<![CDATA[Recent Innovations in Chemical Engineering (Volume 16 - Issue 5)]]> https://www.benthamscience.com/journal/158 RSS Feed for Journals | BenthamScience EurekaSelect (+https://www.benthamscience.com) 2023-12-29 <![CDATA[Recent Innovations in Chemical Engineering (Volume 16 - Issue 5)]]> https://www.benthamscience.com/journal/158 <![CDATA[Meet the Associate Editor]]>https://www.benthamscience.com/article/1367222023-12-29 <![CDATA[Bioleaching Extraction of Valuable Metal From E-Wastes: A Mini Review]]>https://www.benthamscience.com/article/1351082023-12-29 <![CDATA[Preparation of Carbon Nanotubes-Supported CuMn<sub>2</sub>O<sub>4</sub> Nanocomposites for Highly Efficient Degradation of Methylene Blue Dye]]>https://www.benthamscience.com/article/1350292023-12-29 Background: Waste water containing dyes causes serious environmental problems in both aesthetic and toxicological aspects. Although physicochemical and biological treatment processes have been investigated, functional materials are highly demanded for improving the removal efficiency of dye from wastewater.

Objective: To synthesize a heterojunction nanocomposite of CuMn2O4/carbon nanotubes (CNTs) with outstanding catalytic performance for the effective degradation of methylene blue (MB) dye.

Methods: Copper manganese oxide-carbon nanotubes (CuMn2O4/CNTs) nanocomposite was prepared by a solvothermal method. The structure and morphology of the samples were characterized with X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), transmission electron microscopic (TEM), and nitrogen adsorption/desorption on the samples at 77 K. The degradation of methylene blue dye was studied using the prepared nanocomposite as a catalyst.

Results: CuMn2O4 of small particles was loaded on CNTs, forming a porous structure with a specific surface area of 43.5 m2/g and a total pore volume of 0.17 cm3/g. The optimum conditions for achieving full breakdown in 10 minutes are 1g/L of catalyst dosage and a range of initial concentrations at 50-100 mg/L of MB dye at pH 4.

Conclusion: The synthesized CuMn2O4/CNTs nanocomposite exhibited a good prospect as catalyst materials for the decontamination of wastewater polluted with dyes.

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<![CDATA[Preparation and Catalytic Properties of Graphene Oxide/ Phosphotungstic Acid Composites]]>https://www.benthamscience.com/article/1361912023-12-29Background: Cellulose structures are in stable crystalline form. The hydrolysis of cellulose to small reducing sugars is difficult, but essential for its utilization.

Objective: To investigate the effect of graphene oxide (GO) loading on the catalytic performance of phosphotungstic acid (HPW) for the catalyzed hydrolysis of cellulose, with the purpose to get high yield of total reducing sugar (TRS).

Methods: Graphene oxide/phosphotungstic acid (GO/HPW) composites were prepared using a liquid-phase composite method. The materials were applied to catalyze hydrolysis of microcrystalline cellulose in 1-butyl-3-methylimidazole chloride ionic liquid ([Bmim]Cl). The samples were characterized by powder X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FT-IR), field emission scanning electron micrographs (FE-SEM), pyridine IR and acid-base chemical titration.

Results: The Brønsted acidic sites were the main source of acidity in the composites and its concentration was determined to be 0.96 mmol/g. With the use of the GO/HPW composite as catalysts for cellulose hydrolysis, high TRS yield of 90.5% was obtained.

Conclusion: GO/HPW composites retained the functional groups of both materials. It was the Brønsted acidic sites in the materials that effectively promoted the cellulose hydrolysis reaction. The structures of GO/HPW with the agglomeration of HPW scattered on GO had high accessibility of acidic sites and fast mass transfer of the reducing sugars to the outside of the catalysts in time to prevent their further conversion into by-products. TRS yield of 90.5% was obtained from the hydrolysis of cellulose catalyzed by the GO/HPW (1:1.5) composites at 115°C for 4 h using catalysts to cellulose 1:1 ratio.

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<![CDATA[Annual Performance Evaluation of a Novel Industrial-scale Solar Dryer for Phosphogypsum Waste]]>https://www.benthamscience.com/article/1351512023-12-29Introduction: Solar drying is considered one of the most promising technologies for drying the phosphogypsum “Calcium Sulfate Dehydrate” material as a clean source of energy and saving the environment from its negative impact if it is dried in an open landfill.

Method: The dried phosphogypsum (PG) may be recycled and utilized in many useful applications. The presented design of the trapezoidal-shaped greenhouse solar dryer is the preferable solution to perform the drying process in the daytime with solar energy. It may be usable at night, during cloudy and rainy periods, using evacuated tube solar collectors via sensible heat solar thermal energy storage. The system can be operated for 24 hours by solar energy. From theoretical calculations, it was found that the drying time decreased as the gypsum layer in the drying trays decreased due to the improvement of the heat transfer mechanism. The designed solar dryer was studied at various loading capacities depending on the gypsum thickness on the dryer trays. Capacities were 8280 kg, 6624 kg, 4968 kg, 3312 kg, and 1656 kg, corresponding to gypsum thickness of 5 cm, 4 cm, 3 cm, 2 cm, and 1 cm, respectively. The daily collected amount of water and the daily moisture content were estimated with different gypsum thicknesses during all months of the year.

Result: It was found that the solar dryer with a capacity of 1,656 kg weight was technically and economically feasible. It was also found that the maximum reduction of moisture content occurred during the summer season, while the minimum values were achieved during winter.

Conclusion: With a mass of gypsum equal to 1,656 kg weight, the moisture content of gypsum started to decrease from its initial value (35%) until it reached the final value (10%) in 4 scenarios: the first one, 2 days from April to September, 3 days from March to November, more than 3 days in other months while the minimum moisture content, i.e., 20%, was reported in the first day in June.

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<![CDATA[Preparation and Properties of Biocomposite Prepared from Waste Polystyrene and <i>Prospopis africana</i> Biochar]]>https://www.benthamscience.com/article/1354292023-12-29Introduction: In this study, the pods of Prospopis Africana were thermochemically converted into biochar and combined with polystyrene resin in varying proportions to form composites.

Method: The composites were then characterized to determine their characteristics using Fourier transform infrared spectroscopy (FTIR), a Scanning electron microscope coupled with the energy dispersive X-ray Spectrophotometer (SEM-EDX), and a Differential scanning calorimeter (DSC).

Result: The FTIR analysis confirmed the changing or shifting of several peaks in the polystyrene resin and biochar samples. The hardness test showed that incorporating the Prosopis africana biochar into the solvated polystyrene matrix reduced the latter's hardness and reduced the impact value. SEM analysis showed that the biochar was firmly embedded in the polystyrene matrix, showing good adhesion between the matrix and the filler.

Conclusion: This study has demonstrated that composites produced from Prosopis africana biochar filler and polystyrene resin matrix could be used as adsorbents and in the fabrication of materials requiring good electrical and thermal properties.

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<![CDATA[Numerical Investigation and Machine Learning-Based Prediction of the Effect of Using Ring Turbulators on Heat Transfer Characteristics in a Counterflow Heat Exchanger]]>https://www.benthamscience.com/article/1351912023-12-29Background: Pipe-type heat exchangers are commonly used in industrial applications to facilitate heat transfer between two fluids at different temperatures without mixing them.

Method: In this study, turbulators were employed in a counterflow concentric pipetype heat exchanger. Water at a flow rate of 50 l/h and a temperature of 298.14 K, and air at a temperature of 350 K were directed through the inner pipe. The different stages of circular turbulators placed inside the inner pipe were numerically investigated using the feasible κ-ε turbulence model. Heat transfer characteristics were examined for a turbulator-free heat exchanger and for turbulator-heat exchanger models with helical turbulators of 25, 50, 75, and 100 mm pitch at Reynolds numbers ranging from 4000 to 26000. The governing equations for three-dimensional and turbulent flow conditions in a steady state were solved using a computational fluid dynamics program based on the finite volume method. Temperature distributions and velocity contours in the heat exchanger were generated using the data obtained from numerical analysis. Additionally, predictions were made using artificial neural networks.

Results: The results revealed that the highest enhancement in heat transfer, amounting to 233.08% compared to the empty tube case, was achieved with the 25 mm pitch turbulator.

Conclusion: The predictions made using artificial neural networks were in good agreement with the numerical analysis results. The designed turbulators for the heat exchanger model promoted turbulent flow, increased the heat transfer area, and led to an improvement in heat transfer.

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<![CDATA[Acknowledgement to Reviewers]]>https://www.benthamscience.com/article/1367292023-12-29