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We report the synthesis of graphene oxide/nickel oxide/β-cyclodextrin (GO/NiO/β-CD) nanocomposite and the efficiency of the nanocomposite in decolourising two different dyes, methylene blue (MB) and methyl violet (MV). GO was prepared by modified Hummer's method while hydrothermal method was used for the preparation of GO/NiO/β-CD. The as-synthesised nanocomposites were characterised by X-ray diffraction (XRD), and Fourier transform infrared (FTIR) spectroscopy, Raman spectroscopy and high resolution transmission electron microscopy (HR-TEM). Photocatalytic degradation was carried out under solar light by monitoring the concentration of MB and MV dyes. Degradation reaction followed Langmuir-Hinshelwood pseudo first-order kinetic model. The apparent reaction rate constant (k) for MB increased as compared to MV under solar light irradiation. The MB showed better photocatalytic degradation efficiency by GO/NiO/β-CD composites. GO/NiO/β-CD nanocomposite has been very favourable for photocatalytic application. [ABSTRACT FROM AUTHOR]

Among carbon-based nanomaterials, carbon dots (CDs) have received a surge of interest in recent years due to their attractive features such as tunable photoluminescence, cost effectiveness, nontoxic renewable resources, quick and direct reactions, chemical and superior water solubility, good cell-membrane permeability, and simple operation. CDs and their composites have a large potential for sensing contaminants present in physical systems such as water resources as well as biological systems. Tuning the properties of CDs is a very important subject. This review discusses in detail heteroatom doping (N-doped CDs, N-CDs) and the formation of metal-based CD nanocomposites using a combination of matrices, such as metals and metal oxides. The properties of N-CDs and metal-based CDs nanocomposites, their syntheses, and applications in both chemical sensing and biosensing are reviewed. [ABSTRACT FROM AUTHOR]

Graphene oxide (GO) is a sp2 hybridized carbon atom arranged in a honeycomb lattice. Graphene is a new allotrope of carbon compound which could prime new openings in research fields. GO was successfully synthesized via Phyllanthus Emblica (PE) leaf. Structures, morphologies and photo catalytic activities of the as synthesized nanomaterial were determined by using X-Ray diffraction (XRD), UV-Visible spectroscopy, Field emission scanning electron microscopy (FE-SEM), Energy dispersive spectroscopy (EDS), Fourier transform infrared spectroscopy (FTIR), High resolution transmission electron microscopy (HRTEM) analysis. The photo catalytic activities of the as-synthesized GO were estimated for the degradation of malachite green (MG) and methyl violet (MV) in aqueous solution under replicated solar light. The photo catalytic degradation of GO was 94% for brilliant green and 99% for methyl violet in 120 min. [ABSTRACT FROM AUTHOR]

A simple spectrophotometric method is proposed for the rapid determination of mercury(II). The procedure is based on the hydrolysis of iodine in the presence of Hg(II), resulting in the formation of hypoiodous acid, which selectively oxidizes leucocrystal violet to crystal violet. The obtained violet dye shows maximum absorbance at 590 nm. Beer's law was valid in the concentration range of 0-1.0 μg mL-1. The effects of different parameters, i.e., pH, time, temperature were studied. The molar absorptivity for the system was 1.49×105 L mol-1 cm-1. The detection limit and the quantification limit were 2.6×10-3 μg mL-1 and 0.8×10-2 μg mL-1, respectively. The proposed method is simple, selective and was successfully applied for the determination of mercury(II) in several water samples. [ABSTRACT FROM AUTHOR]

Graphene is a radiant star in the field of nanomaterials. It has gained prominent interest since of its very good mechanical, thermal, optical and electronic possessions. The basic chemical reaction elaborate in the Hummer's method was the oxidation of graphite, during which harmful toxic gases used to emit. Nowadays green chemistry is blossoming in the field of nanomaterial. In present work, we fabricate graphene oxide (GO) through different agricultural wastes i.e., Rice bran (RB), Sugarcane bagasse (SB), Orange peel (OP), and mixture of all these three wastes i.e., tricomposite agro waste (TAW) were mixed with ferrocene which gave electron transfer reaction to synthesized GO and compared it. At last, we concluded that particle size obtained for OPGO (23.99 nm) > graphite (17.17 nm) > SBGO (15.5 nm) > RBGO (2.235 nm) > TAWGO (1.77 nm). These green strategies are biocompatible and cost effective too. Basic information of GO crystal was obtained by X-ray diffraction (XRD) for determination of crystal structure, scanning electron microscopy (SEM) for morphological study, high resolution transmission electron spectroscopy (HRTEM) used for determine particle size, fourier transform infrared (FTIR) spectroscopy for functional group detection, thermogravametric analysis (TGA)/differential thermal analysis (DTA) for determine thermal stability of GO. [ABSTRACT FROM AUTHOR]

Wastewater effluent from industries using dyes and pigments contains high concentration of organics. This paper presents a method for degradation of Fast sulphon black-F (FSB), a naphthylazo anionic dye, using Fenton and Fenton-like reaction systems. The degradation of the FSB dye using a Fenton reagent varied with the molar ratios of the reactants ([Fe(II)]:[H2 O2 ]) and pH. Removal of the dye was almost complete within 30 min and a maximum removal of ~99% was achieved with a molar ratio of 1:3.3 at pH 4.0. The degradation of the FSB dye was also carried out by the Fenton-like reaction system. Degradation of the FSB dye in the industrial wastewater sample by the Fenton reaction system was demonstrated by performing Jar tests. Magnetic iron(III) oxide was first prepared, followed by their characterization by X-ray diffraction and scanning electron microscopy techniques. A combination of magnetic iron(III) oxide and H2 O2 (i.e., a Fenton-like reaction system) produced slower degradation of the dye initially than the Fenton reaction system, but was able to degrade the FSB dye completely within 30 min. [ABSTRACT FROM AUTHOR]

The present paper reports the preparation of Cd 0.5 Pb 0.5 S thin films via a simple and inexpensive chemical bath deposition technique. Various preparation conditions were optimized for the deposition of good quality Cd 0.5 Pb 0.5 S thin films. The structural, morphological and optical properties of these films are discussed. The structural studies confirmed the polycrystalline nature of material with cubic structure. Using scanning electron microscopy, the surface morphology of the films was studied. The optical band gap of the film gets modified during annealing. The chemical composition of these thin films was studied by energy dispersive spectroscopy. The optical band gap energy for as-deposited and annealed Cd 0.5 Pb 0.5 S thin films were calculated and found in the range of 2.6 to 2.05 eV. [ABSTRACT FROM AUTHOR]

A sensitive spectrophotometric method for determination of dicofol in subparts per million levels is described, which is based on Fujiwara reaction. Dicofol on alkaline hydrolysis gives chloroform, which reacts with pyridine to produce red color. The color is discharged by addition of glacial acetic acid. The glutaconic aldehyde formed reacts with 4-aminoacetanilide to gave an orange-red dye which is extractable in 3-methyl-1-butanol. The extracted dye shows absorption maximum at 525 nm. Beer's law is obeyed in the range of 0.025–0.25 μg mL−1. Important analytical parameters such as time, temperature, reagent concentration, acidity etc. have been optimized for complete color reaction. Sandell's sensitivity and molar absorptivity for the system were found to be 0.000343 μg cm−2and 1.077 × 106L mol−1cm−1, respectively. The proposed method is satisfactorily applied to microlevel determination of dicofol in various environmental samples. [ABSTRACT FROM PUBLISHER]

The kinetics of micellar catalyzed oxidation of galactose by N-bromophthalimide was studied in the presence of acidic medium at 308 K. The oxidation reaction exhibits first-order kinetics with respect to oxidant ( N-bromophthalimide), fractional order with respect to substrate (galactose) and positive fractional order with respect to HClO 4 on the rate of reaction. The rate of the reaction increased with decreasing the dielectric constant of the medium. With a progressive increase in the concentration of CTAB, the rate of reaction increased and after reaching peak kobs, decreased at higher concentrations of CTAB. There catalytic roles are best explained by Berezin’s model. The influence of salts on the reaction rate was also studied. The various activation parameters have been calculated. The rate constant and binding constant with the surfactant have also been evaluated. A suitable mechanism consistent with the experimental findings has been proposed. [ABSTRACT FROM AUTHOR]

This work investigates the degradation of the azo dye solochrome dark blue (SDB) by measurement of the photocatalytic, sonocatalytic and sonophotocatalytic activities, under low ultrasonic frequency (40 kHz) and UV-C (254 nm) light, using Mn-doped ZnS semiconductor quantum dots (Mn2+:ZnS Qds) as catalysts, prepared by a simple chemical precipitation procedure. In order to study the different morphological and optical crystal properties, various characterization techniques were used, such as high resolution transmission electron microscopy, scanning electron microscopy, energy dispersive X-ray analysis, X-ray diffraction, N2 adsorption-desorption at −196 °C and ultraviolet-visible spectroscopy. The average particle size of the semiconductor Qds was in the range of 3–4 nm. The optimal parameters affecting dye degradation, such as the catalyst loading, solution pH, time of irradiation, initial concentration of dye, dopant concentration, ultrasonic power and frequency effect were evaluated. The synthesized catalytic material exhibited a high activity for sonophotocatalytic degradation of SDB (89%), larger than that observed for sonocatalysis (69.7%) or photocatalysis (55.2%) alone, which was due to the improved electron-holes separation, formation of more reactive radicals and enhancement of the active surface area. Qds showed good stability and reusability after five repeated cycles. Finally, the degradation products were identified by liquid chromatography-mass spectrometry (LC-MS). [ABSTRACT FROM AUTHOR]

A novel beads adsorbent, consisting of calcium alginate entrapped on magnetic nanoparticles functionalized with methionine (MFMNABs), was developed for effective elimination of arsenic from water. The material was characterized by FT-IR (Fourier Transform Infrared Spectroscopy), SEM (Scanning Electron Microscopic), XRD (X-ray Diffraction) and TEM (Transmission Electron Microscopy). The arsenic removal capacity of the material was studied by altering variables such as pH of the solution, contact time, adsorbent dose and adsorbate concentration. The maximal removal of As(III) was 99.56% under optimal conditions with an equilibrium time of 110 min and pH 7.0–7.5. The adsorption followed a second order kinetics and data best fitted the Langmuir isotherm with a correlation coefficient of R2 = 0.9890 and adsorption capacity (qm) of 6.6533 mg/g. The thermodynamic study showed entropy change (∆S) and enthalpy change (∆H) to be 34.32 J mol−1 K and 5.25 kJ mol−1, respectively. This study proved that it was feasible to treat an As(III) solution with MFMNABs. The synthesized adsorbent was cost-effective, environmentally friendly and versatile, compared to other adsorbents. The adsorption study was carried by low cost spectrophotometric method using N- bromosuccinimide and rhodamine-B developed in our laboratory. [ABSTRACT FROM AUTHOR]

Norfloxacin (NOFX), a broadly used fluoroquinolone antibiotic, has been a subject of great concern in the past few years due to its undesirable effect on human beings and aquatic ecosystems. In this study, novel Mn doped ZnS (Mn:ZnS) quantum dots (QDs) were prepared through a facile chemical precipitation method and used as photocatalysts for NOFX degradation. Prior to photodegradation experiments, morphological and optical parameters of the QDs were examined through transmission electron microscopy, scanning electron microscopy, energy dispersive X-ray analysis, Fourier transform infrared spectroscopy, ultraviolet-visible spectroscopy, fluorescence spectroscopy, Brunauer–Emmett–Teller analysis, and differential thermal and thermogravimetric analyses. Mn:ZnS QDs exhibited excellent properties of photodegradation, not only under UV irradiation but also in sunlight, which induced NOFX to photodegrade. The utmost photodegradation efficiency was obtained under optimal conditions (25 mL of NOFX, 15 mg/L, pH 10, 60 min UV irradiation, 60 mgs QDs), adopting first order kinetics. In addition, hydroxyl radicals produced by the conduction band electrons were found to be the primary reason dominating the transformation of NOFX in basic conditions, while holes, oxygen atoms, as well as the doped metal (Mn) enhanced the degradation. The QDs showed excellent reusability and stability in four repeated cycles. Finally, four different pathways were predicted, derived from the identified intermediates, with piperazinyl ring transformation being the primary one. It is expected that the synthesized Mn:ZnS QDs could be utilized as efficient photocatalytic materials for energy conversion and ecological remediation. [ABSTRACT FROM AUTHOR]