Abstract
Recycling waste Styrofoam to new useful materials is essential to both the environment and humans. In this paper, waste Styrofoam (Sfm) was chemically converted via nitration and sulfonation procedures to the corresponding nitrated (Nit-Sfm) and sulfonated (Sulf-Sfm) derivatives for further use as potential cation exchangers. The proposed method is aimed to proceed via surface chemical modification without changing the core of the Styrofoam material. The degrees of incorporated cation exchange properties of Nit-Sfm and Sulf-Sfm adsorbents were determined and found to correspond to 8.2 and 10.6 mmol g(-1), respectively. The potential applications of Nit-Sfm and Sulf-Sfm as efficient adsorbents for the removal of Cd(II), Pb(II), and Hg(II) from aqueous solutions were explored in the presence of various experimental controlling factors using the batch equilibrium technique. The optimum pH for removal of Hg(II) was 4.0 and for Cd(II) and Pb(II) was 7.0, and the optimum contact time for complete removal of the evaluated metal ions was found in the range of 20-30 min. The maximum uptake capacity values of Hg(II), Pb(II), and Cd(II) were characterized in the ranges of 1950-2450 (pH 4.0), 750-1100 (pH 7.0), and 450-600 (pH 7.0) mu mol g(-1), respectively. The feasibility of using Nit-Sfm and Sulf-Sfm as packing materials in a multistage microcolumn technique for removal of Cd(II), Pb(II), and Hg(II) from industrial and drinking tap water samples was also explored, and excellent results were obtained as 80.0-90.2, 81.0-90.6, and 90.1-100.0 +/- 0.5-3.0%, respectively.