ester and N-[4-(2-amino-3-hydroxy-pyridin-6-ylazo)phenyl]-acetamide compounds were studied. The dissociation constants were determined potentiometrically. The thermodynamic parameters of dissociation were evaluated. Regression analysis is applied for correlating the different parameters. The results help to assign the solute-solvent interactions and the solvatochromic potential of the investigated compounds. The electronic character of the substituent and the chemical nature of the solvent are major factors for the observed solvatochromism. Nitroso Pyridin-6-ylazo Triazene Effect of solvents Potentiometry Spectrophotometry
Polymeric nanocomposite materials are very important materials because of their promised applications. However, many of their fundamental physical, mechanical, and chemical behaviors have not been quantified. Depending on the interface forces between polymer and clay, different configurations of polymer–clay nanocomposites exist: intercalated, flocculated, and exfoliated nanocomposites. In this paper, a study on the first two configurations is presented. Poly(vinyl alcohol) (PVA)–Cloisite® 20A was chosen for the intercalated system and PVA–Cloisite® 10A was chosen for the flocculated one. In both cases, the phyllosilicate clays used were organically modified by tallow‐triethanol‐ammonium ion. The morphology of the two systems was investigated by using X‐ray diffraction and nanoscanning electron microscopy. Although both confirmed the intercalation between PVA and 20A nanoclay, they confirmed the nonintercalation between PVA and 10A nanoclay. Another confirmation of the intercalation phenomena in PVA and 20A nanoclay was obtained from differential scanning calorimetry, which showed an increase in crystallinity upon intercalation. A main focus for the intercalated system was to study the effect of the nanoparticle's loading on the mechanical properties. Intercalation markedly affected both Young's modulus and the extent of elongation of the PVA–Cloisite® 20A nanocomposite. Young's modulus and tensile stress increased with the loading of the clay up to 2 wt%. For higher loading, opposite results were reported due to the agglomeration of nanoparticles and as a consequence of the formation of microvoids. J. VINYL ADDIT. TECHNOL., 23:181–187, 2017. © 2015 Society of Plastics Engineers
The present work aimed to study the physicochemical parameters and nutrient salts of El Mex Bay area to evaluate its composition since El-Mex Bay exposed to several kinds of human activities and receive different types of industrial pollutants. Various pollutants are dumped daily by industrial, agricultural and domestic sources over Alexandria coasts through several outfalls, El-Mex Bay one of these disposal sites (El-Mex Pumping Station). Surface and bottom water samples were collected seasonally during the period from September (summer) 2012 to April (spring) 2013. Salinity variation appeared in water quality changes, it ranged from 2.25‰ to 38.87‰ and from 26.21‰ to 39.64‰ at the surface and bottom water, respectively. Dissolved oxygen levels indicated poor aeration conditions along the water column, it is lower in most stations at surface layer (ND-3.15 mgl-1) than that in the bottom layer (0.79-6.28 mgl-1). The pH values of the study area at surface ranged (7.05-8.73), while at the bottom water ranged (7.18-8.45). Inorganic nitrogen species in El-Mex Bay water decreased in the order of NH 4 + > NO 3-> NO 2-. The measured nutrient content varied greatly as follows: NH 4 + , 4.73±5.70 to 99.27±72.53 µM; NO 2-, 0.72±0.43 to 4.34±3.43 µM; NO 3-, 1.33±1.01 to 31.68±24.59 µM Regional and seasonal variations of total nitrogen concentration in El-Mex Bay surface and bottom water ranged from 28.26± 14.87 to 335.12±226.66 µM. The concentrations of reactive phosphate (PO 4) and total phosphorus (TP) were in the ranges of 0.05-17.36 µM and 0.11-28.01 µM, respectively. As a result of nutrient enrichment, phytoplankton growth was very intensive, reflected by an abnormally high concentration of chlorophyll-a (annual average: 13.64±10.69 µg l −1 at surface and 3.96 ±2.42 µg l −1 at bottom water).
The regeneration of pore water (PW) nutrients was investigated and the contribution of benthic nutrient fluxes to the overlying bottom water (BW) was examined. Dissolved inorganic nutrients (
Starch-g-poly(acrylic acid)/Pterocladia capillacea–derived activated carbon (St-g-P(AA)/P-AC) composites were prepared via aqueous solution graft copolymerization using starch, acrylic acid, and activated carbon of red alga Pterocladia capillacea (0–10%) with N,N′-methylenebisacrylamide crosslinker and ammonium persulfate (NH4)2S2O8 initiator. Fourier-transform infrared (FTIR) spectroscopy, Brunauer–Emmett–Teller (BET), X-ray diffraction (XRD), thermogravimetric analysis (TGA), scanning electron microscopy (SEM), and energy dispersive X-ray spectroscopy (EDX) were used to characterize St-g-P(AA)/P-AC composites. Additionally, St-g-P(AA)/P-AC composites were investigated for methylene blue (MB) dye removal from water. The impact of the beginning concentration of MB dye, temperature, pH, and adsorption time on MB dye removal was examined. The maximum adsorption capacity obtained at pH 8 was 496.29 mg/g at 0.02 mg/L composites dose and 100 mg/L MB dye. The properties of adsorption were studied by the adsorption isotherm, kinetic, and thermodynamic models. The pseudo-first-order and Freundlich isotherm models demonstrated the kinetics and equilibrium adsorptions data, respectively. The maximum monolayer capacity (qm) was 1428.57 mg/g from Langmuir isotherm. Thermodynamic parameters indicated that the MB dye adsorption is exothermic physisorption and spontaneous. The results show that St-g-P(AA)/P-AC composites were effective for MB dye adsorption from water solution and could be recycled.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
customersupport@researchsolutions.com
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply.
Copyright © 2025 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.