Wet blue goes green

摘要

A final year student, Sun Lei, at the British School of Leather Technology has been investigating possible substitutes for salt (sodium chloride) in the pickle for his dissertation. The study investigated the use of potassium and ammonium cations combined with sulfate and phosphate anions. The use of ammonium, phosphate and sulfate salts may seem a strange combination as they are considered pollutants in their own right, but a well designed biological effluent treatment plant should be capable of removing these from wastewaters.rnSodium chloride, on the other hand, is difficult and expensive to remove, and cannot be treated biologically.rnThe pickled material was chrome tanned and favourable results were achieved with potassium and ammonium phosphate. The salts, however, produce an aquamarine green colour in place of the traditional blue. Physical and chemical testing is ongoing and plans are underway to optimise the offers and test these pickle salts on glutaraldehyde tanned material.