Volume 236, Issue 1

Commercial Granulated Active Carbon (GAC) has been modified using 10 Gy dose Gamma irradiation (GAC10 Gy) for increasing its ability of air purification. Both, the raw and treated samples were applied for removing Chlorpyrifos pesticide (CPF) from ambient midair. Physicochemical properties of the two materials were characterized by Fourier Transform Infrared (FT-IR) and Raman spectroscopy. The phase formation and microstructure were monitored using X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM), supported with Energy-Dispersive X-ray (EDX). The Surface area measurement was detected using BET particle size prosometry. Obtained outcomes showed that, the maximum adsorption capacity, given by Langmuir equations, was greatly increased from 172.712 to 272.480 mg/g for GAC and GAC10 Gy, respectively, with high selectivity. The overall removal efficiency of GAC10 Gy was notably comparable to that of the original GAC-sorbent. The present study indicated that, gamma irradiation could be a promising technique for treating GAC and turned it more active in eliminating the pesticides pollutants from surrounding air. The data of equilibrium has been analyzed by Langmuir and Freundlich models, that were considerably better suited for the investigated materials than other models. The process kinetics of CPF adsorbed onto both tested carbon versions were found to obey the pseudo first order at all concentrations with an exception at 70 mg/l using GAC, where, the spontaneous exothermic adsorption of Chlorpyrifos is a strong function for the pseudo-first order (PFO) and pseudo second order (PSO) kinetics.

Mn(III) porphyrins display a unique UV–Vis spectrum: compared to the free-base and other metalloporphyrins, a strong red shift of the Soret-band and several extra bands can be observed in their spectra. To understand this behavior, we have recorded the UV–Vis spectra of differently substituted water-soluble Mn(III) porphyrins and conducted extensive theoretical investigations using time-dependent density functional theory. The calculated optical transitions, using the O3LYP functional, agree well with the measured absorption bands. According to the spectral interpretation, the Soret-band involves a mixture of L–L and ligand-to-metal charge transfer excitations, while the Q -bands and the higher-energy bands in the UV region correspond to pure LMCT as well as to ligand to metal-ligand mixed orbital excitations. The impact of the explicit and implicit water solvent on the spectral features is also discussed.

The alarming energy crises has forced the scientific community to work for sustainable energy modules to meet energy requirements. As for this, ZnO/g-C 3 N 4 nanocomposites with proper heterojunction were fabricated by coupling a proper amount of ZnO with 2D graphitic carbon nitride (g-C 3 N 4 ) nanosheets and the obtained nanocomposites were applied for photocatalytic hydrogen generation from water under visible light illumination ( λ  > 420 nm). The morphologies and the hydrogen generation performance of fabricated photocatalysts were characterized in detail. Results showed that the optimized 5ZnO/g-C 3 N 4 nanocomposite produced 70 µmol hydrogen gas in 1 h compare to 8 µmol by pure g-C 3 N 4 under identical illumination conditions in the presence of methanol without the addition of cocatalyst. The much improved photoactivities of the nanocomposites were attributed to the enhanced charge separation through the heterojunction as confirmed from photoluminescence study, capacity of the fabricated samples for •OH radical generation and steady state surface photovoltage spectroscopic (SS-SPS) measurements. We believe that this work would help to fabricate low cost and effective visible light driven photocatalyst for energy production.

The contact between aluminum foil (current collector) and LiTFSI salt electrolyte not only causes surface corrosion problems but also decreases the shelf life of the lithium-ion battery (LIB). In this work, we develop new composites coatings that are able to protect the aluminum foil from corrosion in the LIB. The new composites contain functionalized carbon nanotubes and polyaniline conductive polymer (FCNT/PANI). The performance of new composites is evaluated using various experiments including cyclic voltammetry (CV) and chronoamperometry (CA). The charge and discharge cycles of the LIB cell with scanning electron microscopy (SEM) are used to investigate the battery performance and the morphology of the aluminum foil. Towards anti-corrosion application, FCNT/PANI composites can successfully suppress the pitting corrosion of Al foil in 1.0 M LiTFSI electrolyte. The FCNT/PANI composite that uses 1.0% FCNT shows a superior rate capability and anti-corrosion performance when compared with composites that use the 0.2 and 0.5% FCNT. Further, the lithium-ion battery with coated Al foils with FCNT/PANI composites gives an excellent cyclability. Overall, these results confirm that the FCNT/PANI composites are a determining factor for lithium-ion battery efficiency.

Jellyfish-like graphene nanoflakes (GNF), prepared by hydrocarbon pyrolysis, are studied with electron paramagnetic resonance (EPR) method. The results are supported by X-ray photoelectron spectroscopy (XPS) data. Oxidized (GNF ox ) and N-doped oxidized (N-GNF ox ) flakes exhibit an extremely high EPR response associated with a large interlayer interaction which is caused by the structure of nanoflakes and layer edges reached by oxygen. The GNF ox and N-GNF ox provide the localized and mobile paramagnetic centers which are silent in the pristine (GNF p ) and N-doped (N-GNF) samples. The change in the relative intensity of the line corresponding to delocalized electrons is parallel with the number of radicals in the quaternary N-group. The environment of localized and mobile electrons is different. The results can be important in GNF synthesis and for explanation of their features in applications, especially, in devices with high sensitivity to weak electromagnetic field.

Poly( N -isopropylacrylamide-acrylamide-methacrylic acid) [p(NAM)] colloidal particles were synthesized and stabilized in aqueous medium. Ag nanoparticles were fabricated inside the p(NAM) system by in-situ reduction of Ag + ions with NaBH 4 to obtain Ag-p(NAM) organic–inorganic hybrid with fascinating catalytic properties. Various characterization techniques including XRD, FTIR, DLS, TEM and UV–visible spectroscopy were used to confirm the fabrication of p(NAM) and Ag-p(NAM) in aqueous medium. Loading of silver nanoparticles into the p(NAM) does not affect responsive properties of the colloidal system. Ag-p(NAM) system was used as catalyst for reduction of toxic dyes including methyl orange (MO) and Congo red (CR) from aqueous medium. Ag-p(NAM) catalyzed reduction of dyes was carried out under different reaction conditions to explore the catalytic process of degradation. The Ag-p(NAM) catalytic system is recyclable and reusable with almost same catalytic activity up to four cycles.

Interaction of sodium carboxymethylcellulose (SCMC) with cetyltrimethylammonium bromide (CTAB; cationic in nature) in H 2 O and additives (alcohols and diols) media has been investigated using conductivity technique. The micellar parameters such as critical micelle concentration ( cmc ), fraction of counter ion binding ( β ), thermodynamic parameters, transfer properties, and enthalpy-entropy compensation parameters of CTAB + SCMC mixture have been assessed in water and aq. alcohols/diols media. One cmc value was achieved for CTAB + SCMC mixtures in the entire circumstances and the attendance of SCMC disfavors the CTAB micellization. The cmc values were obtained to be greater in alcohols and diols media compared to H 2 O medium. The cmc values also exhibit a dependency on the solvent composition and temperature variation. In all the cases, the Δ G 0 m values were achieved to be negative which signifying the spontaneous formation of micelles while the extent of spontaneity is decreased in alcohols and diols media. Both the Δ H 0 m and Δ S 0 m reveal that hydrophobic, ion-dipole as well as electrostatic interactions are the proposed binding forces between CTAB and SCMC. The compensation parameters (Δ H 0* m and T c ) are in decent agreement with the biological fluid.

Colored wastewater is the most important problem of textile manufacturing factories, because it contains pollutants with complex structure and toxic, carcinogenic, and mutagenic properties which are non-biodegradable and sustainable in the environment. Reactive Red 198 (RR198) is one of the types of azo dyes which are widely used in the textile industries. Therefore, in this study, the rate of degradation and mineralization of RR198 by UV/US/H 2 O 2 /O 3 hybrid process was investigated. Influencing factors including: initial dye concentration (100, 200, 300, 400, 500 mg/L), contact time (12.5, 30, 47.5, 65, 82.5 min), pH (3, 5, 7, 9, 11), UV (125-W), H 2 O 2 (10, 20, 30, 40, 50 mg/L), US (160 KHz) and O 3 (33 mg/(L·min)) on the removal and mineralization efficiency of RR198 were investigated. Optimization and modeling of the process was done by CCD method. Based on the results of ANOVA analysis, most effective parameters on the RR198 removal efficiency were ozone, US, UV, time, initial dye concentration, pH, and H 2 O 2 , respectively, with an impact percentage of 96.86 and less than 1% for ozone and the rest parameters, respectively. Highest removal efficiency of RR198 was obtained by UV/US/H 2 O 2 /O 3 hybrid process. Optimal conditions for dye removal including: initial dye concentration of 200 mg/L, reaction time of 34 min, H 2 O 2 concentration of 27 mg/L and pH of seven were determined in the presence of ozone gas, UV, and US waves. In these conditions, the removal efficiency of RR198 and TOC were estimated to be 100 and 40.5, respectively. UV/US/H 2 O 2 /O 3 hybrid process as an advanced oxidation process (AOP) with advantages such as high performance and speed, no sludge production and toxic residues in the treated effluent containing hard biodegradable compounds such as RR198 from aqueous solutions, so can be recommended and used.