced with GO is a promising candidate for protective clothing, especially in hot environments. Also, the mathematical model can be useful in predicting thermal stress for designing SPHM‐based PCs in various environmental conditions and activity levels. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 44752.     

Optimization of ultrasound-assisted extraction for the maximum quantity and quality of phenolics from Stachys lavandulifolia

The response surface methodology was used to evaluate the effects of extraction time, power of ultrasound, liquid to solid ratio, and solvent composition on the quantity and quality (from aspect of antioxidant activity) phenolics of Stachys lavandulifolia. The best extraction time, power of ultrasound, liquid to solid ratio, and solvent composition for both the quality and quantity of phenolics were 14 min, 300 W, 40 (v/w), and 57% methanol, respectively. Only the liquid to solid ratio was effective on the quality of phenolics. Also, the comparison between the ultrasound-assisted extraction and maceration methods showed the suitability of ultrasound-assisted extraction for extracting phenolics from this plant.     

Core–shell hexadecane‐polyurethane nanofiber/net structured membrane: Evaluation of surfactant addition on morphology and performance

Coelectrospinning/netting or fabrication of well‐controlled nanofibers/net (NFN) within core–shell hexadecane (HD)–polyurethane (PU) nanofiber membranes is an effective strategy to improve nanostructure morphology, mechanical properties, and performance characteristics. Three types of surfactants were separately added to PU solutions in order to make controlled NFN layers within membrane structures. The experimental results indicated that the NFN layers composed of core–shell nanowires with a diameter of 20–40 nm increased significantly when a cationic surfactant was added. Also, the results confirmed that the NFN structure caused a significant increase in strength and a noticeable decrease in elongation of the membranes. The performance characteristics of the membranes, such as water vapor transmission rate and hydrostatic pressure, were not affected significantly by the addition of the cationic surfactant. The results confirmed that the mechanical properties and morphology of the core–shell HD‐PU nanofiber membranes could be controlled and tuned by the amount and type of surfactant. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 45047.     

Adsorption of platinum(IV) from an aqueous solution with magnetic cellulose functionalized with thiol and amine as a nano‐active adsorbent

In this study, magnetic cellulose was prepared and then functionalized by the grafting of glycidyl methacrylate and reaction with thiourea/amine [to produce grafted magnetic cellulose with thiol/amine (GMC–N/S)]. Thus, GMC–N/S as a nano‐active adsorbent was investigated for the adsorption of Pt(IV) in a batch system. A response surface methodology was used to study the effects of four independent variables [Pt(IV) concentration, temperature, pH of the solution, and adsorbent dose] and to optimize the process conditions for the maximum adsorption of platinum(IV) from aqueous solutions by GMC–N/S. A high coefficient of determination (R² = 98.46) implied the adsorption of Pt(IV) onto the adsorbent in a valid manner, and only 1.54% of the total variable was not explained by the model. The equilibrium adsorption data were fitted to the Langmuir isotherm. The maximum monolayer adsorption capacity of the adsorbent (GMC–N/S) for Pt(IV) was determined to be 40.48 mg/g. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 45361.     

Identification of Oxidized Phosphatidylinositols Present in OxLDL and Human Atherosclerotic Plaque

Oxidized low-density lipoprotein (OxLDL) plays an important role in initiation and progression of atherosclerosis. Proatherogenic effects of OxLDL have been attributed to bioactive phospholipids generated during LDL oxidation. It is unknown what effect oxidation has on the phosphatidylinositol (PtdIns) molecules in LDL, even though PtdIns is 6% of the total LDL phospholipid pool. We sought to identify and quantitate oxidized phosphatidylinositol (OxPtdIns) species in OxLDL and human atherosclerotic plaque. Bovine liver PtdIns was subjected to non-enzymatic and lipoxygenase-catalyzed oxidation. Reversed-phase liquid chromatography with negative ESI–MS identified and confirmed compounds by fragmentation pattern analysis from which an OxPtdIns library was generated. Twenty-three OxPtdIns molecules were identified in copper-oxidized human LDL at 0, 6, 12, 24, 30, and 48 h, and in human atherosclerotic plaque. In OxLDL, OxPtdIns species containing aldehydes and carboxylates comprised 17.3 ± 0.1 and 0.9 ± 0.2%, respectively, of total OxPtdIns in OxLDL at 48 h. Hydroperoxides and isoprostanes at 24 h (68.5 ± 0.2 and 22.8 ± 0.2%) were significantly greater than 12 h (P < 0.01) without additional changes thereafter. Hydroxides decreased with increased oxidation achieving a minimum at 24 h (5.2 ± 0.3%). Human atherosclerotic plaques contained OxPtdIns species including aldehydes, carboxylates, hydroxides, hydroperoxides and isoprostanes, comprising 18.6 ± 4.7, 1.5 ± 0.7, 16.5 ± 7.4, 33.3 ± 1.1 and 30.2 ± 3.3% of total OxPtdIns compounds. This is the first identification of OxPtdIns molecules in human OxLDL and atherosclerotic plaque. With these novel molecules identified we can now investigate their potential role in atherosclerosis.     

Sustainable Oxidative Cleavage of Vegetable Oils into Diacids by Organo-Modified Molybdenum Oxide Heterogeneous Catalysts

Exploiting vegetable oils to produce industrially valuable diacids via an eco‐friendly process requires an efficient and recyclable catalyst. In this work, a novel catalytic system based on organo‐modified molybdenum trioxide was synthesized by a green hydrothermal method in one simple step, using Mo powder as precursor, hydrogen peroxide, and amphiphilic surfactants cetyltrimethylammonium bromide (CTAB) and tetramethylammonium bromide (TMAB) as capping agents. The synthesized materials were first characterized by different techniques including XRD, SEM, TGA, and FT‐IR. Interestingly, various morphologies were obtained depending on the nature of the surfactants and synthetic conditions. The synthesized catalysts were employed in oxidative cleavage of oleic acid, the most abundant unsaturated fatty acid, to produce azelaic and pelargonic acids with a benign oxidant, H₂O₂. Excellent catalytic activities resulting in full conversion of initial oleic acid were obtained, particularly for CTAB‐capped molybdenum oxide (CTAB/Mo molar ratio of 1:3) that gave 83 and 68% yields of production of azelaic and pelargonic acids, respectively. These are the highest yields that have been obtained for this reaction by heterogeneous catalysts up to now. Moreover, the CTAB‐capped catalyst could be conveniently separated from the reaction mixture by simple centrifugation and reused without significant loss of activity up to at least four cycles.     

Induction time,storage capacity,and rate of methane hydrate formation in the presence of SDS and silver nanoparticles

In this communication, the kinetic parameters of methane hydrate formation (induction time, quantity and rate of gas uptake, storage capacity (SC), and apparent rate constant) in the presence of sodium dodecyl sulfate (SDS), synthetized silver nanoparticles (SNPs), and mixture of SDS?+?SNPs have been studied. Experimental measurements were performed at temperature of 273.65?K and initial pressure of 7?MPa in a 460?cm³ stirred batch reactor. Our results show that adding SDS, SNPs and their mixture increases the quantity of gas uptake, water to hydrate conversion, and SC of methane hydrate formation, noticeably. Using 300?ppm SDS increases the SC and the quantity of methane uptake 615, and 770%, respectively, compared with pure water. Investigating the hydrate growth rate at the start of hydrate formation process shows that, using SNPs, SDS, and their mixture increases the initial apparent rate constant of hydrate rate, considerably. Our results show that the system of methane?+?water?+?SDS 500?ppm?+?SNPs 45?µM represents the maximum value of initial apparent rate constant, compared with other tested systems.