Substitution influence of halo polyurethane foam on the removal of bismuth, cobalt, iron and molybdenum ions from environmental samples

Polyurethane foam was modified by the addition of halogen atoms and amino groups into the foam ma- trix in order to increase its polarity for the sorption of ionic species. The halo-modified sorbents (X-PUFs, X = Cl, Br or I) were characterized using FTIR, UV/Vis and Raman spectroscopy, EA, XRD and SEM. The average values of pH ZCP , maximum value of !pH (pH 9) and bulk DC conductivity for X-PUFs are 3.8, −1.9 and 2.6 °— 10 −5 Ω −1 cm −1 , respectively. The activity of the surface functional groups of X-PUFs were evaluated by the extraction of Bi(III), Co(II), Fe(III) and Mo(III) ions and extraction conditions including pH, shaking time, flow rate, temperature and initial metal concentration were optimized. Maximum ex- traction of those ions was achieved as their thiocyanate complexes in acidic medium (pH 1–3, 5–6 and 1.5 –2 mol L −1 H 2 SO 4 ) within 1 –30 min. A perfect isotherm curve with almost zero intercept (0.008), good correlation coefficient R 2 (0.973) was obtained. The values of LOD, LOQ and RSD ( n = 6) for the de- termination of Bi(III), Co(II), Fe(III) and Mo(III) ions are 2 ng L −1 , 7 ng L −1 and 0.75%, respectively. The sorption capacities of the tested metal ions onto Cl-PUF, Br-PUF and I-PUF are 0.16, 0.14 and 0.14 mmol g −1 , respectively. The accuracy of the procedure was verified by the analysis of food, ground water and pharmaceutical samples with recovery and average RSD values of 99 –100% and 2.39%, respectively.