Iranian Journal of Chemistry and Chemical Engineering
Volume:40 Issue: 5, Sep-Oct 2021

The biosynthesis of nanomaterials is an important aspect of nanotechnology due to its cost-effective and eco-friendly procedure. The present study was carried out to fabricate AgCl@TiO2 nanocomposite using the aqueous and ethanolic leaf extracts of Avicennia marina mangrove plant as a reducing and stabilizing agent (RSA). The effect of aqueous and ethanolic leaf extracts with different concentrations on the biosynthesis of AgCl@TiO2 NanoParticles (NPs) was systematically studied by X-Ray Diffraction (XRD), field emission scanning electron microscopy (FE-SEM), Energy Dispersive Spectroscopy (EDS), UV-visible diffuse reflectance spectroscopy (UV-visible DRS), and Fourier Transform InfraRed (FT-IR) spectrometer. The results illustrated the successful synthesis of AgCl@TiO2 nanocomposite without any impurity phase using the aqueous extract. AgCl NPs were uniformly distributed on the surface of TiO2. The absorption intensity of AgCl@TiO2 with a band gap energy of 2.95 was improved both in the UV and VL region and displayed stronger absorption compared with pure TiO2. FT-IR analysis confirmed that the biosynthesized AgCl@TiO2 by using aqueous leaf extract was not just an easy physical mixture of Ag and TiO2 species but it was a molecular-level combining of Ti–O and Ag–O domains in the nanocomposite.

The purpose of this study was to prepare a Double Network (DN) hydrogel made with sodium-alginate (Na-alg) natural polysaccharide and polyacrylamide (PAM) chains that target control release of anticancer drug. To this aim, the entitled submicron particles of double network hydrogels exhibit exceptional properties. A two-step strategy was used to obtain alginate/PAM hydrogels crosslinked by Ca2+ cations and N, Nʼ-methylenebisacrylamide (MBA) as different types of crosslinker. Particles of DN alginate / PAM were employed for entrapping and releasing the model drug 5-fluorouracil (5-FU) as an anticancer drug. Scanning Electron Microscopy (SEM), Fourier Transform InfraRed (FT-IR) spectroscopy, ThermoGravimetric Analysis (TGA), Dynamic Light Scattering (DLS), swelling properties, drug entrapment efficiency, and drug release studies were also done. The particles showed porous structure, good swelling ability, and aqueous dispersibility with a size in the range of 280 nm. The resulting hydrogel was subsequently loaded with 5-FU and released patterns carried in 7.4 pH and 5.8 pH at a temperature of 37 ºC. The controlled drug release behavior was noticed and the finding of the study suggested that the alginate/PAM double network hydrogel is a promising carrier for 5-FU delivery.

The use of nanocarbon support materials such as fullerene (C60) helps the dispersion of catalysts and creates a new method to develop nanomaterials as a result of its garbled structure Pd-supported on Schiff base modified fullerene (C60LPd2+ and C60LPd0) were fabricated. The obtained catalysts were characterized by FT-IR, XRD, TEM, TGA, and ICP. To investigate the catalytic properties, this catalyst was used in aerobic oxidation of alcohols and Heck coupling as model reactions. The results showed that the efficiency of catalysts has about 75% to 92% and 90% to 98% in these two reactions, respectively. The catalyst can be rapidly readily regained and reused at least 5 consecutive cycles without notable leaching and loss of its catalytic actuality.

Graphene containing Co and Mn co-doped NiOnanocrystallinematerials  (with composition graphene - Ni0.95Co0.025Mn0.025O1-δ) were synthesized by chemical synthesis route and studied for potential application as electrode material for supercapacitors. The phase structure of the materials was characterized by XRD technique and the crystallographic parameters were found out and reported. FT-IR spectroscopy revealed the presence of M-O bond in the materials. The morphological phenomenon of the materials was studied by SEM and the particles were found to be spherical with an average grain size of 14 – 28 nm. EDAX analysis confirmed the presence of appropriate levels of elements in the samples. The in-depth morphological characteristics were also studied by HR-TEM (High-Resolution Tunneling Electron Microscopy). Cyclic Voltammetry (CV), charge-discharge, and electrochemical impedance measurements were carried out in an aqueous electrolyte (6 mol/L KOH) to investigate the electrochemical performance of the graphene containing Co and Mn co-doped NiOnanocrystallinebased electrode materials and the material found to exhibit a specific capacitance of 1243 F/g at a current density of 0.5 A/g and hence these electrode materials can be used in electrochemical supercapacitors.

In the present research, Lacunary Keggin-type heteropolyoxometalate, (K7PMo2W9O39) supported on ZnO nanoparticles was prepared by the impregnation method. Nanoparticle characteristics and the remaining Keggin structure in the nanocomposites were confirmed by FT-IR and XRD analyses. The photocatalytic activity of prepared K7PMo2W9O39/ZnO for degradation of phenol under UV light was investigated.  H2O2 was used as an oxidant in the photocatalytic degradation process of phenol. The results indicated that synthesized nano photocatalyst could be considered an appropriate heterogonous photocatalyst in the removal of organic pollutants from aqueous solutions and heterogenization of Lacunary Keggin-type heteropolyoxometalate on ZnO nanoparticles resulted in the improved light absorption intensity and decreased band gap of nanocomposites. Degradation of phenol in the presence of the K7PMo2W9O39/ZnO could lead to the disappearance of approximately 93% of phenol after 60 min. But degradation for the same experiment performed in the presence of the K7PMo2W9O39 or /ZnO was less than 60% at the same time.

The paper presents the enzymatic degumming of soybean oil by immobilization of phospholipase A1 (PLA1) on atmospheric plasma surface modified chitosan nanofibrous membrane. As evidenced by Scanning Electron Microscopy (SEM) images, chitosan nanofibers exhibited a number of properties indicating this polymer as a good enzyme carrier. Fourier Transform InfraRed (FT-IR) spectroscopy showed the reaction between the enzyme and functional groups of chitosan nanofibers. The properties of immobilized PLA1 were compared to free PLA1 in order to evaluate the possibility of using the immobilized enzyme for the degumming of soybean oil. The pH tolerance and thermal stability of the immobilized PLA1 were significantly improved. In addition, the immobilized PLA1 can be easily recovered and retained at 80% of its initial activity after 10 times of recycling. The enzymatic degumming process was carried out at 60°C and pH 6.0. The residual phosphorus content decreased to 8.6 mg/kg after 6 h, which is to meet oil safety standards and suitable for the physical refining of soybean oil.

Modern bio-electrochemical technologies can convert the energy stored in the chemical bonds of biodegradable organic materials into renewable electrical bioenergy through the catalytic reactions of the microorganisms while treating the wastewaters. The present research has been conducted to study the efficiency of the single-chamber bioelectrochemical system with carbon aerogel catalyst as a new, simple, and inexpensive approach to remove and recover the valuable but polluting nutrients (nitrogen and phosphorus) from municipal wastewaters and also determine the optimal conditions to scale up the system in countries with hot, dry climates. In the present study, the bacterial consortium was isolated from the sediments of local lagoons, and municipal wastewater was used as the substrate. During the six months of cell operation, the effluent of BES showed a 54.9% decrease in nitrate concentration and a 59.8% decrease in total N and 90% of phosphate removed from wastewater, the total nitrogen, and total phosphate concentration in effluent were 28.9 ± 24.3 mg/L. and 13 ± 46.8 mg/L, respectively. The maximum removal of COD was 80%, and the maximum power density was 1.82mW/m2. Carbon aerogel, as a novel material with suitable absorbance and resistance to oxidation by urban wastewater pH can be coated on electrodes to facilitate the Oxidation Reduction reactions and electricity transmission.

The oxidation of 216 mg/L o-methylphenol was studied in an acidic aqueous solution using Boron-Doped Diamond (BDD) and platinum (Pt) anodes. o-methylphenol was oxidized by hydroxyl radicals generated on the anode used, however, there was a significant distinction betwixt the BDD and Pt anodes in the effectiveness and accomplishment of electrochemical degradation. o-methylphenol was rapidly mineralized at the BDD anode, but its degradation was much slower at the Pt anode with a Total Organic Carbon (TOC) removal of 98% and 65% for BDD and Pt anodes, respectively. Using BDD anode, 3-methylcatechol, methylhydroquinone, and maleic, fumaric, pyruvic, formic, glyoxylic, succinic, oxalic, and acetic acids were detected. But, there was a formation of dark-colored polymeric compounds and precipitates in the solutions electrolyzed by the Pt anode, which was not observed for the BDD cells.

In this work, four Fenton processes were used for the decolorization of titan yellow. Experimental conditions such as concentration of H2O2, pH, time, zero-valent iron dose, and concentration of Fe2+ were optimized by Doehlert experimental design and response surface models. In the absence of ultrasonic waves, the application of zero-valent iron had an intense effect on decolorization percent (95% for heterogeneous Fenton with respect to 18% for classical Fenton). The optimum conditions were (0.0054M H2O2, 0.031g/L Fe2+, pH 2.5 and reaction time 47 min) and (0.0013M H2O2, 0.194g/L zero-valent iron, pH 2.5, and reaction time 10 min) for homogeneous and heterogeneous Fenton processes, respectively. Both homogeneous and heterogeneous Sono-Fenton processes reached to decolorization percent of 100%. The optimum pH was 2.5 for the two processes. The optimum conditions for homogeneous and heterogeneous sono-Fenton processes were (0.0035M H2O2, 0.0037g/L Fe2+, and reaction time 30 min) and (0.0014M H2O2, 0.4g/L zero-valent iron, and reaction time 10 min), respectively.

The combination of green chemistry and green engineering is needed for the production of minimum waste, renewable sources, increasing utilization of raw materials, the use of simpler and safer products, and novel technologies. The use of novel cleaner technologies leads to effective production in chemical industries. The dyes involve a complex structure, recalcitrant nature, and more intermediates. The generation of oxidative species with higher yields is obtained by advanced oxidation processes as a green and powerful treatment technology. These processes are effective, inexpensive, and eco-friendly methods for decaying toxic pollutants. The AOPs are classified as non-photochemical and photochemical processes. There are included various technologies such as ozonation, Fenton oxidation, wet air oxidation, electrochemical oxidation, and photocatalytic oxidation. The production of highly reactive free radicals is the main purpose of the AOPs process. The generation of free radical increases by the combination of two or more AOPs processes that leads to higher oxidation rates. This study was aimed to present the various attempts for degradation dyes in textile wastewater using the diverse advanced oxidation processes.

The kinetics of the hydrolysis of Alizarin dye (ALZ) in the basic medium is investigated for the purpose of wastewater treatment. ALZ represents a group of aromatic dyes, that are heavy, toxic, and non-biodegradable. The kinetics of the reaction was followed by UV-Vis spectrophotometry and ab-initio computational methods. The effects of initial concentration, ionic strength, and temperature were studied. The kinetic salt effect (ionic strength) demonstrated that OH– is part of the rate-determining step of the reaction. Unlike common reactions, anti-Arrhenius behavior was observed within the temperature range of 25-50°C. Therefore, the apparent activation energy was determined to be -23.91 kcal/mol. Using theoretical quantum calculations, the reaction under study was investigated using the density functionals B3LYP and B97D3, and final energies were obtained using the 2nd order Møller−Plesset (MP2) theory. A complex reaction mechanism is suggested that involves the formation of an intermediate that combines the ALZ anion and water molecule attached by H-bonding. The mechanism accounted for the anti-Arrhenius behavior and the negative Ea. The standard reaction enthalpy (ΔH298) obtained using the B97D3 Grimme’s functional was within the range of the experimental Ea value.

In this study, copper particles were synthesized by using sodium ascorbate as a green reducing agent under atmospheric conditions. The product was micron-sized and mainly formed by metallic copper Cu with a minor presence of Cu2O. The product was used as a catalyst in the discoloration of methylene blue in a heterogeneous Fenton-like process in which H2O2 was produced in situ. The effect of different parameters such as copper loading, dye concentration, pH of the solution, and temperature was studied. The total discoloration was achieved after 42 min with 30 mg of copper at 60 °C and pH= 3. The amount of H2O2 produced in situ during methylene blue discoloration was evidenced by the permanganate method. It was found the formation of 110 µM after 40 min. The external addition of H2O2 at 0.001 M reduced the time for total discoloration to 10 min and the application of 40 kHz ultrasounds reduced the time further to 6 min.

Colored effluents are one of the most important environmental pollutants in the world. This study focused on the removal of dye Reactive Black5 (RB5) using a combination of an anaerobic digester and an Integrated Fixed-film Activated Sludge (IFAS) reactor. The effects of Hydraulic Retention Times (HRT), temperature and filling ratio in the anaerobic digester, the effect of hydraulic retention time and filling ratio in IFAS, and also the effect of initial dye concentration on color removal and Chemical Oxygen Demand (COD) reduction efficiencies were investigated. The Maximum efficiency of color removal and COD reduction in the anaerobic digester at HRT of 2.5 days, 35 °C and 50% of filling ratio was 81% and 99%, respectively, and in IFAS at HRT of 6 h and 70% of filling ratio was 25% and 100%, respectively. According to the Scanning Electron Microscope (SEM) photographs of the microbial community, there were morphological differences in the microorganisms of the two reactors. The Stover–Kincannon and Monod models were used to describe kinetic data. The results showed that Stover–Kincannon model follows the experimental data well. Maximum utilization rate constant and Saturation value constant of Stover–Kincannon model for dye and COD were determined as Umax = 0.15 g / (l day), KB = 0.165 g / (l day) and Umax = 11.31 g / (l day), KB = 11.31g (l day) respectively.

Activated Carbon prepared from Musa Acuminata Banana Bunch (AC-MABB) was proposed in this study. The active sites and morphology structure of three types of the AC-MABB were analyzed using FT-IR and SEM, respectively. The effect of independent variables namely contact time, Cu(II) ions concentration in solution, NaOH activator concentration, initial pH, and temperature on adsorption capacity of the AC-MABB were investigated through batch mode experiments. The Cu(II) ions adsorbed onto the AC-MABB showed excellent fitting to the pseudo-second-order adsorption kinetic with a  correlation coefficient value of  0.999. Meanwhile, it followed Langmuir isotherm with coefficient values of 0.981 and 0.991 at 27 and 57 oC, respectively. The optimum adsorption condition for 1 g of the AC-MABB was observed to be under 0.4 M NaOH activation atmosphere and, stirred at initial pH of 5 with a speed of 100-rpm and a pressure of 1 atm. The maximum Cu(II) ions adsorption capacity based on Langmuir was identified approximately equal to 40.322 and 46.082 mg/g at 27 and 57 oC, respectively.

Magnetic nanoparticles are very effective in removing heavy metals from wastewater that can be produced by adding to mineral adsorbents, a modified adsorbent with high adsorption properties. The addition of magnetite nanoparticles to bentonite increases the cationic adsorption power of bentonite. In this paper, the adsorption of cobalt ions on metal ions is investigated using synthesized magnetite bentonite nano-absorbent (SMB) (30-40 nm). First, The nano-absorbents were produced by co-precipitation and analyzed by Scanning Electron Microscope (SEM), X-Ray Diffraction (XRD), and Fourier Transform InfraRed (FT-IR) spectroscopy, then used as adsorbent. The experiments were designed and evaluated by design expert software. Optimal conditions were obtained by CCD model for metal ion adsorption (removal). The optimum amount of adsorption of Co 2+ ion from the solution was 95%.

Nd/Pd/TiO2 photocatalyst has been synthesized in the presence of Hydroxyl Propyl Cellulose by sol-gel method with Titanium tetra isopropoxide as titanium precursor. Photocatalyst size and structure properties of the nano-catalyst have been determined by X-Ray Diffraction (XRD). It has contained the anatase phase in advance. The surface area is measured by the Brunauer, Emmett, and Teller (BET) method. The presence of Ti, Nd, and Pd in the nanostructure has been confirmed by EDX, equipped tool with SEM. Photocatalytic degradation of PCB-28 under solar light has been investigated by the Taguchi method with five factors such as the amount of HPC (g/gsol), the percentage of Pd (%), the percentage of Nd (%), calcination temperature (°C), and calcination time (h). Under optimal conditions such as 0.003 of HPC (g/gsol), 0.2 percentage of Pd (%), 0.2 percentage of Nd (%), 700°C of the calcination temperature, and 5 hours for the calcination time, the best desorption result monitored by Solid Phase Nano Extraction (SPNE) technique method before degradation process. By GC-ECD, complete degradation of PCBs was observed after solar irradiation in 14min, and no PCBs chromatogram was observed after this time.

In this study, parameters affecting the carbonation reaction of carbon dioxide with sodium metaborate solutions were determined and optimized for a variety of process conditions. These parameters include reaction temperature, sodium metaborate concentration, carbon dioxide flow rate, and sodium metaborate/sodium hydroxide molar ratio. Two experimental designs were created for the carbonation reaction with different parametric ranges based on the solubility of the reactants. One of the designs contains high solubility of carbon dioxide and the other has high solubility of sodium metaborate.  The modeling results exhibit a good agreement with the experimental values for the low-temperature design. The modeled conditions exhibit an optimal reaction temperature of 24.0±1.0 oC, a carbon dioxide flow rate of 300±10 mL/min, and a molar ratio of 1.23±0.03 mol NaBO2/mol NaOH. The design conditions show that the rate of carbon dioxide consumption is 0.80 mol CO2/min at optimum, which is coherent with the experimental mean value of 0.77 mol CO2/min.

Novel poly-substituted quinolin-7-one derivatives have been synthesized using Friedländer hetero-annulation reaction from anthranilic acid and flavanone derivatives catalyzed by nano-zinc oxide. Using eco-friendly Nano-catalyst led to mild reaction conditions and increasing in converted yields. Heterogeneous media makes easy work-up and high isolated yields. The use of ethanol as a green and environmental solvent is the other advantage of this method. Our studies were shown that steric factors have been found to be important in the formation of the desired product. Good and excellent yield (50-97%) was obtained for corresponding compounds. Characterization of products was performed by FT-IR, 1H- and 13C-Nuclear Magnetic Resonance spectroscopies, and elemental analysis. The retention factor, Rf, and melting point for these desired products were determined.

Pure rubber seed oil was epoxidized via in situ conventional method using hydrogen peroxide and acetic acid in the presence of Sulfuric acid as catalyst. Optimization of the effect of process parameters such as time, temperature, and catalyst concentration was studied using Response Surface Methodology (RSM). The optimal condition for the predicted oxirane value, 1.5333%, was obtained at a reaction time of 6.49 hours, stirring speed of 667.26, and catalyst concentration of 1.82 mol. The resultant epoxide product was confirmed using Fourier transform infrared spectroscopy (FTIR) (at 1636.3 cm-1). These findings demonstrated the effects of process parameters on the rate of epoxide formation and the possibility to synthesize bio-based resin from rubber seed oil.

The NixMn1-xFe2O4 oxygen carrier is synthesized through the chemical precipitation method to be applied in the Chemical Looping Steam Methane Reforming (CL-SMR) process. The Response Surface Method (RSM) is adopted based on the Central Composite Design (CCD) model to evaluate the effect of the independent variables on the responses’ functionality and to predict the best response volume. The variables: reaction temperature (550-750°C), Oxygen Carrier (OC) loading rate (0.1-0.9), steam per methane ratio (S/C) (1.5-3.5), oxidation-reduction cycles’ count (1-9), and the responses consisting of CH4 conversion percentage, CO/CO2 molar ratio, and H2 production yield are assessed. The analysis of variance (ANOVA) results indicates that reaction temperature and the OC type are the most effective, while the oxidation-reduction cycles’ count is the least effective on CH4 conversion percentage and H2 production yield. By implementing the optimized results in laboratory conditions, it is revealed that the Ni0.6Mn0.4Fe2O4 OC at operating conditions at 650°C, S/C=2.5, and 9 redox cycles, the best response to the CH4 conversion percentage, CO/CO2 molar ratio, and, H2 production yield with 99.6, 15.7, and 77.6, respectively. The improved stability and functionality of the OC reveal that during the 24 redox cycle the self-supported Ni0.6Mn0.4Fe2O4 OC is of high stability, high CH4 conversion percentage means, and high H2 production yield. The OCs samples are characterized by applying FT-IR, XRD, FESEM with X-ray spectroscopy EDX, BET, and TGA.

This paper deals with the esterification of lactic acid using sulfonated carbon catalyst in a newly designed Microcontroller-Based Automated Reactor (MBAR) and the simulation of process parameters using MATLAB programming. The reactor was accompanied by a moisture sensor, temperature sensor, and solenoid valves in the embedded system. The study of the effect of process parameters such as silica gel weight, hot air temperature, molar ratio, and conversion of lactic acid on the removal of water, generated during esterification reaction, was performed. Water removal by adsorption using silica gel at each stage of conversion was estimated experimentally as well as with the help of developed, simulated linear equations, using MATLAB. The experimental and MATLAB results were compared and found in close vicinity. The simulation results revealed that increased water removal is achieved with increasing conversion and molar ratio. The results also validated that increasing the reaction temperature increases the conversion tremendously with a rapid decrease in hot air flow requirement. The uniqueness of the newly designed reactor is that the silica bed is operated in rotation in such a way that when one is in operation another is regenerated during its idle time.

In this research study, borax particles with different average sizes (1.25, 0.75, 0.60 μ m) were added to a styrene-butadiene rubber compound for reinforcement. This rubber has low mechanical, thermal, and surface properties, as well as low resistance to organic solvents. A laboratory two-roll mill was used at room temperature to add the borax particles to the synthetic rubber, then the rheometer characteristics such as torque, scorch time, and cure time were limited at a temperature of 150°C. The results showed that the torque and CRI (curing rate index) improved by 160% for torque and 600% for CRI respectively, dependent on reducing the particle size from 1.25 μm to 0.6 μm. The surface properties shown by FE-SEM, AFM images, and FT-IR analysis indicated a good dispersion of borax particles with an absence of the aggregates when a low borax particle size of 0.6 μm was used. Furthermore, the properties of tensile strength, elongation at break, and the hardness of the rubber compound were improved by 220% for tensile strength, 37% for hardness, and the reduction in elongation at break improved by 25% depending on the reduction in particle size. On the other hand, the resistance of the rubber compound to flame improved, besides the improvement of the thermal conductivity with decreasing particle sizes. The resistance of the rubber compound to organic solvents, such as toluene, was also improved, which was represented by the properties of swelling, the percentage of swelling index, and the cross-link density with 1.07% for swelling index and 1.3×10-3 mole/cm3 for cross-link density.

The new biologically active integrisides A (1) and B (2) have been isolated from the methanolic extract of Pistacia integerrima J. L. Stewart ex Brandis. The antibacterial activity of both the integrities was tested against four pathogenic bacterial strains, two Gram-positive (Staphylococcus aureus, Streptococcus pyogenes) and two Gram-negative (Escherichia coli, Pseudomonas aeruginosa) as well as four fungal strains (Microsporum canis, Aspergillus clavatus, Candida albicans, and Candida glabrata). Both the isolated compounds showed significant results analogous with Imipenam and Miconazole standard drugs. Carbonic anhydrase-II inhibition of integriside A (1) and B (2) with IC50 value 1.56 µM and 2.85 µM respectively, as compared to standard drug acetazolamide (1.57 µM). Cholinesterase activity was carried out with acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) IC50 values of integriside A (1) (8.6, 4.8) and B (2) (0.91, 2.5) were found as compared with standard galanthamine (0.05, 0.92) and Eserine (0.6, 8.7). Here, various molecular descriptors, frontier molecular orbitals (FMO), electron affinity (E.A), ionization potential (IP), molecular electrostatic potential (MEP), and Hirshfeld analysis were carried out to understand the active sites and biological active nature of the integrisides A (1) and B (2). The energy gap, MEP, Hirshfeld analysis, and reactivity descriptors values demonstrate that the integriside A (1) and B (2) retain decent reactivity, which is in good agreement with current experimental and quantum chemical studies.

The main concept of the present study is taken from the growth pattern of Dunaliella salina (green unicellular eukaryote microalgae) in Urmia Lake which is the second biggest saline lake in the world. In this study, different models of salt stress, including instantaneous (1 and 2 M) and consecutive slow-release salt stresses (0.5 M) were tested, and the amount of beta-carotene for each test was evaluated. According to the results, the highest amount of beta-carotene was obtained by the slow release method of salt injection with the amount of 9.01 µg of beta-carotene per mg of the dry weight of microalgae. The largest amount of beta-carotene production in 1 and 2 M  instantaneous salt stresses method were recorded as 4.35 and 0.65 µg/mg respectively which were up to 2 and 14 times lower than the highest beta-carotene production under the slow-release salt stress method.

In this study, a comparative measurement of bubble sizes in a two-phased medium (water and air) was performed in a mechanical flotation cell by Image Analysis (IA) and Laser Diffraction (LD) methods. The bubbles were generated in a mechanical cell with dimensions of 25*15*17 cm3. To determine the bubbles' size by the LD method, the bubbles were transferred from the cell to the Laser Particle Size Analyzer (LPSA) device through a hole in the cell, and Db(50) of bubbles were also calculated from their scattering pattern data. A bubble viewer, made of Plexiglass with certain dimensions, including two main parts (sampling tube and viewing chamber) was employed for the IA method. Comparative experiments were conducted in the different conditions affecting the bubble sizes, which are the impeller speed, solution temperature, pH value, and frother types. Results indicated that the two measurement methods were in good agreement while bubbles' sizes were in a range of +400-800 microns. The difference between LD and IA results was less than 7% in the range of +400-800. In the size range of -200 microns, LD and IA results difference increased to 36%. Moreover, in all experiments with the same conditions, the size of the bubbles by the LD method was recorded smaller than that by the IA method. Considering the fact that bubbles in the mechanical flotation cell are usually in the size range of +600 -2000 microns, and in this range, LD and IA results had a negligible disagreement, LD can be successfully employed for the bubble size measurement in mechanical flotation cells.

Lignocellulosic biomass can serve as raw material for ethanol production. However, lignocellulosic biomass is a complex mixture of carbohydrates that need additional processes for efficient ethanol production, such as pretreatment and hydrolysis before fermentation into ethanol. Therefore, this work mainly focused on the creation and simulation of a model of ethanol production from Jerusalem Artichoke Stalk (JAS) following experimental data and using the commercial software ASPEN Plus with and without a Heat Exchanger Network (HEN). Alkaline Hydrogen Peroxide(AHP)  pretreatment was the first step for this process. The optimal conditions of AHP were a mixture of 2% w/w sodium hydroxide (NaOH) and 4% v/v hydrogen peroxide (H2O2) at 10% (w/v) solid-liquid ratio and 121°C for 90 min. After treatment, 10% AHP-JAS loading was fed to enzymatic hydrolysis at 50°C and the fermentation process at 30°C. The simulation suggested that a feedstock of 60,000 kg of JAS could yield 3,482.16 kg ethanol. The purification section by the extractive distillation system had 12 stages, a distillate to feed mole ratio (D/F) of 0.13, and a reflux mole ratio (R/R) of 1.5. The purity of the ethanol product was higher than 97 wt%. After the model simulation, HEN was designed by using Aspen Energy Analyzer. After the installation of HEN in this process, the ethanol plant with HEN showed a better result, which at 16.24 percentages reduced total cost compared to the process without HEN.

The present study was undertaken to evaluate the equilibrium, mechanism, and mass transfer of nickel(II) ions adsorption on activated carbon derived from sewage sludge. Batch adsorption experiments were performed as a function of initial Ni(II) ions concentration (10-50 mg/L) and contact time (10-120 min). The experimental data were analyzed by different models and Freundlich model showed a better representation of equilibrium data (R2>0.99) and the mean adsorption energy was found to be E= 3.98 kJ/mol. Mechanism study indicates that both external mass transfer (D2) and mass transfer diffusion coefficient (kL) are important in determining the adsorption rates (5.50 × 10-5 cm/s and 7.30 × 10-7 cm/s). We also found that nickel(II) adsorption onto activated carbon would be attributed to a Physico-chemical adsorption process. The results suggest that sewage sludge-derived activated carbon could be used beneficially as an effective and alternative adsorbent for the removal of nickel(II) ions from aqueous solutions.

This article investigates the mixed convection flow of viscoelastic liquid because of an extending cylinder. The heat transfer investigation has been completed. Energy equation in attendance of heat, radiations are considered. Convective limit conditions for heat and mass exchange are utilized on the outside of the extending cylinder. Suitable transformations are utilized to decrease the overseeing nonlinear partial differential equations into standard differential equations. The subsequent differential equations alongside the boundary conditions are solved analytically by utilizing the homotopy investigation strategy (HAM) for acquiring the convergent series solutions. The effects of physical parameters on the velocity and temperature fields are investigated. Numerical estimations of local Nusselt numbers are computed and analyzed.

A numerical study of MHD nanofluid flow with gyrotactic microorganisms due to a stretching sheet embedded in a porous media is presented. The governing nonlinear Partial Differential Equations (PDEs) are transformed into corresponding ordinary ones through a power tool of similarity transformation. Impressions of important parameters on physical measures through tables as well as figures are discussed. The applied magnetic field tends to rise the shear stress while reducing the rates of heat transfer, nanoparticle volume fraction, and density of microorganisms. The porous medium causes a reduction in velocity distribution while it grows other measures like temperature, nanoparticle volume fraction, and microorganism’s density. The present work has various applications in industry, technology, and biosciences.

Enhanced Oil Recovery from carbonate reservoirs is a major challenge especially in naturally fractured formations where spontaneous imbibition is a main driving force. The Low Salinity Water Injection (LSWI) method has been suggested as one of the promising methods for enhanced oil recovery. However, the literature suggests that LSWI method, due to high dependence on rock mineralogy, injected and formation water salt concentration and complexity of reactions is not a well-established technology in oil recovery from carbonate reservoirs. The underlying mechanism of LSWI is still not fully understood. Due to lack of LSWI study in free clay dolomite fractured reservoir, and to investigate of anhydrate composition effect on oil recovery in this type of reservoir, the main purpose is the experimental evaluation of oil recovery from one of the Iranian naturally fractured carbonated (dolomite containing anhydrate and free clay) reservoirs using LSWI. For this purpose, a set of experiments including spontaneous and forced imbibition is conducted. To obtain the optimum salt concentration for oil recovery, the secondary mode of the spontaneous imbibition tests is performed by seawater in various salt concentrations at the reservoir temperature (75°C). Also, the tertiary recovery mode is subsequently applied with optimum brine salinity. The lab results reveal that by decreasing the injected water salt concentration, oil production increases. Furthermore, in order to upscale the experimental results to the field scale, a more precise dimensionless-time correlation is used. Due to some inconsistencies over the influence of mechanisms on LSWI oil recovery, the mineral dissolution, pH-increase mechanisms, and wettability alteration are also studied. The results indicate that wettability alteration is the main mechanism and mineral dissolution may be the predominant mechanism of the improved oil recovery in the studied reservoir. It is noticed, the elevation of pH led to enhanced oil recovery when high dilution of low salinity water is implemented.