Nanochemistry Research
Volume:4 Issue: 1, Winter-Spring 2019

This study was conducted to investigate the use of cubic LaMnO3 nano-perovskite as a green catalyst for the degradation of an aqueous solution of methyl orange under different conditions. Nanoscale cubic lanthanum manganite with the particle size of ~20 nm was successfully synthesized via citrate sol-gel method. The sample was characterized using the FT-IR and UV-Vis spectroscopy, XRD, SEM, and TEM analysis. The particle size of catalyst was calculated by Scherer equation using data of XRD analysis. The calculations along with an analysis of SEM and TEM confirm the formation of nanosized perovskite phase. The behavior of this nanocatalyst for degradation of an aqueous solution of methyl orange was investigated at wavelengths of 300-700 nm. The effects of the type and different amounts of acid, the absorbent content, pH, and temperature were studied for obtaining the optimal conditions of degradation. The prepared sample shows a suitable activity for the methyl orange degradation under dark (~90%) condition. The solar catalytic degradation is faster and goes up to about 100% after 60 min, indicating a different reaction pathway with less activation energy. Pre-visible-light degradation is the basis of catalytic activity of lanthanum manganite. A parallel photocatalytic reaction, however, is an almost simpler way to destroy the azo dyes over LaMnO3 nanoperovskite, which makes the LaMnO3 as a proper photocatalyst for degradation.

An efficient and rapid method for the synthesis of 3,4,5-substituted furan-2 (5H)-ones has been achieved through a three-component reaction of aniline, dialkyl acetylenedicarboxylate, and aromatic aldehydes using nano-colloidal silica-tethered polyhedral oligomeric silsesquioxanes with eight branches of 3-aminopropyltriethoxysilane (nano-colloidal silica @APTPOSS) as a superior catalyst under microwave irradiations. Microwave irradiation (MWI) is utilized for a diversity of organic syntheses due to short reaction times, easy workup and good yields. The use of highly efficient, economic and retrievable catalysts, with low or nil toxicity is required from the green chemistry viewpoint. Nano-colloidal silica@APTPOSS has been characterized by 1H NMR spectroscopy, dynamic light scattering (DLS), scanning electron microscope (SEM), energy dispersive spectroscopy (EDS) and thermogravimetric analysis (TGA). In this research, microwave irradiation is used as a green and complementary technique for preparation of furan-2 (5H)-ones. The reusability of the catalyst and little catalyst loading, excellent yields, short reaction times, using the microwave as green process and an alternative energy source are some benefits of this method.

In this study, for the first time, a simple immunosensor for ultrasensitive recognition of Human Chorionic Gonadotropin (hCG) in serum samples was fabricated by exploiting a simple approach. In this method, a low-cost and sensitive immunosensor was fabricated based on QDs-N-S/Au nanoparticles (NPs) modified Screen-Printed Carbon Electrode (SPCE). It seems that, QDs-N-S/Au NPs/ antibody as a biocomposite can be a good choice for the development of an impressive immunosensor. It must be said that in the modifying of immunosensor the length of the process have been reduced and the use of another substrates have been eliminated. pH and incubation time were optimized as two important parameters. Under the optimal conditions at modified SPCE, a linear communication in the range of 0.1 to 125 pg mL−1 and the detection limit of 12.5 fg mL−1 were obtained. The present procedure was utilized to the detection of hCG in real samples with the desirable results.

The main function purpose of nanobiosensors is to sense a biologically specific material and the kind of sensing platform and doping engineering has been an emerging topic and plays an important role in monolayer molybdenum disulfide (mMoS2). In this paper, we theoretically reveal the electronic structures of mMoS2 doped by 3d transition metals. Furthermore, adsorption of nucleic acid [Adenine (A), Cytosine (C), Guanine (G), Thymine (T) and Uracil (U)] on monolayers of modified transition-metal dichalcogenides (mTMDs) such as molybdenum disulfide (MoS2) and tungsten disulfide (WS2) as a sensing platform compared using first-principles density functional theory (DFT). We have found that all nucleobases were physisorbed on TMDs due to van der Waals (vdW) interaction and demonstrated that MoS2 is better than other TMDs and may also be used to detect nucleic acid sequence for medical science. Interestingly, the adsorption energies, band structures, electronic and magnetic properties of the transition metal (TM) atom adsorbed mMoS2 efficiently modified by absorbing different TM atoms which related to their number of d electrons. The order of binding energy of the nucleobases with MoS2 and WS2 are G > A > T > C > U using DFT D3 method.

Aflatoxins are a group of fungal mycotoxins produced mainly by molds, e.g. Aspergillus flavus and Aspergillus parasiticus. Among Aflatoxins, Aflatoxin B1 (AFB1) is the most toxic. Therefore, there is a prompt need for determination of AFB1 in food products. This paper reports an electrochemical aptasensor for accurate determination of AFB1, which was constructed by the using gold nanorod sensing interface and aptamer as specific recognition element. The synthesized gold nanorod was characterized by transmission electron microscopy and the electrochemical behavior of fabricated aptasensor was investigated by cyclic voltammetry and electrochemical impedance spectroscopy. Under optimized conditions the detection limit of proposed aptasensor was 0.3 pM with dynamic range of 1.0 pM – 0.25 nM. This aptasensor represents a remarkable improvement in terms of sensitivity, selectivity, reproducibility and stability when compared to other method for the determination of AFB1. This proposed sensor was successfully applied for the analysis of AFB1 in rice and blood serum samples.

Here, we successfully developed the undoped, Ni2+, Cu2+, and Zn2+ doped Zirconia nanoparticles (ZrO2 NPs) by a simple co-precipitation method at room temperature and characterized by various physicochemical measurement techniques to investigate their structure, morphology, and sizes of the particles. The bandgap energy values of doped and undoped ZrO2 NPs were estimated using optical absorption spectroscopy and it was found to be in the range of 4.1-4.4 eV. The UV (304-352 nm) and visible (402-415 nm) emissions and the oxygen vacancies and band gap of the particles were investigated through PL analysis. The structure, morphology, and well-dispersed particles with the size in the range of 10-40 nm of the prepared ZrO2 NPs were deliberated by SEM and TEM analysis. The Zr–O stretching vibration and Zr–O–Zr bending vibrations were confirmed through FTIR analysis. The catalytic reduction of 4-nitrophenol (4-NP) using NaBH4 as a reducing agent was studied by the prepared doped and undoped ZrO2 NPs. The efficient catalytic activity was observed in the presence of Cu2+ doped ZrO2 NPs than the Zn2+, Ni2+ doped and undoped ZrO2 NPs due to the small size and large surface area of the particles. The results showed that 97% conversion was achieved from 4-NP to 4-aminophenol (4-AP) within 90 min and stable up to 5 consecutive recycles.

Nano-Fe3O4 attached to Crosslinked sulfonated polyacrylamide (Cross-PAA-SO3H) as a superior catalyst has been utilized for the preparation of 3-alkyl-4-phenyl-1,3-thiazole-2(3H)-thione derivatives through a three-component reactions of phenacyl bromide or 4-methoxyphenacyl bromide, carbon disulfide and primary amine. The best results were gained in ethanol and we found that the reaction gave convincing results in the presence of cross-PAA-SO3H@nano-Fe3O4 (5 mg) under ultrasonic irradiation. The structures of the products were fully established on the basis of their 1H NMR, 13C NMR and FT-IR spectra. A proper, atom-economical, straightforward one-pot multicomponent synthetic route for the synthesis of 1,3-thiazoles in good yields has been devised using crosslinked sulfonated polyacrylamide (Cross-PAA-SO3H) tethered to nano-Fe3O4. The remarkable advantages of this methodology are short reaction times, high to excellent yields, operational simplicity, low catalyst loading and reusability of the catalyst. The catalyst has been characterized by Fourier-transform infrared spectroscopy (FT-IR), scanning electron microscope (SEM), X-ray powder diffraction (XRD), energy dispersive spectroscopy (EDS), thermo- gravimetric analysis (TGA) and vibrating-sample magnetometer (VSM).

The aim of the present study is to demonstrate how mesoporous nanostructures of Zinc Sulfide (ZnS) will precipitate in an ethanol media in spite of negligible solubility of Sodium Nitrate (Na2S), which is role-played as sulfur precursor. On the following, the role of such synthesizing method on the photocatalytic behavior of ZnS mesoporous nanostructures has been investigated. Characterization of the synthesized samples was carried out through X-ray diffraction patterns (XRD), Furrier Transformation Infrared Spectroscopy (FTIR), Transmission Electron Microscopy (TEM), Diffuse Reflectance Spectroscopy (DRS), Field Emission Scanning Electron Microscopy (FESEM) and N2 adsorption – desorption analysis. Formation of NaNO3 in assistance with negligible solubility of Na2S in ethanol enhances the stability of ZnS nanoparticles. Besides, formation of NaNO3 as well as sonication process can induce mesopores in the ZnS nanoparticles. Changes in the critical micelle concentrations (CMCs) of CTAB had impacts either in the lattice properties or in the textural structure of the mesopores of the synthesized samples. An attempt was made to explain how enhancement of CMCs values made crystallite size decreased and subsequently lattice strain increased. The photocatalytic behavior and the adsorption capacity of the ZnS mesoporous structures were studied through methylene blue degradation from aqueous solution. It was found that adsorption capacity and photocatalytic efficiency of synthesized samples were improved by modification of CMC values of CTAB. Findings were in compatibility with the band gap energy values and water droplet contact angle measurements. This study is finalized with explaining how the synthesized photocatalysts remove contaminations under ultraviolet irradiation.

The burden of life on the earth is the source of biological contamination in water. Nanotechnology has promising contributions in control of microbial contaminations and medicinal plants further increase these properties. Presently, copper acetate and nickel oxide nanoparticles were synthesized using 1mM solution of each with Ziziphus mauritiana leaves extract as reducing agent. Nanoparticles were characterized through UV vis-spectroscopy and scanning electron microscope and antimicrobial properties were determined through disc diffusion method. Copper and nickel nanoparticles were adsorbed on filter paper strips and used in biological water purification. The pre and post treatment viable bacterial count of water was analyzed statistically. Absorbance peaks of copper acetate nanoparticles were recorded at 650nm while for nickel oxide nanoparticles at 250nm. The particles size of copper acetate nanoparticles through SEM was calculated up-to 47.90nm while 48.40 nm nickel oxide nanoparticles at resolution of 15kv x 60,000. The application of nanoparticle coated strips in water indicated a significant reduction of 24% and 18% in total plate count of water samples during first 2hrs of treatment. Study concluded the antimicrobial properties of copper acetate and nickel oxide nanoparticles and pawed a path for use of nanoparticles coated membranes in filtration units for biological purification of water.

In this study, we have reported the green synthesis magnesium ferrite using tragacanth gel by the sol-gel method without using any organic chemicals. The sample was characterized by powder X-ray diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR), vibrating sample magnetometer (VSM) and scanning electron microscopy (SEM). The X-ray powder diffraction (XRD) analysis revealed the formation of cubic phase ferrite MNPs. Magnetic analysis showed that the MgFe2O4 had a superparamagnetic behavior with a saturation magnetization of 14 emu/g at room temperature. The present catalyst displays high photocatalytic activity for the removal of malachite green dye under irradiation with visible light. The effects of MgFe2O4 dosage, initial dye concentration and visible light irradiation on dye degradation were evaluated. The results demonstrated that the catalyst can degrade ca. 98% of the malachite green dye. The catalyst can be easily recovered by a simple magnetic separation and can be recycled six times with no significant loss of photocatalytic activity.

Nano-structured copper oxides were successfully prepared through direct calcination of 1D ladderlike metal-organic framework [Cu2(btec)(2,2'-bipy)2]∞, (btec = 1,2,4,5-benzenetetracarboxylate and 2,2'-bipy = 2,2'-bipyridine) and porous coordination polymer [Cu(BDC)(bipy)](BDCH2), (BDC = 1,4-benzenedicarboxylate; bipy = 4,4'-bipyridine). The nano-structure of the as-synthesized samples are characterized by X-ray powder diffraction (XRPD), Energy dispersive X-ray microanalysis (EDX) and scanning electron microscopy (SEM). Different reaction conditions were discussed. This study demonstrates the metal-organic frameworks may be adequate precursors for the preparation of nanoscale materials with different and remarkable morphologies. Abstract Nano-structured copper oxides were successfully prepared through direct calcination of 1D ladderlike metal-organic framework [Cu2(btec)(2,2'-bipy)2]∞, (btec = 1,2,4,5-benzenetetracarboxylate and 2,2'-bipy = 2,2'-bipyridine) and porous coordination polymer [Cu(BDC)(bipy)](BDCH2), (BDC = 1,4-benzenedicarboxylate; bipy = 4,4'-bipyridine). The nano-structure of the as-synthesized samples are characterized by X-ray powder diffraction (XRPD), Energy dispersive X-ray microanalysis (EDX) and scanning electron microscopy (SEM). Different reaction conditions were discussed. This study demonstrates the metal-organic frameworks may be adequate precursors for the preparation of nanoscale materials with different and remarkable morphologies.