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The removal of water pollutants by photocatalysis is a promising technique, mainly due to its environmentally friendly and sustainable nature. In this study, the degradation of a recalcitrant organic pollutant, malachite green (MG), was investigated in water by a microstructured silver oxide photocatalyst. The silver oxide (Ag2O) microparticles (MPs) were synthesized by a low-cost, green method, mediated by green tea leaves extract. The surface, morphological and optical properties of the synthesized Ag2O MPs were determined by scanning electron microscopy (SEM), energy dispersive X-ray (EDX) analysis, X-ray diffraction (XRD) analysis, Fourier transform infrared (FTIR) spectroscopy, and ultraviolet-visible (UV-visible) spectrophotometry. The synthesized Ag2O MPs showed good photoactivity, represented by 83% degradation of malachite green (MG) ([C]0 = 0.4 mM, Ag2O loading = 0.1 g L−1) at neutral pH, in 3 h. Persulfate ions (PS) showed a strong synergistic effect on the efficiency of solar/Ag2O photocatalysis, represented by complete MG removal in 15 min, in the presence of 1.6 mM PS. The results revealed that solar/Ag2O, particularly solar/Ag2O/PS photocatalysis is a promising method for the elimination of toxic organic pollutants, such as malachite green, from the water environment. [ABSTRACT FROM AUTHOR]

Poly(3-hydroxybutyrate) grafted multiwall carbon nanotubes (g-MWCNTs) were synthesized while using purified MWCNTs (p-MWCNTs). Functionalization of MWCNTs was confirmed by FTIR, TGA, and XRD measurement. Comparative study of ammonia sensing performance of p-MWCNTs, carboxylated MWCNTs (a-MWCNTs), amine-functionalized MWCNTs (f-MWCNTs) and g-MWCNTs were performed. Among all g-MWCNTs showed a large variation in resistance over an entire concentration range of ammonia vapors. The calculated limit of detection for g-MWCNTs was found to be 0.236 ppm. Sensor response of g-MWCNTs reaches full saturation at 150 ppm ammonia. The f-MWCNTs and g-MWCNTs showed a highly reversible response to ammonia vapors at 250 ppm at 25°C. [ABSTRACT FROM AUTHOR]

Oxidation of the iodide ion is an important facet of the solar cells such as perovskite solar cells and dye‐sensitized solar cells. The rate of reaction undoubtedly depends upon several factors. Such parameters include reaction media, electrolyte, and the nature of solvents, and electrolyte. If these factors are optimized then the rate of the reaction can be controlled and could be used to get the maximum benefit out of it such as economically and industrially cost‐effective uses of the reaction and globally environmentally benign. We studied the kinetics of the oxidation of the iodide ion in the binary solvent system that consisted of 10% (v/v) tertiary butyl alcohol and water. The transition metal complex such as dicyanobis(phenanthroline)iron(III) oxidizes the iodide ion spontaneously without any external triggering with a fast rate at 293 ± 1 K. The reaction was probed under the pseudo–first‐order condition with an excess concentration of the iodide ion over dicyanobis(phenanthroline)iron(III) at 0.06 M ionic strength. The reaction was observed independent of the concentration of dicyanobis(phenanthroline)iron(III), that is, the zero order and third order with respect to the iodide ion in the selected solvent system. An overall third‐order was observed for the redox reaction. The value of the multiplication product of the molar absorptivity (ɛ), path length of the cuvette (b), and overall rate constant (k) was deduced to be 1.59 × 106 M−3 s−1. The observed zero‐order rate constant of the reaction was increased by the fractional (1.5) power of the concentration of protons in the excess concentration of acid 1 mM to 0.1 M. The multiplication product of ɛ⋅b to the fractional order rate constant (k′) was found 0.773 M−1.5 s−1 that confirms protonation of triiodide in acidic‐10% (v/v) tertiary butyl alcohol‐water. The effect of ionic strength showed a similar impact in different compositions of solvents such as 5, 10, and 20% (v/v) tertiary butyl alcohol‐water. The observed zero‐order rate constant was decreased upon increasing the ionic strength in each medium consisting of the binary solvent system. [ABSTRACT FROM AUTHOR]

Recent developments in nanoscience and technology have increased the importance of electron microscopes, specifically the scanning electron microscope (SEM) and transmission electron microscope (TEM), in almost all fields of science and technology. Electron microscopes provide information such as morphology, composition, crystal structure, and crystal phase. They have the capability to confirm the formation of required products and also provide information on any defects that may occur in the product. SEM and TEM have been used in various disciplines including chemistry, physics, biology, pharmacy, archaeology, materials science, agriculture, soil science, environmental science, forensic sciences, civil engineering, and electronic engineering. All these features and advantages of electron microscopes contribute to their importance in academic as well as industrial research, thereby enriching the development and growth of nanoscience and nanotechnology. [ABSTRACT FROM AUTHOR]

The present study is aimed at the synthesis and exploring the efficiency of a novel activated carbon incorporated polyindole (AC@PIN) composite for adsorptive removal of Malachite Green (MG) dye from aqueous solution. An AC@PIN hybrid material was prepared by in situ chemical oxidative polymerization. The physico-chemical characteristics of the AC@PIN composite were assessed using Fourier-transform infrared spectrometer, X-ray diffraction, scanning electron microscopy, energy dispersive X-ray spectroscopy, ultraviolet visible spectroscopy, and determination of point of zero charge (pHPZC). A series of adsorption studies was conducted to evaluate the influence of operational parameters such as pH, contact time, initial dye concentration, AC@PIN dosage, and temperature on dye adsorption behavior of developed composite. A maximum dye removal percentage (97.3%) was achieved at the pH = 10, AC@PIN dosage = 6.0 mg, initial dye concentration 150 mg L−1, and temperature = 20 °C. The kinetic studies demonstrated that the adsorption of MG on AC@PIN followed pseudo-second-order model (R2 ≥ 0.99). Meanwhile, Langmuir isotherm model was founded to be the best isotherm model to describe the adsorption process. Finally, the recyclability test revealed that the composite exhibits good recycle efficiency and is stable after 5 cycles. The obtained results suggest that AC@PIN composite could be a potential candidate for the removal of MG from wastewater. [ABSTRACT FROM AUTHOR]