Iranian Journal of Chemistry and Chemical Engineering
Volume:42 Issue: 11, Nov 2023

In recent times, there has been an increasing interest in Carbon NanoTubes (CNTs) reinforced metal matrix composites due to their promising properties such as high Young’s modulus and tensile strength. Carbon NanoTubes (CNTs) are known for their extraordinary mechanical, electrical, and thermal properties. These properties make them ideal reinforcements in the metal matrix. Out of all fabrication processes, the powder metallurgy technique was frequently used due to the fewer defects, lesser chance of formation of agglomerations, and the possibility of fabricating composites with nearly net shape in powder metallurgy technique. This research work focuses on developing and analyzing the thermal and mechanical properties of Cu-CNT metal matrix composite. The experimental specimens were fabricated using powder metallurgy in which Copper was ball-milled with Nickel, Zinc, Tin, and Carbon nanotubes of varying compositions were added to the ball-milled copper composites. The resulting powder was compacted using a hydraulic press to form pellets and finally sintered using a Tubular Furnace. Thermal conductivity test and Differential Scanning Calorimetry test were conducted to study the thermal properties of the composites. Mechanical and microstructural studies were conducted on the fabricated components to explore their competency.

This research aimed to prepare and utilize a novel hybrid nanofluid (GO-SiO2-TiO2–SDS) to significantly reduce the InterFacial Tension (IFT) to a level lower than the IFT value of the SDS surfactant solution at the Critical Micelle Concentration (CMC) point. Accordingly, the GO-SiO2-TiO2 nanocomposite was synthesized, and its properties were evaluated through six different analyses, including Field Emission Scanning Electron Microscopy (FESEM), Energy Dispersive X-ray Spectroscopy (EDXS), Map Analysis, Fourier Transform InfraRed (FT-IR), spectroscopy X-Ray Diffraction (XRD),and ThermoGravimetric Analysis (TGA). To assess the effects of GO-SiO2-TiO2–SDS hybrid nanofluids on IFT reduction, SDS surfactant solutions were prepared at varying concentrations of SDS (0, 200, 500, 1000, 2000, 3000, 4000, 5000, and 6000 ppm), and 500 ppm was determined as the CMC. Different concentrations of the GO-SiO2-TiO2 nanocomposite (100, 500, 1500, and 2500 ppm) were separately added to deionized water, and then the SDS surfactant was added at the CMC value to prepare hybrid nanofluids. The results of IFT measurements reported by the Du Noüy ring method indicated that IFT values at the interfaces between 500-ppm SDS surfactant solution/kerosene and (2500 ppm GO-SiO2-TiO2–500 ppm SDS) hybrid nanofluid/kerosene decreased from 23.59 mN/m to 2.48 mN/m and 0.51 mN/m, respectively. Therefore, using the GO-SiO2-TiO2–SDS hybrid nanofluid could reduce the IFT value to a level lower than that of the SDS surfactant solution at the CMC point.

The fabrication of sustainable and efficient metal oxide-based semiconductor materials for effective degradation of environmental pollutants and other applications are currently attracting major interest from researchers. For this reason, magnetic iron oxide (Fe3O4) and zinc incorporated magnetic iron oxide (Zn@Fe3O4) nanoparticles were successfully synthesized by a co-precipitation method and tested for their physical properties and also as a photocatalysts for the degradation of toxic dye from the environment. The photocatalyst were analyzed by the use of scanning electron microscopy (SEM), x-ray diffraction (XRD) and Ultra-Violet Visible spectrophotometer to evaluate their morphology, crystallinity and band gap properties, respectively. The photocatalytic degradation performance of synthesized Fe3O4 and Zn@Fe3O4 was studied for their degradation efficiency on methylene blue (MB) dye. The photocatalytic activity of Fe3O4 was affected by doping with Zn ion. The highest methylene blue degradation (83.80 % and 70.50 %) for Fe3O4 and Zn@Fe3O4 were obtained at 0.5 g dose. The XRD and SEM results approved the existence of Fe3O4 and Zn@Fe3O4, and also highlighted the successful entrance of zinc ion onto Fe3O4. The introduction of zinc dopant into Fe3O4 lattices increases the band gap from 2.77 eV to 2.80 eV. The study of electronic structure of methylene blue was examined through quantum chemical calculations using density functional theory method (DFT) in order to give an insight on the nature of MB interaction with synthesized photocatalyst. The DFT results revealed that the nitrogen atom of the MB molecule is the favorite sites of interaction with the metal oxide surface. Furthermore, the experimental findings showed that magnetic iron oxide demonstrated a good photocatalyst in degradation of methylene blue as compared to the zinc doped magnetic iron oxide particle.

Novel magnetic adsorbents of Clinoptilolite/Fe3O4 (Clin/Fe3O4) nanocomposite powders and Alginate/Clinoptilolite/Fe3O4 (Alg/Clin/Fe3O4) nanocomposite granules were synthesized to efficient removal of the cationic crystal violet (CV) dye in single and CV/methylene blue (MB) binary systems. The prepared adsorbents were characterized by FT-IR, XRD, SEM, EDX, dot mapping, and BET analysis. Adsorption tests showed that Clin/Fe3O4 and Alg/Clin/Fe3O4 had high affinity toward CV removal at 94.32% and 92.35%, in the single system and 84.19% and 80.23%, in the binary system, respectively. Based on the findings, pH was the most effective variable in the elimination process and the highest yield was obtained at pH 8 for both adsorbents. The equilibrium data followed the Langmuir model (R2 > 0.9) based on which the maximum adsorption capacity (qmax) using Clin/Fe3O4 and Alg/Clin/Fe3O4 was determined as 44.662 mg/g and 16.528 mg/g, respectively in the single system and it was computed to be 15.797 mg/g and 11.476 mg/g, respectively in the binary system. The kinetic data fitted well to the pseudo-second-order model in both systems. The adsorption process was exothermic and thermodynamically spontaneous. Moreover, Clin/Fe3O4 and Alg/Clin/Fe3O4 adsorbents showed 91.43% and 82.01% recyclability over the desorption tests, thus leading to promising and green-based adsorbents for the removal of dyes. The Electrical Conductivity (EC) of MB, CV, and CV/MB solutions and also real wastewater sampled from a dyeing unit were measured before and after treatment and the results showed that the EC of all samples was reduced.

The removal of heavy metal ions (Cr, Pb, and Zn) present in aqueous solutions has been examined using Sargassum Wight (SW) - brown algae – as an organic adsorbent. The functional groups of SW were determined by FT-IR analysis before and after heavy metal ion adsorption. Because of the strong Van der Walls forces, the SEM/EDX picture reveals the presence of heavy metal ions on the surface of the SW. The influence of adsorption was studied in different settings by adjusting the parameters of pH, SW dosage, metal ion concentration, time of contact, and temperature. In addition, thermodynamic and isotherm investigations were carried out in order to determine the adsorption process and its connection. It was found that by adding 0.3 N H2SO4, the maximal desorption rate was achieved. Around 99.6% of chromium ions, 89.27% of lead ions, and 82.39% of zinc ions were removed from the synthetic solutions through batch-mode adsorption studies.

The performance of the electrochemical oxidation of wastewater contaminated with Astrazon Red Violet 3RN Dye on Ti/IrO₂/RuO₂ was evaluated under a range of significant process variables: support electrolyte type and concentration, initial dye concentration, pH, current density, and temperature. ARV-3RN dye removal efficiency was over 90% at the high concentrations of NaCl (≥ 5.0 mM) and lower pH values (3.0 ≤ pH≤ ~7.5). At the same time, the temperature increases promoted faster degradation and less energy consumption except at 10°C temperature. While the increase in the initial dye concentration had a negative effect on the removal efficiency (from 99.84% to 65.02%), energy consumption increased from 2.5 kW-h/m3  to 3.25 kW-h/m3. Although the change in applied current density did not cause a significant difference in the removal efficiency (from 99.34% to 92.79%), it caused the energy consumption to increase from 3.10 kW-h/m3 to 25.767 kW-h/m3. Electrooxidation kinetics were evaluated using Pseudo-zero-order, Pseudo-first-order, and pseudo-second-order models. Kinetic data fitted best Pseudo-first-order model. The activation energy (Ea) of the EAOP process calculated using the Arrhenius equation is 13.707 kJ/mol. Thermodynamic parameters ΔH°, ΔS°, and ΔG° evaluated by Eyring's equation calculated 11.196 kJ/mol, -0.1244 kJ/mol, and 47.662 for 293 K, respectively.

Using density functional methods, the results of the analysis of traditional adsorbents and adsorbents based on nanosized particles capable of trapping acetamiprid molecules in fruits and plants are presented. We considered the following interacting compounds: acetamiprid@ fullerene C20, a fragment of the structure of activated carbon. We determined the optimal configurations of the corresponding interacting structures, estimated their electrochemical parameters and binding energies, and chemical potentials. The highest binding energy was obtained -0.70 eV adsorbed on C20 fullerene. At the same time, the energy gaps between the occupied HOMO and unoccupied LUMO molecular states were calculated, which makes it possible to characterize the reactivity and stability of molecules. acetamiprid has rather large gaps HOMO-LUMO. Using the concept of the electronic localization function, we found that a covalent bond is formed between acetamiprid and C20 fullerene with a sufficiently high degree of electron localization in the bond region. In other cases, the value of the localization function indicates the absence of a chemical bond between the compounds. The proposed study gives recommendations on the adsorption of acetamiprid for further electrochemical analysis, which will allow them to be found in fruits and plants by gas chromatography using a flame ionization detector.

Due to the harmful effects on the environment and public health, Atorvastatin calcium (ATO) has to be removed from wastewater using the photo-Fenton process. The novelty of this study is based on the modeling and the optimization of the operating parameters affecting the efficiency of the process by using the Box-Behnken Design (BBD). Operating factors such as pollutant concentration [20-40 mg/L], iron concentration [1-5 mM], and H2O2 concentration [5-10 mM] were investigated to evaluate the Chemical Oxygen Demand (COD) abatement. A mathematical model of pollutant degradation was established using the MODDE 6.0 software and statistical analysis showed good agreement between experimental results and predictive values with an error of less than 5%, which indicates the soundness of the developed model. The results suggested that the most influential factor on the photo-Fenton degradation of the drug was the initial ATO concentration with an effect of (-22.86), the second was the amount of the H2O2 with an effect of (+2.82), the third was the concentration of Fe3+ ions with an effect of (-2.79). The model obtained by BBD corresponding to the best value of the COD abatement rate (100%)   of ATO led to the following optimal conditions: initial concentration of pollutant equal to 20 mg/L, a catalyst concentration equal to 1 mM and a concentration of hydrogen peroxide equal to 10 mM.

The study investigates the application of clinoptilolite for the elimination of textile basic dye from water. It is about modeling the process of dye adsorption from an aqueous solution to a natural adsorbent. The natural adsorbent-clinoptilolite is originally from Serbia, it has been characterized by chemical analysis which determined that SiO2 dominates (58.23%). The most common mineral phase in clinoptilolite is a mineral from the group of clinoptilolite with a mineral content in the tuff of about 85%. The concentration of basic dye and adsorption time were varied in the study (20–120 mg/dm3 and 2-60 min), while the amount of clinoptilolite was constant (1 g). Two-, three-, four- and five-parameter models were used to describe the adsorption process. The two-parameter Langmuir linear model perfectly describes equilibrium adsorption, whereas the Radke-Prausnitz isotherm proved to be the best of the several parametric models (R2=0.999). In kinetics, the dominance of the Pseudo-second order adsorption mechanism was confirmed. According to the results, it can be said that clinoptilolite is an effective adsorbent for removing the basic dye from an aqueous solution.

Effluent, containing toxic and hazardous wastes, discharged by industries has been an eye-catching issue for researchers over the past few years. Mainly, this hazardous waste incorporates a large variety of dyes, chemicals, and traces of heavy metals. This work focuses on the treatment of industrial wastewater using the adsorption technique for Graphite Intercalation Compound (GIC) as an adsorbent. NyexTM 1000, a commercial adsorbent with a surface area of 1.0 m2/g, offering a Bulk density of 0.88 g/cm3 and Pore diameter of 133 Å respectively, was utilized to remediate an industrial contaminant. A GIC adsorbent was found to reduce COD by about 90% i.e., 150 mg/L to 10 mg/L. The outcome of this research has revealed that Graphite intercalation compound (GIC) as an adsorbent is suitable for the reduction of COD from industrial effluent. Kinetic studies reveal adsorbent surface heterogeneity is increased and multilayer adsorption was observed. 6 cyclic adsorption studies were performed by regenerating the adsorbent 5 times consecutively. The GIC adsorbent was regenerated via an electrochemical reactor and has shown a significant regeneration efficiency of more than 99%. The electrochemical reactor was integrated with a solar energy system to make the process cost-effective.

The study presents a TGA-FT-IR analysis of low-temperature thermochemical transformations of Rice straw hydrolysis residue (RSHR). Isothermal decomposition of RSHR was carried out for 3 h, at decomposition temperatures of 200, 250, 300, and 350 oC. At 200 oC, the rate of mass loss never exceeds %1/min and except for the first five minutes, it is less than %0.5/min. The initial rate of mass loss at 250 oC is %1.6/min which quickly drops to %0.6/min in the first 10 minutes and goes on further decreasing thereafter. At 300 oC, there is a rapid initial mass loss with the initial rate peaking at %8.8/min. At 350 oC, there is an initial burst of volatiles accounting for most of the mass loss with the initial rate of mass loss being %50/min. The residual mass obtained after these runs was 81.5, 38, 24, and 15%, respectively. FT-IR spectra of evolved gases suggest that volatile oxygenated organics along with non-condensable components like CO2, and CO are evolved during low-temperature thermal decomposition of RSHR. Carbonyls – acids, esters, aldehydes, and ketones – are the main functional groups in the volatiles. Strong absorption bands ranging 3400 – 3900 cm-1 indicated the presence of alcohols and phenols as other functional groups. Decomposition residues, the biochar, were demethoxylated and dehydrogenated compared to RSHR but retained their basic lignocellulosic nature.

As waste management becomes a competitive sector, it is evident that international guidelines will further encourage the reuse of waste materials. While aluminium hydroxide sludge (AHS) is a problematic waste associated with health and environmental impacts, it is also a valuable material in terms of treating textile wastewater. This paper focuses on the green synthesis of Cu-doped AHS using lavender extract for the adsorption of a reactive azo dye, Remazol Red (RR)239. Results of SEM and FT-IR analyses show that AHS is in the form of aluminium hydroxide and its chemical structure comprises approximately 9.88±0.56% C, 63.39±0.63% O, 21.94±0.10% Al, and 4.04±0.14% S content by weight. Adsorption studies demonstrated that the lowest RR239 uptake was 18.7% at pH 11, while it increased as the pH value decreased to 7. It was also determined that RR239 dye adsorption with Cu-AHS is more suited to pseudo 2nd-order kinetics. The comparison of the RR239 dye uptake capacities of Cu-AHS and AHS adsorbent exhibited that there is a great reduction in RR239 dye removal of Cu-AHS and AHS adsorbents after 75 mg/L RR239 dye concentration. However, across all concentrations, Cu-AHS exhibited a higher RR239 dye uptake capacity than that of AHS. Adsorption isotherms also presented that the dye adsorption of AHS and Cu-AHS is more suitable for the Langmuir isotherm. The environmental advantages of the green synthesis method used in this study and the outstanding capacity of AHS in RR239 dye removal are vital in terms of guiding other studies in waste management.

In this study, poly (ɛ-Caprolactone-co-Tetrahydrofuran) copolymer was synthesized using a green solid acid catalyst prepared with Montmorillonite clay (MMT). The prepared nanocatalyst was characterized by X-Ray Diffraction (XRD) analysis. The synthesized copolymer was investigated with Fourier Transform InfraRed (FT-IR), Hydrogen Nuclear Magnetic Resonance (HNMR), Gel permeation Chromatography (GPC), and Differential Scanning Calorimetry (DSC) analysis. Tg of the synthesized copolymer was found to be 28.91 °C. The highest average molecular weight (Mn) was calculated at about 2366 at 65 °C and 24 h of reaction time. The PDI data extracted showed a narrow PolyDispersity Index (PDI) of the synthesized copolymers.  The reaction conditions were optimized with the Taguchi method and Design of Experiments (DOE). 10%wt of nanocatalyst amount, 65 °C of reaction temperature, 24 h of reaction time, and Toluene as solvent were found to be optimum levels for the reaction. Up to 64% of the yield was obtained for copolymerization. Different factor interactions were studied with ANOVA interaction plots. Taguchi analysis results were in agreement with GPC results. The prepared nanocatalyst was recovered and its reusability for three cycles was approved.

The Water Gas Shift reaction is essential to numerous activities, including the production of Hydrogen and the reforming of natural gas. This reaction is enhanced by various catalysts. However, the catalyst acidity is a crucial parameter that affects catalyst performance. In this work, using the co-precipitation method, the effects of catalyst acidity on the low-temperature Water Gas Shift (WGS) reaction were examined. In this way, ternary Cu/ZnO/ZrO2 and Cu/ZnO/Al2O3 catalysts were selected and made. XRD, SEM, BET, NH3-TPD, CO-TPD, and TGA studies were used to characterize the catalysts. The catalytic performance was tested at atmospheric pressure, 180°C, and space velocity 3600 /h, with the inlet gas composition H2O/CO= 1/1 in a fixed bed micro-reactor for around 6 hours. Weak and moderately acidic sites were shown to be preferable to strong sites for the water gas shift reaction. The Cu/ZnO/ZrO2 catalyst was the best one to use in the WGS process because of its acidity, which mostly consisted of mildly acidic sites.  Based on the experimental results, Cu/ZnO/ZrO2 had a hydrogen selectivity and conversion of around 61% and 98%, respectively.

The present work describes the corrosion inhibition of one of the widely used alloys in the industrial process, i.e., Mild Steel in Fresh water and demineralized water using acrylic polymer coating, Acrylic/8% Zn3(PO4)2 coatings, and Acrylic/8% Zn3(PO4)2/ 5mM AgNPs coating. The efficiency of coating on mild steel in fresh water and demineralized water was studied using suitable gravimetric and electrochemical techniques and the surface texture of mild steel after coating was studied by Scanning Electron Microscope. The electrochemical study reveals that the coating efficiency was found to decrease with an increase in temperature and Acrylic/8% Zn3(PO4)2/5mM AgNPs exhibited the highest inhibition efficiency of 94% and 95% in fresh water and demineralized water respectively at 303K. The excellent corrosion coating performance is attributed to the physisorption process of adsorption of the coatings on the metal surface which in turn followed the Langmuir adsorption isotherm. The results obtained by both Tafel polarization and electrochemical impedance spectroscopy methods were in good agreement with each other. The density functional theory in the study of acrylic coating also supported the obtained experimental results. To sum up, the acrylic coating with and without 8% Zn3(PO4)2/ 5mM AgNPs is an efficient corrosion coating material.

Cadmium oxide (CdO) thin films were produced in this study utilizing a spray pyrolysis approach using a perfume atomizer at varied substrate temperatures. The cubic crystal structure of the CdO was shown by XRD analysis. The size of the crystallites, dislocation density, and microstrain were determined and studied. All samples exhibit a sharp shift in transmission, indicating a straight transition and high crystallinity. In the wavelength range 400 nm - 800 nm, raising substrate temperature from 200 - 300 °C increases film transmission by up to 45 - 58%. The band gap Eg is calculated and found to be between 2.23 and 2.40 eV for the substrate temperature of 200 – 300°C. Scanning electron microscopy and energy-dispersive X-ray spectra were used to determine morphology and elemental composition, respectively. The photoluminescence spectra of the samples show violet to blue emission peaks centered around 439 nm. The films were found to have good optical properties, making them ideal for optoelectronic applications.

The V-doped starch/graphitic carbon nitride was synthesized for the degradation of organic pollutants. This novel photocatalyst was characterized by various techniques including Fourier Transform InfraRed (FT-IR) spectroscopy, Field Emission Scanning Electron Microscopy (FESEM), X-ray Diffractometer (XRD), Photoluminescence (PL) spectroscopy, Energy Dispersive X-ray (EDX), Transmission Electron Microscopy (TEM), and Brunauer-Emmett-Teller (BET) analysis. Based on the Central Composite Designs-Response Surface Methodology (CCD-RSM) design, 50 full experiments were done including pH (7.8-9.8), adsorbent dose (0.01-0.1 g), MB concentration (2-12 ppm), time (30-240 min), and temperature (15-45 °C) for the methylene blue removal by V-doped starch/graphitic carbon nitride, and the best removal yield (90.8 %) was obtained at pH=8.33, 0.08 g adsorbent dose, 12 ppm of MB concentration, 215 min, and 15 °C. Further, the interaction of adsorption parameters was considered, and the Freundlich and pseudo-second-order were shown as the best adsorption models. After the adsorption process, the photocatalytic degradation of MB was conducted under UV irradiation with high yield (92 %), and the trapping experiments confirmed the photocatalytic degradation. As a result, the V-doped starch/graphitic carbon nitride can be employed for the adsorption and photocatalytic activities for the removal of organic pollutants from aqueous solution.

Dehydrogenation of liquid organic hydrides is the key reaction for the process where these hydrides are viewed as a potential candidate for hydrogen storage and delivery application. Methylcyclohexane is used as a liquid organic hydride for dehydrogenation reaction. Using a spray pulse reactor, we determine the possible reaction conditions for the greatest percentage conversion of methylcyclohexane during dehydrogenation and hence maximal hydrogen evolution with the help of response surface methodology. The suggested regression model with independent variables based on the Box-Behnken design is explained using an Analysis of Variance. R2 and R2adj correlation coefficients of 0.90 and 0.74 are used in this model. The estimated optimum conditions for percentage conversion of methylcyclohexane in this study are 389 °C temperature, 14 sec pulse frequency interval, and 1 ms pulse width where 44.51 % conversion of methylcyclohexane is expected. This was confirmed by the actual experimental value of  46.36 % conversion of methylcyclohexane during dehydrogenation using a 5 wt% Pt/ Activated carbon cloth catalyst. The entire study demonstrates that the Box-Behnken design combined with response surface methodology may be utilized to efficiently optimize the reaction conditions of a spray pulse reactor during methylcyclohexane dehydrogenation with 5 wt% Pt/Activated carbon cloth catalyst.

Combining highly ionic and very insoluble materials can be used to separate solvents with high water miscibility. In this work cellulose and Graphene Oxide (GO) were cross-linked by highly ionic N, N′-bis-(2-aminoethyl)-4,4′-dipyridinium bromide (BAEB) molecules to the preparation of CELL-BAEB and GO-BAEB membranes for alcohol dehydration. Fourier Transform InfraRed (FT-IR), proton nuclear magnetic resonance (1HNMR), X-Ray Photoelectron Spectroscopy (XPS), Field Emission Scanning Electron Microscopy (FE-SEM), Energy Dispersive X-ray Spectroscopy (EDS), and Thermogravimetric Analysis (TGA) analyses were used to characterize the synthesized compounds. For ethanol, isopropyl alcohol (IPA), and n-butanol in a feed water concentration of 5-40 wt% and at a temperature range of 40-70°C, sorption parameters, including water content in the membrane, alcohol content in the membrane, swelling, and selectivity also pervaporation parameters, including water content in permeate, total flux, and separation factor, have been evaluated. The water content in the membrane was as high as 269 wt%, 276 wt%, 287 wt% for CELL-BAEB, and 188 wt%, 193 wt%, and 211 wt% for GO-BAEB in 40 wt% feed water at room temperature, and the separation factor was 3951, 4491, and 5616 for CELL-BAEB, and 2423, 3094, and 3741 for GO-BAEB in 10 wt% feed water at70 oC, for ethanol, IPA, and n-butanol, respectively. It was shown that the high flux and selective CELL-BAEB and GO-BAEB membranes are highly effective in separating water from alcohol.

Heat treatment is a promising approach to reducing the viscosity and improving the combustion behavior of black liquor. The bagasse-based kraft black liquor was heated in a series digester at a constant temperature of 180˚C in three batches for 15, 20, and 25 min to investigate its physicochemical and rheological properties before and after heat treatment. Black liquor heated for 25 min showed the highest residual active alkali consumption of 28.37%. The optimum heat treatment time was 20 min, and the heat-treated black liquor at this condition exhibited residual active alkali 5.02% as Na2O and an increase in swelling volume ratio from 12 ml/g to 18 ml/g. Rheological studies of original and heat-treated black liquors were carried out in a rotational rheometer at 90˚C and 105˚C in the shear rate range of 1-100 s-1. 20 min heat-treated black liquor showed 74.09% and 71.56% reduction in viscosity at 90˚C and 105˚C, respectively, for 65% solids concentration. The effect of temperature and solids content on the rheological properties of black liquor was discussed. The results showed that black liquors obtained after heat treatment were non-Newtonian (pseudoplastic) in nature with a power law index less than unity (n<1). The power law (Ostwald de Waele) model best fits the obtained viscosity data of heat-treated bagasse black liquor. The work presented here gives an insight into the importance of the heat treatment process for the viscosity reduction of bagasse black liquor. It may help better understand various Physicochemical properties and the flow behavior of heat-treated bagasse black liquor for chemical recovery.

Quinoa (Chenopodium quinoa Willd) is recently introduced to Iran as a salt‐tolerant crop of high nutritional value. To investigate the physiological and biochemical responses of three quinoa varieties (‘NSRCQE’, ‘NSRCQB’, and ‘Titicaca’) were compared at ≤ 2 as control, 10, 17 dS/m saline water in an experimental farm of Yazd Province, Iran in 2017-2018. This experiment was conducted as a split plot based on a randomized complete block design with three replications, whereas the salinity treatment was in the main plots and the varieties in the subplots. Salinity and varieties significantly affected DPPH radical scavenging activity, phenol, anthocyanin, flavonoid, and Malondialdehyde (MDA) contents, accumulation of Na+ and K+, and Na+/K+ ratio, as well as seed protein and saponin contents. Salinity was caused by increasing DPPH radical scavenging activity, phenol, anthocyanin, flavonoid, and MDA contents, and accumulation of Na+ in the leaves and seeds. ‘NSRCQB’ had the highest average of most measured traits under all salinity levels. The DPPH radical scavenging activity in leaves was significantly and positively correlated with phenol content, anthocyanin content, flavonoid content, MDA, Na+ accumulation in the leaves, and DPPH activity, protein content, and Na+ accumulation in the seeds. Results indicated that the salinity stress increased the amount of paracomaric, quercetin acid, and camphor acids in the leaves and seeds of quinoa; also, the highest amount of these compounds was found by ‘NSRCQB’, also, ‘NSRCQE’ had the lowest average of most of these compounds. Based on these findings, we conclude that the salt tolerance of quinoa grown on salt‐affected soils of Yazd, Iran was linked with better crop stand establishment, low Na+ accumulation in leaves as well as increased activities of enzymatic and non‐enzymatic antioxidants, also, ‘NSRCQB’ variety showed the best potential under salinity conditions.

This study aimed to investigate the potential of three Paeonia species, Paeonia peregrina Mill., Paeonia mascula (L.) Mill., and Paeonia officinalis L., as sources of natural antioxidants and antimicrobials. Different parts of the plant were extracted with solvents of varying polarities and the extracts were subjected to various tests to determine their total phenolic content, total flavonoid content, antiradical activity, potential antioxidant activity, ferric reducing antioxidant power, superoxide anion radical and hydrogen peroxide scavenging activity and microbial activity. Paeonia Officinalis was found to have the best antioxidant and antimicrobial activity. The results demonstrated that P. officinalis is a rich source of polyphenolic compounds with higher antioxidant and antimicrobial potential compared to P. peregrina and P. mascula.     The ethyl acetate extract of P. officinalis showed the highest levels of phenolic content (62.45 mg GAE/g DW) and antioxidant potential as well as the strongest antimicrobial activity against various microbial strains. Ethyl acetate extract of P. officinalis effectively inhibited all of the examined bacteria and the fungus; however, it had a stronger impact on Gram-negative bacteria than it did on Gram-positive bacteria. The highest activity was observed against the Gram-negative pathogen P. aeruginosa with an inhibitory zone of 24 mm.  Pearson correlation analysis revealed different correlations for the three Paeonia species in different extracts and plant parts. Overall, the study highlights the potential of P. officinalis as a source of natural antioxidants and antimicrobials.

In the present study, red beetroot extract was encapsulated within a double emulsion and added to a dairy dessert. In the first part, the effect of red beetroot extract added to the inner aqueous phase of the W/O/W double emulsion was studded by some properties such as droplet size, zeta potential, physical stability, pH, color, turbidity, viscosity, and microstructure. After that in part 2, different dairy dessert samples (control dessert, dessert containing double emulsion, dessert containing free beetroot extract, and dessert with double emulsion containing beetroot extract) were prepared and analyzed for 30 days of storage time. The formation of double emulsion systems was confirmed by the microscopy technique. The droplet size of the control double emulsion and the double emulsion containing red beetroot extract was 3.47 µm and 4.27 µm, respectively. The results showed good antioxidant (51.94 %) and anti-microbial activities for the dairy dessert containing encapsulated extract during the storage time. The pH of this sample did not change after 30 days and its sensorial properties showed good overall acceptance. While increase in the microbial count and decreasing in the pH and antioxidant activity were observed for the dairy dessert containing the free extract. These results showed that the application of fortified double emulsion can improve the quality of cream and other oil products.

In the present work, some thermophysical properties are correlated and predicted for seven Ionic Liquids (ILs) n-alkyl triethylammonium bis(trifluoromethylsulfonyl)imide ([N222(n)][Tf2N]). In this way, the Cubic Plus Association (CPA) Equation of State (EoS) singly, and in combination with the Free Volume Theory (FVT) and the modified Pelofsky models were employed to estimate the density, dynamic viscosity, and surface tension of the ILs, respectively. The properties of three of the ILs were correlated and the parameters of the models were optimized. Then, the achieved parameters were correlated as a unified-form function of carbon number in cationic alkyl chains of the ILs so that the model parameters could be predicted for the other four ILs. Indeed, three ILs with pentyl, octyl, and dodecyl alkyl chains were used in the correlation scenario, and the others were utilized in the predicting approach. According to the results, correlation, and prediction approaches present Absolute Average Deviations (AADs%) equal to 0.0207 & 1.1393 for density, 4.4478 & 12.8312 for dynamic viscosity, and 0.1632 & 1.3820 for surface tension, respectively. As can be concluded from the output, both correlative and predictive approaches demonstrate good accuracy. Therefore, the inter/extrapolation of the results could be performed for other ILs from this family.

A shake-flask method was used to investigate the solubility and thermodynamic properties of budesonide (BDS) in the temperature scope of 293.2-313.22 K in aqueous mixtures of 2-propanol. There are two categories of mathematical models used to fit the experimental data: linear and non-linear cosolvency mathematical models, such as the van't Hoff's model, Yalkowsky's equation, CNIBS/R–K model, Buchowski, and Ksiazczak equation, modified Wilson model, the Williams-Amidon excess Gibbs energy model, and two Jouyban-Acree models: the Jouyban-Acree and the Jouyban-Acree-van't Hoff. The experimental data for BDS solubility at 298.1 K was also represented with KAT-LSER model. Using back-calculated solubility data, mean relative deviations (MRDs %) of used models were calculated to illustrate fitness and accuracy. Furthermore, van't Hoff and Gibbs equations have been applied to describe how BDS dissolves in binary solvent mixtures with entropy, enthalpy, and Gibbs free energy included.

The inhibition effect of Bhumyamalakhi (Phyllanthus Niruri) on 6061 aluminium alloy erosion-corrosion in simulated seawater was explored using potentiodynamic polarisation (PDP) and electrochemical impedance spectroscopy (EIS) techniques. Experiments were performed to examine the hydrodynamic effects on the behavior of the inhibitor. Conditions were optimized to achieve maximum inhibition efficiency by varying the concentration of inhibitor (500 and 1000ppm), temperature (30 , 40 , 50 ), and flowrate (4, 8, 12 L/min) of slurry. Surface morphology was studied with Scanning Electron Microscopy (SEM) and Energy Dispersion X ray (EDX) studies. The experimental findings indicated that an increase in flowrate and temperature decreased the efficiency of inhibitor and an increase in inhibitor concentration caused an increase in inhibitor efficiency. The inhibition efficiency of 80% and 53% was obtained at 30 °C and 50 °C at 4 L/min for 1000 ppm of inhibitor. Surface morphology demonstrated the complete damage of the material due to erosion corrosion and the surface became relatively smooth after the addition of the inhibitor.

The purpose of this study is the 3D CFD numerical modeling of a coaxial borehole heat exchanger. The operating fluid inlet velocity, the groundwater seepage velocity, the soil porosity, and the use of nanofluids instead of pure water are investigated. Ansys Fluent software is used for numerical simulation and the k-ε turbulence model is employed for turbulent flow modeling. The results show that they significantly increase the operating fluid temperature. The presence of groundwater seepage decreases the temperature of the working fluid which is related to the groundwater flow velocity. High soil and backfill porosity affect the thermal performance of CBHE, and increase thermal resistance, and decrease thermal conductivity. The nanofluids utilization with a higher thermal conductivity than pure water increases the temperature growth rate along the outer pipe. Kriging optimization method suggested that the best operating conditions for the system are inlet water velocity 0.03 m/s, groundwater velocity 5 m/d, soil porosity 0.28, backfill thermal conductivity 3.3 (W/m.K) and CuO/water nanofluid. By considering the mentioned operating conditions, the working fluid temperature increases by about 6% at the depth of 60 m.

Ethanol is considered a renewable fuel that can be produced via fermentation of sugarcane molasses. The fermented solution that is fed to the distillation column has suspended solid content that tends to block distillation trays leading to low ethanol recovery. In this study, performances of microfiltration and centrifugation processes were investigated for the separation of suspended solids from the fermented solution of sugarcane molasses. The filtration process using a ceramic filter under pressure differences of 1, 2, 3, and 4 bars was studied. Based on the results of this study, the overall filtration process can be divided into three stages pore blocking, cake filtration, and cake layer compression which were more pronounced as pressure difference across filter media increased. In addition, increasing pressure difference across the filter caused a sharp decrease in permeate flux due to faster pore blocking and higher turbidity removal, 96.99% due to cake filtration, and compaction of the cake layer. A comparison of curve-fitted experimental data and blocking models showed that the full cake model had the best fit with an Average Absolute Relative Error (AARE) of 0.112. Further, in this study, experimental design was used to optimize the operating parameters of centrifugation for separation and removal of suspended solids from fermented solution. Single complete and complete-standard models among blocking models had the best fit for filtration after centrifugation under optimal operating conditions that correspond to the filtration pressure difference of 4 bars. The measured data showed that the permeate volume in centrifugation plus filtration increased about threefold compared to filtration alone, although the turbidity removal decreased slightly from 96.99 to 89.78%.

The primary purpose of this feasibility study is to use an appropriate decentralized control configuration (based on PID controllers) to automatically navigate the startup trajectory of a reactive distillation column in the presence of azeotropic points. The purpose of this article is to show how a conceptual understanding of the Reactive Residual Curve Map (R-RCM) may be utilized to define a trajectory for directing the control variables during startup. The results demonstrate that steering the startup operation using a two-point temperature control structure with the feed rate of the reactants specified as the control manipulator is more efficient than other structures. Examining the various startup strategies shows several steady-state conditions at the end of the start-up time. This is because only a unique approach will achieve the desired steady-state condition. According to the findings, the controller tuning parameters play a significant impact in steering the startup trajectory. For this case study, the gain and integral time values for both controllers should be approximately one-third and three times, respectively, of the values found under normal operating conditions.

The economic development of a country depends on the management, applicability, and utilization of its resources. Efficient energy generation and application in the industrial and agricultural sectors are of paramount importance. Due to the high need for a healthy environment coupled with sustainable energy, it has become necessary for the government and industries to look beyond carbon-based energy sources, which most developing countries depend on heavily for their energy generation, and begin to consider other sources of energy. These carbon-based energy sources generate greenhouse gases, causing global warming and climate change. Microbial Fuel Cells (MFCs) are a promising energy source, providing sustainable and environmentally friendly energy. They can harness the chemical energy in organic compounds and channel it to the generation of electrical energy while providing environmental remediation. Its functioning is efficient, widespread, convenient, and promising. This review considers the various types of MFCs, their mode of operation, strategies for improving their performance, and future prospects.

The heat exchanger, an integral component in diverse processes, finds extensive application across industrial and domestic sectors. Functioning as a mechanical apparatus, it is designed to transfer or exchange heat between different mediums, thereby enhancing energy efficiency by redirecting surplus heat from unnecessary systems to those in need. Heat exchangers have become essential equipment in various end-user applications due to their environmentally friendly nature and their ability to boost overall energy efficiency in systems. The global market for heat exchangers has undergone significant changes in recent years, with manufacturers increasingly emphasizing efficiency and performance improvements. The enhanced performance of heat exchangers, driven by technological advancements, contributes to heightened energy consumption efficiency in the systems where these devices are employed. Exergetic assessments play a crucial role in improving heat exchanger efficiency from a thermodynamic standpoint. This study provides a comprehensive review of scientific papers, examining the exergetic aspects of various heat exchanger types. The literature survey explores the impact of parameters such as entropy generation, cumulative exergy destruction, nanofluids, geometry, and two-phase fluids on heat exchanger exergetic performance. It also discusses the effectiveness of different optimization approaches on the second law’s efficiency. Primarily, the study comprehensively reviews four types of heat exchangers—double-pipe, plate, cross-flow, and shell & tube—and briefly explains new types of heat exchangers. Part 1 of this study, presented in this manuscript, focuses on the fundamentals of exergy analyses in heat exchangers, with an emphasis on double-pipe and shell & tube heat exchangers. Future research directions aim to explore advanced materials with superior properties, innovative geometries for optimal performance, integration with renewable energy sources, smart technologies for adaptive control, machine learning applications for predictive modeling, and the potential of miniaturization and microscale heat exchangers. These endeavors seek to propel the field towards greater efficiency, sustainability, and adaptability across various applications.