In this research, a syntan containing active chlorine groups (SACG) was synthesized by the condensation of phenol sulfonic acid condensation product (PSAC) and cyanuric chloride (TCT). The structure and composition of as-received syntans were characterized by Fourier transform infrared spectrometer (FT-IR), nuclear magnetic resonance spectroscopy ( 1 H-NMR), and gel permeation chromatography (GPC). The thermal properties and morphology of the tanned leather were analyzed using thermogravimetric analysis (TGA) and scanning electron microscope (SEM). The results indicated that the multi-point active chlorine groups in syntans had an excellent cross-linking effect on collagen fibers, which increased the shrinkage temperature of leather to 81.6 °C. The tensile strength , the tearing strength, and the thickening rate of the tanned leather were 14.26 MPa, 42.56 N/mm, and 78.3%, respectively. The tanned leather exhibited flat and fine grain. The collagen fibers showed uniform dispersion. Besides, the SACG had remarkable environmental benefits compared with the traditional chrome tanning system by significantly reducing the content of chemical oxygen demand (COD), total solids (TS), dissolved solids (DS), suspended solids (SS), chloride, and total chromium analyses (T Cr ) in tannery wastewater and thus could be applied to non-pickling tanning system. Moreover, the SACG tanning technology is a promoting chrome-free tanning technology because of the facile, cost-effective, and environment-friendly performance, suggesting that this technology has great potential to be widely applied in leather manufacturing.
Shuyuan Jin,Jingwei Gong,Chao Yang,Yi Cheng,Jie Lu,Qiang Yang,Haisong Wang
Effective hydrolysis of cellulose to glucose is a crucial step to utilize lignocellulosic biomass for fuels and chemicals. In this study, we adopted the simple Blanc chloromethylation of commercially available Amberlyst-15 to fabricate enzyme-mimic solid acid (A-15-Cl) for cellulose hydrolysis. The results indicated that the chlorine group in A-15-Cl adsorbed cellulose and particularly oligosaccharides through hydrogen bonding while the sulfonic acid group cleaved the β-1,4 glycosidic bonds in cellulose and oligosaccharides. Due to the synergistic effect between the chlorine (adsorbing cellulose) and sulfonic acid (hydrolyzing cellulose) groups, A-15-Cl effectively hydrolyzed cellulose in water achieving a 67.2% glucose yield at 170 °C in 2 h. Moreover, A-15-Cl can be readily separated from the reaction medium by an 80-mesh screen for reuse at least five times without significant loss of catalytic activity .
Jing-Wen Zhang,Lun Pan,Xiangwen Zhang,Chengxiang Shi,Ji-Jun Zou
Carbon nitride (C 3 N 4 ) is promising for photocatalytic hydrogen production , but photogenerated electrons and holes in C 3 N 4 usually tend to exist as excitons due to intrinsic Coulomb interactions making its photocatalytic activity unsatisfactory. Herein, a well-designed intramolecular C 3 N 4 -based donor-acceptor (D-A) photocatalytic system was constructed to promote exciton dissociation. Due to its good chemical compatibility with melamine and appropriate sublimation property, 2-amino-4,6-dichloropyrimidine unit was chosen as the monomer to react with melamine to construct intramolecular D-A system (CNCl x ). The hydrogen evolution rate of CNCl 0.15 is 15.3 times higher than that of bulk C 3 N 4 under visible light irradiation, with apparent quantum efficiency of 13.6% at 420 nm. The enhanced activity is attributed to introduced electron-withdrawing −Cl group as terminal group in the resulted CNCl x samples, which can build internal electric field to promote the exciton dissociation into free electron and hole. In addition, lower work function value of CNCl x samples indicates that internal electric field can help free electrons and holes transfer to the surface of CNCl x samples for photocatalytic reaction.
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