In this study, a flower-like SnIn₄S₈/SmVO₄ heterostructure was synthesized by applying a hydrothermal approach and used as a visible-light-driven photocatalyst to remove hexavalent chromium (Cr⁶⁺) and Rhodamine B (RhB). The process design and optimization were carried out by response surface methodology (RSM). An artificial neural network (ANN) was also used to determine the relative importance of operational factors. Under RSM-based optimal conditions, the Cr⁶⁺ and RhB removal efficiency reached 90.93 and 97.57%, respectively. Process modeling by ANN revealed pH as the most influential factor in Cr⁶⁺ and dye removal. The predominant photocatalytic activity of SnIn₄S₈/SmVO₄ was attributed to its Z-scheme structure, leading to the significant separation of charge carriers and conserving the redox capacity of the photogenerated electron-holes. Kinetic studies revealed that the SnIn₄S₈/SmVO₄ could achieve considerable rate constants of 0.036 and 0.080 min⁻¹ to remove Cr⁶⁺ and RhB, respectively. Furthermore, the catalyst’s reusability was confirmed under optimal conditions.

The adsorption characteristics of 4-chloro-2-nitrophenol (4C2NP) onto single-walled and multi-walled carbon nanotubes (SWCNTs and MWCNTs) from aqueous solution were investigated with respect to the changes in the contact time, pH of solution, carbon nanotubes dosage and initial 4C2NP concentration. Experimental results showed that the adsorption efficiency of 4C2NP by carbon nanotubes (both of SWCNTs and MWCNTs) increased with increasing the initial 4C2NP concentration. The maximum adsorption took place in the pH range of 2–6. The linear correlation coefficients of different isotherm models were obtained. Results revealed that the Langmuir isotherm fitted the experimental data better than the others and based on the Langmuir model equation, maximum adsorption capacity of 4C2NP onto SWCNTs and MWCNTs were 1.44 and 4.42 mg/g, respectively. The observed changes in the standard Gibbs free energy, standard enthalpy and standard entropy showed that the adsorption of 4C2NP onto SWCNTs and MWCNTs is spontaneous and exothermic in the temperature range of 298–328 K.

Today, the tendency to use of natural preservatives to increase food security has expanded. In the present study, antibacterial effects of Areca Nut fruit extracts were evaluated against Staphylococcus aureus, Escherichia coli, Salmonella enterica, and Enterobacter aerogenes bacteria using agar disc diffusion technique. Methanol, ethanol, and water were used as solvents for extraction by maceration method, and extracts were analyzed by GC‐MS. The antibacterial activity was evaluated using microtiter broth dilution method to determine minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC). Results revealed that all ATCC strains were significantly inhibited by ethanolic and methanolic extracts. Escherichia coli produced a significantly larger zone of inhibition for Gentamicin (35 ± 0.65 mm) and Penicillin (25 mm ± 0.56), while Enterobacter aerogenes produced smaller zone of inhibition for Gentamicin (20 ± 0.87 mm) and Penicillin (15 ± 0.87 mm). Also, methanolic extract had considerable antibacterial activity with MIC value of 1.56 mg/mL against Escherichia coli. All of extracts were used to evaluate antibacterial effects in prepared cake, and as a result, all pathogenies were the most sensitive by methanolic extract in 100 mg/L of concentration except Escherichia coli that were more sensitive by ethanolic extract. In conclusion, the Areca Nut fruit extracts may be used as a natural preservative in food industries. Future studies should focus on the effect of Areca Nut fruit extracts in bakery and drinking industries.