Effects of fluoride on coagulation performance of aluminum chloride towards Kaolin suspension
Effects of fluoride on coagulation performance of aluminum chloride towards Kaolin suspension
复制标题
氟化物对氯化铝对高岭土悬浮液混凝性能的影响
DOI：
10.1016/j.colsurfa.2012.12.047
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发表时间：
2013-03-20
影响因子：
5.2
通讯作者：
Qu, Jiuhui
中科院分区：
文献类型：
--
作者：
Liu, Ruiping;Zhu, Lijun;Qu, Jiuhui
虽然许多研究已经研究了铝（Al）混凝去除氟，很少有研究集中在氟对胶体，如高岭土悬浮液的混凝行为的影响。通过一系列间歇实验研究了不同氟铝比（R-F：Al）下氟对浊度去除、Zeta电位、絮体生长和残余铝含量的影响，并利用Visual MINTEQ软件分析了不同R-F：Al浓度下铝和氟的形态分布。在不足的Al剂量范围内，在R-F：Al高于10：10时，氟化物显示出不利影响，而在pH 8时，在R-F：Al低于2：10时，氟化物对混凝几乎没有影响< 8. At pH >，在宽的R-F：Al范围内，从1：10到30：30，几乎没有观察到影响。氟化物的不利影响与zeta电位降低、絮凝体变小和残留铝水平升高有关。在pH 6时，在R-F：Al为10：10时，氟化物导致zeta电位从-1.7 mV降低到-6.7 mV，絮凝体尺寸从119.7 μ m降低到29.0 μ m，残留铝增加0.22 mg/L（以铝计）。对于过量剂量20 mg/L（以铝计），氟化物的存在使残留浊度从22.7 NTU降低到20.6 NTU，这是由于zeta电位降低和颗粒的再稳定化受到抑制。此外，本研究还表明，新鲜制备的氢氧化铝（原位生成的Al 2 O3中心点xH（2）O）在吸附氟离子后，经酸溶液溶解后，可作为混凝剂回收用于除胶。这一策略对于降低原位Al 2 O3中心点xH（2）O除氟的试剂成本具有重要意义。(C)2013爱思唯尔有限公司版权所有。
Although many studies have investigated the removal of fluoride by aluminum (Al) coagulation, few studies focus on the effects of fluoride on the coagulation behaviors towards colloids such as kaolin suspensions. In this study the effects of fluoride at different molar ratios of fluoride to Al (R-F:Al) on turbidity removal, zeta potential, flocs growth, and residual Al levels were investigated by a series of batch experiments, and the Visual MINTEQ software was also used to illustrate the species distribution of Al and fluoride at different R-F:Al levels. In insufficient Al dose ranges, fluoride showed adverse effects at R-F:Al above 10:10, whereas fluoride exhibited little effect on coagulation at R-F:Al below 2:10 at pH < 8. At pH > 8, little effect was observed over wide R-F:Al ranges, from 1:10 to 30:30. The adverse effects of fluoride were related to decreased zeta potential, smaller flocs, and elevated levels of residual Al. At pH 6, the fluoride at R-F:Al of 10:10 contributed to the decrease of the zeta potential from -1.7 to -6.7 mV, decrease of floc size from 119.7 to 29.0 mu m, and increase of residual Al of 0.22 mg/L as Al. For the overdosed dose of 20 mg/L as Al, the presence of fluoride decreased residual turbidity from 22.7 to 20.6 NTU, owing to the lowered zeta potential and the inhibited re-stabilization of particles. Moreover, this study indicates that after adsorbing fluoride, the spent freshly-prepared aluminum hydroxides (in-situ Al2O3 center dot xH(2)O) may be reclaimed as coagulants for colloid removal after being dissolved by acid solution. This strategy is valuable to minimize the reagent cost for the removal of fluoride by in-situ Al2O3 center dot xH(2)O. (C) 2013 Elsevier B.V. All rights reserved.