title: Stabilization of chromium: an alternative to make safe leathers.
abstract: In this study, the original causes for hexavalent chromium presence in the leather were first evaluated by ageing of chromium(III) solutions and chrome tanned hide powder (50 degrees C, UV lightening at 340 nm, 0-36 h). The results showed that the trivalent chromium at instable coordination state was easy to convert into hexavalent chromium in high pH environment, and the probability of the oxidation increased in this order: multi-coordinate chromium, mono-coordinate chromium, and free chromium. For this reason, the process for stabilizing chromium in the leather was designed with the specific material, which was mostly consisted of the reducers and the chelating agents. After treated with the developed process, these leathers were aged (50 degrees C, UV irradiance as 0.68 W/m(2) at 340 nm, 0-72 h) to estimate chromium(VI) presence. Hexavalent chromium was not found in these treated leathers even if the leathers were aged for 72 h. Moreover, the physical and mechanical properties for the leathers varied little after treating. In a word, an inherent safe and effective process was proved to avoid the formation of hexavalent chromium in the leather.
authors.affiliation: National Engineering Laboratory for Clean Technology of Leather Manufacture, Sichuan University, Chengdu 610065, Sichuan, China. gongying 85@126.com
authors.forename: Ying
authors.initials: Y
authors.lastname: Gong
authors.forename: Xiaoling
authors.initials: X
authors.lastname: Liu
authors.forename: Li
authors.initials: L
authors.lastname: Huang
authors.forename: Wuyong
authors.initials: W
authors.lastname: Chen
mesh_terms: D000818:Animals; D002857:Chromium / Q000737:chemistry*; D003094:Collagen / Q000737:chemistry; D004785:Environmental Pollutants / Q000737:chemistry*; D007220:Industrial Waste / Q000032:analysis*; D007700:Kinetics; D011208:Powders; D012996:Solutions; D013056:Spectrophotometry, Ultraviolet; D013552:Swine; D013633:Tanning
chemical_list: D004785:Environmental Pollutants; D007220:Industrial Waste; D011208:Powders; D012996:Solutions; D002857:Chromium; D003094:Collagen