El-Bayaa A A, Badawy N A, Alkhalik E Abd
Chemistry Department, Faculty of Science, Al-Azhar University (Girls), Nasr City, Cairo, Egypt.
J Hazard Mater. 2009 Oct 30;170(2-3):1204-9. doi: 10.1016/j.jhazmat.2009.05.100. Epub 2009 May 27.
It is important to assess the effects of ionic strength when studying adsorption of metal ions on clay mineral because the background salt may complex metals and compete for adsorption sites. The sorption behavior of vermiculite pure clay mineral has been studied with respect to copper and chromium as a function of ionic strength in single metal ion solutions. Background electrolytes used in these experiments were KCl, NaCl and NH4Cl. The studies were conducted by a batch method at temperature 25 degrees C. The adsorption capacity and adsorption energy for each metal ion were calculated from the Langmuir adsorption isotherm. Also the competitive adsorption behavior of some heavy metal ions such as Cr(III), Cu(II), Ni(II) and Co(II) by vermiculite pure clay mineral was studied. The result shows the competition between coexisting heavy metal cations for the same adsorption sites of an adsorbent. However, when trivalent metal was added to the solution it competitively replaced divalent ions that had been previously adsorbed onto the vermiculite pure clay mineral, resulting in the desorption of these metals into the solution.
在研究金属离子在粘土矿物上的吸附时，评估离子强度的影响很重要，因为背景盐可能会使金属络合，并竞争吸附位点。已针对蛭石纯粘土矿物在单一金属离子溶液中对铜和铬的吸附行为，作为离子强度的函数进行了研究。这些实验中使用的背景电解质是氯化钾、氯化钠和氯化铵。研究采用批量法在25摄氏度的温度下进行。根据朗缪尔吸附等温线计算每种金属离子的吸附容量和吸附能。还研究了蛭石纯粘土矿物对一些重金属离子如Cr(III)、Cu(II)、Ni(II)和Co(II)的竞争吸附行为。结果表明共存重金属阳离子对吸附剂相同吸附位点的竞争。然而，当向溶液中加入三价金属时，它会竞争性地取代先前吸附在蛭石纯粘土矿物上的二价离子，导致这些金属解吸到溶液中。
