Removal of fluoride from semiconductor wastewater by electrocoagulation-flotation
Removal of fluoride from semiconductor wastewater by electrocoagulation-flotation
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DOI：
10.1016/j.watres.2004.11.034
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发表时间：
2005-03-01
期刊：
影响因子：
12.8
通讯作者：
Lee, YD
中科院分区：
文献类型：
--
作者：
Hu, CY;Lo, SL;Lee, YD
采用阳极型表面活性剂十二烷基硫酸钠(十二烷基硫酸钠)改善电絮凝-气浮(ECF)工艺处理含氟半导体废水的浮选性能。ECF工艺能同时有效去除沉钙后废水中溶解的氟离子和CaF2颗粒。由于氢氟铝浮选可以在ECF中捕集CaF2颗粒，ECF工艺所需的十二烷基硫酸钠用量比分散气浮(DIAF)或溶解气浮(DAF)工艺的用量少得多。因此，在ECF除氟过程中，十二烷基硫酸钠只起到了起泡剂的作用，使气泡变得细小而稳定。增加钙离子和十二烷基硫酸钠的投加量可以克服共存阴离子的干扰。ECF的最佳初始酸度接近钙沉淀后的初始氟浓度；当初始酸度超过最佳值时，由于水氟铝粒子表面电荷的增加，SS的脱除量迅速下降。通过改变[Ca(OH)(2)]/[Ca~(2+)](T)的比值可以改变沉钙后废水的初始酸度，合适的比值由氢氟酸的酸解离常数和沉钙前废水的初始pH近似给出。(C)2005爱思唯尔有限公司。保留所有权利。
This work employs an anodic surfactant, sodium dodecyl sulfate (SDS), to improve the flotation performance of the electrocoagulation-flotation (ECF) process to treated fluoride containing semiconductor wastewater following calcium precipitation. The dissolved fluoride ions and CaF2 particles in the wastewater after calcium precipitation were effectively removed in the ECF process simultaneously. The dosage of SDS required for ECF was much less than those for dispersed air flotation (DiAF) or dissolved air flotation (DAF) processes because the CaF2 particles can be collected by hydro-fluoro-aluminum floes in ECF. Thus, SDS only served as a frother to make the bubbles tiny and stable in the ECF defluoridation process. The interference of co-existing anions can be overcome by increasing the dosage of calcium ions and SDS. The optimum initial acidity for ECF is close to the initial fluoride concentration after calcium precipitation; the amount of SS removed dropped rapidly if the initial acidity exceeded the optimal value because the surface charge of the hydro-fluoro-aluminum particles increased. The initial acidity of the wastewater after calcium precipitation can be modified by changing the [Ca(OH)(2)]/[Ca2+](T) ratio and the appropriate ratio is approximately given by the acid dissociation constant of hydrofluoric acid and the initial pH of the wastewater before calcium precipitation. (c) 2005 Elsevier Ltd. All rights reserved.