弗雷德盐作为重金属絮凝-吸附剂 对电镀废水的深度净化

弗雷德盐是一种层状双金属氢氧化物（LDHs）——水铝钙石（铝-钙层状双金属氢氧化物）。它可以通过3种不同的机制即表面吸附、层间阴离子交换、记忆效应的重建（层板阳离子交换），从水介质中去除不同的重金属阳离子和阴离子污染物。开发了一种以液态含钙聚合铝（PACCa）和石灰乳为原料，采用氧化物-盐分解沉淀法合成水铝钙石的方法。PACCa中的络离子［Ca2Al（OH）6］+作为弗雷德盐的成核中心，在碱性条件下直接与溶液中的钙离子、铝离子、氯离子加合生长形成弗雷德盐晶体。该方法省去了成核反应，并由此降低了能耗、加快了反应速率。以弗雷德盐作为重金属絮凝-吸附剂对电镀废水进行了深度净化实验。

Friedel′s salt as flocculation-adsorbent of heavy metals on electroplating waste water deep purification

Friedel′s salt belongs to a kind of mineral-hydrocalumite（aluminum-calcium layered double hydroxide LDHs）.It can through three different mechanisms，namely the surface adsorption，interlayer anion exchange，and the reconstruction of the memory effect（cation exchange of layer board），to remove various heavy metals cationic and anionic pollutants from water. A oxide-salt precipitation synthesis method was developed with lime milk and liquid calcium containing polymerization alu- minum（PACCa） as raw materials，in which complex ion of ［Ca2Al（OH）6]+ as Friedel′s salt nucleation center，in alkaline conditions directly interaction with the Ca2+，Al3+，and Cl- in the solution，to take part in Friedel′s salt crystal growth.The procedure saved the nucleation reaction，thus had lower energy consumption and an accelerated reaction rate.On this basis，the experiment of Friedel′s salt as flocculation-adsorbent of heavy metals on the electroplating waste water deep purification was carried out.