Iranian Journal of Chemistry and Chemical Engineering
Volume:42 Issue: 3, Mar 2023

DFT studies were performed to evaluate the interaction between the H2S gas and the surface of a Carbon NanoCone (CNC) decorated with a boron atom as a chemical sensor. The optimized and electronic characteristics of pristine CNC, H2S gas, A and B configurations showed that the pristine CNC wasn’t a good candidate to sense the H2S gas and consequently, its electrical properties are changed insignificantly. To improve the properties of the CNC, several strategies were tried: functionalizing by pyridinol (Pyr) and pyridinol oxide (PyrO) and decorated with metals (M= B, Al, Ga, Mg, and Sc). The obtained data demonstrated that promising results were obtained by decorating the CNC with a boron atom. After full optimization, we achieved two stable configurations between the H2S gas and CNC/B structure (C and D configurations) with Eads= -10.16 and -11.36 kcal/mol using B3LYP/6-311+G(d) level of theory, respectively. The electronic properties of the CNC/B structure are meaningfully changed after the H2S molecule is adsorbed. According to the calculation, the energy gap between HOMO and LUMO orbitals of C and D configurations is decreased which could be applied to a chemical signal. Eventually, we concluded that the CNC/B structure could be a potential sensor for the detection of H2S gas, and decorated with boron atoms is a promising strategy.

Analysis and speciation of chromium ions are important due to the contrasting nature of essential Cr(III) and toxic Cr(VI) ions. Here, the first simultaneous determination of Cr(III) and Cr(VI) ions is introduced using gold nanoparticles (AuNPs) as a colorimetric agent and subsequent detection using an application attached to a smartphone, in addition to the UV-vis spectrometer. A small amount of AuNPs (1 mM) was used as a result of its excellent selectivity and sensitivity toward Cr(III) and Cr(VI) ions. The color change of AuNPs was monitored using a smartphone and validated by a UV-vis spectrometer. The peak absorbance of AuNPs’ surface plasmon resonance (520 nm) was red-shifted to 630 nm when Cr(III) was introduced, while it was blue-shifted to 370 nm when Cr(VI) was added to the system. The absorbance shifts of the system produce a color change that is linearly proportional to the Cr concentration. At pH 5.0, a linear relationship of Cr(III) occurred at an absorbance ratio of 630/520 nm in the concentration range of 0.2-1.0 ppm (R2 = 0.9911), while those of Cr(VI) at an absorbance of 370 nm in the concentration range of 0.05-1.0 ppm (R2 = 0.9909). The method’s detection limit of UV-Vis spectrometer was found to be 0.051 ppm (0.98 uM) and 0.035 ppm (0.67 uM) for Cr(III) and Cr(VI), respectively. The detection limit of smartphone-digital image colorimetry compared to UV-vis spectrometer was better at about 22%. Finally, the proposed method was tested to analyze Cr concentration in actual samples (drinking and tap water) that give satisfactory accuracy (< 2.0%) and precision (< 5.0%).

Titanium dioxide (TiO2) has received much attention, owing to applications in various areas including photocatalysis and photovoltaics. It is a wide band gap n-type semiconductor.  Production of p-type TiO2 is challenging and interesting research work for its utilization in wider areas of applications. In this study, band structures and corresponding density of states of undoped and scandium (Sc)-doped TiO2 with different concentrations of Sc doping are calculated using Density Functional Theory (DFT). Sc doping in TiO2 converts intrinsically n-type TiO2 into p-type TiO2. An increase in doping concentration generates shallow acceptor levels ranging from 10 meV to 25 meV above the Fermi level. The study has the potential to improve the conductivity of TiO2 via different concentrations of Sc dopants and produce p-type TiO2 for applications in photocatalytic water-splitting technology in low-cost and eco-friendly hydrogen production and solar cell technology to support future energy demand.

A digital baffle batch reactor (DBBR) for oxidative desulfurization (ODS) reactions is designed and applied here to reduce the sulfur concentration presented in light gas oil (LGO) based on a novel homemade nano-catalyst (Copper Oxide (CuO)/Activated Carbon (AC)). With efficient impregnation, good pore size distribution, high activity, and higher surface area, the designed nanocatalyst (CuO/AC) demonstrated excellent catalytic efficiency. To evaluate the effectiveness of nanocatalyst (prepared experimentally), several experiments related to ODS reactions using the digital baffle batch reactor are carried out under moderate process conditions (reaction temperature (100, 120 and 140 °C), contact time (15, 30, and 45 min) and oxidant (H2O2) amount (2, 3 and 5 mL)). The experimental outcomes indicated that increasing the reaction temperature, batch time, and oxidant amount led to the reduced sulfur concentration of oil feedstock leading to a greener fuel. The efficiency of sulfur conversion is reported to be 83.1 % using the modified nano-catalysts and new reactor (DBBR) at reaction temperature 140 oC, batch time 45 min, and H2O2 amount of 5 mL. So, such new results using DBBR for ODS reactions based on CuO/AC as a new modified nanocatalyst have not been reported in the public domain and it is considered new results.

In the current study, an in-depth examination was conducted to evaluate how the particle size of titanium dioxide (TiO2) will affect the mechanical, thermal, and morphological properties of the modified Pebax/TiO2 nanoparticle membrane. TiO2 nanoparticles were initially modified with amino silane and then incorporated into the nanocomposite Pebax/TiO2 membrane. The obtained membranes were characterized by FT-IR, SEM, TEM, TGA, and XRD to assess the effect of modification. The result of membrane performance evaluation indicated that the solubility of the gas molecules increased within the polymer matrix when an increase in CO2 permeability was observed. To test the performance of the nanocomposite membrane in the high-pressure separation process, the feed pressure was increased from 2 to 10 bar and the results demonstrated that the CO2/CH4 selectivity boosted from 16.05 to 97.74, respectively. Furthermore, when the surface of TiO2 nanoparticles was modified by amino silane and its concentration increased in the polymer matrix, the CO2 permeability of the nanocomposite membrane increased from 87.12 to 24.71 compared to that of the pure Pebax membrane. Experimental data were correlated with ANN (artificial neural network. The ANN of the model applied in this study includes the Levenberg-Marquardt algorithm, purelin or a linear transfer function at the output layer, and tansig or a tangent sigmoid transfer function in the hidden layer with 5 neurons.

Industries pollute the environment by emitting organic substances known as Volatile Organic Compounds (VOC). One of the outstanding materials utilized to eliminate VOCs is nanoporous graphene. However, graphene's physical and chemical characteristics are influenced by a range of factors, including activation temperature, mass ratio, activation duration, adsorption capacity, N2 adsorption-desorption, and morphology, Among other factors, the porosity of graphene is one of the crucial which has a direct influence on the adsorption capacity. In the current study, the adsorption capacity of graphene was investigated using cyclohexane and n-hexane adsorbents. In addition, the neural network has been employed to predict the adsorption capacity of graphene, and the Levenberg–Marquardt backpropagation (LM-BP) mechanism was utilized to determine model accuracy. The results show that at an activation temperature of 700°C, and mass ratio of  6, cyclohexane displayed a better performance with an adsorption capacity of 500 mg/g, as a comparison to n-hexane. The model demonstrated a suitable prediction with a  correlation coefficient of 0.99966 (R2) within the range of cyclohexane parameters such as impregnation ratio, activation time, and activation temperature between 3 to 9, 120 to 180 min, and 500 to 700°C  respectively.

In this research, the adsorption of heavy metals (Chromium and Lead) in aqueous solutions was investigated using a Bentonite-Polypyrrole composite. The composite was synthesized via in situ polymerization of pyrrole in the presence of bentonite (40%). Tests were conducted under various conditions to study the influence of different parameters (pH, initial concentration, contact time, competing ions, Zeta potential, organic matter) on the adsorption process. Langmuir and Freundlich's isothermal models were applied to assess the equilibrium data The kinetics of adsorption were determined using the Lagergren pseudo-second-order model. The characterization of the composite was tested by Scanning Electron Microscopy (SEM), Fourier Transform InfraRed (FT-IR) spectroscopy, and X-Ray Diffraction (XRD), and the results show intercalation of polypyrrole in the bentonite layers. The best results were obtained for a contact time of 60 minutes, an initial concentration of 10 mg/L, pH 2 for chromium, and pH 5 for lead. The presence of humic acids can modify the surface characteristics of the composite and affect the adsorption capacity. The measurements of the electrokinetic potential show that the zeta potential of the composite after adsorption of the metal cations is greater than that of the corresponding composite. The presence of organic matter regularly decreases the maximum exchange capacity with respect to metal cations. The Langmuir and Freundlich isotherm indicated a high affinity of Bentonite-Polypyrrole composite for chromium (VI) and lead (II) ions.

Dye discharge in industrial effluents is a major source of concern, as its existence and accumulation can be harmful or carcinogenic to living organisms. This research focuses on using the Fenton process to treat dyes, Congo Red (CR) and Rhodamine B (RB), in aqueous solutions. The effects of the three independent variables considered for the optimization of the oxidative process: temperature, Fe (II), and H2O2 concentrations were evaluated using Response Surface Methodology (RSM). The experimental results are reported in terms of the degradation percentage of the dye. The optimal reaction conditions to degrade the congo red from aqueous solutions were: pH 3; T 298 K; 1.03 mM Fe2+ and 11.77 mM H2O2. The optimal reaction conditions to degrade the rhodamine B from aqueous solutions were: pH 3; T 298 K; 1.038 mM Fe2+ and 12.14 mM H2O2. Under these conditions and with a 120 min treatment, it was possible to reach 74.75 and 97.63 % of decolorization efficiency, for CR and RB, respectively. The model (R2) correlation coefficients for CR (congo red) and RB (rhodamine B) were 0.979 and 0.986, respectively, in the optimization. The Fenton process also showed a higher removal efficiency of RB compared to RC. RSM was clearly demonstrated to be one of the most effective methods for optimizing operating conditions in this study.

Organophosphorus compounds such as diethyl dithiophosphate (DEDTP) are extremely toxic and cause significant environmental and water contaminations in nature. To mitigate its hazardous influence on the wastewater treatment processes, the present study was implemented focusing on the operating variable of the ion flotation technique. The effects of different parameters including initial pH (4-10), impeller speed (700-1000 rpm), and conditioning time (2-4 min) were investigated to maximize DEDTP removal from synthetic wastewater with an initial amount of 58 ppm. The N-Cetyl-N,N,N-trimethyl-ammonium bromide (CTAB) was used as the collector and frother in the ion flotation tests. The experimental results were analyzed based on the foamability, foam stability, and turbidity. The ion flotation experimental results showed that the DEDTP could be removed with the percentage removal of 91 under the optimum operating conditions of pH=10, collector dosage 1.09 ´ 10-3 M, impeller speed 850 rpm, and conditioning time with the collector for 3 min. It was observed that the percentage removal of DEDTP was dependent on the foam properties and electrostatic interactions between CTAB and DEDTP. The turbidity studies proved that DEDTP formed 1:2 complexes with CTAB at pH 10.

A novel magnetic biochar (Fe3O4-biochar) using rice straw as the raw material and magnetite (Fe3O4 nanoparticles) as the objective magnetic medium was successfully synthesized under high-temperature and oxygen-free conditions. Several techniques and methodologies (SEM/EDX, FT-IR, N2 adsorption-desorption isotherms, and pHpzc measurements) were used to determine the surface functional groups and physicochemical properties of Fe3O4-biochar, which showed that the Fe3O4-biochar was successfully synthesized and deposited on the surface of the pristine biochar. The surface area of the Fe3O4-biochar was measured as 337.77 m2/g and 0.227 cm3/g pore volume. Then the adsorption behavior of phosphate (PO43-) and methyl orange (MO) from the aqueous solution onto the Fe3O4-biochar was investigated. The influence of variables including pH, initial concentration of PO43-/MO, adsorbent dosage, and contact time was studied in detail. The optimal adsorption amount of PO43- (189.2 mg/g) was obtained with 0.1 Fe3O4-biochar g/L, at pH of 2 for 240 min; whereas the optimal adsorption amount of MO (37.31 mg/g) was obtained with 0.03 Fe3O4-biochar g/L, at pH of 2 for 240 min. The equilibrium data were fitted to both Langmuir and Freundlich isotherms (R2>0.92 for PO43-, R2 >0.96 for MO). Besides, the pseudo-second-order exhibited a better fit for the kinetic studies (R2>0.79 for PO43-, R2>0.88 for MO). This study showed that Fe3O4-biochar could be utilized as an efficient, magnetically separable adsorbent for the removal of anions PO43 and MO from the aqueous mediums.

In this theoretical report, we are focused on the substituent effects of titanium dopants on the band gap, NBO, and global reactivity of C20-nTin metallofullerenes (n = 1 - 5), at DFT. The C18Ti2-2 metallofullerene is found as the most stable analog with the highest band gap, in which carbon atoms are replaced by Ti dopants in the equatorial location, separately. The charge on carbon atoms of C20 is estimated roughly zero, while the high positive charge on the C16Ti4-2 surface prompts this metallofullerene for hydrogen storage. The positive charge on Ti heteroatoms and the negative charge on their adjacent C atoms implies that these sites can be able to be influenced more readily by nucleophilic and electrophilic reagents, correspondingly. The electronic transitions are usually classified according to the orbitals engaged or the involved specific parts of the metallofullerene. Common types of electronic transitions in organic compounds are “π–π*”, “n–π*” and “π* (acceptor) – π (donor)”. Fascinatingly, the charge transfer (CT) tack places via the suitable overlapping among σC―Ti bondingʼs orbital along with σ*C―Ti anti-bondingʼs orbital of C20-nTin metallofullerenes. For example, the NBO analysis of C19Ti1 metallofullerene points out higher CT energy of σC―Ti → σ*C―Ti (16.31 kcal/mol) with respect to σC―Ti → σ*C―C (0.63 kcal/mol). The reactivity of metallofullerenes can be affected by the number and topology of the substituted dopants. Based on these results we infer that metallofullerenes are a potential material for hydrogen storage with high capacity and the driving force for reactivity of them is the relief of π-curvature strain and leads sp2→sp3 hybridized atoms.

An efficient, facile, and green synthesis of 4H-pyran and 4H-chromene derivatives in Magnetized Distilled Water (MDW) has been described. In this work, magnetized distilled water was applied as a green-promoting medium for a practical, and environmentally benign three-component reaction of an aldehyde, ethyl acetoacetate/resorcinol, and malononitrile in the presence of potassium carbonate as a catalyst at 70 ºC. This method offers the advantages of simplicity, low costs, high reaction yields, being green, and no need for any organic solvent. Also, the chemical structures of the synthesized new compounds were confirmed using Nuclear Magnetic Resonance (NMR), and InfraRed (IR) spectroscopy analysis.

The alternative renewable energy of Palm BioDiesel (PBD) is gaining eminence to be used in transportation and industrial applications. However, its regular usage in temperate countries has the main issue to be solved due to its poor cold flow properties. The Pour Point Depressant (PPD) is required to enhance the PBD cold flow properties to a certain acceptable range.  In this work, environmentally green PPD diesters for PBD were synthesized through the acid catalyst esterification process between selected dicarboxylic acids (succinic, suberic, and dodecanedioic) with branched alcohols (2-butyl-1-octanol and 2-ethyl-1-hexanol) in the presence of sulphuric acid. The resultant synthesized dicarboxylate esters were successfully produced at high yield percentages in the range of 85-98%. The chemical structures of dicarboxylate esters were confirmed by using FT-IR, 1H, and 13C NMR. The results showed that green PPDs derived from the dicarboxylic acids with the same carbon chain length of the respective branched alcohol have more capability to reduce PBD pour point. On the other hand, green PPDs derived from the same alcohol of the respective increasing dicarboxylic acids carbon chain length showed a slight reduction in PBD pour point. A selected blending green PPD of di(2-butyloctyl) suberate (D2BOsub) into PBD has produced the lowest PBD pour point down to 3°C. Therefore, properly chosen green PPDs capable of reducing the PBD pour point are to be regularly used as an alternative fuel in tropical countries.  It is plausible for the synthesized PPD to be used together with petrol-diesel blends in selected proportions or as a full substitute for diesel engines.

In the present study, the loading and releasing of Diclofenac Sodium (DS) were investigated using a pH-sensitive magnetic nanocomposite hydrogel. The hydrogel was prepared through grafting copolymerization of Acrylic Acid (AA) and acrylamide (AAm) and using ammonium persulfate (APS) as a free radical initiator in the presence of Fe3O4@SiO2@ (3-Aminopropyl) trimethoxysilane (APTMS)@Maleic anhydride (MAN) as a cross-linker. The nanocomposite hydrogel structure (Fe3O4@SiO2@APTMS@MAN) was confirmed as the result of XRD, VSM, FT-IR, SEM, EDS, and TEM spectroscopy techniques. Furthermore, thermal properties were deliberated using TGA and DTG. The effects of different parameters such as pH, time, Fe3O4@SiO2@APTMS@MAN content, and salt solutions on swelling behavior were investigated considering the abovementioned outcomes. The adsorption isotherm was studied at 25°C using Langmuir, Freundlich, and Temkin. The adsorption data were well described by the Langmuir isotherm model. A kinetic study revealed the applicability of pseudo-first-order and pseudo-second-order models for the adsorption of mentioned DS. Moreover, the pH sensitivity of nanocomposite hydrogel and loading/releasing drugs were studied. Examining in vitro drug release in different buffer solutions indicated that the pH of the solution could mainly lead to the DS drug-releasing behavior of hydrogel. However, the cumulative release ratio of DS in pH: 7.4 solutions reached up to 93% within 120 min. Consequently, the investigated nanocomposite hydrogel of this study (Fe3O4@SiO2@APTMS@MAN) can be applied in widespread biomedical applications, particularly for controlled, targeted drug delivery purposes.

This review is a denote to the detailed analysis of the self-healable features of Carbon Fiber-Reinforced Polymer (CFRP) composites. It discusses the different healing strategies, types of employed healers, time to healing, mechanical recovery, inherent properties such as glass transition temperature, and the advantages and disadvantages of each healing strategy. Composite materials with self-healing capabilities can automatically repair themselves after being degraded. As a result, maintenance tasks are greatly simplified. This paper aims to give a concise overview of the most recent advancements in self-healing composites. The article complements earlier survey papers by offering an updated overview of the many self-healing theories over the preceding two decades and a comparison of healing processes and manufacturing methods for creating micro-capsules and microvascular networks. The review also dispenses a summary of diverse chemistries utilized to fabricate self-healable polymeric composites and their future scope to humankind. To identify significant challenges and prospective research insight, elements that affect healing efficiency are provided based on the research assessment. This provides a basis for the researchers for future applications based on these intelligent self-healing composites.

In this study, new silica-coated magnetic nanoparticles modified with p-(4-methoxy phenyl)-N-(3-triethoxy silyl) phosphonamide dithioic acide were synthesized using a normal method. The structure of the newly obtained nanoparticles was characterized by Fourier Transform InfraRed (FT- IR) spectroscopy, X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM), Vibrating Sample Magnetometry (VSM), and Thermogravimetric Analysis (TGA). The surface of the nanoparticles modified with p-(4-methoxy phenyl)-N-(3-triethoxy silyl) phosphonamide dithioic acide showed to be an effective adsorbent for the selective extraction of the ion of Ag (I) from aqueous mixed metal ions solution also containing Co(II), Cu(II), Ni(II) and Pb(II). Moreover, the silver ion desorption was most efficient in thiosulfate (S2O32-).

Extensive research has begun on the production of naturally occurring red colorants as permitted food additives. The Betalain in Beetroot (Beta vulgaris) cells can be used to prepare a natural red color additive for food products. Betalains are more resistant to acidic conditions and high temperatures than other red pigments such as anthocyanins. However, the low stability of Betalain compared to synthetic colorants is considered a big challenge in its extraction, processing, and storage. Therefore, it is very important to use a suitable extraction method for it. In recent years, the use of supercritical carbon dioxide (scCO2) for isolation and extraction of natural products instead of conventional methods such as extraction with organic solvents has attracted interest because the final product may become contaminated with the solvents. In the same vein, this research evaluated the effects of microwave power (100-450 W), carbon dioxide flow rate (1-3 mL/min), temperature (30-70℃), and pressure (15-40 MPa) on extraction efficiency, 2,2-diphenyl-1-picrylhydrazyl, and the quantities of phenolic compounds extracted from Beetroot. The results suggested that temperature, pressure, flow rate, and microwave power significantly influenced the amounts of phenolic compounds, extraction efficiency, and antioxidant properties of the compounds extracted from Beetroot. Increases in temperature, pressure, microwave power, and carbon dioxide flow rate in the (50-60℃), (20-30 MPa), (300-400 W), and (1-2 mL/min) ranges, respectively, increased the quantities of phenolic compounds, ability to suppress free radicals and extraction efficiency as the response. However, increases beyond the mentioned ranges caused decreases in the response variables. Optimal extraction of Betalain from Beetroot using supercritical carbon dioxide and microwave pretreatment was achieved at a temperature of 45 °C, pressure of 27.5 MPa, CO2 flow rate of 2 mL/min, and microwave power of 300W.

It is necessary to determine the thermophysical properties of the various types of agricultural products in order to control thermal operations, as well as processes such as drying, freezing, cooling, and pasteurization. Moreover, most of the products' thermophysical properties vary by the temperature changes and the percentage of water content. Therefore, the mathematical models expressing the relationship of these properties serve as a beneficial tool for designing automatic processes and equipment. The present research entails the examination of the impact of four levels of soluble solid content 15, 20, 25, and 30 %, and nine levels of temperature 28.6, 35.4, 40.5, 47.6, 56.1, 63.3, 72.3, 83.2, and 90 °C on the thermophysical properties of lime juice including density, specific heat, thermal conductivity coefficient, and thermal diffusivity coefficient. Based on the results, soluble solid content and temperature had a significant impact (p≤ 0.05) on the thermophysical properties of lime juice. By increasing the percentage of the soluble solid content, the properties such as specific heat (from 3321 to 2897 J/kg°C), thermal conductivity coefficient (from 0.69 to 0.54 W/m°C), and thermal diffusivity coefficient (from 2.10×10-7 to 1.61×10-7 m2/s) decreased but the density was increased (from 1013 to 1057 kg/m3). Furthermore, by increasing the temperature, the values of specific heat, thermal conductivity coefficient, and thermal diffusivity coefficient increased but the density was decreased. Consequently, to model the thermophysical properties, the multivariable regression method and Matlab software were employed and the results of the examination were fitted. The coefficient of determination of linear models of density 0.94, specific heat 0.93, thermal conductivity, and thermal diffusivity 0.98. In accordance with the results, all thermophysical properties had a linear relationship with the independent variables such as temperature and soluble solid content. 

Ferronickel production from electric furnaces with increased concentrations of sulfur (S) and silicon (Si) and low concentration of carbon (C), has resulted in a relatively low Fe-Ni casting temperature and conditions, which have reduced the chances of desulfurization of metal outside the furnace as well as have reduced the Ni/Fe-Ni utilization coefficient. Thus, although less than 80% of sulfur is separated, the desulfurization process has resulted in a long stay of the metal in the converter with increased consumption of energy sources, high consumption of refractory materials, increased metal losses with scrap, and low utilization of production capacities. De-sulfuring and heating of metal in the electro-reduction furnace would allow better temperature control, injection of the lime combination with calcium carbonate, and the possibility of de-sulfuring grime removal. A shorter time of effective distention and standing of the metal in the converter will increase the the resistance of fire-proof material by up to 200%, compared with projected parameters and 240% compared with actual parameters, in addition, it will decrease oxygen expenses by up to 50% and amalgamation for more than 70%. The total refinement cycle, including the time in the electro-reduction stove in the boiler, will take approximately 167min, the effective distention time in the converter will be approximately 36 min, whereas the working coefficient of Ni will reach up to 0.9. Evaluation of operating conditions and parameters, as well as the composition of process products, through quantitative and qualitative methods and quality control through XRD analysis during the study has proven that with partial modifications of the refining process, the application of desulfurization in the electro-arc furnace would result in reducing normative resource costs, improving the metal utilization coefficient, reducing production costs, increasing the degree of safety and process control, and increasing the utilization rate of production capacities in converters and in the ferronickel plant in Drenas.

In this work, the oil treatment plant of the Rumaila oil field in Iraq was simulated using Aspen HYSYS. Industrial data from the plant was applied to validate the simulation results. The process was optimized in single-objective and multi-objective modes using a genetic algorithm. The process was optimized for reducing CO2, H2S, and CH4 in the outlet oil flow and the energy of the heater simultaneously by changing the molar flow and temperature of dry crude oil and water. The result shows that by decreasing the temperature of the dry crude oil and water, the amount of the consumed energy will decrease to a large extent, but the amount of H2S, and CH4 in the outlet oil will decrease. Also, it can be concluded that by separating more CO2, H2S, and CH4 in the outlet oil, the temperature should be increased and as a result, the consumption of the energy will be increased. The single-objective optimization results showed that the amount of CO2, H2S, and CH4 was decreased by 46.52%, 43.,94%, and 27.8%, respectively. On the other hand, the results from multi-objective optimizations illustrated a lower reduction in the amounts of CO2, H2S, and CH4. Consequently, it was concluded that single-objective optimization results were better than multi-objective optimizations.

The non-linear process control is the most important problem of statement in chemical industries. Stirred tanks are frequently used as industrial reactors, where a chemical component of a flow stream resides in the tank for a period of time before proceeding to other steps in a chemical process. In this research article, a computational intelligence-based controller is introduced for CSTR concentration control model. The proposed RBFNN model is optimally tuned by two-hybrid optimization strategies based on combining the best features of Particle Swarm Optimization (PSO), Gravitational Search Algorithm (GSA), and their variants such as Deterministic Particle Swarm Optimization Algorithm, and Differential Gravitational Search algorithm (DPSO-DGSA). An experiment is conducted to examine the effectiveness of the proposed controller methodology to compare it to other state-of-the-art approaches.

Most of the global energy demand is related to the residential and commercial sectors. This significant share in the energy demand portfolio also shows a significant share of greenhouse gas emissions from the great cities. This is why renewable and other cleaner energy sources have been attractive in the last three decades. Solar collectors, energy storage, and photovoltaic cells are the most suitable clean technologies applicable to generate and store electricity, cooling, and heating demand in the residential sector. Due to this increasing attractiveness, much research has been done on those technologies to increase the systems' efficiency. One of the most important methods to improve these systems' performance can directly improve thermal conductivity and heat transfer. In this study, the collector is modeled in the system's fluent software and the main parameters
are estimated for different nanoparticles. Then an exergy analysis is done to find the entropy generation and exergy destruction of the system to detect the main sources of the irreversibility in the system. Also, the effect of different parameters is studied on the exergy efficiency of this system. The results show that the value of temperature generation in cold climates has been higher than in hot climates, and increasing the inflow and collecting water level has increased consumer water Temperature. Using copper nanofluids increases solar water heaters' efficiency by up to 67%, while aluminum oxide and copper oxide nanofluids have 74% and 47% efficiency, respectively.

The entropic potential losses number shows the reduction of energy quality as a function of the entropy produced in a process. In this research, using the Harris Hawks Optimization (HHO) method, the minimization of the entropic potential losses in a gasket-plate heat exchanger has been studied. Considering six design variables: number of plates, cold inlet fluid temperature, mass flow rate of hot fluid, hot inlet fluid temperature, plate pitch, and plate width. The results showed that minimizing the entropic potential losses number increases the heat transfer rate by 103% and the efficiency of the heat exchanger by 27%. Also, the effect of some geometric and process parameters on the entropic potential loss number has also been investigated in this research. It was observed that by increasing the mass flow rate of the hot fluid in the gasket-plate heat exchanger, the entropic potential losses number will increase. It was also seen that the entropic potential loss number will also increase with the increase of hot outlet fluid temperature. It was found that with a decrease of 20 degrees Kelvin in the outlet temperature of the hot fluid, the entropic potential losses number decreased by about 0.06.

Membrane technology is a clean technology for various separation processes, in which additional waste products are not produced. Poly(vinylidene fluoride) (PVDF) is one of the synthetic polymers widely used as commercial ultrafiltration membranes. Unfortunately, this polymer is hydrophobic and consequently, it has low flux in the aqueous system and creates fouling phenomena on the surface of the membrane. Therefore, the objective of this work is to improve the hydrophilicity of PVDF membranes by preparing blend membranes using cellulose acetate. Cellulose Acetate (CA) with varied concentrations ranging between 1 and 10 wt.% were added to poly(vinylidene fluoride) and those blend membranes were prepared via the phase inversion method. The effects of CA on various membrane characteristics such as hydrophilicity, membrane porosity, antifouling properties, and separation performances were investigated using Methylene Blue (MB) as a dye. It was found that the PVDF-CA membranes were more hydrophilic compared to the pristine PVDF membrane, revealed by the decrease of water contact angle from 72.93˚ to 56.43˚ along with CA addition. The water flux increased with CA concentration; its value reached 132.95 L/m2 h for blend membranes with 5% CA. Moreover, this composition also exhibited the optimum MB rejection of 90.24%. Furthermore, the improvement of hydrophilicity increased the antifouling properties, indicated by the increase of Flux Recovery Ratio (FRR) from 45-96%, the decrease of irreversible fouling from 60-3%, and the improvement of reversible fouling from 10-55%.

The electrocoagulation method was selected for the removal of Zn+2. The effects of the parameters such as current density, pH, and supporting electrolyte concentration on this method were studied. The Zn+2 concentration, mixing speed, and temperature were 250 mg/L, 150 rpm, and 293 K in the determination of the optimum pH the results obtained showed that a pH of 6 provided the highest Zn+2 removals. A pH of 6 was taken to be a constant optimum value while studying the effects of current density and supporting electrolyte concentration on removal. Current density values were chosen as 0.25, 0.50, 1.00, and 1.50 mA/cm2. Increasing current density increased Zn+2 removals significantly. Removal of 48.86%, 71.03%, 84.12%, and 97.39% were found for current densities of 0.25, 0.50, 1.00, and 1.50 mA/cm2 with an initial concentration of 250 mg/L with a reaction time of 30 minutes, respectively. An increase in current density caused an extreme increase in energy consumption. Energy consumption was 1.06 kW-h/m3 for a current density of 0.25 mA/cm2 with a reaction time of 30 minutes while it was 1.98, 3.46, and 5.31 kW-h/m3 for a current density of 0.50, 1.00, and 1.50 mA/cm2 at a pH of 6, respectively. It was found that the effect of supporting electrolyte concentration on removal efficiency was negative. Aluminum anodes were used in electrocoagulation processes. As supporting electrolyte concentration increased, removal efficiency decreased, and the energy consumption rate increased. It was determined, as the result of the experiments, that Zn+2 ions can be removed at the rate of 84.12% with a pH of 6, a 250 mg/L Zn+2 concentration, a 150 rpm mixing speed, a temperature of 293 K and a current density of 1.50 mA/cm2 in an aqueous solution.

This paper reports the preparation of biochar from sludge generated in a wastepaper-based paper mill operating on the Zero liquid discharge principles. Biochar has been prepared from sludge, hereafter referred to as Zero liquid discharge sludge, in a laboratory muffle furnace using the slow pyrolysis method. The effect of pyrolysis temperature and pyrolysis time on biochar' yield, surface area, and pore volume of biochar has been studied by applying response surface methodology. The pyrolysis temperature and pyrolysis time were maintained in the range 450-750oC and 100-200 min. respectively, under the central composite design. It was found that temperature and time significantly impacted the biochar’s yield, surface area, and pore volume of biochar showing strong linear, quadratic, and interaction effects. ANOVA of the empirical models developed in this study was found to be efficient with high R2predicted, (R2adjusted – R2predicted) < 0.2, adequate precision ˃ 4, and non-significant lack of fit value.  The optimum pyrolysis temperature and pyrolysis time were determined to be 539.65°C and 176.67 min correspondingly having desirability value 0.651. The optimized values of biochar’s yield, surface area, and pore volume for Zero liquid discharge sludge biochar were found to be 63.95%, 40.23 m2/g, and 0.048 cm3/g respectively. The physicochemical (proximate and CHNS) and instrumental (XRD, TGA, DSC, FT-IR, and SEM) analyses along with their comparison with other biochar reported in the literature confirmed the use of this biochar as an adsorbent in wastewater treatment.

Compressed Earth Bricks (CEBs) are the main constituents used in building materials like the pillar which holds the whole building. Scientists are struggling to produce stronger materials with the least cost and much more efficient strength. CEB products can very easily bear comparison with other materials such as the sand-cement block or the fired brick. Compressed Stabilized Earth Blocks (CSEBs) are environmentally friendly as these blocks are un-burnt and are economically cheap. These blocks required less labor with respect to fired bricks, so one can prepare them easily. To make CEB’s water resistant and durable 8%, 10%, and 12% cement as a stabilizer is added to the dry soil. The compressive strength measured was much better and increased with an increase in cement content i.e. 17.71MPa for 8% cement additive, 18.334MPa for 10%, and 21.229MPa for 12% as compared to commercially fired clay bricks which are up to 13MPa. The compressive strength increases with an increase in cement proportion. By studying the XRD analysis it was observed that Calcium Aluminum Silicate Hydrate (CASH) peak intensity increases by adding cement to the dry soil. However, crystallinity size decreases. The elemental composition shows that quartz and calcite are the major constituents of these samples which gives them better compressive strength. Hence unfired compressed earth bricks are environmentally friendly and cost-effective by using a very minute amount of cement i.e. 8% and its compressive strength is high as compared to fired clay brick.

One of the strategies to mitigate industrial accidents is by developing competent engineers in process safety where graduates play an important role. This research investigates the essential process safety topics in the downstream industry and determines graduates’ competency on these topics via a survey questionnaire. Responses from students, graduates, and employees with chemical engineering and process safety backgrounds are analyzed. Fire prevention and protection and management topics i.e., hazard and risk management and process safety management, are ranked with the highest importance. On the other hand, asset integrity and reliability, economics, process control, software, toxicology, and risk management are the top graduates’ knowledge that dissatisfied the employees. The connection between these topics depicts students are unable to visualize the relations due to lack of industrial operation exposure thus they underestimate its importance for process safety in the industry. To mitigate this gap, direct learning with industry and personnel is commonly highlighted by participants.

In this study, biomass dry weight [DW (0.912 g/L)] was markedly enhanced at pH of 10 for 24 h of aeration. The maximum production of protein (14.239 mg/L) was obtained at the highest photoperiod. The highest content of PC and APC (0.129 and 0.099 mg/L, respectively) was recorded at pH of 10 for 24 h of aeration. The highest content of total chlorophyll (Ca and Cb) and carotenoids (K) (6.436, 3.421, and 2.856 mg/L) was recorded at pH of 9. The content of photosynthesis pigments (Ca, Cb, and K) was reduced by increasing pH from 9 to 10, while the high alkaline pH (10) may favor the over-production of biomass, protein, phycobiliprotein pigments (PC and APC). Moreover,  A. maxima increased the accumulation of photosynthesis pigment under strong illumination and decreased the accumulation of phycobiliprotein pigments by increasing the light irradiance time