Mercury(II) Adsorption from Wastewaters Using a Thiol Functional Adsorbent

The removal of mercury(II) from wastewaters (coal-fired utility plant scrubber solutions) using a thiol functional organoceramic composite (SOL-AD-IV) is investigated. A simulant is employed as a surrogate to demonstrate the removal of mercury from real waste solutions. Equilibrium studies show a mercury uptake capacity of 500 mg/g at a low mercury concentration of 0.5 mg/L and 726 mg/g at saturation. Adsorption is observed to be independent in the pH range 3−5. The kinetic performance assessed on a recycle batch reactor shows a rapid rate of adsorption. Selectivity is found to be in the order Hg(II) > Pb(II) ∼ Cd(II) > As(V) > Cr(III). Regeneration of SOL-AD-IV is accomplished using 12 M HCl. Effluent mercury concentrations of <0.001 mg/L are achieved using a fixed-bed adsorption column. A stability test operated for 25 cycles indicates a capacity loss of <10%. A high potential is demonstrated for application for mercury cleanup of wastewaters.