Ding Li, Snoeyink Vernon L, Mariñas Benito J, Yue Zhongren, Economy James
Department of Civil and Environmental Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA.
Environ Sci Technol. 2008 Feb 15;42(4):1227-31. doi: 10.1021/es0710555.
The pore size distribution (PSD) of adsorbents has been found to be an important factor that affects adsorption capacity for organic compounds; consequently, it should influence competitive adsorption in multisolute systems. This research was conducted to show howthe PSD of activated carbon affects the competition between natural organic matter (NOM) and the trace organic contaminant atrazine, with a primary emphasis on quantifying the pore blocking mechanism of NOM competition. Isotherm tests were performed for both atrazine and NOM from a groundwater on five powdered activated carbons (PACs) with widely different PSDs. The capacity for NOM correlated best with the surface area of pores in the diameter range of 15-50 A, although some NOM also adsorbed in the smaller pores as evidenced by a reduction in capacity for atrazine when NOM was present. Kinetic tests for atrazine on PACs with various levels of preadsorbed NOM showed that the magnitude of the pore blockage effect by NOM was lower for PACs with higher surface area of pores with diameter in the range of 15-50 A. Therefore increasing pores in the size range where NOM adsorb can reduce the extent of the pore blockage competitive effect on the target compound atrazine. The effect of PSD was further studied with a flow-through PAC-membrane hybrid watertreatment system, in which experimental results successfully verified model simulations by the COMPSORB model.
已发现吸附剂的孔径分布（PSD）是影响有机化合物吸附容量的一个重要因素；因此，它应会影响多溶质体系中的竞争吸附。本研究旨在表明活性炭的PSD如何影响天然有机物（NOM）与痕量有机污染物阿特拉津之间的竞争，主要重点是量化NOM竞争的孔堵塞机制。对来自地下水的阿特拉津和NOM在五种具有广泛不同PSD的粉末活性炭（PAC）上进行了等温线试验。NOM的吸附容量与直径在15 - 50 Å范围内的孔表面积相关性最佳，不过当存在NOM时阿特拉津吸附容量降低，这表明一些NOM也吸附在较小的孔中。对预吸附不同水平NOM的PAC上的阿特拉津进行动力学试验表明，对于直径在15 - 50 Å范围内具有较高孔表面积的PAC，NOM的孔堵塞效应程度较低。因此，增加NOM吸附的尺寸范围内的孔可以降低对目标化合物阿特拉津的孔堵塞竞争效应程度。使用流通式PAC - 膜混合水处理系统进一步研究了PSD的影响，其中实验结果成功验证了COMPSORB模型的模拟结果。
