Role of collector alternating charged patches on transport of Cryptosporidium parvum oocyst in a patchwise charged heterogeneous micromodel

Journal Article · Mon Feb 04 04:00:00 EST 2013 · Environmental Science & Technology, 47(6):2670-2678

DOI:https://doi.org/10.1021/es304075j· OSTI ID:1072867

Liu, Yuanyuan; Zhang, Changyong; Hu, Dehong; Kuhlenschmidt, Mark S; Kuhlenschmidt, Theresa B; Mylon, Steven E; Kong, Rong; Bhargava, Rohit; Nguyen, Thanh H

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 single collector removal efficiencies (η) of the Fe2O3 patches and on the entire collectors were determined. In the presence of significant (>3500 kT) Derjaguin–Landau–Verwey–Overbeek (DLVO) energy barrier between the microspheres and the silica collectors at pH 5.8 and 8.1, the values of η determined for Fe2O3 patches were significantly less (p < 0.05, t-test) than that obtained for collectors coated entirely with Fe2O3. However, η on 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. 200-360 kT), were significantly greater (p < 0.05, t-test) than that on the collectors coated entirely with Fe2O3. The dependence of η determined 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 η and that predicted by a patchwise geochemical heterogeneous model was observed, but can be explained by the model’s lack of consideration for the spatial distribution of charge heterogeneity on the collector surface and colloid migration on patchwise heterogeneous collectors.

• Research Organization: Pacific Northwest National Laboratory (PNNL), Richland, WA (US), Environmental Molecular Sciences Laboratory (EMSL)
• Sponsoring Organization: USDOE
• DOE Contract Number: AC05-76RL01830
• OSTI ID: 1072867
• Report Number(s): PNNL-SA-91345; 44692; KP1704020
• Journal Information: Environmental Science & Technology, 47(6):2670-2678, Journal Name: Environmental Science & Technology, 47(6):2670-2678
• Country of Publication: United States
• Language: English

Related Subjects

Colloids transport
Environmental Molecular Sciences Laboratory
porous media
surface charge