[Preparation of polyacrylonitrile/natural sand composite materials and analysis of adsorption properties of Pb(II) on it by FAAS].

Surfaces of natural sand particles were modified with (3-chloropropyl) trichlorosilane, so that bridging groups were introduced on the surfaces of natural sand particles; By grafting polyacrylonitrile onto the modified surfaces of the natural sand particles, a novelpolyacrylonitrile/natural sand composite material was prepared from the acrylonitrile, the azobisisobutyronitrile, the divinylbenzene and the modified natural sand particles, which are as functional monomer, initiator, either skeleton monomer or cross-linking agent and carrier respectively; the composite materials were characterized by using infrared spectroscopy and scanning electron microscopy; On the FTIR spectrum, the main characteristic peaks of various functional groups including nitrile, benzene ring, and silicon hydroxyl, which were from functional monomer, cross-linking agent and carrier respectively, were observed. On the SEM, two different cross section morphologies having different density which were from acrylonitrile and modified sand particles were observed; This proved that the polyacrylonitrile was decorated on modified sand particles during our preparation process. After preparing the composite materials, micro-column of separation and preconcentration was prepared using the composite materials as filler; the adsorption of some toxic heavy metal ions onto the composite materials was observed by flame atomic absorption spectrometry (FAAS); The results show that the adsorption of Pb2+ onto the composite materials was more stronger than the absorption of other toxic heavy metal ions, therefore, in this paper, the adsorption of Pb2+ onto the composite materials was mainly studied, at room temperature, when pH and flow rate of solution were 5. 4 and 4 mL x min(-1) respectively, the trace Pb(II) ions could be quantitatively adsorbed onto the composite materials; the maximum adsorption capacity of Pb(II) on the composite materials can reach 62.9 mg x g(-1). The column was eluted by 0.5 mol x L(-1) HCl and recovery of Pb(II) was more than 96%.