Synthesis And Ion-exchange Behaviours Of Organic-inorganic Hybrid Ion Exchangers

Heavy metal wastewater produced from the industrial production need to deal with and cannot be discharged directly, since it is extremely easy to cause the surrounding soil and water polluted. The treatment for the wastewater includes two aspects, one is to remove toxic and harmful heavy metal ions, the other is to reues the metal and water resources.In this paper, with great consideration of features for the manganiferous wastewater produced from electrolytic manganese industry and the leaded wastewater derived from battery industry, some ion-exchange materials have been prepared and applied both in the removal of calcium ions to guide the smooth operation of manganese recovery and in the removal of lead ions from the wastewater.The synthesis of five pyrophosphate heteropolyacid salts were studied and optimazied by response surface experiments(RSM) methodology. The Ca-exchange preformances and behaviors including selectivity in containing manganese wastewater for the samples obtained under optimal conditions were studied and compared with two kinds of calcium molecular sieves in details, which indicated that zirconium tungstopyrophosphate ZWPP has better properties than the other four onesZWPP was characterized by means of Fourier transform infrared spectroscopy, scanning electron microscopy, X-ray diffraction spectroscopy, thermal analyzer and automatic specific surface area and porosity analyzer test, and its empirical expression was also figured out The results showed that ZWPP is a kind of nano particles with mesoporous and microcrystalline structures, BET specific surface area, and pore distribution were not changed before and after ion-exchange with Ca ions.Its calcium ion exchange process conformed to the pseudo-second order, Boyd kinetic model and the Langmuir single molecule layer adsorption model. That means exchange reaction is a chemical adsorption and liquid film diffusion controlled speed of reaction. Exchange process is endothermic and spontaneous in nature.Zirconium tungstopyrophosphate-polystyrene(ZWPP-PS) composited materials has been prepared and tested for its calcium or lead ion selectivity in containing manganese wastewater or lead wastewater. The result of removal lead ion shows that ZWPP-PS has the higher selectivity to lead.Structural characterization of ZWPP-PS was analysised and compared with ZWPP. The results showed that ZWPP-PS has bigger values in BET surface area, average pore size and pore volume than ZWPP does. The polystyrene composed with heteropoly acid salt via electrostatic interaction and benzene ring interfered the crystal growth through electron-withdrawing. Crystal growth was defected or distorted, which leads to ZWPP-PS amorphous characteristic.