ASIAN JOURNAL OF GREEN CHEMISTRY
Year:2024 | Volume:8 | Issue:6|Papers Count:9

Biopolymers are characterized by their three-dimensional polymeric networks, high hydrophilic properties, affordability, physical and chemical stability, non-toxicity, and exceptional ability to absorb water and other substances. In this work, the adsorption capacity of an inexpensive, biodegradable adsorbent, poly (AAC-co-AM) hydrogel, prepared by the free radical polymerization method, was studied for the removal of heavy metals such as Fe (II) ions. Several analyses of the hydrogel were performed, including FESEM, TEM, and XRD. The effects of various conditions on the adsorption process were investigated, such as hydrogel weight, Fe (II) ion concentration, equilibrium time, and adsorption isotherms. Iron ion adsorption increased from 77.25% to 97.91% as the weight of the hydrogel increased from 0.01 to 0.1 g/50 mL. However, the adsorption capacity decreased from 29.14 to 233.33 mg/g at a fixed Fe (II) ion concentration of 30 mg/L, an equilibrium time of 1 hour, the temperature of 25 °C, and a stirring speed of 150 rpm. As the equilibrium time increased, both the adsorption efficiency and removal percentage rose. In addition, increasing the weight of the poly (AAC-co-AM) hydrogel led to an increase in the removal percentage. The results revealed that the adsorption efficiency of poly (AAC-co-AM) hydrogel was 55.62 mg/g with a removal percentage of 92.78% at pH 7, a dose of 0.1 g/50 mL, an equilibrium time of 1 hour, an Fe (II) ion concentration of 30 mg/L, and the temperature of 25 °C. Beyond this, the adsorption efficiency began to decrease. Finally, the adsorption equilibrium was studied using the Langmuir and Freundlich isotherms. The data were best described by the Freundlich model.

Chlorofluorocarbons (CFCs) are among the environmental pollutants that destroy the ozone layer, and it is necessary to explore materials with good ability for adsorption of them. In this study, the structure of armchair graphene (3,3) with a length of 10 Å was optimized using quantum mechanical calculations, and then it was functionalized with hydroxyl and fluorine groups to interact with environmental pollutants such as methane, chlorofluoromethane (R-31) and chlorodifluoromethane (R-22). Adsorption of these substances comprehensively on graphene functionalized with O-H···F groups and virgin graphene from It was investigated through quantum mechanical calculations, molecular dynamics, and Monte Carlo simulations. Energy data, structural parameters, electronic properties, electron charge density, molecular electrostatic potential maps, charge transfer, density of states diagrams, and non-covalent interactions were were analyzed to evaluate adsorption potential. The adsorption sites with the lowest energy value ​​and possible configurations were identified by tracking the Metropolis Monte Carlo probes from the location of the configuration of the absorber-adsorber pairs. Using adsorption isotherms, adsorption energy, binding energies, and isosteric heat values, adsorption effectiveness was considered. The obtained structures showed suitability after the equilibrium and product steps for structural, dynamic, and statistical properties calculations.

This study investigates the thermal, morphological, mechanical, and biodegradation properties of blends comprising poly(L-lactide)-b-poly (ethylene glycol)-b-poly(L-lactide) triblock copolymer (PLLA-PEG-PLLA) and polypropylene (PP) compared to the PLLA/PP blends. All the blends were prepared using a melt-blending technique. The ability to crystallize and the thermal stability of the PLLA-PEG-PLLA were enhanced by blending PP, whereas these properties were not enhanced for the PLLA. The crystallinity of PLLA-PEG-PLLA increased from 20.4% to 23.5-38.8%. The temperature at maximum decomposition rate (Td,max) of PLLA end-blocks increased from 310 °C to 327-332 °C. The phase compatibility between the PLLA-PEG-PLLA and PP was better than between the PLLA and PP, as indicated by the smaller size of dispersed PP particles in the PLLA-PEG-PLLA matrix. The PLLA-PEG-PLLA/PP blends showed greater flexibility, higher wettability, and faster biodegradation rates than the PLLA/PP blends. This suggests that these PLLA-PEG-PLLA/PP blends may be used as flexible and partially biodegradable plastics.

The modification of carbon from Nut shell was done via carbonization at 500 °C and activated under acidic conditions with H3PO4. Thus, Nutshell (NS) and chemically activated carbon utilizing acid H3PO4, the biochar surface will be referred to as NS-H3P will exhibit comparable capacity in removing BB dye compared to commercial activated carbon (CAC). The NS-H3P adsorbent has been characterized by field emission scanning electron microscope (FESEM), energy-dispersive X-ray spectroscopy (EDX), and transmission electron microscope (TEM). Effect of several factors like equilibrium time (5-60 min), the weight of adsorbent (0.01-0.08 g), the concentration of dye (10 -50 mg/L), pH solution (2.8-10.3), and solution of temperature (10-45 oC) were investigated. The equilibrium result tends to fit best with isotherm Freundlich than isotherm Langmuir. The isotherm Freundlich model with a high R2 was utilized to describe multi-layer adsorption. Desorption of dye studies was performed with NaOH, HCl, and H2O. Computational modeling was performed to obtain deeper mechanistic insights on the adsorption behavior of the BB dye molecules onto (002) sheet of Biochar. This modeling section includes Monte Carlo space exploration for the lowest adsorption energy configurations of the BB dye molecule on the Biochar surface. The process included an adsorption locator calculations module.

In the study, corn cob is activated carbon (AC) by treating it with H3PO4 to obtain a constant weight of activated carbon corn cob (AC-CC). The AC-CC characterized via SEM, EDX, and TEM. Copper ions were removed from an aqueous solution utilizing AC-CC. The surface before the adsorption process contains irregular gaps and stomata, which create many active sites on the surface where the acid works to prepare active sites capable of adsorption, but the surface after adsorption displays very clear distinct black spots that confirm the high adsorption of copper ions into the pores and cavity of the adsorbent. The TEM image for AC-SFS appears from the bulk background color attributed to the AC resulting from the acid activation process and EDX patterns of AC-CC, which verified the presence of carbon and oxygen groups and also phosphorus resulting from surface activation by phosphoric acid. The best isotherm analysis was performed via isotherm Langmuir and Freundlich models. The data showed that the removal of Cu (II) via AC-CC carefully applies to the Freundlich model with a (R2 =0.9593), and also the maximum removal adsorption is 92.44 % and adsorption capacity is 53.56 mg/g. These data showed that the utilizing of corn cob as activated carbon to remove copper ions would be an interesting option as cost-effective and eco-friendly.

A series of benzothiazole based triazole derivatives (7a-o) was designed and synthesized via click chemistry. The newly synthesized molecules were elucidated by various spectral analyses, such as 1H-NMR, 13C-NMR, Mass, IR, and elemental composition. Based on the therapeutic importance of benzothiazole and triazole the newly synthesized molecules (7a-o) were evaluated for antibacterial activity against the bacterial strains (Gram-negative: P. Aeruginosa, K. Aerogenes, and C. Violaceum and Gram-positive: B. Subtilis, B. Sphaericus, and S. Aureus), compound 7g exhibit maximum zone of inhibition compared to standard drug Streptomycin. This study evaluates the antifungal activity of derivatives (7a-o) against four fungal strains: C. albicans, A. fumigatus, T. rubrum, and T. Mentagrophytes, compound 7m shows the maximum zone of inhibition compared to the standard drug Amphotericin B. Furthermore, in vitro anticancer assays were conducted using three human cancer cell lines: MCF-7 (Breast cancer), PC-3 (Prostate cancer), and HeLa (Cervical cancer). Among all the synthesized compounds, 7m showed significant anticancer activity with IC50 value of 2.32±0.03 µM against MCF-7, 3.57±0.05 µM against PC-3 and 2.93±0.05 µM against Hela cancer cell lines. Molecular docking studies of newly synthesized compounds (7a-o) against the Human Myosin 9b protein (PDB ID: 5C5S), associated with fast lung cancer progression, revealed that all compounds exhibits better binding energies than Doxorubicin. Notably, compounds 7a and 7d achieved high negative binding energies of -8.2 kcal/mol.

A simple, green, rapid, sensitive, and eco-friendly ultrasonic-assisted deep eutectic solvent-dispersive liquid-liquid microextraction method (USA-DES-DLLME) was developed using modified nanoparticles (ZnO NPs) for the separation and pre-concentration of crystal violet and Congo red dyes in water samples, analyzed by UV-Vis spectrophotometer. In this method, synthesized ZnO NPs were characterized using various techniques, including UV-Vis, FT-IR, FE-SEM, EDX, and AFM. The optimum conditions for the quantitative recovery of the analytes included the effects of pH, type and volume of DES, volume of ZnO NPs, extraction time, THF, and centrifugation speed and duration. Under the optimized experimental conditions, the relative standard deviation (RSD%) at a concentration of 0.05 µg mL-1 was found to be 2.71% and 2.77%. The limits of detection (LOD) were 0.0351 µg mL-1 and 0.0561 µg mL-1, while the limits of quantification (LOQ) were 0.017 µg mL-1 and 0.0187 µg mL-1. The enrichment factors (EF) were 42.914 and 47.392, with the pre-concentration factor being 41.411 for crystal violet (CV) and Congo red (CR) dyes, respectively, at 53.713. The intra- and inter-day precision of the method were calculated at concentrations of 0.3 and 0.5 µg mL-1. For crystal violet dye, the intra-day precision was 2.9% and 3.2%, while the inter-day precision was 2.8% and 3.4%. For Congo red dye, the intra-day precision was 2.0% and 4.2%, with inter-day precision at 3.8% and 4.4%. The method was successfully applied to the determination of crystal violet and Congo red dyes in water samples.

In this work, novel antibacterial drugs that are tetrazole derivatives connected to the 1-position of the heterocyclic ring (benzimidazole) via a methyl bridge were designed and synthesized. The final chemical structures of the prepared tetrazole derivatives were confirmed by nuclear magnetic resonance (1H NMR and 13C NMR), and Fourier-transform infrared spectroscopy (FTIR) spectroscopy. Three types of Candida were used to investigate the synthetic compounds' antifungal properties: Candida albicans, Candida glabrata, and Candida parapsilosis. Compounds e1 and b1 have greater efficacy against Candida albicans than normal fluconazole, while compound d1 shows greater efficacy against Candida glabrata. The ability of compounds to combat gram-positive and gram-negative, Klebsiella pneumoniae, Staphylococcus aureus, Escherichia coli, and Enterococcus faecalis was also assessed. The lowest inhibitory concentrations of compounds e1, b1, and c1 against E. faecalis were comparable to those of the control drug azithromycin. Modeling studies were conducted against the 14-α demethylase enzyme found in Candida species. When it came to combating Candida species, e1 was the most effective chemical and had the highest docking contact energy. Based on the theoretical ADME of prepared compounds calculated, the molecule profiles meet the limitation rule requirements.

The current study aimed to investigate the optimum conditions for the green synthesis of nickel nanoparticles (NPs) with the highest antimicrobial activity instead of the Candida albicans. To this end, nine experiments were designed using the Taguchi method, and nickel NPs were synthesized biologically using the bacterium Halomonas elongata. According to the findings, the most suitable level for nickel nitrate, incubation temperature, and incubation duration was the third level (0.7 M), the second level (32 °C) and the first level (48 h), respectively. It was calculated that the NPs under synthesis in optimum conditions inhibited more than 72% of fungal growth. Moreover, the current study examined the features of nickel NPs under synthesis by various analyses that confirmed the formation of nickel NPs with favorable structural and morphological properties. Therefore, these nanoparticles can be used in medicine and dentistry as an effective antifungal compound.