Enhancing the seawater desalination performance of multilayer reduced graphene oxide membranes by introducing in-plane nanopores: a molecular dynamics simulation study

In this study, using MD simulation, the effect of creating in-plane nanopores in a reduced graphene oxide (rGO) membrane and the formation of a reduced nanoporous graphene oxide (rNPGO) membrane is proposed to increase salt rejection and water flux. To this end, the desalination performance of r1NPGO, r2NPGO and r4NPGO membranes, which have 1, 2 and 4 pore(s), respectively, with a diameter of 0.9 nm and the r1NPGO-3 nm membrane, which has 1 pore with an approximate diameter of 3.0 nm, was investigated and compared from a molecular point of view. The simulation results show that in the rNPGO membranes, by increasing the number of pores from 1 to 4, water flux increases by ∼6 times compared to the rGO membrane. Meanwhile, upon increasing the pore size from 0.9 to 3.0 nm, water flux is enhanced by ∼16 times compared to the rGO membrane. The simulation results also demonstrate that the rGO membrane has two paths for water penetration, which are called the interlayer pathway and in-slit pathway. Moreover, pores in the rNPGO membranes provide another additional path for water transfer by shortening the lateral size of the membranes. This path is referred to as the in-pore pathway. By increasing the size of the pore in the r1NPGO-3 nm membrane, the contribution of the in-pore pathway increases and plays an important role. Furthermore, the simulation results show that in all rGO and rNPGO membranes, the interlayer space acts as a barrier for ions. Therefore, complete salt rejection is observed. Interestingly, by increasing the pore size in the r1NPGO-3 nm membrane, this membrane still maintains complete salt rejection. The observed phenomenon can be a result of very high water flux in this membrane. By increasing water flux, the presence of water molecules around Na+ and Cl- ions decreases. As a result, the formation of Na+Cl- ionic clusters is strengthened in such a way that these clusters do not have the ability to pass through large pores of 3.0 nm.

ZnO-ZnS Heterostructure as a Potent Photocatalyst in the Preparation of Some Substituted Chromenes and Remarkable Antigastrointestinal Cancer Activity

The nanosized hybrid material ZnO-ZnS was synthesized using the well-known sol-gel method, as a simple and environmentally friendly procedure. The material was then characterized using various techniques including FESEM, TEM, UV-vis, DRS, EDS, XRD, and FT-IR. The characterization studies revealed the generation of ZnO-ZnS nanoparticles with a mean size of around 25 nm. Moreover, DRS analysis provided a band gap of 3.05 eV for this nanomaterial. The photocatalytic properties of the ZnO-ZnS heterojunction was investigated in the synthesis of some substituted chromenes under mild reaction conditions. The results showed that the prepared nanophotocatalyst exhibits significantly higher activity compared to its individual components (ZnO and ZnS) and provides 73-87% yield with 0.01 g of ZnO-ZnS after 30 min. In addition, the nanophotocatalyst demonstrated a high reusability in the desired condensation reaction. The enhanced photocatalytic activity of ZnO-ZnS can be attributed to the slower recombination of the electron-hole pairs in this semiconductor material. The reactive species OH•, •O2-, and h+ are believed to play important roles in the photocatalytic system. Furthermore, cellular toxicity of ZnO-ZnS nanoparticles was evaluated on HCT-116 human gastrointestinal cancer cell line by MTT assay. The results proved a distinct reduction of cell viability, proofing cytotoxicity of nanoparticles on the cancer cells. This study highlights the potential of the nanoparticles against gastrointestinal cancer.

Photofixation of N2 to ammonia utilizing Ni@TPP-HPA nanocomposite under visible-light illumination

The production of ammonia as an important raw material in the chemical, agricultural, and food industries has been always a significant concern. However, conventional ammonia production methods require high energy consumption and costs. The photocatalytic rotes use green light sources and cost-effective photocatalysts to obtain ammonia from water under aerobic conditions and preventing production of greenhouse gases in the environment. To produce an effective heterogeneous catalyst, a new tetraphenylporphyrin-heteropolyacid (TPP-HPA) nanohybrid material is synthesized and loaded onto Ni nanoparticles in this work. Then, FE-SEM, EDS, XRD, and FT-IR analyses were applied to characterize the prepared nanohybrid material Ni@TPP-HPA. After that, the new inorganic-organic nanohybrid photocatalyst was introduced as an effective, environmental friendly, and recyclable mediator for N2 photofixation. The results showed that Ni@TPP-HPA is a good photocatalyst for the N2 fixation reaction and can be easily recycled without losing its activity for at least five runs. The Ni@TPP-HPA nanocomposite demonstrated the maximum ammonia generation by 2760 μmol L-1 g-1 under mild conditions when using methanol as a hole scavenger. Additionally, effects of solvent type, temperature, reaction time, irradiation source, solution pH, and other electron scavengers on the rate of NH4+ production were investigated and discussed.

A new formulation of Ni/Zn bi-metallic nanocomposite and evaluation of its applications for pollution removal, photocatalytic, electrochemical sensing, and anti-breast cancer

Nanocomposites have gained attention due to their variety of applications in different fields. In this research, we have reported a green synthesis of a bi-metallic nanocomposite of nickel and zinc using an aqueous extract of Citrus sinensis in the presence of chitosan (Ni/Zn@orange/chitosan). The nanocomposite was characterized using different techniques. We have examined various applications for Ni/Zn@orange/chitosan. The NPs were manufactured in spherical morphology with a particle range size of 17.34-90.51 nm. Ni/Zn@orange/chitosan showed an acceptable ability to remove dyes of Congo red and methyl orange from an aqueous solution after 80 min furthermore, it uptaking the drug mefenamic acid from a solution. Ni/Zn@orange/chitosan also exhibited great photocatalytic activity in synthesizing benzimidazole using benzyl alcohol and o-phenylenediamine. Ni/Zn@orange/chitosan was found as a potent electrochemical sensor to determine glucose. In the molecular and cellular section of the current research, the cells with composite nanoparticles were studied by MTT way about the anti-breast adenocarcinoma potentials malignant cell lines. The IC50 of composite nanoparticles were 320, 460, 328, 500, 325, 379, 350, and 396 μg/mL concering RBA, NMU, SK-BR-3, CAMA-1, MCF7, AU565, MDA-MB-468, and Hs 281.T breast adenocarcinoma cell lines, respectively. The results revealed the newly synthesized nanocomposite is a potent photocatalyst, dye pollution removal agent, and an acceptable new drug to treat breast cancer.

Delivery of anti-cancer and anti-depression doxepin drug by nickel oxide nanoparticles originated from the Cressa nudicaulis plant extract

In this research, the extract of Cressa nudicaulis plant has been used as a natural reducing agent in order to prepare stable nickel oxide nanoparticles (NiO NPs) using an aqueous solution of nickel(ii) nitrate under the sol-gel method. Additionally, NiO NPs were distinguished using FT-IR (Fourier transform infrared spectroscopy), XRD (X-ray diffraction), FESEM (field-emission scanning electron microscopy), EDS (energy-dispersive X-ray spectrometry), TEM (transmission electron microscopy), and UV-Vis (ultraviolet-visible spectroscopy) techniques. The integrated NiO NPs were loaded with doxepin drug as an effective medication for head and neck cancer as well as depression. Then, the ideal loading circumstances such as pH of the medium, response time, and amount of nanoparticles were assessed to attain that pH 6, time 12 h, and nanoparticle amount of 0.02 g are optimal to accomplish the best drug loading of around 68%. The drug release properties of drug-loaded NiO were also investigated at pH 6.5 and 37 °C. This study showed that ∼73% of the loaded drug was released after 80 h. Therefore, the introduced delivery system shows sufficiently long targeted-release properties. Besides, the MTT experiment was utilized to investigate the cytotoxicity of NiO NPs on the human hepatocellular carcinoma cell line Huh-7.

Synthesis, band gap structure and third order non-linear optical properties of zinc tungsten oxide nanocomposite using a single CW laser beam

In this study, a composite of zinc tungsten oxide nanoparticles (W-ZnO NPs) has been synthesized via mixing Na₂WO₄ and zinc acetate in water, followed by dropwise addition of NaOH. The synthesized W-ZnO NPs were characterized using measurement methods such as XRD, dynamic light scattering (DLS), Scanning electron microscopy (SEM) and UV-Vis. Also, the results were compared with the pure synthesized ZnO and WO₃ NPs. Non-linear optical properties of the synthesized composite were measured using the Z-scan technique with a continuous wave Nd-Yag laser. The negative non-linear absorption coefficient of the components was obtained which indicates that the saturation absorption occurred in this composite. In comparison with pure ZnO NPs, non-linear absorption decreases which can be attributed to the negligible optical response of WO₃ structures. Also, the negative value of the close aperture Z-scan curve shows that the thermal lensing effect is the main reason for the third-order non-linear refraction.

Magnetic nanoparticle-supported eosin Y salt [SB-DABCO@eosin] as an efficient heterogeneous photocatalyst for the multi-component synthesis of chromeno[4,3-b]chromene in the presence of visible light

Heterogeneous photocatalysts present a favourable procedure to realize green and eco-friendly organic reactions. We have demonstrated an SB-DABCO@eosin catalyst in a green one-pot multi-component protocol for the production of various chromeno[4,3-b]chromenes via condensation of aromatic aldehydes and dimedone under the photo-redox catalyst bearing eosin Y using visible light. The synthesized nanocatalyst was characterized using various physicochemical techniques such as FT-IR, XRD, EDX, UV-vis, SEM, TGA and DRS. The significant advantages of the present methodology include excellent yield, cost-effectiveness, easy work-up, 100% atom economy, broad substrate scope, easy separation and efficient recycling. Furthermore, the evidence showed that the investigated condensation reaction proceeds via a radical mechanism, which proved the need for reactive species such as OH˙ and ˙O₂ ^- in the photocatalytic process. In addition to the improved handling and process control, the yield of products and the rate of reactions have increased considerably in the present strategy. Reproducibility studies also guarantee good reusability and stability of the nanocatalyst for at least five runs.

Correction to New Task-Specific and Reusable ZIF-like Grafted H6P2W18O62 Catalyst for the Effective Esterification of Free Fatty Acids

[This corrects the article DOI: 10.1021/acsomega.0c00358.].

One-pot multicomponent green LED photoinduced synthesis of chromeno[4,3-b]chromenes catalyzed by a new nanophotocatalyst histaminium tetrachlorozincate

Histaminium tetrachlorozincate nanoparticles are prepared, characterized and applied as an effective and recoverable photocatalyst in the one-pot, green and multi-component synthesis of various chromenes by the reaction of dimedone and/or 1,3-cyclohexanedione, arylaldehyde and 4-hydroxycoumarin in high yields under solventless conditions at ambient temperature. This new catalyst is characterized by FT-IR, XRD, EDX, NMR, SEM and TEM techniques. The incorporation of histaminium ions into the framework of ZnCl₄²⁻ significantly affected the photocatalytic activity of tetrachlorozincate such that good reusability and recyclability are attained. Moreover, reactive species such as ˙O₂⁻ and hydroxyl radicals have proved to be active species in the presented photocatalytic reaction. In addition, the hot filtration test confirms enough stability of the photocatalyst and no significant leaching and destruction of the framework in the course of the reaction. The major advantages of the presented methodology include easy work-up, cost effectiveness, nontoxic nature, broad substrate scope, 100% atom economy, ease of separation, and environment friendly reaction conditions. Finally, the catalyst could be reused many times without significant loss of activity.

(His.)ZnCl₄ nanocatalyst is realized for the preparation of chromenes with a green LED. ˙O₂⁻, OH˙ and h⁺ are reactive species for this reaction. Complementary tests assured good stability and reusability of the nanophotocatalyst.

Eco-friendly synthesis of chromeno[4,3-b]chromenes with a new photosensitized WO3/ZnO@NH2-EY nanocatalyst

A new heterogeneous photoredox nanocatalyst WO₃/ZnO@NH₂-EY (EY: eosin Y) was fabricated and characterized employing some instrumental techniques such as XRD, FT-IR, ICP, TGA, and SEM. The photocatalytic efficiency of the prepared material was investigated in the preparation of various chromeno[4,3-b]chromenes via a simple and practical method. The chromene derivatives were prepared through the condensation of aromatic aldehydes, dimedone, and coumarin under an open-air atmosphere in the presence of a green LED under solventless conditions. The significant advantages of this new method include low reaction time, easy work-up, cost-effective, wide substrate scope, excellent yield, and complete atom economy of the final products. Moreover, the prepared photocatalyst could be frequently recovered up to four times with only a little decrease in the catalytic activity. Furthermore, the progress of the condensation reaction is demonstrated to occur via a radical mechanism, which shows that reactive species such as ˙O₂⁻ and OH˙ together with h⁺ would be involved in the photocatalytic process. Stability and reusability studies also warranty good reproducibility of the nanocatalyst for at least 4 runs. Eventually, a hot filtration test ensured that the nanohybrid catalyst is stable in the reaction medium and its catalytic activity originates from the whole undecomposed conjugated composite.

WO₃/ZnO@NH₂-EY is disclosed in the preparation of chromenes under air in the presence of a green LED. ˙O₂⁻, OH˙, and h⁺ are proposed as reactive species and hot filtration test assured stability and reusability of the nanocatalyst.

UV-visible light-induced photochemical synthesis of benzimidazoles by coomassie brilliant blue coated on W-ZnO@NH2 nanoparticles

Heterogeneous photocatalysts proffer a promising method to actualize eco-friendly and green organic transformations. Herein, a new photochemical-based methodology is disclosed in the preparation of a wide range of benzimidazoles through condensation of o-phenylenediamine with benzyl alcohols in the air under the illumination of an HP mercury lamp in the absence of any oxidizing species catalyzed by a new photocatalyst W–ZnO@NH₂–CBB. In this photocatalyst, coomassie brilliant blue (CBB) is heterogenized onto W–ZnO@NH₂ to improve the surface characteristics at the molecular level and enhance the photocatalytic activity of both W–ZnO@NH₂ and CBB fragments. This unprecedented heterogeneous nanocatalyst is also identified by means of XRD, FT-IR, EDS, TGA-DTG, and SEM. The impact of some influencing parameters on the synthesis route and effects on the catalytic efficacy of W–ZnO@NH₂–CBB are also assessed. The appropriate products are attained for both the electron-withdrawing and electron-donating substituents in the utilized aromatic alcohols. Furthermore, preparation of benzimidazoles is demonstrated to occur mainly via a radical mechanism, which shows that reactive species such as ·O₂⁻, OH˙ and h⁺ would be involved in the photocatalytic process. Stability and reusability studies also warrant good reproducibility of the nanophotocatalyst for at least five runs. Eventually, a hot filtration test proved that the nanohybrid photocatalyst is stable in the reaction medium. Using an inexpensive catalyst, UV-vis light energy and air, as a low cost and plentiful oxidant, puts this methodology in the green chemistry domain and energy-saving organic synthesis strategies. Finally, the anticancer activity of W–ZnO nanoparticles is investigated on MCF7 breast cancer cells by MTT assay. This experiment reveals that the mentioned nanoparticles have significant cytotoxicity towards the selected cell line.

A new photochemical route is disclosed in the preparation of a wide range of benzimidazoles in air under the illumination of an HP mercury lamp in the absence of any oxidizing species catalyzed by heterogenized W–ZnO@NH₂–CBB.

Bio-inspired synthesis of palladium nanoparticles fabricated magnetic Fe3O4 nanocomposite over Fritillaria imperialis flower extract as an efficient recyclable catalyst for the reduction of nitroarenes

This current research is based on a bio-inspired procedure for the synthesis of biomolecule functionalized hybrid magnetic nanocomposite with the Fe3O4 NPs at core and Pd NPs at outer shell. The central idea was the initial modification of magnetic NP by the phytochemicals from Fritillaria imperialis flower extract, which was further exploited in the green reduction of Pd2+ ions into Pd NPs, in situ. The flower extract also acted as a capping agent for the obtained Pd/Fe3O4 composite without the need of additional toxic reagents. The as-synthesized Fe3O4@Fritillaria/Pd nanocomposite was methodically characterized over different physicochemical measures like FT-IR, ICP-AES, FESEM, EDX, TEM, XPS and VSM analysis. Thereafter, its catalytic potential was evaluated in the reduction of various nitrobenzenes to arylamines applying hydrazine hydrate as reductant in ethanol/water (1:2) medium under mild conditions. Furthermore, the nanocatalyst was retrieved using a bar magnet and recycled several times without considerable leaching or loss of activity. This green, bio-inspired ligand-free protocol has remarkable advantages like environmental friendliness, high yields, easy workup and reusability of the catalyst.

Studying Adsorption and Cellular Toxicity of Boron Nitride Nanostructure versus Melphalan Anti-ovarian Cancer Drug

BACKGROUND

Inclusion of anticancer drugs into biocompatible nanoparticulate carriers decreases the general toxicity and improves the efficacy of clinical treatments due to the reduction of soluble circulating free drug.

METHODS

In addition, removal of emerging drug contaminants from wastewaters is a necessity that should be seriously attended. Boron nitride (BN) is choice in drug delivery because of many surprising properties. Here, boron nitride nanoparticles are prepared, characterized by Fourier-transform infrared spectroscopy (FT-IR) and x-ray diffraction (XRD) and used in the delivery of melphalan anti-cancer drug.

RESULTS

Then, density functional theory (DFT) calculations are carried out to study adsorption of this drug on the surface of pure boron nitride fullerene via familiar hybrid functionals B3LYP and B3PW91. In addition, the polarizable continuum model (PCM) calculations show that BN is stable in water.

CONCLUSION

Finally, the in vitro cellular toxicity and viability of BN nanoparticles was examined on ES-2 cancer cells. The inhibitory dose IC50 of the material confirmed an acceptable cytotoxicity and nanoparticles affected the average growth of ES-2 cancer cells.

Selective photocatalytic oxidation of aromatic alcohols to aldehydes with air by magnetic WO3ZnO/Fe3O4. In situ photochemical synthesis of 2-substituted benzimidazoles

Recently, visible light-driven organic photochemical synthesis has been a pioneering field of interest from academic and industrial associations due to its unique features of green and sustainable chemistry. Herein, WO3ZnO/Fe3O4 was synthesized, characterized, and used as an efficient magnetic photocatalyst in the preparation of a range of 2-substituted benzimidazoles via the condensation of benzyl alcohol and o-phenylenediamine in ethanol at room temperature for the first time. The key feature of this work is focused on the in situ photocatalytic oxidation of benzyl alcohols to benzaldehydes under atmospheric air and in the absence of any further oxidant. This new heterogeneous nanophotocatalyst was characterized via XRD, FT-IR, VSM and SEM. Short reaction time, cost-effectiveness, broad substrate scope, easy work-up by an external magnet, and excellent product yield are the major advantages of the present methodology. A number of effective experimental parameters were also fully investigated to clear broadness and generality of the protocol.

New Task-Specific and Reusable ZIF-like Grafted H6P2W18O62 Catalyst for the Effective Esterification of Free Fatty Acids

The catalytic esterification of free fatty acids is an important reaction pathway for chemical synthesis and biodiesel production, wherein efficient heterogeneous catalysts are sought to replace mineral acids. Herein, the esterification of oleic acid together with some familiar fatty acids is demonstrated with methanol over a heterogeneous heteropolyacid-functionalized zeolite imidazolate framework [H6-n P2W18O62 n-/ZIF(H n His.)+n ]. This new heterogeneous catalyst (named as HPA/ZIF(His.) throughout the text) with an average particle size of 80 nm was prepared via condensation of histamine with zinc chloride and characterized by means of Fourier transform infrared (FT-IR), X-ray diffraction (XRD), UV-vis, energy-dispersive X-ray spectrometry, Brunauer-Emmett-Teller, thermogravimetric analysis (TGA), inductively coupled plasma - optical emission spectrometry (ICP-OES), and scanning electron microscopy. According to the performed characterizations, an HPA loading of 40.5 wt % is obtained for HPA/ZIF(His.) from ICP-OES analysis. Moreover, a typical type-IV isotherm with similar adsorption-desorption properties as seen for ZIF-8 is attained. In addition, TGA measurement confirms less stability of HPA/ZIF(His.) compared to that of pure ZIF(His.). The catalytic performance of the nanomaterial is evaluated with respect to temperature, catalyst loading, and methanol/oleic acid ratio and leads to a high yield of methyl ester (>90%) under reflux for 4 h. The preliminary kinetic studies confirm a pseudo-first-order kinetic model for the esterification of oleic acid. To explore the scope of the HPA/ZIF(His.) catalyst in methyl ester production, other free fatty acids with various chain lengths are also successfully tested. Although the nanocatalyst loses a part of its activity during reuse, however, it is stable over at least four recycles as confirmed by XRD and FT-IR. Eventually, the response surface methodology (RSM) is used as a statistical modeling approach to get the best-optimized reaction conditions compared to the performed single-variable benchmarking experiments. Therefore, the central composite design (CCD) and RSM attained a platform to determine the relationship among the reaction time, acid/methanol molar ratio, and catalyst dosage.

The efficient biogeneration of Ag and NiO nanoparticles from VPLE and a study of the anti-diabetic properties of the extract

Vitex pseudo-negundo leaf extract (VPLE) is used to mediate the green biosynthesis of Ag and NiO nanoparticles in aqueous solutions under mild conditions. The synthesized nanoparticles, with a narrow size range and good distribution, are characterized by means of powder X-ray diffraction (PXRD), Fourier-transform infrared (FT-IR), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), and transmission electron microscopy (TEM) techniques. SEM and TEM micrographs proved formation of mostly spherical or ellipsoidal nanoparticles with little agglomeration, and the average particle size was less than 20–35 nm for both types of nanoparticle. Then, the protective role of VPLE toward the liver is assessed in streptozotocin-induced diabetic rats. For this purpose, diabetes is induced in rats through the intraperitoneal injection of streptozotocin, and VPLE is administered via oral gavage for 6 weeks. This study suggests that VPLE can ameliorate biochemical and structural changes in the livers of diabetic rats, showing that VPLE can improve the condition of rats with diabetic hepatopathy via a decrease in oxidative stress and an enhancement in the activity of antioxidant enzymes in the liver.

Vitex pseudo-negundo leaf extract (VPLE) is a mediator for the green biosynthesis of Ag and NiO nanoparticles, and its protective effects are assessed in the livers of streptozotocin-induced diabetic rats.

Photocatalytic efficacy of supported tetrazine on MgZnO nanoparticles for the heterogeneous photodegradation of methylene blue and ciprofloxacin

MgZnO@SiO₂-tetrazine nanoparticles were synthesized and their photocatalytic efficiency was demonstrated in the decomposition of ciprofloxacin and methylene blue (MB). This new heterogeneous nanocatalyst was characterized by FT-IR, XRD, UV-vis, DRS, FE-SEM, ICP, and CHN. Distinctive variables including photocatalyst dose, pH, and degradation time were investigated. Up to 95% photodegradation was gained under the optimum conditions (20 mg photocatalyst, 3.5 ppm MB, pH 9) by using MgZnO@SiO₂-tetrazine nanoparticles after 20 min. An elementary kinetic study was carried out, and a pseudo-first-order kinetic with a reasonably high rate-constant (0.068 min⁻¹) was derived for the MB decay. Photoluminescence (PL) studies confirmed that the photocatalytic activity of MgZnO@SiO₂-tetrazine was almost consistent with the Taugh plots. Thus, it can be envisaged that the photocatalytic activity is closely related to the optical absorption. Furthermore, a photoreduction mechanism was suggested for the degradation process. Addition of scavengers and some mechanistic studies also revealed that O₂˙⁻ is the original radical accounting for the degradation of MB, considering this latter compound as a model type pollutant. Finally, efficacy of the present photocatalytic process was assessed in the degradation of ciprofloxacin as a model drug under the optimum reaction conditions.

MgZnO@SiO₂-tetrazine nanoparticle was synthesized and its photocatalytic efficiency was demonstrated in the decomposition of methylene blue (MB) and ciprofloxacin.

One-Pot Synthesis of 1,8-Dioxodecahydroacridines and Polyhydroquinoline using 1,3-Di (bromo or chloro)-5,5-Dimethylhydantoin as a Novel and Green Catalyst under Solvent-Free Conditions

Solvent-free, one-pot synthesis of polyhdroquinoline and 1,8-dioxodecahydroacridine derivatives have been described via Hantzsch condensation of various aldehydes, ammonium acetate with (<em>i</em>) cyclic 1,3-dicarbonyl compounds and ethyl acetoacetate and (<em>ii</em>) cyclic 1,3-dicarbonyl compounds (2 mmoles) in a very simple, efficient, and environmentally benign method using 1,3-(dibromo or dichloro)-5,5-dimethylhydantoin as a cheap, non-toxic and neutral catalyst with up to excellent yields.