The discharge of industrial effluents, such as phenol, into aquatic and soil environments is a global problem due to its serious negative impacts on human health and aquatic ecosystems. In this study, the ability of polyvinylpolypyrrolidone (PVPP) to remove phenol from an aqueous medium was investigated. The results showed that a significant proportion of phenol (up to 74.91%) was removed using PVPP at pH 6.5. Isotherm adsorption experiments of phenol on PVPP indicated that the best-fit adsorption was obtained using Langmuir models. The response peaks of the hydroxyl groups of phenol (OH) and the carboxyl groups (i.e., CO) of PVPP were altered, indicating the formation of a hydrogen bond between the PVPP and phenol during phenol removal, as characterized using 1D and 2D IR spectroscopy. The resulting complexes were successfully characterized based on their thermodynamic properties, Mulliken charge, and electronic transition using the DFT approach. To clarify the types of interactions taking place in the complex systems, quantum theory of atoms in molecules (QTAIM) analysis, reduced density gradient noncovalent interaction (RDG-NCI) approach, and conductor-like screening model for real solvents (COSMO-RS) approach were also successfully calculated. The results showed that the interactions that occurred in the process of removing phenol by PVPP were through hydrogen bonding (based on RDG-NCI and COSMO-RS), which was identified as an intermediate type (∇2ρ(r) > 0 and H < 0, QTAIM). To gain a deeper understanding of how these interactions occurred, further characterization was performed based on adsorption mechanisms using molecular electrostatic potential, global reactivity, and local reactivity descriptors. The results showed that during hydrogen bond formation, PVPP acts as a nucleophile, whereas phenol acts as an electrophile and the O9 atom (i.e., donor electron) reacts with the H22 atom (i.e., acceptor electron).
Chemosensor using organic based compound offering superior alternative method in recognizing metal ion in environmental water. The optimization process strongly affected the performance of the designed sensor. In this study, a highly sensitive and selective colorimetric sensor system utilizing an organic compound, namely thiosemicarbazone-linked acetylpyrazine (TLA), to recognize Co2+ ions in different environmental water samples was successfully developed using the response surface methodology (RSM) approach. The developed model was optimized successfully and had statistically significant independent variables (p < 0.05), with optimum recognition occurring in 8:2 v/v DMSO/water at a pH of 5.3, a 100:70 µM TLA/Co2+ concentration, and 15 min of reaction time. Under optimum conditions, the TLA sensor recognized Co2+ ions at concentrations as low as 1.637 µM, which is lower than the detection limit of flame atomic absorption spectroscopy (FAAS). Theoretical approaches supported the experimental data as well as characterized and predicted the mechanistic non-covalent interactions of TLA-Co2+ within the chemosensing system. Finally, all the positive results produced in this study point to TLA as an alternative and comparable probe for recognizing Co2+ pollution in water that is cost effective, movable and easy-to-handle, requires no special training and ecofriendly.
The sensitive and selective chemosensor for copper(II) ions (Cu 2+) was successfully optimized using the 1,5-diphenylthiocarbazone (DPT) compound. The result showed that dimethyl sulfoxide (DMSO) in a 9:1 (DMSO:water) ratio at a pH of 3 was the optimum medium for DPT to act as chemosensor of Cu 2+ recognition. The DPT chemosensor did not encounter any interference from other metal ions, including
An alternative natural additive from Manihot esculenta has been recently discovered. Using a response surface methodology (RSM) approach, a high content of antioxidant activity based on DPPH inhibition from the plant source was found, with the optimum production conditions being 45.9°C, 4,100 psi, and 44 min for temperature, pressure, and time, respectively. The optimized extract was analyzed using gas chromatography–mass spectrometry (GC–MS), Fourier‐transform infrared spectroscopy (FTIR), and UV–Vis spectroscopy. Based on the GC–MS result, the optimized extract contains two major compounds, namely, hexadecanoic acid (40.43%) and 9‐octadecenoic acid (32.75%). The optimized extract also showed good activity in inhibiting Bacillus cereus (9.9 ± 0.17 mm) and Escherichia coli (10.7 ± 0.18 mm). To verify the activity of these two compounds toward B. cereus and E. coli, a theoretical approach with molecular docking was used. These two compounds demonstrated good binding affinity toward 2HUC and 1L8A proteins and could be isolated for use as alternative additives in the food industry.
Practical Application
Because there will always be substantial spoilage, losses and wastage in the food supply chain, preserving foods is essential to reduce food waste and ensure safety for consumers. M. esculenta extract can be used as an alternative food additive or preservative in the food industry that can enhance the shelf life of foods with a safe, inexpensive and less time‐consuming additive.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.