PREPARATION AND CHARACTERIZATION OF A MERCAPTAN DERIVATIVE OF CHITOSAN FOR THE REMOVAL OF MERCURY FROM BRINES

Chitosan, [(1,4)-2-amino-2-deoxy-beta-D-glucan], was reacted consecutively with epi-chlorohydrin and thiourea. Subsequent hydrolysis of the isothiouronium salt yielded the mercaptan derivative of chitosan, which scavenges mercury ions from solution in the presence of a considerably high concentration of chloride ions. Sulfur contents varied with reacting conditions and reached values up to 7.3%. The derivative is insoluble due to partial crosslinking of chitosan during the reaction with epichlorohydrin and was characterized by IR spectroscopy, solid-state C-13 NMR, thermal analysis and pyrolysis-mass spectrometry.