碱洗—氧化钙煅烧两段法改性粉煤灰脱除废水中Cr（VI）的性能研究

Research on Removal of Chromium (VI) from Waste water on Fly Ash Modified with Alkali Washing and Calcium Oxide Calcining Method

摘要: 采用碱洗—氧化钙煅烧两段法对粉煤灰进行改性处理，利用红外光谱和扫描电镜对改性前后的粉煤灰的键位基团及形态进行表征，以投加量、pH值、煅烧温度和吸附时间作为变量对含Cr（VI）废水进行吸附处理。结果表明，当改性粉煤灰投加量为6 g/L、废水初始pH值为8、第二段煅烧温度为800℃、粉煤灰与氧化钙配比为3∶1时，吸附容量为16.06 mg/g，吸附效率达96.38%。动力学拟合过程表明该改性粉煤灰对Cr（VI）的吸附符合伪二阶动力学方程，以化学吸附为主，吸附过程具有持续性。

Abstract: Fly ash was modified by the alkali washing and calcium oxide calcining method The infrared spectrometer and scanning electron microscopy were used to characterize the bond groups and morphology before and after modification fly ash. The dosage, pH, calcined temperature and adsorption time were used as variable factors to adsorb Cr (VI)-containing waste water. The results showed that the removal rate of Cr(VI) can reach 96.38% under modified fly ash dosage at 6 g/L, initial pH value at 8, secondary calcination temperature at 800℃ and the ratio with calcium oxide at 3∶1. The adsorption capacity reached 16.06 mg/g. The kinetic fitting process shows that the adsorption of Cr (VI) by the modified fly ash conformed to the pseudo-second-order kinetic equation. This process was dominated by chemical adsorption and continuous.