Limits of RO recovery imposed by calcium phosphate precipitation
Limits of RO recovery imposed by calcium phosphate precipitation
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DOI：
10.1016/j.desal.2005.04.026
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发表时间：
2005-11-01
期刊：
影响因子：
9.9
通讯作者：
Semiat, R
中科院分区：
文献类型：
--
作者：
Greenberg, G;Hasson, D;Semiat, R
磷酸盐离子的存在给二次处理废水的RO净化带来了困难，并限制了水的回收。这些离子很容易通过沉淀微溶的磷酸钙盐而导致膜堵塞。目前，尚不清楚是否可以通过添加阻垢剂来可靠地抑制磷酸钙垢沉积。主要努力致力于对现有磷酸钙阻垢剂的有效性进行系统评估。使用配备管式 RO 膜的连续流实验室系统评估受测阻垢剂的抑制能力。添加了阻垢剂的受控成分的进料溶液连续通过膜。浓缩液和渗透液均循环至进料容器。阻垢剂的有效性通过膜渗透性衰减速率来评估。在不同的溶液过饱和条件和阻垢剂浓度下测试了五种阻垢剂。事实证明，所有阻垢剂对于大多数测试的溶液组合物均无效。这项研究的结果描绘了当前可用的阻垢剂可能提供可接受的磷酸钙阻垢抑制的有限条件范围。
The presence of phosphate ions causes a difficulty confronting RO purification of secondary treated wastewater and limits the water recovery. These ions can readily lead to membrane blockage by precipitation of sparingly soluble calcium phosphate salts. Currently, it is far from clear if calcium phosphate scale deposition can be reliably inhibited by dosage of antiscalants. Major efforts were devoted to a systematic evaluation of the effectiveness of currently available calcium phosphate antiscalants. The inhibitory capability of the tested antiscalants was assessed using a continuous-flow laboratory system, equipped with a tubular RO membrane. Feed solution of controlled composition, dosed with an antiscalant, was continuously passed through the membrane. Both concentrate and permeate recycled to the feed vessel. Antiscalant effectiveness was evaluated from the rate of membrane permeability decay. Five antiscalants were tested under various solution supersaturation conditions and antiscalant concentrations. All antiscalants proved to be ineffective over most solution compositions tested. Results of this study delineate the restricted range of conditions under which currently available antiscalant are likely to provide an acceptable calcium phosphate scale inhibition.