Effect of pH, ionic strength, temperature and humic substances on the sorption of Ni(II) to Na-attapulgite
Effect of pH, ionic strength, temperature and humic substances on the sorption of Ni(II) to Na-attapulgite
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pH、离子强度、温度和腐殖质对钠凹凸棒土吸附Ni(II)的影响
DOI：
10.1016/j.cej.2008.12.024
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发表时间：
2009-07-15
影响因子：
15.1
通讯作者：
Wang, Xiangke
中科院分区：
文献类型：
--
作者：
Fan, Qiaohui;Shao, Dadong;Wang, Xiangke
研究了在环境条件下Ni（II）在Na-Al 2 O3上的吸附随pH和离子强度的变化规律。结果表明，在pH < 8时，Ni（II）的吸附强烈依赖于离子强度，而在pH > 8时，吸附与离子强度无关。Ni（II）从裸和HA绑定的H2O杂化物的解吸试验的结果表明，吸附是可逆的，在pH 6.0。在pH < 8时，外球络合或离子交换可能是镍（II）在凹土上的主要吸附机制，而在pH > 8时，镍（II）的吸附主要由内球络合主导。pH > 7时，FA和HA的存在明显降低了Ni（II）在FA/HA-HA杂化材料上的吸附，pH < 7时影响较小。随着温度的升高，Ni（II）在Na-Na 2SO 4上的吸附量增加。由吸附等温线计算得到的热力学数据（Δ H度、Δ S度、Δ G度）表明，Ni（II）在硅藻土上的吸附过程是自发的吸热过程. (C)2008 Elsevier B. V.保留所有权利。
Sorption of Ni(II) on Na-attapulgite as a function of pH and ionic strength is investigated under ambient conditions. The results indicate that sorption of Ni(II) is strongly dependent on ionic strength at pH < 8, and independent of ionic strength at pH > 8. Results of the desorption tests of Ni(II) from bare and HA bound attapulgite hybrids indicate that the sorption is reversible at pH 6.0. Outer-sphere complexation or ion exchange may be the main sorption mechanism of Ni(II) to attapulgite at pH < 8, whereas the uptake of Ni(II) at pH > 8 is mainly dominated by inner-sphere complexation. The presence of FA and HA decreases Ni(II) sorption to FA/HA-attapulgite hybrids at pH > 7 obviously, and the influence at pH < 7 is weakly. Sorption of Ni(II) to Na-attapulgite increases with increasing temperature. The thermodynamic data (Delta H degrees, Delta S degrees, Delta G degrees) are calculated from the temperature-dependent sorption isotherms, and the results suggest that sorption process of Ni(II) on attapulgite is spontaneous and endothermic. (C) 2008 Elsevier B.V. All rights reserved.