An alternative approach for grafting of acrylate esters from crosslinked polystyrene beads by ATRP and their modification for selective mercury extraction

摘要

Poly(methylmethacrylate) (PMMA) and Poly(ethyl acrylate) (PEA) have been grafted in high yields (i.e., 1000%) from 2-bromo, 2-methyl propionyl (BMP) groups on crosslinked poly(styrene beads), using copper-mediated atom transfer radical polymerization (ATRP) methodology. Graft reactions were first order with respect to the monomer concentrations in each case. Only minute amounts (2%) of free polymer formation have been observed. BMP groups have been anchored via acetoxy mercuration of the polystyrene beads. Aminolysis of the graft polyacrylate chains with ethanolamine yields corresponding hydroxyethyl acrylamides, which are capable of selective mercury binding from aqueous solutions. Aminolysed PMMA and PEA grafts show reasonable mercury uptakes (2.8 and 3.6 mmol g~(-1), respectively) with high selectivity over potentially contaminating ions such as Zn(Ⅱ), Cd(Ⅱ), Pb(Ⅱ) and Fe(Ⅲ) ions. Sorbed mercuries can be eluted by repeatedly treating with hot acetic acid. Although both polymers are also efficient for removal of trace (71 ppm) quantities of mercuric ions, the regenerated aminolysis product derived from PEA graft sample represents somewhat activity loss (27%) in the mercury sorption. Fortunately, aminolysed PMMA graft samples do not loose their activity even after the third regeneration. The material presented here is regenerable and has the advantage of mobility of the graft chains in the selective mercury removal from aqueous mixtures.