EXTRACTION OF MERCURY(II) BY THIOUREA-BASED REAGENTS

The extraction of mercury(II) by novel thiourea-based extraction reage nts: nonylthiourea (NTH), dodecylthiourea (DTH), benzylthiourea (BTH), dinonylthiourea (DNTH) and dioctylthiourea (DOTH) from hydrochloric a cid solutions has been studied. The kinetics of extraction of Hg(II) b y these reagents were found to be very fast, where equilibrium can be achieved in two minutes. The extraction of mercury(II) extracted by DT H was studied in more details and the equilibrium data have been analy zed by graphical as well as numerical methods. The extraction of mercu ry(II) by DTH is explained by the formation of HgCl2DTH and HgCl2(DTH) (3) complexes. The other reagents have been also found to form the sam e type of complexes and the stability constants were inversely proport ional to the chain length. The stability constants of the HS(II) compl exes formed with different reagents are summarized in Table 3. Two of the reagents were found to be very selective for the extraction of mer cury over cadmium(II) and zinc(II).