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构建离子交换膜化学反应器,研究其在无外加电压作用下去除饮用水中Cr(Ⅵ)的效果。结果表明,当原水Cr(Ⅵ)初始浓度为0.019 2mmol/L,补偿溶液NaCl浓度为100mmol/L,流量为2.5mL/min时,给体池Cr(Ⅵ)分离去除率为86.2%。随着给体池共存离子浓度的增加,其对Cr(Ⅵ)交换竞争作用加强,给体池Cr(Ⅵ)分离去除率逐渐降低;在相同共存离子浓度条件下,3种共存离子对Cr(Ⅵ)分离效果的影响程度依次为SO24-、NO3-、Cl-。补偿溶液NaCl浓度由1mmol/L增加至100mmol/L时,Cr(Ⅵ)分离去除率基本不变,但是Don-nan分离12 h后化学反应池Cr(Ⅵ)浓度由0.001 5 mmol/L增加至0.016 0 mmol/L。Cr2O27-离子交换过程可用一级反应动力学方程描述,离子交换反应速率常数为0.014 2 min-1。加入10 mmol/L共存离子Cl-、NO3-和SO24-后,离子交换反应速率常数分别降低至0.013 5min-1、0.010 5 min-1和0.008 9 min-1。Cr(Ⅵ)在化学反应池中浓缩富集,离子交换26 h后化学反应池Cr(Ⅵ)浓度为0.069 8 mmol/L,可通过投加硫酸亚铁还原剂和碱液将其去除。
An ion exchange membrane chemical reactor was constructed to study its effect of removing Cr (Ⅵ) in drinking water without voltage. The results showed that when the initial Cr (Ⅵ) concentration was 0.019 2 mmol / L, the NaCl concentration was 100 mmol / L and the flow rate was 2.5 mL / min, the removal rate of Cr (Ⅵ) in the donor pool was 86.2%. With the increase of ion concentration in donor pool, the competition of Cr (Ⅵ) exchange was enhanced and the removal rate of Cr (Ⅵ) in donor pool decreased gradually. Under the same coexisting ion concentration, Ⅵ) The effect degree of separation effect is SO24-, NO3-, Cl-. The removal rate of Cr (Ⅵ) remained unchanged after NaCl concentration was increased from 1 mmol / L to 100 mmol / L, but the concentration of Cr (Ⅵ) in chemical reaction tank increased from 0.001 5 mmol / L to 0.016 0 mmol / L. Cr2O27- ion exchange process can be described by the first-order kinetic equation, the ion exchange reaction rate constant 0.014 2 min-1. After adding 10 mmol / L of coexisting ions Cl-, NO3- and SO24-, the rate constant of ion exchange reaction decreased to 0.013 5min-1, 0.010 5 min-1 and 0.008 9 min-1, respectively. Cr (Ⅵ) enriched and concentrated in the chemical reaction tank. After 26 h of ion exchange, the concentration of Cr (Ⅵ) in the chemical reaction tank was 0.069 8 mmol / L, which could be removed by adding ferrous sulfate reducing agent and lye.