Degradation of Synthetic Reactive Dye Wastewater Based on Amine-Functionalized Polyacrylonitrile Fiber

A series of functional fibers have been prepared by modifying a commercially available polyacrylonitrilefiber (PANF) with polyamines such as ethylenediamine, tetraethylenepentamine and hyperbranched polyethylenimine (HPEI), and then used to coordinate with Fe3+, respectively, to produce Fe-modified PAN fiber complexes. The chemical structures of modified PANFs were verified by Fourier transform infrared spectroscopy (FT-IR). X-ray Diffraction (XRD) characterization showed that the inner crystal region of PANF was damaged during the introduction of amine groups.. Organic elemental analysis results to a certain extent demonstrate the success of modification. The coordination of Fe3+ was verified by Energy Dispersive Spectroscopy (EDS). The Fe-modified PAN fiber complexes were were used to eliminate the color from synthetic reactive dye wastewater (SRDW, including Reactive Red 195, RR 195) under normal conditions. This study presents a valuable route towards wastewater treatment in dyeing and finishing.

Designing of Collagen Based Poly(3-hydroxybutyrate-co-4-hydroxybutyrate) Scaffolds for Tissue Engineering

P(3HB-co-4HB) copolymer was modified using collagen by adapting dual solvent system. The surface properties of samples were characterized by Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), organic elemental analysis (CHN analysis), and water contact angle measurements. The effects of collagen concentration, scaffold thickness, and 4HB molar fraction on the hydrophilicity were optimized by the Taguchi method. The orthogonal array experiment was conducted to obtain the response for a hydrophilic scaffold. Analysis of variance (ANOVA) was used to determine the significant parameters and determine the optimal level for each parameter. The results also showed that the hydrophilicity of P(3HB-co-4HB)/collagen blend scaffolds increased as the collagen concentration increased up to 15 wt% with a molar fraction of 50 mol% at 0.1 mm scaffold thickness. The biocompatibility of the P(3HB-co-4HB)/collagen blend surface was evaluated by fibroblast cell (L929) culture. The collagen blend scaffold surfaces showed significant cell adhesion and growth as compared to P(3HB-co-4HB) copolymer scaffolds.

Preparation of N-alkylamides of highly methylated (HM) citrus pectin

N-Alkylamides of highly methylated (HM) citrus pectin (DM = 73%) were prepared using heterogeneous amino-de-alkoxylation (aminolysis) with five selected n-alkylamines. The reaction was carried out in N,N-dimethylformamide at 8°C (n-butylamine), 25°C (n-hexylamine), and 45°C (n-octylamine, n-dodecylamine and n-octadecylamine). All the derivatives were converted into acid forms by washing with acidic water-ethanol mixture. The products were analysed by organic elemental analysis, diffusion reflection FT-IR spectroscopy and by 13C CP/MAS NMR. Both FT-IR and NMR spectra indicate the presence of alkylamide substituents bound to pectin. The degrees of amidation (DA) of the derivatives and molar and mass reaction yields (Y_mand Y_n) were calculated based on the results of elemental analysis. The DA values of the N-alkylamides were 39–55% that corresponded to Y_nof 54–75%.