Several potential sorbent materials containing iron oxides were prepared and evaluated for potential to remove divalent metals from waste waters. These included a ferrihydrite-coated sand, maghemite incorporated in Dowex[Trademark] ion exchange resin, gothite and two thermally activated ferrihydrites. Attempts to prepare sorbents from steel shot by coating with ferrihydrite or by thermal oxidization resulted in cemented solids rather than pellets. Ferrihydrite activated at 295��C had a surface area of 113-202 m��/g, followed by gothite at 72-92 m��/g and ferrihydrite-coated sand at 0.78-1.4 m��/g. Zinc adsorption was evaluated by placing 5 g ferrihydrite-coated sand, 0.1 g maghemite in Dowex or 0.1 g gothite in batch reactors containing 40-50 mL of zinc solution, adjusting to various pH values, allowing to react for 96 hours, and analyzing the supernatant for zinc. The data fitted poorly to an ion exchange model using nonlinear regression. The adsorption site densities determined from the regression analysis were 8.0x10������ moles per gram of ferrihydrite-coated sand and 4.1x10������ moles per gram of White. Maghemite in Dowex did not provide any additonal zinc removal capacity in excess of the ion exchange capacity of the resin. Kinetic experiments showed that zinc adsorption onto ferrihydrite-coated sand was 86% complete after 96 hours. Based upon this study, the most promising sorbent appears to be gothite, although the "activated ferrihydrites" are also worthy of further study. Neither ferrihydrite-coated sand and maghemite in Dowex appear to be practical sorbents, based on their low zinc adsorption site density. Maghemite in Dowex might be useful in applications requiring magnetic sorbents. / Graduation date: 1999
| Identifer | oai:union.ndltd.org:ORGSU/oai:ir.library.oregonstate.edu:1957/33649 |
| Date | 28 October 1998 |
| Creators | May, Michael Lee |
| Contributors | Nelson, Peter O. |
| Source Sets | Oregon State University |
| Language | en_US |
| Detected Language | English |
| Type | Thesis/Dissertation |
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