کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
6386547 1627044 2014 10 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Consideration of grain packing in granular iron treatability studies
ترجمه فارسی عنوان
بررسی بسته بندی دانه در مطالعات کشیدگی دانه ای
کلمات کلیدی
موضوعات مرتبط
مهندسی و علوم پایه علوم زمین و سیارات فرآیندهای سطح زمین
چکیده انگلیسی
Commercial granular iron (GI) is light steel that is used in Permeable Reactive Barriers (PRBs). Investigations into the reactivity of GI have focused on its chemical nature and relatively little direct work has been done to account for the effects of grain shape and packing. Both of these factors are expected to influence available grain surface area, which is known to correlate to reactivity. Commercial granular iron grains are platy and therefore pack in preferential orientations that could affect solution access to the surface. Three packing variations were investigated using Connelly Iron and trichloroethylene (TCE). Experimental kinetic data showed reaction rates 2-4 times higher when grains were packed with long axes preferentially parallel to flow (VP) compared to packings with long axes preferentially perpendicular to flow (HP) or randomly arranged (RP). The variations were found to be explainable by variations in reactive sorption capacities, i.e., sorption to sites where chemical transformations took place. The possibility that the different reactive sorption capacities were related to physical pore-scale differences was assessed by conducting an image analysis of the pore structure of sectioned columns. The analyses suggested that pore-scale factors - in particular the grain surface availability, reflected in the sorption capacity terms of the kinetic model used - could only account for a fraction of the observed reactivity differences between packing types. It is concluded that packing does affect observable reaction rates but that micro-scale features on the grain surfaces, rather than the pore scale characteristics, account for most of the apparent reactivity differences. This result suggests that treatability tests should consider the packing of columns carefully if they are to mimic field performance of PRBs to the greatest extent possible.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Journal of Contaminant Hydrology - Volume 164, August 2014, Pages 230-239
نویسندگان
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