Preparation Of Functional Polymer Microspheres And Application Of Dealing With Zn²⁺、Pb²⁺and Cu²⁺ In Water

Porous polymer microspheres are widely used as new active carrier systems in medicine, chemical industry, chemical analysis, wastewater treatment, etc.Especially, in the field of wastewater treatment, porous polymer microspheres have advantageous in dealing with heavy metal ions in wastewater because of porous structure and the large surface area. Poly（styrene-divinylbenzene） microspheres are very efficient carrier materials both for their stable chemical properties--unsolvabe in acid, alkali, ethanol, acetone, hydrocarbons or other organic solvents, and stable porous structure. In this article, monodisperse PSt-DVB microspheres are prepared by the surfactant reversed micelles method.The produced modified porous microspheres are applied as an adsorbent in handling heavy metal ions in wastewater treatment. The performance of adsorption and elution is researched. And the produced porous microspheres behave effectively as an adsorbent to heavy metal ions.The uniformity of pore structure and particle size of PSt-DVB microspheres are two key factors that affect its application performance.Polymer microspheres are normally produced by traditional suspension polymerization. However, the traditional suspension process gives relatively large particles with a broad particle size distribution and pore size distribution. And they must be repeated screening before use. In this paper, the use of surfactant reversed micelles method makes it possiable to uniform the particle size and control the pore size. The effects of the amount of surfactant span80, the stirring speed and electrolytes types on the size of microspheres were both studied, so were the effects of the amount of surfactant span80 and the crosslinking agent content on the pore size.It was found that the Tgof miicrospheres is 170℃; with the increase of the amount of surfactant span80, the size of polymer microspheres particles decreases and then increases;high stirring speed causes microsphere particle size reduction; and this deduction also follows after high intensity of the electrolyte on the emulsion. With the increase of the amount of surfactant span80, polymer microspheres’ pore size increases; with the increase of theconcentration of cross-linking monomer, polymer microspheres’ surface area increases while the pore size diminishes.Under this experimental condition, when the amount of surfactant span80 is 40%, the stirring speed is 250 r/min, the mass ratio of DVB and ST is 1:3, using Na2SO4 as electrolyte, the porous microspheres which with good monodispersity（110-140μm）,larger specific surface（272.12 m2�'g-1） area and pore size（97.36nm） is obtained.Chloromethylation and sulfonation of prepared poly（styrene-divinylbenzene） microspheres were researched and the results of the characterization showed that the average chlorine content was 15.98% and degree of sulfonation was 22.33%. The EDTA and dithiocarbamic acid resin wereprepared by using modified poly（styrene-divinylbenzene） microspheres as parent. The resin was characterized by elemental analysis and infrared spectrum. The adsorption behaviors of Zn²⁺, Pb²⁺, and Cu²⁺ on the resin were also studied. The result supports that the orptimun p H for Zn²⁺ adsorption is 5.0 with saturated adsorption capacity under static conditions to be 0.885mmol/g. The removal rate was 98% after five cycles stripping using8% hydrochloric acid solution.Kinetic experiments showed that the resin adsorption rate is fast and it could achieve balance in 25 minutes. When the p H is 5.0, the saturated adsorption capacity for Pb²⁺ is 1.94mmol/g. 8% hydrochloric acid solution was used in stripping experiment and the removal rate was 92% after five cycles and kinetic experiments showed that the resin adsorption rate is fast and it could achieve balance in 32 minutes. When the p H is 4.0, the saturated adsorption capacity for Cu²⁺ is 1.34mmol/g. 8% hydrochloric acid solution was used as eluent and the removal rate was 94% after five cycles.Kinetic experiments showed that the resin adsorption rate is fast and it could achieve balance in 15 minutes. In ternary mixed solution of heavy metals, laden dithiocarbamate groups of microspheres presented selective adsorption of heavy metal ions. With the increase of p H, the removal rates of these three kinds of heavy metal ions were increased. When the quantity of resin changed, a certain competitive adsorption between heavy metal can be oberserved. The ability of competitive adsorption is Cu²⁺>Pb²⁺> Zn²⁺.