Role of Collector Alternating Charged Patches on Transport of Cryptosporidium parvum Oocysts in a Patchwise Charged Heterogeneous Micromodel

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• 作者：Yuanyuan Liu ; Changyong Zhang ; Dehong Hu ; Mark S. Kuhlenschmidt ; Theresa B. Kuhlenschmidt ; Steven E. Mylon ; Rong Kong ; Rohit Bhargava ; Thanh H. Nguyen
• 刊名：Environmental Science & Technology (ES&T)
• 出版年：2013
• 出版时间：March 19, 2013
• 年：2013
• 卷：47
• 期：6
• 页码：2670-2678
• 全文大小：397K
• 年卷期：v.47,no.6(March 19, 2013)
• ISSN：1520-5851

文摘

The role of collector surface charge heterogeneity on transport of Cryptosporidium parvum oocyst and carboxylate microsphere in 2-dimensional micromodels was studied. The cylindrical silica collectors within the micromodels were coated with 0, 10, 20, 50, and 100% Fe₂O₃ patches. The experimental values of average removal efficiencies (畏) of the Fe₂O₃ patches and on the entire collectors were determined. In the presence of significant (>3500 kT) Derjaguin鈥揕andau鈥揤erwey鈥揙verbeek (DLVO) energy barrier between the microspheres and the silica collectors at pH 5.8 and 8.1, 畏 determined for Fe₂O₃ patches on the heterogeneous collectors were significantly less (p < 0.05, t test) than those obtained for collectors coated entirely with Fe₂O₃. However, 畏 calculated for Fe₂O₃ patches for microspheres at pH 4.4 and for oocysts at pH 5.8 and 8.1, where the DLVO energy barrier was relatively small (ca. 200鈥?60 kT), were significantly greater (p < 0.05, t test) than those for the collectors coated entirely with Fe₂O₃. The dependence of 畏 for Fe₂O₃ patches on the DLVO energy barrier indicated the importance of periodic favorable and unfavorable electrostatic interactions between colloids and collectors with alternating Fe₂O₃ and silica patches. Differences between experimentally determined overall 畏 for charged heterogeneous collectors and those predicted by a patchwise geochemical heterogeneous model were observed. These differences can be explained by the model鈥檚 lack of consideration for the spatial distribution of charge heterogeneity on the collector surface.