Green synthesis, characterization, and application of Fe3O4 nanoparticles for methylene blue removal: RSM optimization, kinetic, isothermal studies, and molecular simulation

Green Organo-Photooxidative Method for the Degradation of Methylene Blue Dye

This study used an organophoto-oxidative material to degrade the toxic azo dye, methylene blue (MB), due to its hazardous effects on aquatic life and humans. MB is traditionally degraded using metal-based catalysts, resulting in high costs. Several organic acids were screened for organo-photooxidative applications against various azo dyes, and ascorbic acid (AA), also known as vitamin C, was found to be best for degradation due to its high photooxidative activity. It is an eco-friendly, edible, and efficient photooxidative material. A photocatalytic box has been developed for the study of organo-photooxidative activity. It was found that when AA was added, degradation efficiency increased from 42 to 95% within 240 min. Different characterization techniques, such as HPLC and GC-MS, were used after degradation for the structural elucidation of degraded products. DFT study was done for the investigation of the mechanistic study behind the degradation process. A statistical tool, RSM, was used for the optimization of parameters (concentration of dye, catalyst, and time). This study develops sustainable and effective solutions for wastewater treatment.

Green synthesis of iron nanoparticles using mulberry leaf extract: characterization, identification of active biomolecules, and catalytic activity

The synthesis of iron-based nanoparticles (Fe NPs) using traditional preparation methods suffered from the disadvantages of high cost, environmental harm, and easy agglomeration. In this study, a novel eco-friendly method was proposed for the synthesis of iron nanomaterials (ML-Fe NPs): using antioxidant components extracted from mulberry leaf to reduce divalent iron (II). The preparation conditions of ML-Fe NPs were optimized by orthogonal tests. The prepared ML-Fe NPs exhibited an amorphous core-shell structure, displaying excellent dispersion and stability. During the synthesis process of ML-Fe NPs, the polyphenol molecules in mulberry leaf extract played a dominant role. A possible synthetic mechanism involving complexation, reduction, and encapsulation was proposed. Furthermore, the ML-Fe NPs were utilized to construct an ML-Fe NPs/peroxymonosulfate catalytic system for the degradation of Rhodamine B dye wastewater. The ML-Fe NPs demonstrated remarkable catalytic potential, achieving a 99% degradation efficiency for Rhodamine B within a span of 40 min.

Adsorption of contaminants by nanomaterials synthesized by green and conventional routes: a critical review

Nanomaterials, due to their large surface area and selectivity, have stood out as an alternative for the adsorption of contaminants from water and effluents. Synthesized from green or traditional protocols, the main advantages and disadvantages of green nanomaterials are the elimination of the use of toxic chemicals and difficulty of reproducing the preparation of nanomaterials, respectively, while traditional nanomaterials have the main advantage of being able to prepare nanomaterials with well-defined morphological properties and the disadvantage of using potentially toxic chemicals. Thus, based on the particularities of green and conventional nanomaterials, this review aims to fill a gap in the literature on the comparison of the synthesis, morphology, and application of these nanomaterials in the adsorption of contaminants in water. Focusing on the adsorption of heavy metals, pesticides, pharmaceuticals, dyes, polyaromatic hydrocarbons, and phenol derivatives in water, for the first time, a review article explored and compared how chemical and morphological changes in nanoadsorbents synthesized by green and conventional protocols affect performance in the adsorption of contaminants in water. Despite advances in the area, there is still a lack of review articles on the topic.

A facile strategy for preparation of Fe3O4 magnetic nanoparticles using Cordia myxa leaf extract and investigating its adsorption activity in dye removal

This study demonstrates the successful, facile, and cost-effective preparation of magnetic Fe3O4 nanoparticles (MNPs) via green procedure using Cordia myxa leaf extracts for efficient adsorption of methylene blue (MB) as a model of organic pollutant. The formation of Fe3O4 NPs was confirmed by a range of spectroscopy and microscopy techniques including FT-IR, XRD, FE-SEM, TEM, EDS, VSM, TGA, and BET-BJH. The synthesized spherical nanoparticles had a high specific surface area of 115.07 m2/g with a mesoporous structure. The formed Fe3O4 MNPs exhibited superparamagnetic behavior with saturation magnetization of 49.48 emu/g. After characterization, the adsorptive performance of the synthesized MNPs toward MB was evaluated. To achieve the maximum removal efficiency, the effect of key parameters such as adsorbent dosage (MNPs), initial adsorbate concentration, pH, and contact time on the adsorption process was evaluated. A maximum adsorption capacity of 17.79 mg/g was obtained, after one-hour incubation at pH 7.5. From the pHPZC of 7.1 of the synthesized adsorbent, the electrostatic attraction between MB and Fe3O4 NPs plays an important role in the adsorption process. The adsorption experimental data showed the closest match with the pseudo-second-order kinetic and Langmuir isotherm. The prepared Fe3O4 NPs were easily recovered by an external magnet and could be reused several times. Therefore, the synthesized MNPs seem to be excellent adsorbents for the removal of MB from aqueous solution.

Photodynamic Action of Curcumin and Methylene Blue against Bacteria and SARS-CoV-2-A Review

Coronavirus disease 19 (COVID-19) has occurred for more than four years, and the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) causing COVID-19 is a strain of coronavirus, which presents high rates of morbidity around the world. Up to the present date, there are no therapeutics that can avert this form of illness, and photodynamic therapy (PDT) may be an alternative approach against SARS-CoV-2. Curcumin and methylene blue have been approved and used in clinical practices as a photosensitizer in PDT for a long time with their anti-viral properties and for disinfection through photo-inactivated SARS-CoV-2. Previously, curcumin and methylene blue with antibacterial properties have been used against Gram-positive bacteria, Staphylococcus aureus (S. aureus), and Gram-negative bacteria, Escherichia coli (E. coli), Enterococcus faecalis (E. faecalis), and Pseudomonas aeruginosa (P. aeruginosa).

METHODS

To conduct a literature review, nine electronic databases were researched, such as WanFang Data, PubMed, Science Direct, Scopus, Web of Science, Springer Link, SciFinder, and China National Knowledge Infrastructure (CNKI), without any regard to language constraints. In vitro and in vivo studies were included that evaluated the effect of PDT mediated via curcumin or methylene blue to combat bacteria and SARS-CoV-2. All eligible studies were analyzed and summarized in this review.

RESULTS

Curcumin and methylene blue inhibited the replication of SARS-CoV-2. The reactive oxygen species (ROS) are generated during the treatment of PDT with curcumin and methylene blue to prevent the attachment of SARS-CoV-2 on the ACE2 receptor and damage to the nucleic acids either DNA or RNA. It also modulates pro-inflammatory cytokines and attenuates the clotting effects of the host response.

CONCLUSION

The photodynamic action of curcumin and methylene blue provides a possible approach against bacteria and SARS-CoV-2 infection because they act as non-toxic photosensitizers in PDT with an antibacterial effect, anti-viral properties, and disinfection functions.

Drug permeation enhancement, efficacy, and safety assessment of azelaic acid loaded SNEDDS hydrogel to overcome the treatment barriers of atopic dermatitis

Atopic dermatitis is one of the most widespread chronic inflammatory skin conditions that can occur at any age, though the prevalence is highest in children. The purpose of the current study was to prepare and optimize the azelaic acid (AzA) loaded SNEDDS using Pseudo ternary phase diagram, which was subsequently incorporated into the Carbopol 940 hydrogel for the treatment of atopic dermatitis. The composition was evaluated for size, entrapment efficiency, in vitro, ex vivo, and in vivo studies. The polydispersity index of the optimized preparation was found to be less than 0.5, and the size of the distributed globules was found to be 151.20 ± 3.67 nm. The SNEDDS hydrogel was characterized for pH, viscosity, spreadability, and texture analysis. When compared to the marketed formulation, SNEDDS hydrogel was found to have a higher rate of permeation through the rat skin. In addition, a skin irritation test carried out on experimental animals showed that the SNEDDS formulation did not exhibit any erythematous symptoms after a 24-h exposure. In conclusion, the topical delivery of AzA through the skin using SNEDDS hydrogel could prove to be an effective approach for the treatment of atopic dermatitis.