August 2018 Abstracts

Natural Sunlight Assisted Bentonite-ZnO Mixed Oxide Catalyst for Organic Pollutant Removal in Leather Post Tanning Wastewater with Solar Reactor

by  E. T. Deva Kumar, Sathya Ramalingam, K. Thirumalai, R. Aravindhan, M. Swaminathanb, and J. Raghava Rao

Organic pollutants in leather post tanning wastewater were degraded by the advanced oxidation process using semiconductive photocatalysis technique. A mixed oxide nanocatalyst Bentonite-ZnO was employed for the degradation process and the same has been prepared by hydrothermal method. The morphological and optical characteristics of the nanocatalyst was well characterized by using X-ray diffraction (XRD), Scanning Electron Microscope (SEM), Diffuse Reflectance Spectroscopy (DRS) and Fluorescence Spectrophotometer studies. The diffraction peak of the mixed oxide catalyst confirms the formation of wurzite structure of ZnO with the incorporation of bentonite clay particles. The SEM image displayed the formation of nanosized particles with porous spherical texture. The optical band gap of the bare ZnO (3.3 eV) and Bentonite-ZnO (2.5eV) catalysts were measured by DRS studies. A comparative study of photoluminescence spectra of ZnO and Bentonite-ZnO showed the suppression of charge carrier recombination in case of Bentonite-ZnO than bare ZnO. Existence of suitable charge carriers and vectorial transportation between bentonite and ZnO makes Bentonite-ZnO as an appropriate catalyst for degradation of organic pollutants present in leather post tanning liquor. The semiconductive photocatalysis on leather tannery post tanning wastewater was carried out in a specially designed pilot scale solar light reactor with Bentonite-ZnO, the results are compared with bare ZnO catalyst, where the degradation property with mixed oxide catalyst Bentonite-ZnO is better than bare ZnO. The decrease in COD with Bentonite-ZnO nanocatalyst is found to be 35.3% for three hours of continuous reaction under solar light. Such percentage of COD reduction suggest to offer this nanocatalyst treatment as preliminary step for better performance of further treatment process.

Register Today To Read Entire Article

3D Reconstruction Method of Leather Fiber Bundle Weaving Network

by Huayong Zhang and Tianduo Li

A 3D reconstruction method of leather fiber bundles and their weaving network was developed. The main steps included: leather metallographic sample preparation, sequential section images acquisition, registration and alignment, image preprocessing and 3D reconstruction. Metallographic sample preparation and layer-by-layer grinding methods were used to obtain sequential sections images. 3D-Doctor medical reconstruction software was used to implement the 3D reconstruction of leather fiber bundles. Features and cautions of each step were discussed, and some reconstruction results were displayed.

Register Today To Read Entire Article

The Reinforcement of Leather Split by Constructing an Interpenetrating Network via In-situ Recombination of PVA

by Weixing Xu, Hui Zeng, Jianfei Zhou, Ya-nan Wang and Bi Shi

In order to improve the quality and utilization of leather split, the strength of leather split should be enhanced. The in-situ polymerization of some monomers has proven to be an effective approach in constructing an interpenetrating network (IPN) in split and increasing its strength. But this method is almost unacceptable in practice because of the use of volatile monomers and organic solvents. In this study, a new method to construct the IPN structure in split, in-situ recombination, was developed. Polyvinyl alcohol (PVA) was used as compositing agent, and its molecular structure and modification conditions were optimized. Scanning electron microscope (SEM), potentiometric analyzer and differential scanning calorimeter (DSC) were used to characterize the mechanism of in-situ recombination. The results suggested that PVA with an average polymerization degree of 500 and an average alcoholysis degree of 88% could enhance the strength of split most effectively through compositing reaction of PVA and split in 5% PVA aqueous solution for 120 min under 80°C and pH 7.0. The IPN structure was successfully constructed between PVA and collagen fibers via in-situ recombination. A method to enhance the strengths of leather split with practical application was established.

Register Today To Read Entire Article

Fabrication, Characterization and Tanning Performances Investigation of a Novel Epoxide

by Xiaoyan Pang, Jianfei Zhou, Zhiwen Ding, Xuepin Liao and Bi Shi

A novel epoxide (IEGA) is synthesized using isophorone diamine (IPDA) and epichlorohydrin (ECH) as starting materials. The structure of IEGA is characterized by Fourier transform infrared (FT-IR) and 1H nuclear magnetic resonance (1H NMR). The tanning performance of IEGA is tested in ethanol from the aspects of the IEGA dosage, tanning temperature, pH value, and tanning time on shrinkage temperature (Ts) of sheep skin. It is found that under the optimized conditions with IEGA, the Ts of sheep skin tanned with IEGA is about 86°C, which is higher than normal epoxide tanned leather. Furthermore, SEM showed that IEGA tanned leather obtained better opened-up fiber structure than glycerol triglycidyl ether (GTE) tanned leather. Tanning mechanism investigation suggested that the cross-linking process should be predominately taking place among the -NH2 groups of collagen fibers by the epoxy groups of IEGA.

Register Today To Read Entire Article