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Removal of iodide from water by chlorination and subsequent adsorption on powdered activated carbon
| Title: | Removal of iodide from water by chlorination and subsequent adsorption on powdered activated carbon |
| Authors: | Ikari, Mariya Browse this author | | Matsui, Yoshihiko Browse this author →KAKEN DB | | Suzuki, Yuta Browse this author | | Matsushita, Taku Browse this author | | Shirasaki, Nobutaka Browse this author |
| Keywords: | Iodide | | Iodate | | SPAC | | PAC | | NOM |
| Issue Date: | 1-Jan-2015 |
| Publisher: | Elsevier |
| Journal Title: | Water research |
| Volume: | 68 |
| Start Page: | 227 |
| End Page: | 237 |
| Publisher DOI: | 10.1016/j.watres.2014.10.021 |
| PMID: | 25462731 |
| Abstract: | Chlorine oxidation followed by treatment with activated carbon was studied as a possible method for removing radioactive iodine from water. Chlorination time, chlorine dose, the presence of natural organic matter (NOM), the presence of bromide ion (Br-), and carbon particle size strongly affected iodine removal. Treatment with superfine powdered activated carbon (SPAC) after 10-min oxidation with chlorine (1 mg-Cl-2/L) removed 90% of the iodine in NOM-containing water (dissolved organic carbon concentration, 1.5 mg-C/L). Iodine removal in NOM-containing water increased with increasing chlorine dose up to >0.1 mg-Cl-2/L but decreased at chlorine doses of >1.0 mg-Cl-2/L. At a low chlorine dose, nonadsorbable iodide ion (I-) was oxidized to adsorbable hypoiodous acid (HOI). When the chlorine dose was increased, some of the HOI reacted with NOM to form adsorbable organic iodine (organic-I). Increasing the chlorine dose further did not enhance iodine removal, owing to the formation of nonadsorbable iodate ion (IO3-). Co-existing Br- depressed iodine removal, particularly in NOM-free water, because hypobromous acid (HOBr) formed and catalyzed the oxidation of HOI to However, the effect of Br- was small in the NOM-containing water because organic-I formed instead of SPAC (median particle diameter, 0.62 gm) had a higher equilibrium adsorption capacity for organic-I than did conventional PAC (median diameter, 18.9 mu m), but the capacities of PAC and SPAC for HOI were similar. The reason for the higher equilibrium adsorption capacity for organic-I was that organic-I was adsorbed principally on the exterior of the PAC particles and not inside the PAC particles, as indicated by direct visualization of the solid-phase iodine concentration profiles in PAC particles by field emission electron probe microanalysis. In contrast, HOI was adsorbed evenly throughout the entire PAC particle. |
| Type: | article (author version) |
| URI: | http://hdl.handle.net/2115/58012 |
| Appears in Collections: | 工学院・工学研究院 (Graduate School of Engineering / Faculty of Engineering) > 雑誌発表論文等 (Peer-reviewed Journal Articles, etc)
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Submitter: 松井 佳彦
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