Advanced Materials Research Vols. 821-822

Abstract: Kinetics of destruction of acid and mordant dyes in Fenton reaction was investigated by the use of spectral method. Inhibition of destruction of some mordant dyes was observed. A simple theory for describing this phenomenon was proposed, which is based on consideration of participation of iron ions in complex formation with mordant dye ligands. By the use of chemical software JChem (ChemAxon) it was found that mordant dye exhibiting stability in Fenton solution bears hydroxyl group with high dissociation constant, pK=2,57. On the contrary, another dye bearing hydroxyl with low dissociation constant, pK₁=6,65, does not exhibit any inhibition in oxidation process. UV-Vis spectral studies of the complexes of several mordant dyes prove correlations with their stability in Fenton reaction, however some dyes exhibit no relationship of this kind.

Abstract: The adsorption behavior of acid red G from aqueous solution onto raw bentonite (RB) and raw bentonite/ cationic starch (RB/CS) composite samples was investigated as a function of parameters such as contact time, salt concentration, initial dye concentration and temperature. The results showed that an amount of 0.12g of RB/CS composite could removal more than 90% of dye from 150ml of 100 mg L^-1 acid red G solution with a contact time of 60 min, at room temperature and no salt addition. The adsorption rate was fast and more than half of the adsorbed acid red G was removed in the first 10 min for RB and 5 min for RB/CS at room temperature.(C_o=100 mg L^-1)The results also indicated that the RB/CS composite had a shorter equilibrium time, higher color removal and stronger adsorption properties of acid red G than RB. In summary, the results suggests that RB/CS can be employed as a kind of low-cost material for the removal of acid red G from aqueous solution.

Abstract: Based on the carboxymethyl reaction of the medical cotton gauze, the paper analyzed absorbency and strength of the carboxymethyl medical cotton gauze. According to different concentrations of sodium hydroxide, molar ratio of sodium hydroxide and chloroactic acid, and mass ratio of chloroactic acid and cotton gauze, we found the best conditions on the excellent absorbency and strength of the carboxymethyl medical cotton gauze. It`s shown that, when the concentration of sodium hydroxide is 20%, the molar ratio of sodium hydroxide and chloroactic acid is 2.7:1, and the mass ratio of chloroactic acid and cotton gauze is 1.5:1, the substitution degree of the carboxymethyl cotton gauze will be 0.2132, the water absorption will be 370.5%, the salt absorption will be 292.3% and the breaking force will be 181.8N. After the carboxymethyl reaction of proper condition, the cotton gauze possesses the excellent mechanical properties based on the good absorbency.

Abstract: This paper stated the preparation of nano-modified polyacrylic acid sizing agents by adding self-made hybridized nano-TiO₂(titanium dioxide)/PSt(Polystyrene) and nano-SiO₂(silica dioxide)/PSt emulsion respectively into self-made polyacrylic acid sizing agents which called SW. Influences of two kinds of nano hybrid particles in nano-modified SW with different dosages on the strength of sizing yarns and mechanisms of increasing adhesion were analyzed. Experimental results showed that: 1. when two kinds of nano particles’ weight was about 1.1% of SW solid content, adhesion force of nano-modified sizing agents with Terylene/Cotton(T/C)fibers will reach the maximum,while when the weight of nano particles were less than 1.1% or more than 1.1%, the adhesion force between sizes and (T/C)fibers increased obviously or declined evidently; 2. scanning electronic microscope(SEM) photograph of roving chips displayed that fibers’ surface were completely covered by smooth size film and many hybrid nanoparticles between macromolecules of sizes, thus engendering huge bonding force between sizes and fibers, and increasing the slip resistance between fibers.

Abstract: A solvent-free process for the stereoselective preparation of (E)-ethyl-3-aryl-acrylates by grinding is described. Its advantages are easy workup, mild reaction conditions, high yields, and environmental friendliness.

Abstract: This paper describes the synthesis of two photochromic 2-indolyl-fulgides by stobbe condensation of the corresponding 2-acyl-1,3-dimethyl-indole derivatives with diethyl isopropylidene succinate in the presence of hexamethyldisilazane potassium. The overall yields was up to 41% for 3 steps. Both prepared compounds are sensitive to UV light and change colors upon irradiation. And the two fulgides can be switched back and forth 100 times without obvious degradation. Thermal stabilities of the fulgides in acetonitrile at room temperature for 30 days and at 80 °C for 12 h were measured using UV-vis and 1H NMR spectroscopy. The absorption spectra of both forms did not exhibit any sign of degradation. The NMR data indicated that no new compounds were detected. The utilization of these materials for use in photochromic textiles were discussed.

Abstract: Effects of several surfactants on the activity of acid cellulase enzyme were studied in this paper. The results show that addition of ionic surfactants to the enzyme decrease the enzymatic hydrolysis of cellulose sodium, while nonionic surfactants increase the activity of the enzyme. Among the surfactants examined, fatty amine polyoxyethylene ether (AC-1860) was the most effective. In the presence of 0.5 wt % of AC-1860, the activity of acid cellulose enzyme increased by 25.8%. This finding could lead to a reduction in the enzyme requirement for cellulose utilization.

Abstract: In order to increase the positively charge, solubility in water and grafted degree of chitosan, quaternary chitosan was synthesized with chitosan and glycidyl-trimethyl-ammonium chloride by the heterogeneous reaction. FT-IR was used to characterize the structure of the synthesized. The quaternary chitosan was then used to treat simulated acid dyeing wastewater, the effect of quaternary chitosan concentration, agitation mode and pH values on flocculation were discussed. The results indicated that the H⁺ in nucleophilic center-NH₂ was displaced by-CH₂CH(OH)CH₂N⁺(CH₃)₃ and the 2-hydroxypropyltrimethyl ammonium chloride chitosan (quaternary chitosan) was synthesized. When applied to treatment of acid dye waste water, the decolorization rate was 95.5%, and the COD removal was 86.4%.

Abstract: In order to increase the adsorption capacity of bentonite, a novel and cost-effective cationic starch (CS) intercalated raw bentonite (RB) composite matrix was prepared by controlling the weight ratio of RB and CS. The intercalated microstructure of the RB/CS composite was then characterized by Fourier transform infrared spectroscopy (FTIR), X-ray-diffraction (XRD), respectively. The acid red G adsorption from aqueous solution on RB/CS composite was studied using batch technique and compared with the adsorption onto RB under various parameters such as weight ratio of RB to CS, initial dye concentration, contact time, pH, and adsorbent dosage. It was found that more than 90% of the dye from 100 ml L^-1 solution was removed by RB/CS composite under the optimal conditions and it had a higher color removal efficiency and a shorter adsorption equilibrium time compared with the RB as the adsorbent for acid red G dye. In summary, the result showed that RB/CS could be as a kind of low-cost material for the removal of acid red G from aqueous solution.

Abstract: The adsorption of acid red G dye onto raw bentonite/cationic starch (RB/CS) and raw bentonite (RB) was investigated in aqueous solution in a bath system with respect to the adsorption kinetics and adsorption isotherms, respectively. For RB and RB/CS composite, the kinetic data showed that the kinetics of adsorption was best described by a pseudo-second-order expression than the pseudo-first-order. Adsorption isotherms of acid red G dye onto RB and RB/CS composite were determined with common isotherm equations such as the Langmuir and Freundlich models. The results showed that for RB/CS composite, the Langmuir model agreed very well with the experimental data, whereas the RB was fitted to both Langmuir and Freundlich models. In summary, the results showed that RB/CS could be employed as low-cost materials for the removal of acid red G dye from effluents compared to RB.