In this study, the drying of oyster mushrooms (P. ostreatus) in a tray dryer was optimized. The parameters used to optimize the drying process were drying temperature, airspeed, mass loading, and moisture content. Its drying kinetics were investigated at the optimum drying parameters. A quadratic equation was obtained to predict the moisture content of mushrooms at the given drying temperature, airspeed, and mass loading, and it was validated against experimental results. A minimum moisture content (9.99 wt%) was obtained at the optimum conditions of 60 °C, 3 m/s airspeed, and mass loading of 200 g using a tray dryer. Proximate analysis, shelf-life analysis, inorganic elemental analysis, and functional group analysis were done as a characterization method for mushrooms after drying at the optimum drying conditions. About 27.8 wt% protein and 50.2 wt% carbohydrates were found in proximate results. Besides, potassium and sodium were the dominant elements as estimated by spectrophotometry analysis. The induction period (IP) of dried mushrooms at room temperature is 3520:47 (hour: minute) from the oxidation stability analysis, and the water activity of dried mushrooms was found to be 0.36. The drying kinetics of oyster mushrooms were studied at various temperatures (50-75 °C), optimum airspeed (3 m/s), and mass loading (200 g). The best-fit model describing the mushrooms drying kinetics was found to be Midilli et al., with the lowest RMSE (0.008749), X² (0.0014), and the highest R²(0.9993) values. The kinetic triplet activation energy, effective diffusivity, and diffusivity constant (Ea, D_eff, D₀) for oyster mushrooms drying were determined and found to lay in the general range for foodstuffs. The value of D_eff results lies within the range of 10^-8 to 10^-12 m²/s, with Ea of 15.32 kJ/mol and D₀ value 2.263 × 10^-6 m²/s.

The objective of this study is to investigate the adsorption performance of activated carbon derived from the leaves of Cordia africana for the removal of Cr (III) from an aqueous solution. The plant sample was collected, washed, dried, grounded, and sieved at 125μm mesh size. Adsorbent activation was done using H₃PO₄ at concentrations of 2585 and pyrolysis temperature of 400500°C. The activated carbon was characterized by proximate, SEM, BET, and FTIR analyses. A batch adsorption study was conducted to determine the effect of contact time, adsorbent dose, initial chromium concentration, and mixing speed on Cr (III) removal. The regeneration of the activated carbon was investigated by using 1M of HNO₃ as a desorbing solution for seven cycles. At optimum acid concentration and pyrolysis temperature, a surface area of 700m²/g was recorded. The moisture content, volatile matter, ash composition, fixed carbon, and bulk density of the activated carbon were found to be 5.3, 24.2, 6.2, 64.3, and 0.75g/mL, respectively. The SEM and FTIR analyses indicated that the surface morphology was full of cracks and different peaks were associated with plenty of functional groups, respectively. The maximum Cr (III) removal was attained at a contact time of 180min (89), adsorbent dose of 1.5g (54), initial concentration of 0.6g/L (47), and mixing speed of 300rpm (64). The equilibrium data were better described by Freundlich isotherm at R² value of 0.88, which implies that the adsorption process is conducted on a heterogeneous surface. The pseudo-first-order kinetics model with R² value of 0.99 best fits with the equilibrium data, which implies that physisorption controls the adsorption kinetics. Generally, it can be concluded that this locally prepared adsorbent is promising for the removal of chromium from industrial wastewater, but further factorial approach assessment has to be checked.

Treatment of harmful chemicals using materials at our disposal is the way forward. This study activated bio-adsorbent from waste banana for dye removal from an aqueous solution. The banana peel was activated both thermally and chemically with a preliminary study of a 0.5−2.5 M sulfuric acid concentration, and 50−90 °C of temperature for 1−5 h activation time. Activation at 1.5 M acid concentration, 70 °C for 3 h showed a promising efficacy of about 90% of removing dye. Activated banana peel was characterized using proximate analysis, BET, TGA, SEM, XRD, and FTIR. BET results showed activated banana peel to be porous material with a surface area of 432 m2/g. The adsorption capacity of the adsorbent with different variables range (adsorption time 20−140 min, pH 1.0−7.0, adsorbent dose 1−4 g/L and initial dye concentration 20−80 mg/L) was tested based on a preliminary study. The adsorption process was optimized numerically and the results were; adsorption time 60 min, pH 3, adsorbent dose 2 g/L and initial dye concentration 40 mg/L. The pseudo-second-order kinetics model and Langmuir isotherm model were the best fit to describe the adsorption process.

The production of biodiesel conventionally relies on batch reactors for the transesterification of oil and alcohol. However, the inherent limitations of batch-wise biodiesel production, including biphasic oil and alcohol, the establishment of equilibrium during transesterification, and heightened manufacturing costs, underscore the need for intensifying biodiesel synthesis. The integration of microreactors and micromixers presents a promising avenue to achieve these objectives, driving significant interest in the development of continuous biodiesel synthesis within microreactor systems. Continuous microreactors, empowered by micromixers, offer key advantages such as a heightened interfacial area between immiscible reactants and phases, as well as reduced mass transfer resistance, culminating in elevated biodiesel yields. Consequently, the micromixer emerges as a pivotal component in microreactor systems. This review delves into the pivotal role of micromixers in biodiesel production within microreactors, shedding light on micromixer types, channel configurations, reactor dimensions, mixing indices, and the influence of co-solvents in micromixers. The efficiency of various micromixer types is meticulously analyzed using a mixing index and yield of oil. Furthermore, the review addresses the challenges inherent in biodiesel production when employing micromixers and microreactors.

Corrosion of mild steel has gained a lot of attention by many industries and academia. This study was aimed to find the corrosion inhibition properties of hydrazine and its 11 derived molecules for mild steel using computational method, namely, the density functional theory with Beck 3‐parameter Lee Yang and Parr functional along with the 6‐311++G (d, p) basis set using simple quantum chemical parameters. The main quantum chemical parameters were energies of highest occupied and lowest unoccupied molecular orbitals and their energy gap, dipole moment, hardness, softness, electrophilicity index, the fractions of electrons transmitted, the change energy back‐donation, electron‐donating power, electron‐accepting power, molecular electrostatic potential, and Fukui function as well as polarizability. The results indicated that hydrazine derivatives have good anticorrosion nature which is consistent with the experimental findings. Out of the 12 target inhibitor molecules, N′‐(3‐nitrobenzylidene) hydrazine carbodithioic acid (NBHCA) and N′‐(4‐dimethylaminobenzylidene) hydrazine carbodithioic acid (DABHCA) are the most effective inhibitors. According to the value of the quantum chemical parameters, E_HOMO, ΔE_gap, Χ, η, σ, ε, ΔN, α, and ΔE_b-d DABHCA showed the top effective anticorrosion inhibitor, and by the value of the quantum chemical parameters, E_LUMO, TE, ω⁻, and ω⁺ NBHCA showed an effective anticorrosion inhibitor. The quantum chemical parameter data showed that NBHCA and DABHCA are nearly equivalent in their values, which is consistent with experimental values. Furthermore, a multiple‐linear regression equation was proposed as a quantitative structural activity relationship model to relate the calculated molecular descriptors of hydrazine derivatives to their experimental inhibition efficiencies obtained from literature. As a result, this model showed an excellent accuracy with an R‐squared of 0.924 and this uses to predict inhibition efficiencies of another molecules.

Purifying water for diverse uses is vital, but concerns lie with the sustainability and accessibility of purification materials. As such, this study converted readily available water treatment plant sludge (WTPS) into activated adsorbent for phosphate removal in wastewater. WTPS was activated via thermal activation at 300 °C temperature and chemical activation processes of 3 M acid concentration, 4 h activation time, and 75 °C activation temperature, and then characterized using Brunauer-Emmett-Teller (BET), scanning electron microscopy (SEM), Fourier transform infrared, elemental analyzer, and differential scanning calorimetry. SEM and BET analyses revealed a highly porous adsorbent (279.2 m2/g) for efficient adsorption. On top of the activation process, preliminary experiments and numerical optimization using response surface methodology (RSM) were designed and conducted. Through optimizing conditions, it was found that 70 min of contact time, pH 3, 3 g/L adsorbent dose, and 30 mg/L initial phosphate concentration as optimal, yielding 83% removal efficiency. Furthermore, adsorption kinetics and isotherm models were examined and the second-order kinetics and Langmuir isotherm models indicated best fit. Notably, the activated sludge could be regenerated for three cycles before efficiency dropped below 70%. Thus, activated WTPS presents a promising, sustainable, and readily available adsorbent for phosphate removal in wastewater treatment.