Luo Pei, Sun Hong-wen, Zhang Peng
Key Laboratory of Pollution Processes and Environmental Criteria, Ministry of Education, College of Environmental Science and Engineering, Nankai University, Tianjin 300071, China.
Huan Jing Ke Xue. 2012 Aug;33(8):2882-8.
In order to reveal the sorption behavior of phenanthrene (PHE) on engineered nano-silica, batch equilibriums were conducted to study the effects of heating, solution pH, and heavy metal ion (Ni2+) on PHE sorption, and a site energy distribution model was used to analyze the changes of sorption behavior. The results demonstrated that the sorption isotherm of PHE could be fitted well by the Freundlich model. The sorption capacity of the original nano-silica (PNS) was enhanced by heating (heated nano-silica, HNS), with the Freundlich adsorption coefficient (lgK(F)) increasing from 1.48 to 2.43. The nonlinearity of sorption isotherm increased after heating. The sorption characteristics together with pore distribution and surface area analysis suggested that PHE sorption on nano-silica was a combination of pore-filing and surface sorption, with the microspores and mesopores of nano-silica playing a major role. While changes in solution pH did not show a significant effect on the sorption of PHE on PNS, the sorption of PHE on HNS decreased significantly with increasing pH, with IgK(F) reducing by 73.7% when pH increased from 4.0 to pH 8.0. The pH caused differences in sorption capacity could be mainly explained by zeta potentials of nanoparticles. High pH enhanced the charge of nanoparticles, and reduced the pore accessibility. The effect of Ni2+ on PHE sorption on HNS varied with its concentration. At low concentration (<5 mmol x L(-1)), Ni2+ suppressed PHE sorption, while at a higher concentration, NiZ2 enhanced the sorption of PHE at a lower concentration (50 microg x L(-1)), and the inhibition on the sorption of PHE at a higher concentration (500 microg x L(-1)) did not increase further. This complex pattern was a result of concurrence of multiple processes.
为了揭示菲（PHE）在工程纳米二氧化硅上的吸附行为，进行了批量平衡实验以研究加热、溶液pH值和重金属离子（Ni2+）对PHE吸附的影响，并采用位点能量分布模型分析吸附行为的变化。结果表明，PHE的吸附等温线能很好地用Freundlich模型拟合。加热（加热纳米二氧化硅，HNS）提高了原始纳米二氧化硅（PNS）的吸附容量，Freundlich吸附系数（lgK(F)）从1.48增加到2.43。加热后吸附等温线的非线性增加。吸附特性以及孔隙分布和比表面积分析表明，PHE在纳米二氧化硅上的吸附是孔隙填充和表面吸附的结合，纳米二氧化硅的微孔和中孔起主要作用。虽然溶液pH值的变化对PHE在PNS上的吸附没有显著影响，但PHE在HNS上的吸附随着pH值的增加而显著降低，当pH值从4.0增加到8.0时，IgK(F)降低了73.7%。pH值导致的吸附容量差异主要可以通过纳米颗粒的zeta电位来解释。高pH值增加了纳米颗粒的电荷，降低了孔隙可及性。Ni2+对PHE在HNS上吸附的影响随其浓度而变化。在低浓度（<5 mmol x L(-1)）时，Ni2+抑制PHE的吸附，而在较高浓度时，NiZ2在较低浓度（50 microg x L(-1)）下增强PHE的吸附，在较高浓度（500 microg x L(-1)）下对PHE吸附的抑制没有进一步增加。这种复杂的模式是多种过程同时发生的结果。
