Mercury sorption by ''non-functional'' crosslinked polyacrylamides

Three powdered crosslinked ''non-functional'' polyacrylamide gels and four spherical crosslinked polyacrylamide resins have been prepared by aqueous solution and inverse suspension polymerisation respectively. Methylene bisacrylamide, ethylene bisacrylamide and N,N-bisacryloyl piperazine have been used as crosslinkers. The seven polymers readily and rapidly sorb Hg(II) quantitatively from a 100 ppm solution (pH 6.4), and maximum Hg capacities are similar to 1.5 g per g of dry polymer. Quantitative stripping has been demonstrated using hot acetic acid. Qualitative experiments with linear polyacrylamide show that other metal ions NI(II), Cu(II), Co(II), Cd(II), Zn(II), Fe(II) and Fe(III) are unaffected and so the resins offer the prospect of a very cost effective selective sorbent for Hg removal and recovery.