A Chromium Discharge Minimizing Tanning Technology Assisted by O2 Low Temperature Plasma

Substantial quantities of solid and liquid wastes generate in the chrome tanning process, posing major environmental problem if not managed effectively. In order to minimize the emissions of chromium, a high exhaustion chromium tanning method was designed in this study. Low temperature plasma (LTP) technology has the characteristics of economy, pollution-free and high efficiency. The pioneering works were carried out by applying LTP to surface modification of natural leather before tanning process. The effects of different treatment time on micro-structure, chemical compositions, active groups, tanning absorption rate of leather fiber were studied. The SEM results showed that the leather surface was etched rougher. The XPS data showed that the O1s area ratios increased from 18.8 % to 27.6 % after O-2 LTP treatment. The optimal O-2 plasma treatment time is 10min. The results show O-2 LTP treatment effectively improves the chrome tanning absorption rate from 78.68 % of conventional process to 94.47 % of the novel process, which reduces the emission of heavy metal chromium and protects the environment.