Iranian Journal of Chemistry and Chemical Engineering
Volume:38 Issue: 3, May-Jun 2019

Polypyrrole/silver (PPy/Ag)nanocomposite was synthesized by a chemical oxidative method. SEM and TEM analyses were performed for studying the morphology of the nanocomposite. It was shown that the obtained nanocomposite particles have a spherical structure with the high surface area to volume ratio that is the important factor in the biological application. The particle sizes of the PPy/Ag were 15–25 nm obtained by TEM. The antibacterial property was assessed by the disk diffusion method against gram-negative Escherichia coli and gram-positive Staphylococcus aureus bacteria. The antibacterial mechanism of action for PPy/Ag nanocomposite was discussed. PPy/Ag showed antibacterial activity against S. aureus (5 ± 0.5 mm) and E. coli (8 ± 0.5 mm). Based on satisfactory antibacterial properties of PPy/Ag nanocomposite, it could be considered as a suitable material in biomedical applications.

This paper applied a simple and cost-benefit method for the production of regenerated bacterial cellulose. The inexpensive production of cellulose with complex media derived from wastewater from food industries such as molasses adds a lot of contaminants to the produced bacterial cellulose, which puts a lot of challenges in cellulose purification. Therefore, the present study aimed to develop an inexpensive strategy for the complete dissolution of the very dirty cellulose produced from the low-cost medium containing molasses and corn steep liquor, and the reconstruction of pure bacterial cellulose that can be used for all types of cellulose. The bacterial cellulose was produced by Gluconacetobacter xylinus BRP2001 in an effective and inexpensive culture media including a mixture of molasses and corn steep liquor, then cuprammonium rayon method as a cost effective approach was modified for quick and complete dissolution of the bacterial cellulose. The main parameters in cuprammonium method such as the value of sodium hydroxide and copper sulfate, the water removal method and dissolution process were optimized by irregular fraction design. In addition to cost, the time of dissolution process of bacterial cellulose was reduced to less than 1 hour which is unprecedented in comparison with other conventional methods. Regeneration of bacterial cellulose for the fabrication of novel regenerated bacterial cellulose was carried out using dilute sulfuric acid. Under the optimum rayon method comprising 3 wt% NaOH/ 6 wt% copper sulfate solution, the diameter of the nanofibers of bacterial cellulose and regenerated bacterial cellulose ranged between 20-80 nm and 60-120 nm, respectively. Also, the crystal sizes of bacterial and regenerated bacterial cellulose were estimated at about 59.74nm and 6.13nm and the crystallinity indexes of bacterial cellulose and regenerated bacterial cellulose were calculated as 89% and 64%, respectively. The mechanical modulus and crystallinity of regenerated bacterial cellulose were significantly reduced because of the disruption of the hydrogen bond.

Polyacrylonitrile nanofibrous tubular structures were produced through typical and opposite charge electrospinning methods and the effect of the method as well as the two key electrospinning parameters, namely concentration of the electrospinning polymer solution and rotational speed of mandrel collector on properties of such tubular structures were studied. The smples were characterized by X-ray diffraction, scanning electron microscopy, Fast Fourier Transform method and tensile tests. Increasing polymer solution concentration considerably increased the diameter of the nanofibers and decreased the bead formation, where the increasing ranges of the average diameters were larger and sizes of beads were smaller for the nanofibers produced by the opposite charge set-up. Nanofibers' diameter, on the other hand, decreased as the speed of the rotational mandrel increased and the observed decline was greater in the opposite charge method, especially at higher concentrations of polymer solution. An inversion point for the anisotropy of mechanical properties was found to be around 2164 rpm. The aspect ratio of the nanofibers also increased with increasing the take-up speed. Increasing the take-up speed increased the mechanical force of pulling the jet, resulting nanofibers with smaller diameter, which in turn improved the crystallinity and molecular orientation of the fibers that explained the enhanced tensile properties for smaller diameter fibers. Different breaking mechanisms for the randomly oriented fibers and directionally aligned nanofibers were observed.

The electronic structure, Non-Linear Optical (NLO) properties and Natural Bonding Orbital (NBO) analysis of 1,4-dioxane were investigated using the theoretical study of Density Functional Theory (DFT) calculations at the B3LYP/6-311G (d,p) level of theory. The optimized structure is nonlinear as indicated from the dihedral angles.  Natural bonding orbital analysis has been analyzed in terms of the hybridization of each atom, natural charges (Core, Valence and Rydberg), bonding and antibonding orbital's second order perturbation energy (E(2)</sup>). The calculated EHOMO</sub> and ELUMO</sub> energies of the title molecule can be used to explain the charge transfer in the molecule and to calculate the global properties; the chemical hardness (η), softness (S) and electronegativity (χ). The NLO parameters: static dipole moment (µ), polarizability (α), anisotropy polarizability (Δα) and first order hyperpolarizability (βtot</sub>) of the studied molecule have been calculated at the same level of theory. The Molecular Electrostatic Potential (MEP) and  Electro Static Potential (ESP) for 1,4-dioxane were investigated and analyzed.  Also, the electronic absorption spectra were discussed by Time-Dependent Density Functional Theory (TD-DFT) calculations for 1,4-dioxane in 10% ethanol/water. From the experimental conductance measurements, the association thermodynamic parameters (KA, </sub>∆GA</sub>, ∆HA</sub> and ∆SA</sub>) and complex formation thermodynamic parameters (Kf, </sub>∆Gf</sub>, ∆Hf</sub> and ∆Sf</sub>) of nano-CuSO4</sub> in the presence of 1,4-dioxane as a ligand in 10% ethanol-water at different temperatures (298.15, 303.15, 308.15 and 313.15 o</sup>K) were applied and calculated.

In this study, β-cyclodextrin(β-CD) supported, hydroxyapatite encapsulated γ-Fe2</sub>O3</sub> (γ-Fe2</sub>O3</sub>@HAp@β-CD) was successfully prepared and evaluated as a solid-liquid phase transfer catalyst and also a molecular host system and nanoreactor for the nucleophilic ring-opening of epoxides in water for the preparation of β-azido alcohols, β-nitro alcohols, and β-cyanohydrins. The catalyst was characterized by FT-IR, XRD, TGA, and SEM. This procedure offers several advantages including excellent regioselectivity, high yields, short reaction times, recyclable catalyst, easy separation of the catalyst through external magnet, and easy work-up.

One of the principal air pollutants is sulfur dioxide (SO2</sub>). The removal of SO2 </sub>from flue gas has been one of the key challenges in the control of SO2</sub> emission. In this work, experimental scale photocatalytic oxidation</span> of SO2</sub> is a major process leading to H2</sub>SO4</sub> as a new method was suggested on the Liquid phase using Manganese supported on Copper Slag (Mn/CS)</span> under UltraViolet (UV) irradiation</span>. Mn/CS recognized as a novel</span> nanocatalyst for photocatalytic </span>oxidation of SO2</sub> from simulated flue gas.  In this study, a Column Packed Photo Catalytic Reactor (CPPCR)</span> was applied. Firstly, the Mn/CS was perpetrated by the impregnation method. Analysis of X-Ray Diffraction (XRD), Field Scanning Electron Microscopy (FESEM), Energy Dispersive X-ray (EDX), FT-IR and X-Photoelectron Spectroscopy (XPS) were used for detection structure, morphology, and size of a particle of Mn/CS nanocatalyst and mechanism of manganese onto copper slag. FESEM results show a good agreement with those determined by the XPS. Box–Behnken Design (BBD) </span>was used for optimization of variables, such as gas flow rate (L/min), Temperature (°C), Reaction time</span> (</span>min) and SO2</sub> concentration (mg/L).</span> Removal of SO2 </sub>under the optimal conditions, (8.1414, 25, 60 and 3.94) for Gas flow rate, Temperature, Reaction time and SO2</sub> Concentration respectively were obtained</span>. The most efficiency SO2</sub> removal achieved at the optimal operating conditions is around 99%.</span> It is concluded that the usage of this photocatalytic oxidation of SO2</sub> process, can significantly reduce SO2</sub> air pollution.

An efficient solventless one-pot procedure for the synthesis of imidazolium-based ionic liquid under microwave irradiation is described in which 1-methylimidazole was modified by organosilane (3-chloropropyl triethoxysilane). This ionic liquid 1-methyl-3-[(triethoxysilyl)propyl]imidazolium chloride (TMICl) is immobilized on Mechanically activated Fly Ash (MFA) by co-condensation method to develop an active organocatalyst (TMICl/MFA). The mechanical activation has generated significant number of silanol groups suitable for immobilizing ionic liquids. For characterization of various materials, different techniques viz, XRD, FTIR, SEM-EDX, TGA, BET surface area, H1</sup>NMR are used. The prepared TMICl/MFA exhibited high catalytic activity for a series of microwave assisted esterification of aliphatic alcohols and salicylic acid for four successive reaction cycles under optimized conditions.

Several new 2-pyridyl-4-thiazolidinones are synthesized in an efficient manner evading using any catalyst or base. Simple workup procedure, good yields, and mild reaction conditions are the salient features of this method. All the synthesized compounds are screened for antimicrobial activity against several organisms.

BXFL (bagasse xylem ferulate)-g-AM (acrylamide)/MAA (methyl methacrylate) was synthesized based on bagasse xylan(BX)-g-AM/MAA in 1-Butyl-3-methylimidazolium chloride ([Bmim] Cl) ion solution with Ferulic Acid (FL) as esterification agent. The various factors that were investigated influenced carboxylic acid ester substitution degree (DSC</sub>) of BXFL-g-AM/MAA. The structures of BXFL-g-AM/MAA were confirmed by IR, SEM and 1</sup>H NMR analysis. The cytotoxicity of BXFL-g-AM/MAA was investigated against twelve kinds of protein through Surflex-Dock Mode of Sybyl-X 2.0 software, and on three kinds of human cancer cells line and the human normal cells line were detected by MTT assay. It was shown that the maximum DSC</sub> was 1.09 in ion solution, which was superior to DSC </sub>of conventional method in organic solvent. The results of MTT assay were consistent with docking results. BXFL-g-AM/MAA exhibited relative high cytotoxicity against human gastric cancer cells (MGC-803) line.

A corrosion inhibitor suitable for industrial production and field application was rapidly synthesized from benzene-1,2-diamine, benzaldehyde, methanol, hydrochloric acid, and FeCl3</sub>. The mechanism of corrosion and its inhibition was proposed. We investigated the effect of the main reactants on corrosion rate, and optimal synthetic composition (benzene-1,2-diamine 10 g,</em> benzaldehyde 10 g and ferric chloride hexahydrate</em> 8 g) of the inhibitor was determined by using an orthogonal experimental design. The corrosion inhibition performances for N80 and Q235 steel in acid medium and oilfield water-injection were studied by employing the weight loss method. </em>The inhibition efficiency for N80 steel reached to 99.24% in 15 wt.% HCl solution for 4 hours at 90 °C</em>at the dosage of 1.2 wt.%, while in the water-injection, the efficiency for Q235 steel was 82.4% at 50 </em>°C</em> for 7 days at the concentration of 30 mg/L. Corrosion rates in acid medium and water-injection showed that the inhibitor has good corrosion inhibitive behavior for the steel surface and the inhibition efficiency increased with increasing concentration. Three kinds of compounds with synergistic corrosion inhibition were introduced to study, and ammonium bromide exhibited the best synergy. Attempts were made to fit the test values to different isotherms, it was found that the adsorption of the inhibitor on Q235 steel surface obeys Langmuir adsorption isotherm. </em>The calculated value indicated </em>that the adsorption reaction could spontaneously occur and</em>the inhibitor molecules could be well adsorbed on Q235 steel surface in </em>oilfield water-injection</em> at 50 °C.

A mono- and a bi-functional dithiocarbamates as sodium salts were obtained by treating p-peridine or p-perazine in aceton-water mixture with CS2</sub> in the presence of NaOH. These anionic water soluble compounds have been characterized by elemental analysis, IR and 1</sup>H NMR spectroscopic studies. Both compounds (p-peridine (I</strong>) and p-perazine-bis dithiocarbamate (II</strong>) sodium salts) were examined for inhibition of mushroom tyrosinase (MT) activity. The results showed that they inhibit MT competitively. KI </sub>values of two compounds at 27°C are 2 and 4 mM. Therefore, the compound (I</strong>) is more potent than (II</strong>). They chelate active site of tyrosinase via electrostatic interactions. These conclusions are proved by obtained thermodynamic parameters and fluorescence studies. Extrinsic fluorescence studies disprove any tertiary structure changes of MT. Major enthalpy changes in binding of compound (II</strong>) in comparison to (I</strong>) show that including two carbamate tails in such compounds disturb balancing of hydrophobic interactions with vicinity of active site of enzyme.

A series of symmetric and asymmetric binuclear α-diimine nickel(II) complexes toward ethylene polymerization were successfully synthesized and characterized by 1</sup>HNMR. </em>All the catalysts were typically activated with MAO and displayed good activity at room temperature</em> under 1atm ethylene pressure. The symmetric catalyst containing </em>isopropyl on </em>ligand-activated with</em> 500 </em>equiv</em> MAO produced high molecular weight polyethylene with a PDI=1.75, while the symmetric</em> catalyst containing </em>methyl on ligand produced relatively low molecular weight polyethylene with a PDI=1.74. By contrast, the molecular weight, branching density of resultant polymer </em>produced by asymmetric catalyst decrease roughly somewhere between that of polymers prepared by</em> two symmetric catalysts.

In this research, 1D four-coordinate copper(I) coordination Polymer [Cu(Clba2</sub>-1,2-pn)(NCS)]n</sub> (1</strong>) with thiocyanate anion as bridging ligand, where Clba2</sub>-1,2-pn = N,Nʹ-bis(2,4-chlorobenzylidene)propane-1,2-diamine), was synthesized by slow evaporation of solvent at room temperature and characterized by elemental analysis (CHN) and single-crystal X-ray diffraction. Microparticles of 1</strong> were prepared by an ultrasonic bath assisted synthesis and characterized by Scanning Electron Microscopy (SEM) and elemental analysis. Thermal stability of 1</strong> was studied by ThermoGravimetry (TG) and Differential Thermal Analysis (DTA). </strong>The structure of 1</strong> consists of 1D polymeric chain in which copper(I) ions are bridged by two thiocyanate groups in an end-to-end fashion, with Cu</em>×××</em>Cu separation 5.686(4) Å.

Light hydrocarbons in water emulsions are formed in many gas refinery wastewaters, and its stability depends on some parameters such as temperature, pH and salinity</em>. In this study, different surfactants have been used to prepare gas condensates in water emulsion along with four surfactant kinds namely, Span 80, Tween 80, CTAB, SDS and Span 80 and Tween 80 mixture. For this purpose, the effects of temperature (25 and 60° C), pH (3, 5, 7 and 11) and salinity (2, 10 and 26 wt. % NaCl in water) on the stability of the emulsion have been studied. In order to evaluate the stability of these emulsions, the droplet size distribution was measured by an optical microscope. The results confirm that the increasing of salinity, as well as temperature of non-ionic surfactants (Such as Span 80 and Tween 80), lead to more stability of the emulsion. The increasing temperature didn’t have a dominant effect on the stability of those emulsions which contain the ionic surfactants i.e., CTAB and SDS. Those emulsions formed by the combination of Span 80 and Tween 80 are more stable than the other ones. Results of the investigation the effect of pH on the emulsion stability clear that the emulsions are less stable at high pH than other ones.

In this work, the electrocatalytic oxidation of ethanol was studied in acidic media at the wholly electrosynthesized nanocomposites: platinum and its alloys (copper and nickel) anoparticles/reduced graphene oxide on the carbon-ceramic electrode (Pt/rGO/CCE, Pt-Cu/rGO/CCE, and Pt-Ni/rGO/CCE electrocatalysts). The electrosynthesized nanocomposites </span>were characterized by scanning electron microscopy, X-ray powder diffraction, and energy-dispersive</span></span> X-ray spectroscopy. </span></span>Electrocatalytic activities of the Pt/rGO/CCE, Pt-Cu/rGO/CCE and Pt-Ni/rGO/CCE toward ethanol oxidation were investigated via cyclic voltammetric and chronoamperometric techniques in 0.1 M H2</sub>SO4 </sub>solution containing 0.3 M ethanol. The obtained results show that the Pt-Ni/rGO/CCE was catalytically more active and exhibits better electrocatalytic performance toward ethanol oxidation (ECSA=25.28, Jpf=0.156 mA/cm2</sup>, Jpf/Jpb=1.12 and Eonset</sub>=0.2 V) than Pt-Cu/rGO/CCE (ECSA=19.09, Jpf=0.108 mA/cm2</sup>, Jpf/Jpb=0.99 and Eonset</sub>=0.3 V) and Pt/rGO/CCE (ECSA=28.28, Jpf=0.092 mA/cm2</sup>, Jpf/Jpb=0.55 and Eonset</sub>=0.35 V). The result of some effective and important investigational factors was studied and optimize conditions were suggested. Based on the </span>obtained data</span> one can be expected</span> that the studied systems are promising systems for ethanol fuel cell applications.

Reducing agents-Enhanced electrokinetic Soil Remediation (EKSR) was performed for the removal of chromium (Cr), cobalt (Co) and nickel (Ni) from contaminated soil. The reducing agents oxalic acid and ascorbic acid were investigated under constant voltage gradient (2.0 V/cm), current changes, pH, redox potential, concentration changes and removal performance of Heavy Metals (HMs). The results indicated that the reducing agents were effective in the desorption of metals at the cathode with catholyte conditioning pH. The removal performance of heavy metals in reducing agents-enhanced EKSR was about 2-2.5 times more than in unenhanced treatment. The amount of HMs migrated to the catholyte was more than in the anolyte, which might be evidenced that the negatively charged metal-oxalate/ascorbate complexes migrated via electroosmosis. However, positively charged HM-oxalate/ascorbate complexes and free HM cations moved to the catholyte by electromigration action. Furthermore, the mass balance and cost analysis were performed for all EKSR experiments after 20 days of operation. The energy consumption per cubic meter of treated soil was 1104-18496 kWh/m3</sup> and the total cost was about US$ 110.4-2095, including the cost of the enhancing agents. The study demonstrated that reducing agents-enhanced EKSR is cost-effective and efficient in the removal of HMs from contaminated soil.

The graphene (GR) has attracted intensive interest due to its two-dimensional and unique physical properties. In the present study, the graphene sheets were synthesized by electrochemical exfoliation of graphite in sulfuric acid solution. The polybithiophene-graphene (PbTh-GR) composite films deposited onto indium tin oxide substrate (ITO/PbTh-GR) have been prepared by the incorporation of graphene sheets into the PbTh matrix during electropolymerization under magnetic stirring from the LiClO4</sub>/CH3</sub>CN electrolyte containing the bithiophene (bTh) monomer and graphene sheets. The incorporation of graphene sheets at different masses (1, 2 and 3 mg) is ensured by the effect of the stirring of the electrolyte. The characterisation of films is effected by electrochemical methods (cyclic voltammetry and impedance spectroscopy), spectroscopic technics (FT-IR, UV-Visible), X ray diffraction, thermogravimetric analysis, and scanning electron microscopy. It was observed that the electrochemical performance measurements of the ITO/PbTh-GR (3 mg) film show a specific capacity of around 65 F/g, which is six times higher than that of ITO/PbTh films, 11 F/g.

Fatty Acids, α-tocopherol, β-caroten, minerals, and some pomological properties of walnut genotypes from four locations (Iğdır, Tuzluca, Karakoyunlu, Kağızman) of Aras Valley (Eastern Turkey) were examined. In this study, the differences among the genotypes were determined in terms of some fruit characteristics, oil and protein contents, fatty acid composition, selenium content, α-tocopherol content, β-carotene content and some macro- and microelement contents. The genotypes different in the values of nut weight from 8.89 to16.22 g, kernel weight from 4.72 to 9.64 g, kernel ratio from 36.74 to 59.59%, and shell thickness 1.04-3.60 mm, respectively. The contents of fat and moisture of the selected genotypes were in the range of 59.18 to 68.12% and 10.49 to 23.31%, respectively. The contents of most common fatty acids determined in the genotypes were linoleic acid (58.15-64.07%), oleic acid (12.93-17.49%), linolenic acid (9.37-13.61%), palmitic acid (5.60-8.62%) and stearic acid (4.68-6.69%), whereas the contents of remaining fatty acids were rarely detected in trace amounts. In the genotypes, the amount of α-tocopherol was in the range of 8.75 to 35.11 mg/kg, β-carotene was in the range of 0.03 to 0.12 mg /kg and selenium was in the range of 15.89 to 68.19 ng/g. The  genotypes were found to have  1.09 to 2.47% N,  230.36 to 451.48 mg/100g P, 350.74 to 666.20 mg/100g K,  2.30 to 3.86 mg/100g Cu,  1.71 to 3.91 mg/100g Zn,  7.16 to 18.82 mg/100g Fe,  144.0 to 452.08 mg/100g Ca, 110.25 to 342.44 mg/100g Mg,  1.73 to 9.67 mg/100g Mn and  7.11 to 25.51 mg/100g Na. The present results revealed that the high nutritional values of walnut genotypes selected from the Aras Valley(Eastern Turkey) could have health benefits effects on human nutrition.

Kinetics and selected variables (temperature, particle size and time) for extraction of Terminalia Catappa L Kernel Oil (TCKO) were investigated using solvent extraction. Kinetic models studied were: parabolic diffusion, power law, hyperbolic, Elovich and pseudo-second-order. In ascending order, the best-fitted models at the optimum temperature and oil yield were Elovich’s model, hyperbolic model, and Pseudo second-order model. Due to the highest value of linear correlation coefficient (R2</sup>) and lowest average values of Root Mean Square (RMS), absolute relative deviation (AARD %) and Standard Error of Estimation (SEE) recorded for Pseudo second order, it was selected as the best fit model. Parabolic and power-law models failed to give a good fit. The average maximum oil yield of 60.45 </em>± 0.05 % was obtained at a temperature of 55 °C, time of 150 min and an average particle size of 0.5 mm. The physicochemical properties of the TCKO showed its potential for industrial applications.

An experimental study was conducted to determine the effects of the leaching parameters on impurity ion concentrations of the liquid phase in ulexite leaching. Powdered ulexite ore was leached in an aqueous medium with sulfur dioxide. The Taguchi experimental design approach and statistical methods were used to evaluate the effects of the leaching parameters (solid/liquid ratio, temperature, pH, particle size, time) on impurity ion concentrations (concentrations of magnesium, calcium, iron ions) in the liquid phase. The average B2</sub>O3</sub> leaching ratio of ulexite ore was found as 98.56 % (± 0.95). Statistically effective leaching parameters on impurity concentrations (and delta values for concentrations) were found as pH (770 ppm) for magnesium, solid/liquid ratio (372 ppm) </em>for calcium ion concentrations. The examined parameters were not found effective for iron ion concentrations.

In this research new catalyst prepared by supporting ZnFe2</sub>O4</sub> on Copper Slag (CS) and characterization of this catalyst was done by using Scanning Electron Microscopy (SEM) image, </em>Energy-Dispersive X-ray (EDX) spectroscopy</em>, BET surface area, and X-Ray Diffraction (XRD) patterns. UV + H2</sub>O2</sub> processes by ZnFe2</sub>O4</sub>/CS photocatalyst was used for the degradation of  Resorcinol as a pollutant in water. Circulate Packed Bed Reactor (CPBR) with a total volume of 1 liter and effective volume of 0.2 liters was used in this process. Design of Experiments (DoEs) was utilized and kinetics of the photocatalytic degradation process was modeled using full factorial design. The experiments were designed considering three variables at three-levels (including pH, the initial concentration of Resorcinol, and initial concentration of H2</sub>O2</sub>). The results showed that pH=5, the initial concentration of Resorcinol=50 ppm and H2</sub>O2</sub> initial concentration=40 ppm had the highest Resorcinol degradation constant rate (k= 3.506 × 10-3</sup>).

In this research, the capabilities of Henna and Henna with chitosan microparticles adsorbents were studied in order to remove the ion Cd (II). Response Surface Method (RSM) and Central Composite Design (CCD) were used to minimize the number of experiments (21 runs) for Henna and (26 runs) for the Henna with chitosan microparticles. The parameters were pH (2-9), initial solution concentration [10-100 mg/L (ppm)], adsorbent dosage (0.1-1 g) and process time (20-150 min). It was concluded that Cd (II) removal increased from 13.78% to 70.06% with increasing the pH from 2 to 9 (maximum adsorption was at pH 9) for Henna and 82.81% to 97.60% for the Henna with chitosan microparticles. The Cd (II) removal was decreased from 78.73% to 40.44% for Henna and 96.47% to 90.37% for the Henna with chitosan microparticles with increasing the initial solution concentration (from 10 to 100 ppm). Furthermore, the Cd (II) removal was increased from 37.5% to 64.59% for Henna and from 86.74% to 97.76 % for the Henna with chitosan microparticles with the adsorbent dosage increment (from 0.1 to 1 g). The error for the optimum point between the statistical data and experimental ones were at 1.53% for Henna and at 1.61% for the Henna with chitosan microparticles. The Langmuir and Freundlich isotherm models were applied as the adsorption mechanism. Two correlations (with R2</sup>=0.9750 for Henna and R2</sup>=0.8538 for the Henna with chitosan microparticles) between the Langmuir model and experimental data were investigated‍ although Freundlich model showed the better agreements between the theoretical data and experimental ones (R2</sup>=0.9949 for Henna and R2</sup>=0.9955 for the Henna with chitosan microparticles). It also showed that the Henna with chitosan microparticles is a fantastic adsorbent for Cd (II) removal.

Acetic acid was separated from a dilute mixture using a commercial polyvinyl alcohol (PVA) membrane.  Intrinsic separation characteristics of the membrane were studied as a function of temperature.  The degree of membrane swelling decreased marginally with increase in feed temperature. At 25o</sup>C the maximum degree of swelling was found out to be 46.3%, which reduced to 39.5% at 65o</sup>C. Although the pervaporation flux increased with increasing temperature of the liquid feed mixture, the separation factor decreased. From the temperature dependence of diffusion and permeation values, the Arrhenius apparent activation parameters for water permeation were estimated. Diffusion and partition coefficient for water and acid were found to increase with temperature, but the diffusion coefficient of water was substantially higher than that of acetic acid at a constant feed concentration. The membrane used in the present study could tolerate highly concentrated corrosive acetic acid, thus may be useful for dehydration of other organics.

This study presents the adsorption performance indicator for the evaluation of thermal power plant CO2</sub> capture on mesoporous graphene oxide/TiO2</sub> nanocomposite. To begin, this adsorbent was synthesized and characterized using N2</sub> adsorption-desorption measurements </em>(BET and BJH methods), X-Ray Diffraction (XRD), Field Emission Scanning Electron Microscopy (FE-SEM)</em> and FT-IR spectroscopy. </em>Subsequently,</em> the pure single-component adsorption isotherms measured at 298 K and the Ideal Adsorbed Solution Theory (IAST) solved with direct search </em>minimisation</em> were applied to estimate the selectivity of the synthesized mesoporous graphene oxide/TiO2</sub> nanocomposite for CO2</sub> over N2</sub> and predict CO2</sub> adsorption capacity in the CO2</sub>:N2</sub> binary gas mixtures, including the molar ratio of 5:95, 10:90 and 15:85. Finally, the results validated by the breakthrough experiments at a fixed-bed column were applied to estimate the Adsorption Performance Indicator (API) for the evaluation of CO2</sub> separation from N2</sub> in the Pressure Swing Adsorption (PSA) process with respect to different types of thermal power plants.</em>

This study has primarily aimed at the examination of the effect of flow rate, solid volume fraction and their interactions on the Nusselt number of Al2</sub>O3</sub>/water nanofluids. To investigate the main and interaction effects on the response, Response Surface Methodology (RSM) has been used based on the miscellaneous design. By using the analysis of variance (ANOVA) the significance of the model is tested. The responses to the Nusselt number of nanofluids are also estimated using second-order polynomial equations.  The results show that the Nusselt number increases with a higher amount of flow rate and solid volume fraction. According to the analysis of variance, the Reynolds number (A), first and second order of effects of volume fraction (B, B2</sup>), the interaction of Reynolds number and volume fraction (AB) is the most effective factors on the Nusselt number. Finally, the optimum condition of the process is predicted based on the RSM method. Having considered the optimum condition, the Nusselt numbers are compared with experimental data. The results show that there is a good agreement between the results of the proposed model and experimental data. Therefore, according to the results, the Nusselt number is precisely predictable in the model proposed by the Design Expert software.

In this experimental study, the rheological behavior of Al2</sub>O3</sub>-MWCNT (90%:10%)/10W40 hybrid nano-lubricant has been determined at the temperature range of 5°C to 55°C. Al2</sub>O3</sub> nanoparticles (average size of 50 nm) and MWCNTs (inner and outer diameter of 2-6 nm and 5-20 nm, respectively) were dispersed in engine oil (10W40) to prepare 0.05%, 0.1%, 0.25%, 0.5%, 0.75% and 1% solid volume fractions. For each sample, dynamic viscosity was measured at shear rates ranging from 666.5 s-1</sup> to 13330 s-1 with an uncertainty of about 0.6%. The findings insinuated that at the most range of temperature and solid volume fraction the nano-lubricant,  as well as the base oil, are non-Newtonian fluids. Thus, by curve fitting the indexes of power law and consistency were calculated. Eventually, the correlations indicated a very well compromise with experimental data.