POLYELECTROLYTE ENHANCED REMOVAL OF MERCURY FROM MIXED WASTE DEBRIS

摘要

We have developed a process for dissolving and removing elemental and ionic forms ofmercury from solid surfaces. The process uses water-soluble chelating polymers (WSCP) thathave been designed for mercury-ion selectivity and performance in the presence of dilute acidand mild oxidant. After a solution of the polymer is used to selectively leach the solids (e.g.,mixed waste debris) and assist in the oxidation of elemental mercury, Hg(0), to ionic mercury,Hg(II), the resulting aqueous wash and rinse phases are treated by ultrafiltration withcommercially available membranes to concentrate the mercury-polymer complex. The metal ionconcentrate is released from the WSCP by adjusting the chemistry of the system, and thepolymer and the original permeate waters are recycled for further debris-leaching, greatlyreducing secondary wastes. The mercury concentrate is precipitated as the stable sulfide (HgS)for solid waste management.