In this study, orange peel (OP) biochar was used as a bio-sorbent for the removal of copper and lead from wastewater in single and binary systems. The equilibrium and kinetic studies were conducted at a pH value of 5, which was the maximum adsorption pH value for both metal ions. The equilibrium studies were investigated at a varying initial concentration (10–200 mg/L) with a constant dosage of 0.1 g, while the kinetic studies were conducted at a fixed initial concentration of 200 mg/L with a constant dosage of 1 g/L for both single and binary systems. The maximum adsorption capacity of the orange peel biochar was 28.06 mg/g, 26.83 mg/g, 30.12 mg/g and 27.71 mg/g for single Cu²⁺, binary Cu²⁺, single Pb²⁺ and binary Pb²⁺ systems, respectively. The Langmuir isotherm model fitted the experimental data, suggesting that adsorption occurred on a monolayer, while the pseudo-second-order model performed well with the kinetic data. The point of zero charge (pH_pzc) of the orange peel biochar was found to be 10.03, which revealed that the surface of the bio-sorbent contains basic groups. A Fourier infrared transform (FTIR) spectroscope and scanning electron microscope, coupled with energy dispersive x-ray (SEM-EDX) and x-ray diffraction analyses, were used to determine the functional groups, surface morphology, and inorganic elements present on the surface of the bio-sorbent, respectively. The results obtained have shown that orange peel biochar is efficient for the removal of Cu²⁺ and Pb²⁺ ions from an aqueous solution.

Apple pomace (AP) from the food industry is a mixture of different fractions containing bioactive polyphenolic compounds. This study provides a systematic approach toward the recovery and evaluation of the physiochemical and biological properties of polyphenolic compounds from AP. We studied subcritical water extraction (SCW) and solvent extraction with ethanol from four different AP fractions of pulp, peel, seed, core, and stem (A), peel (B), seed and core (C), and pulp and peel (D). The subcritical water method at the optimum condition resulted in total polyphenolic compounds (TPC) of 39.08 ± 1.10 mg GAE per g of AP on a dry basis compared to the ethanol extraction with TPC content of 10.78 ± 0.94 mg GAE/g db. Phloridzin, chlorogenic acid, and quercetin were the main identified polyphenolics in the AP fractions using HPLC. DPPH radical scavenging activity of fraction B and subcritical water (SW) extracts showed comparable activity to ascorbic acid while all ethanolic extracts were cytocompatible toward human fibroblast (3T3-L1) and salivary gland acinar cells (NS-SV-AC). Our results indicated that AP is a rich source of polyphenolics with the potential for biomedical applications.

Agricultural waste materials have been proven to be efficient for heavy metal sequestration from wastewater. In this paper, the interactive effects of initial concentration, adsorbent dosage, and particle size on the removal of copper and lead ions in a binary system onto orange peels were investigated using a central composite design. The pHpzc of orange peels was determined to be 3.85. The Fourier transform infrared (FTIR) and energy dispersive x-ray (EDX) revealed the functional groups and elemental composition present on the surface of the bio-sorbent, respectively, before and after adsorption. The ANOVA showed a good fit with a coefficient of determination (R²) of 0.973 and 0.993 for Cu and Pb, respectively. The bio-sorption of Cu and Pb increased with increasing adsorbent dosage while the percentage removal of Pb was consistently higher than Cu. The highest percentage removal of Cu and Pb gave 86.27% and 98.85%, respectively. The kinetic and isotherm studies showed that pseudo-second-order and Langmuir isotherm models fitted the experimental data suggesting chemisorption and monolayer adsorption, respectively. The treatment of wastewater is very essential to avoid water scarcity and to achieve the Sustainable Development Goals (SDGs). This study demonstrates the potential of utilizing orange peels as bio-sorbent for the treatment of wastewater containing Cu and Pb ions.

The drive for renewable energy as an alternative to fossil fuel is on the increase globally. Modeling a renewable energy process is crucial for increasing process monitoring and control of plant efficiency for the ultimate objective of optimal biorefinery operations. This study aims to develop and compare models that best predict the fermentation process parameters of bioethanol production using corn‐steep liquor (CSL) as a media supplement. The response surface method (RSM), artificial neural networks (ANNs) and adaptive neuro‐fuzzy inference system (ANFIS) were tested in the modeling of bioethanol fermentation processes. Box–Behnken design was used to investigate fermentation process parameters considering the effect of CSL (0.5–5.5 w/v), pH (4, 5), time (12–36 h), temperature (25–35°C) and inoculum size (0.5–5.5 v/v). The results from the kinetics study show media formulation with corn steep liquor results in a comparable yield with that substituted with yeast extract. The study shows that, for CSL, a maximum ethanol concentration of 17.40 g L⁻¹ was obtained after 48 h of fermentation while 21.53 g L⁻¹ was attained after 6 h for the media formulation with yeast extract. Based on the model evaluation using statistical error indices, ANN predictability was better at R² = 0.90; R = 0.95; SEP = 1.73. The ANN models described the process better than ANFIS and RSM. This study shows the intelligent predictive ability of ANN that could be useful for the scale‐up process of ethanol production in industry. © 2023 The Authors. Biofuels, Bioproducts and Biorefining published by Society of Industrial Chemistry and John Wiley & Sons Ltd.

The commercial Calcium oxide was successfully embedded on activated carbon surfaces to increase the reactive surface area of a composite catalyst material CaO/AC. The composite catalyst material was also successfully packed in the tubular titanium dioxide/Aluminum dioxide ceramic membrane reactor used to separate the biodiesel produced. Virgin soybean oil was used as precursor feedstock for the reaction. Using a central composite approach, response surface methodology (RSM) was employed to obtain the optimum conditions for producing biodiesel from soybean oil. A total of four process factors were examined (2⁴ experimental designs). 30 experiments were derived and run to investigate the effects of temperature, reaction time, methanol to oil molar ratio, and catalyst concentration (calcium oxide attached on activated carbon). 96.9 percent of soybean oil methyl ester (SOME/biodiesel) was produced at 65 °C temperature, 90 min of reaction time, 4.2:1 molar ratio of methanol to oil, and 3.0 wt.% catalyst concentration. The measured yield and expected biodiesel production values were correlated in a linear sequence. The fuel qualities of SOME/biodiesel were tested, including kinematic viscosity, density, flash point, copper corrosion, calorific value, cloud point, pour point, ash content, and carbon residue.