高钙粉煤灰地聚合物固化/稳定重金属离子研究

Research on Solidification/Stabilization of Heavy Metal Ions by Class C Fly Ash Geopolymer

利用高钙粉煤灰研制地聚合物来固化/稳定重金属离子,研究了高钙粉煤灰地聚合物对重金属离子的固化/稳定效果,并进一步初探了高钙粉煤灰地聚合物对重金属离子的固化/稳定作用机制.研究表明:高钙粉煤灰地聚合物分别固化/稳定质量分数为0.025%的Pb(Ⅱ),0.025%的Cr(Ⅵ)和0.010%的Hg(Ⅱ)后,重金属离子的浸出浓度远低于规定的上限值,固化率均在98%(质量分数)以上;高钙粉煤灰地聚合物固化/稳定重金属离子后,有无定形的地聚合物凝胶及类沸石矿物CaAl2Si2O8.4H2O生成,重金属阳离子部分置换了Na+或Ca2+,被键合在地聚合物的网状结构中,引起了分子基团的显著变化;在无定形凝胶之间分别出现了细丝状、膨化状以及粒状产物.

Class C fly ash was used to prepare the geopolymer for solidification and stabilization of the heavy metal ions. The effect of the solidification and stabilization of heavy metal ions by class C fly ash geopolymer was investigated and its mechanism was discussed. The results show that after solidification and stabilization of 0. 025%（by mass） of Pb（ II ）,0. 025%（by mass）of Cr（VI） and 0. 010%（by mass） of Hg（ II ） by class C fly ash geopolymer,the leaching concentrations of heavy metal ions are far lower than the upper limit, and all the solidified/stabilized ratios of heavy metal ions reach 98%. Amorphous geopoly- rneric gel and similar zeolite mineral of CaAl2Si2O4·4H2O are formed when the geopolymer solidified/stabilized the heavy metal ions. Cations of heavy metal partly replace Na＋ or Ca2＋ and are bond in the geopolymeric network with the result that the molecule radical is significantly changed. When the geopolymer solidified/stabilized Cr （VI）, Pb （ II ）, and Hg （ II ） the filamentous product, swelling product, and granule product are observed among the amorphous gel.