Iranian Journal of Chemistry and Chemical Engineering
Volume:42 Issue: 4, Apr 2023

Hydrogels are 3-D (three-dimensional) polymer networks that can be natural or synthetic. After encountering water, do not dissolve but swell. Hydrogels swell in different conditions, such as temperature, pH, and ionic strength, and show other behaviors. Two initiators are used to prepare hydrogels: chemical and radiation initiation. Today, hydrogels have many applications, especially in medical and biomedical science. Vinyl hydrogels are the most applicable ones by worldwide 'polymer chemists'. Allylic monomers cannot be easily polymerized by the free radical polymerization method. The achieved polymers have low molecular weight and cannot convert to hydrogels typically. Inter-penetrating polymer network (IPN) hydrogels can be used in the wastewater remediation industry. Amphiphilic and amphoteric semi-(IPN)s are asserted in the metal adsorption and water purification industry. 

Biomimetic chemistry is a new environment-friendly approach that is inspired by biological processes, to produce new catalysts, and to develop ‘green’ synthetic routes to chemical catalysts based on the benefits of biological systems, aimed to find sustainable solutions to environmental and economic problems. In this paper, we will begin with overviews of two metalloproteins containing copper, which are catechol oxidase and phenoxazinone synthase; this is followed by analysis, and interpretation of some published results in the literature, concerning several attempts to elaborate new catalysts via biomimetic approach for diphenols and aminophenols aerobic oxidation. In order to save the cost of product development, increase efficiency, and eliminate waste; we have presented a theoretical study named Quantitative Structure–Activity Relationship (QSAR) to predict the catalytic activity and physicochemical properties by rational means, with the aim of contributing to the development of the biomimetic approach, and to increase the efficiency of catalysts, by not following leads that are unlikely to be successful.

Nowadays antimicrobial resistance is one of the important concerns caused by the extensive use of antibiotics. Efforts to find new materials with antimicrobial effects have been more serious than before. In this study, MgO/MgAl2O4 nanoparticles were synthesized by hydrothermal technique. To investigate the physicochemical properties, scanning electron microscopy, dynamic light scattering, X-Ray Diffraction (XRD), ThermoGravimetric Analysis (TGA), and atomic force microscopy were carried out. For the purpose of evaluation of the MgO/MgAl2O4 nanoparticles, energy dispersive Scanning Electron Microscopy (SEM), Dynamic Light Scattering (DLS), (TGA), Transmission Electron Microscopy (TEM) and Fourier-Transform InfraRed (FT-IR) spectroscopy ran then minimum inhibitory concentration measured on eight bacterial strains. The majority of nanoparticles were in the range of 90 to 150 nm which is the well-optimized size for our purpose. Antimicrobial analysis showed the effect of synthesized MgO/MgAl2O4 NPs on every eight microbial strains including 4-gram positive Staphylococcus epidermidis, Staphylococcus aureus, Micrococcus luteus, Bacillus subtilis and 4-gram negative strains Serratia marcesens, Escherichia coli, Pseudomonas aeruginosa, Klebsiella pneumoni.

A novel 5-fluorouracil and graphene oxide [GO-5-FU] mediated drug delivery system was prepared that involves uniquely combining Graphene Oxide (GO) with anticancer 5-fluorouracil (5-FU) drug for controlled drug release. The nanocarrier system was synthesized by attaching 5-FU to graphene oxide via a strong π–π stacking interaction. The loading and release of 5-FU   indicated strong pH dependence and implied hydrogen-bonding interaction between graphene oxide and 5-fluorouracil. The [GO-5-FU] system increased significantly in acidic pH and higher temperature without any burst release. In addition, the equilibrium adsorption data were analyzed by the Langmuir and Freundlich models. The results showed that the adsorption behavior could be fitted better by the Freundlich model. We believe that these materials and pH-dependent properties allow developments in controlled drug release techniques for biological and biomedical applications. It is obtained that about 66% of 5-FU was released in the simulated intestinal fluid (pH 7.4) at 37◦C over a period of 30 h, while at this temperature and pH environment of the gastric fluid (pH 1.2), ltngvk.tyn 5 5-FU was released approximately 90% over a period of 30 h. At 37◦C and this period of time, the amount of 5-FU release was 78% at pH 10. As can be observed, as the temperature is raised, the release of 5-FU is increased.

A novel lubricating grease additive comprised of a new nanohybrid and a suitable base fluid has been proposed in this research. The addition of this nano additive (5 wt%) to the lithium grease improves 1.5 times the extreme pressure property and can reduce lithium grease wear scar diameter better than the other similar nanomaterials reported in the previous research. For preparing the nanohybrid, during the hydrothermal synthesis reaction of nano metal borate, a suitable amount of nano transition metal dichalcogenides was added to the reaction vessel under the nitrogen atmosphere and high temperature for 18h. The base fluid comprises fatty amines, fatty oils, fatty amides, fatty acid esters, and Zinc dialkyl dithiophosphate (ZDDP) with optimum ratios. Nano lubricant additive was prepared by adding the 0.1 wt% nanohybrid to the base fluid at 80 oC with mixing for 30 minutes.

With the expansion of the scope of lubricant oils and fuels, the requirements for their performance properties are increasing. One of the performance characteristics of these petroleum products is their resistance to oxidation. It is known that as a result of oxidation, their performance properties deteriorate. Antioxidant stabilizers are used to increase the resistance of organic materials against oxidation. The study of the mechanism of action of oxidation inhibitors is one of the most important tasks in this field, the solution of which is the creation of a theoretically substantiated approach to the targeted synthesis of more effective antioxidants. To create the theoretical and practical foundations of solving this problem was to find novel classes of effective additives of multivalent activity, particularly antioxidants, a series of recently synthesized nitrogen, sulfur, selenium and phosphorus polyfunctional compounds, including pyrroledithioates, 6,8-bicycloctanes, aminopyrimidine, tris(2-pyridyl)phosphinesulfide and -selenide have been investigated using model oxidative reactions. The compounds studied appear to be perspective inhibitors of hydrocarbon oxidation. Some of them are antioxidants of combined action, breaking the chains of the oxidative reactions with cumene peroxide radicals and catalytically decomposing cumene hydroperoxide.

 Phytochemical investigation on dichloromethane (CH2Cl2) fraction from fruit seeds of Syzygium cumini provided two new esters Syzygioate A (1) and Syzygioate B (2), along with known compounds dipropyl succinate and dioctyl phthalate. The isolated compounds were characterized via spectroscopic techniques such as 1H, 13C NMR, EI-MS spectrometry, and FT-IR. The bioassay studies were also conducted for the isolated compounds where the new compound 1 and 2 exhibited significant inhibition potential against acetylcholinesterase (AChE), butylcholinesterase (BChE) & antioxidant activity against Diammonium 2,2'- azino -bis (3-ethyl benzo thiazoline-6-sulfonic acid (ABTS), superoxide anion radical scavenger & 2,2-di phenyl-1-picryl hydrazyl (DPPH). The IC50 values of compounds 1 and 2 for their cholinesterase inhibition were 7.15, 4.54µM against AChE, and 9.21 & 6.31µM against BChE. The DPPH radical scavenging potential for compounds 1 & 2 exhibited IC50 values as 69.4µg/ml and 74.6µg/ml respectively.

Zinc Oxide (ZnO) chemical bonds have stayed between covalent and ionic liaisons; this appears in its thermodynamic behavior and the atomic distances under extended pressure and temperature. In this work, the impact of pressure and temperature is focused on the distance between the atoms of unit cell O-O, O-Zn, and Zn-Zn (1458 atoms of O2- and 1458 of Zn2+) under the range of pressure (0-200 GPa) and temperature of range 300-3000K. Molecular Dynamics technique (MDs) and DL_POLY_4 software are employed on the RAVEN Supercomputer of Cardiff University (UK). The interatomic interactions are modeled using Buckingham potential for short-range and Coulomb potential for long-range. This paper calculates and confirms the effect of pressure and temperature on Zn-O bond length which is less than that on Zn-Zn and O-O bonds, the relationship of these lengths, standard error, standard deviation, the mean, the maximum values of the radial distribution function, the percentage of variation, and finally the validity of Buckingham's potential for ionic and covalent chemical liaisons are reported. The obtained results are in the vicinity of available theoretical and experimental data; these results would have great importance in nanotechnology and technology fields, especially in Medicine and Pharmaceutics.

Favipiravir is a broad-spectrum antiviral drug and it has increasing interest regarding its potential use in Covid-19 therapy.  In the present work, a simple, fast, precise Reverse-Phase High-Performance Liquid Chromatography (RP-HPLC) technique was developed for the quantification of favipiravir (FVP) from pharmaceutical formulation. Moreover, the spectral and chromatographic behavior of FVP was investigated. The developed method was performed using an ACE 5 C18 column (250 mm × 4.6 mm, 5 µm), with the mobile phase composition 10 mM phosphate buffer (pH = 2.5): methanol (80:20, v/v) at a flow rate 0.6 mL/min. The method validation parameters, such as linearity, precision, accuracy, and robustness, were determined. The recovery yields for accuracy were between 99.9 and 101.4 % for three concentrations. The linearity range was determined between 0.5 and 100 µg/mL with a regression coefficient (R2) 0.99998. The limit of detection and limit of quantification values were evaluated as 0.02 µg/mL and 0.05 µg/mL, respectively. The precision of the method was evaluated in inter-day and intra-day precision studies with a relative standard deviation of less than 2%. The method's robustness was investigated using the alteration of flow rate, detection wavelength, and mobile phase ratio.  Moreover, the effect of the pH and mobile phase ratio on the capacity factors was analyzed and the pKa value of the FVP was determined chromatographically as 5.03 ± 0.02.

In this study, α-Fe2O3/α-AgVO3 nanocomposite was successfully synthesized via a solvothermal process, followed by a co-precipitation method. The products were characterized by X-Ray Diffraction (XRD), Field Emission Scanning Electron Microscopy (FESEM), Energy Dispersive X-ray (EDX) spectroscopy, Fourier Transform InfraRed (FT-IR) spectroscopy, Diffuse Reflectance Spectroscopy (DRS). The photocatalytic activity of α-Fe2O3/α-AgVO3 nanocomposite was investigated for the removal of Methylene Blue (MB) dye from aqueous solutions under UltraViolet (UV) light irradiation. The results revealed that the photocatalytic performance of the nanocomposite is higher than that of the pure compounds. The effect of pH, MB concentration, and photocatalyst dosage on the removal efficiency of MB was also evaluated. The solution pH of 5.9, MB concentration of 20 mg/L, and photocatalyst dosage of 1.5 g/L were obtained as the optimal conditions. The kinetics of MB degradation was studied, and it was found that the reaction follows the pseudo-first-order equation. Under the optimal conditions, the MB removal efficiency of 98% was obtained, and the rate constant was calculated to be 0.0312 min-1. A possible mechanism for the p-n heterojunction was proposed to describe the enhanced photocatalytic activity of the α-Fe2O3/α-AgVO3 nanocomposite. The findings demonstrated that the α-Fe2O3/α-AgVO3 nanocomposite with improved photocatalytic activity can be used to remove contaminants from aqueous media.

In this research, TiO2 nanoparticles were synthesized by sol-gel method and coated on the tile by using the Doctor Blade method. The TiO2 hydrophobic coatings were prepared by applying oleic acid and an organic binder on the tile substrate. The XRD, FESEM, Contact Angle, and FT-IR analyses characterized the manufactured coatings. According to the XRD pattern, the synthesized nanoparticles have good crystallinity, and two anatase and rutile phases have formed. The contact angle analysis showed that the contact angle increased by surface modification by using oleic acid. The antibacterial and photocatalytic activity of the coatings were evaluated in the decomposition of Escherichia Coli in various concentrations of bacteria and various dyes. The results confirmed the good antibacterial and photocatalytic activity of TiO2 coatings. The stability and durability of the coatings were examined by applying the salt spray test, Shore D test, and ultrasonic bath. The coatings revealed good anti-corrosion properties, and the hydrophobicity of the coatings was preserved after the salt spray test.

Activated carbon from the walnut shell modified by sepiolite (AC/SEP) composite was synthesized and applied for the adsorption of toxic lead (Pb(II)) ions from industrial effluents.  AC/SEP composite was characterized by Fourier Transform InfraRed (FT-IR) spectrometer, Field Emission Scanning Electron Microscopy (FESEM), Brunauer–Emmett–Teller (BET), and X-Ray Diffraction (XRD) analyses. Effects of pH, amount of adsorbent, Lead initial concentration, and contact time on removal percentage were studied by Central Composite Design  (CCD). The optimal condition for maximum Lead removal by AC/SEP adsorbent (99.07%) was as follows: pH= 5.00, adsorbent amount: 0.05 g, initial concentration 20.00 mg/L, and contact time: 25.00 min in 10 mL of pollutant volume. Also, the adsorption kinetics, thermodynamics, and isotherms were determined. Adsorption isotherms (qmax: 269.67 mg/g) and kinetics showed that the sorption process was better modeled by the Langmuir and pseudo-second-order equation.

The concern for the removal of pesticides in water resources is grown in recent years, which justifies the search for alternative technologies to those applied in conventional water treatment processes. The use of agricultural wastes directly for the preparation of the adsorbents, is a viable method, combining removal efficiency, low cost, and biodegradability of the material applied. The present work was carried out to evaluate the employability of Rice Husk (RH), a waste from rice agriculture, in Methyl parathion (MP) removal from aqueous solutions. To find the optimum removal yield of (MP) onto (RH), the effects of various experimental factors: adsorbent dosage, pH, and the effect of contact time were studied by using the batch experiments mode. The adsorption kinetic data were analyzed using the Pseudo First Order (PFO), Pseudo Second Order (PSO), and Elovich models. For the kinetic study, the adsorption process fitted the PSO model. Three adsorption isotherms namely the Langmuir, Freundlich, and Sips isotherms were applied to the adsorption equilibrium data. The results indicated that the parameters isotherm models are found to be suitable for fitting the present adsorption isotherms data in the following subsequent order: Sips > Langmuir> Freundlich.  The Sips isotherm exponent n is near the unity indicating that the adsorption data were more of Langmuir form suggesting that the surface of RH is homogeneous for MP adsorption. The monolayer adsorption capacity, qm, was found to be 4.38 mg/g. The present study showed that RH is a promising adsorbent for the removal of MP from an aqueous solution.

Sulfide ions in the solution of the Bayer process can accelerate the corrosion of the equipment and increase the impurity of the final product. In the current investigation, sulfide ions concentration of the aluminate solution during the Bayer process was determined using an indirect and inexpensive method. The method did not require any advanced apparatus, which made it suitable for sulfide concentrations over the range of 0.001-1 g/L. To investigate the source of sulfide ions in the aluminate solution, the chemical composition and crystalline structure of the bauxite used to produce alumina were characterized via XRF, XRD, and SEM analyses. The results demonstrated that the main source of sulfide ions was pyrite in bauxite. The advantages and disadvantages of sulfide removal method by nitrate from aluminate solution were investigated. Thermodynamically, the spontaneity of different half-reactions during the reduction of NO3- and oxidation of S2- was studied. Finally, a technique was proposed for the removal of sulfide ions in the aluminate solution by adding nitrate. Moreover, the effect of nitrate concentration on lowering of sulfide ions concentration was evaluated in practical conditions of the bauxite digestion during the Bayer process. The results demonstrated that in conditions of bauxite digestion (at 270 °C, 52 bar, and 60 minutes) by adding 2.5 g/L nitrate ions, the majority of sulfide ions (more than 96%) were eliminated and their undesirable effects were prevented.

Electroplating is a preferred method of coating the surface of metallic materials such as steel for wear and appearance reasons. Recently, zinc, nickel, or zinc-nickel coatings have been widely used to prevent corrosion of vehicle parts such as brake pads and connecting equipment. However, in the plating bath used in the plating processes, iron contamination might occur due to the partial dissolution of the metal parts over time, causing dark-colored defects on the plating material during electroplating. In this study, the recycling of the plating bath electrolyte by precipitation of iron ions from the solution was investigated. The addition of 7 g/L zinc dust at 30° C minimized the iron concentration in a short time (20 minutes) without affecting the quality and content of the coating bath. The chemical and physical analyses of the precipitate and electrolytes were performed by AAS, XRD, and EDX. The galvanic quality of the decontaminated electrolyte was tested at a current density of 250 A /m2 and 298 K.

Miscellas of canola were obtained by mixing its crude oil with hexane solvent at 80:20 and 70:30 ratios. Then, 16.1 M of phosphoric acid and 6.92 M of sodium hydroxide were mixed with the resulting micelles at 0.3% (w/w for degumming) and 13% (w/w for neutralizing), respectively, before two sequential Membrane Filtrations (MF). The MF unit had a crossflow mode equipped with three independent variables of transmembrane pressures or TMP (at 2, 3, and 4 bar), feed velocity (at 0.5 and 1 m/s), and temperatures (at 30, 40, and 50˚C) were used to determine the efficiencies of two MF processes and find out their optimum conditions. When the crude canola oil was mixed with 20-30% solvent and passed the two stages of MF (for degumming and refining) at TMP=2 bar, feed velocity=1 m/s, and temperature = 50˚C, the final polished canola oil had < 5% soap, < 5% phosphorus, < 5% fatty acids, and < 15% wax. Membrane refining, compared to chemical refining, significantly reduced the phosphorus content (50%), free fatty acids (29%), soap (99%), and wax (72%) of refined canola oil. While the permeate flux of canola miscella with 20% solvent increased with rising TMP, feed velocity, and temperature, the ones with 30% solvent did not increase with a similar trend. The highest permeate flux of refined canola oil reached 0.03 Kg/m2, s for miscella with 20% solvent when the feed velocity, TMP, and temperature of degumming or neutralization were 1m/s, 3-4bar, and 30-40oC, respectively. The dominant fouling changed from standard to cake blocking when the crude oil was mixed with 20 or 30% solvent, and the TMP of the MF process in each stage of degumming and neutralization was > 2 bar.

Calcined Kaolin / Calcium carbonate / TiO2 (KCT) composites were prepared using 1:1:1 and 1:1:2 proportions at 1000 °C calcination temperature.  The efficiency of KCT composites on the decolorization of Reactive Black 5 (RB5) effluent was investigated based on the composite concentration, pH, and time of treatment. Box and Behnken experimental design was used to optimize the decolorization efficiency of RB5 using KCT composites, followed by modeling of the treatment using an artificial neural network. Optimized parameters based on the Box and Behnken design for 1:1:1 KCT composites resulted in a decolorization efficiency of 94.5 %, using 20 g/L composites treated at pH 3 for a treatment duration of 3 hours 48 minutes. Similarly, for 1:1:2 KCT composites, 94 % decolorization efficiency of RB5 effluent has been achieved using 18.9 g/L composite treated at pH 3.5 for a treatment duration of 3 hours 56 minutes. Experimental results and the predicted results show close conformity in decolorizing RB5 effluents using KCT composites. Physico-chemical treatment of dyes using KCT composites was found to be efficient due to the formation of calcium silicate and calcium titanate, resulting in a strong photocatalytic adsorbent, leading to physical sorption and photochemical oxidation.

In this study, a new Solid Phase Extraction (SPE) method was developed for the detection of cobalt ions in water and food samples with High-Resolution Continuum Source Flame Atomic Absorption Spectroscopy (HR- CS FAAS). Cobalt ions were recovered and separated for the first time using grape stalk-based active carbon in this work (ACGS). Separation and preconcentration operations were carried out using the column method. Sample solution pH, eluent type and concentration, flow rates of the sample solution and eluent, sample solution volume, the influence of foreign ions, and adsorbent capacities were tested to find the best conditions for the recovery of analyte ions. The pH was set to 7.0, the extraction eluent volume was 5 mL 2 mol/L, and the sample flow rate was 4 mL/min in order to produce the best extraction possible. Under optimum conditions, the Limits of Detection (LOD) and Relative Standard Deviation (RSD) were obtained as 0.27 µg/L and 2.3%, respectively, and the maximum adsorption capacity based on the Langmuir was found to be 8.1 mg/g. Analyte ions were added to real samples to test the method's accuracy, and the results were then compared to those of other methods and reference materials (SRM). More than a few water and food samples were successfully tested this way.

Heavy metals, saturated and trans-fatty acids are considered one of the most important food contaminants and health threats caused by natural phenomena or human activities. In this regard, fast foods are one of the sources that have to be monitored regularly as the potent points for potentially toxic elements and saturated and trans-fatty acids. The concentrations of lead, cadmium, and arsenic were measured using atomic absorption spectroscopy in fast foods (pizza, falafel, and chicken nuggets). The public health hazard from the consumption of fast food contaminated with heavy metals was determined using estimated daily intake, target hazard quotients, hazard index, and carcinogenic risk. The concentrations of saturated and trans-fatty acids were measured through the Gas chromatography method. A chicken nugget (0.133 mg/kg) had the highest concentration of arsenic, a pizza (0.123 mg/kg) had the highest concentration of lead, and falafel (0.137 mg/kg) had the highest concentration of arsenic. The majority of the estimated daily intake, target hazard quotients, and hazard index were lower than the world standards except for arsenic in chicken nuggets. The mean concentrations of saturated fatty acids in falafel, mixed pizza, and chicken nuggets were 18.02g/100g, 36.35g/100g, and 19.11g/100g respectively. The mean concentrations of trans-fatty acids in falafel, mixed pizza, and the chicken nugget were 1.12 g/100g, 1.32 g/100g, and 0.79 g/100g respectively. The mixed pizza had a higher saturated fatty acids content of 36.35% (heptadecanoic, stearic acid, and short-chain fatty acids). Therefore, heavy metals such as arsenic and saturated fatty acids in fast foods are a risk to the health of consumers and the only solution for this is to minimize the consumption of fast foods.

The anti-cancer properties of fermented Wheat Germ Extract (FWGE) have been proven due to the active ingredient benzoquinones, especially 2, 6-dimethoxybenzoquinone (2, 6-DMBQ).  In this research, the development of the FWGE production process with a higher content of 2, 6-DMBQ with respect to the bench-scale was considered and simulated by SuperPro Designer (SPD) software. To evaluate the effect of wheat germ granulation, the fermentation process was performed in 250 mL and 2-liter shake flasks and 3.6- and 13-liter bioreactors. Then, the possibility of yeast complete separation in the final product was investigated by combining centrifugation in 3000 g and pressure filtration with linen, polyester, polypropylene, and cellulose membranes. A comparison of the dryer type effect including oven, spray dryer, freeze dryer, and rotary vacuum dryer in terms of drying time and final moisture content of FWGE showed that the spray dryer gives the product with the least humidity 5 (w/w)% in the lowest time 15 min. Examination of the effect of granulation also showed that at higher scales, non-granulated wheat germ produces more 2,6-DMBQ. Yeast complete removal from the final product was achieved using initial centrifugation at 3000 g and then a filter press with a combination of polypropylene membranes 8-10 µm, polyester 5 µm, and a polymer membrane 1-2 µm. Finally, the production process on scales of 10, 100, and 1000 liters was simulated by SPD software. On the basis of investment cost, the return rate of investment (ROI) equaled 4, 1.9, and 0.4 years on scales of 10, 100, and 1000 liters, respectively. These results showed that the scale-up of the FWGE production process significantly decreases the ROI and can be considered a high-value-added production line at higher scales.

This investigation reports the synthesis and characterization of a graft copolymer of methyl methacrylate (MMA) and styrene (Sty) onto starch.  The copolymers of MMA with Styrene, P(MMA-co-Sty) and the graft copolymer, Starch-g-P(MMA-co-Sty) were prepared via emulsion polymerization using the thermal initiator potassium persulfate (KPS). Sodium dodecyl sulfate (SDS) was used as a surfactant in both cases. The polymerizations were carried out at 70ºC for 30 minutes for P(MMA-co-Sty) and 3 hours for Starch-g-P(MMA-co-Sty). Attempts had also been made to prepare copolymers with different monomer compositions. The progress of the polymerizations with time was monitored by measuring the conversion of monomers gravimetrically. The grafted Starches were characterized by Nuclear Magnetic Resonance (1H-NMR) and Fourier Transform InfraRed (FT-IR) spectroscopy analyses. The FT-IR and 1H NMR analysis of the purified copolymers revealed successful grafting of MMA and Styrene copolymerization onto Starch. The surface morphology was studied by SEM and the thermal study of the graft copolymer was studied by TGA.

Natural fiber is growing relevant in composite processing due to its low cost, lightweight, and good mechanical properties; therefore, increased natural fiber composite development is desirable. This study predicted the mercerization effect on the moisture absorption properties of groundnut shell samples using neuro-fuzzy modeling. The groundnut shells were processed, dried, and treated with NaOH varying the time and concentration of the treatment. Sensitivity analysis using the adaptive neuro-fuzzy inference system) ANFIS's exhaustive search showed that treatment time and concentration impacted the moisture absorption rate of groundnut shells. Parametric analysis via ANFIS surface plot indicated that an increase in treatment time and concentration decreased the moisture absorption rate of the samples. The characterization results from SEM(Scanning electron micrograph) and FT-IR (Fourier Transform Infrared Spectroscopy) showed that the groundnut shells were suitably mercerized. ANFIS optimum result showed that the moisture absorption rate of 1.23% was obtained at a treatment time of 4 hours and a concentration of 4 mol; pi membership function (mf) had the best coefficient of determination R2 (0.99364) and Mean Square Error (MSE, 0.011679) amongst other membership functions demonstrating a significant predictive behavior for the model. The observations from the study prove that the ANFIS technique is a practical approach for the prediction of the groundnut shell mercerization process.

For the first time, a numerical study has been carried out to investigate the flow and heat transfer from a partially immersed rotating sphere in a bounded boundary stationary fluid with variable distances from its surface. The simulations are performed for different boundary distances under various types of rotational speed of the sphere using the two-phase VOF model. The flow and thermal fields are investigated through streamlines, isotherm, and volume fraction contours, as well as through the average Nusselt number and the thickness of the water film. The numerical results demonstrate that the water is drawn up the sphere's lower pole because of the centrifugal force generated by the rotation, and its motion continues due to the water film formation. Then, the water film is radially thrown out because of the inertial forces dominance. Moreover, the sinusoidal pulsation rotational speed indicates higher heat transfer performance among various functions. Compared with the exponential function by increasing the boundary radius from [ ] to [ ] the time-surface-averaged Nusselt number increases by about 35%. Also, it is found that as the immersion angle increases from  to , the time-surface-averaged Nusselt number increases about 51% on average for the uniform rotational speed of the sphere.

With climatic conditions and close to flooding areas for the system under construction, an energy production system using two types of renewable energy, estuary, and wind, has favorable wind speed conditions. The Steam cycle is designed with a parabolic-linear collector to maximize the use of the heat generated by the system, which is then transferred by an evaporator and a steam turbine to produce energy. The evaporator must generate a single-effect absorption refrigeration system to generate a cooling load. Its main components are a steam-Rankine cycle, organic Rankine cycle, thermoelectric, absorption refrigeration, reverse osmosis, and a parabolic-linear manifold. The system was modeled using EES software to obtain thermodynamic results. Based on the results, solar systems with a central receiver have the highest energy losses. The exergy analysis revealed that the solar system has 60%, and the wind turbines have 17% of the system’s exergy losses.

The present work aims to examine the susceptibility to soil corrosion of base metal (BM) and heat affected zone (HAZ) of API L5 X60 steel pipeline, and to assess the ability of Di-(2-ethylhexyl) phosphoric acid (D2EHPA) to inhibit the corrosion of the two samples. An overview of the literature reported almost no studies related to the corrosion inhibition of pipeline in soil solutions. The experiments were carried out in a simulated soil solution (NS3) using electrochemical methods, a thermodynamic approach, and surface analysis. The results demonstrated that D2EHPA is a potent inhibitor for both steels in the soil solution. Indeed, its efficiency increased with the increase of its concentration, exceeding 98 % at the optimal concentration, even for HAZ which is less resistant to corrosion than BM, due to the coarsening  of α-ferrite grains. Polarization curves showed that D2EHPA acts as an anodic-type inhibitor, and the calculated standard free adsorption energy values deduced by Langmuir isotherm indicated that the phosphoric compound adsorbs via electrostatic and chemical bindings. The stability of the adsorbed D2EHPA layer, on both the surfaces of BM and HAZ that were immersed in the inhibitive solution for 168 h, has been proven by EIS studies. Moreover, the effective adsorption of D2EHPA at the steel/SN3 interface is clearly highlighted by Scanning Electron Microscopy (SEM) and FT-IR spectra. Theoretical DFT calculations were also performed to determine some electronic properties of the studied molecule and to find a correlation between the inhibitive effect and the electronic structure of the neutral form and the deprotonated form of D2EHPA.

Greenhouse gases can be defined as air pollutants that cause global climate warming. In order to reduce their harmful effects, these gases like methane and carbon dioxide can be stored in the form of compact gas hydrates. Prediction of gas hydrate formation conditions is very important for gas hydrate production and storage in industries. The goal of this study is to develop machine learning methods based on support vector regression and adaptive boosting models for predicting gas hydrate formation conditions for CO2 and natural gas. In this regard, SVR, AdaBoost.R2, VQ-SVR, VQ-AdaBoost.R2, CS-VQ-SVR, and CS-VQ-AdaBoost.R2 models have been developed and compared to obtain a model with the best performance. The cuckoo search optimization algorithm and vector quantization technique have also been utilized to determine the optimal values of the models’ hyper-parameters, reduce the computation time, and improve the accuracy and robustness of the models. As a result, since the values of the coefficient of determination and root mean square error for the CS-VQ-SVR model are 0.0215 and 0.9995, respectively, and the best agreement between predicted and actual values in this model’s graphs is obtained, it can be concluded that the CS-VQ-SVR model has the best accuracy and robustness among other developed models in predicting gas hydrate formation pressure with time. These results show that machine learning is viable for predicting the conditions of gas hydrate formation and preventing greenhouse gas emissions in industries.