Pb/Ca ion exchange on kaolinite clay modified with phosphates
文献类型：期刊论文
| 作者 | Unuabonah, Emmanuel I.1; Olu-Owolabi, Bamidele I.2; Oladoja, Abiola N.3; Ofomaja, Augustine E.4; Yang, Zhang L.5 |
| 刊名 | JOURNAL OF SOILS AND SEDIMENTS
 |
| 出版日期 | 2010-09-01 |
| 卷号 | 10期号:6页码:1103-1114 |
| 关键词 | Adsorption capacity Equilibrium Ion exchange Kaolinite Lead Phosphate Thermodynamics |
| ISSN号 | 1439-0108 |
| DOI | 10.1007/s11368-009-0177-7 |
| 通讯作者 | Unuabonah, Emmanuel I.(iyaemma@yahoo.com) |
| 英文摘要 | Purpose Pollution of soils by heavy metal ions has attracted global concern because of the subsequent translocation into food chain which when taken up to a certain level can cause serious health problems. The influence of preadsorbed calcium by kaolinite clay modified with orthophosphate and tripolyphosphate reagents on the mobility of Pb(2+) in kaolinitic soil system is studied. This is with the view to understand the fate of Pb(2+) in phosphate-fertilized kaolinitic soils that are subsequently limed. Materials and methods Potassium dihydrogen phosphate (98%) and sodium tripolyphosphate (87%) were purchased from Aldrich and Merck, respectively. They were used to modify locally obtained kaolinite clay. These adsorbents were further pretreated with 0.1 M Ca(NO(3))(2). These phosphate-modified kaolinite clay adsorbents pretreated with Ca(2+) were used in the adsorption of Pb(2+) from aqueous solution in a batch mode. Results and discussion X-ray diffraction spectra of the various adsorbents indicated that modification of kaolinite clay with the reagents were effective on the surface of the clay mineral and not on the crystal structure of the clay mineral. Treatment with 0.1 M Ca(NO(3))(2) gave K-Ca (for unmodified kaolinite clay), K-O-Ca (for potassium-dihydrogen-phosphate-modified kaolinite clay), and K-TPP-Ca (for sodium-tripolyphosphate-modified Kaolinite clay) samples. The pH(PZC) of the adsorbents before pretreatment with Ca(2+) decreased when compared with the unmodified kaolinite clay. Further pretreatment of these adsorbents with Ca(2+) largely decreased the adsorption capacity of all three adsorbents for Pb(2+) from aqueous solution due to the higher reactivity of Ca(2+) compared with Pb(2+). Data from all three adsorbents failed the nonlinear single Langmuir model fit while data from K-O-Ca adsorbent failed the competitive Langmuir model fit. Delta S (o) data were used to support the proposed structures of adsorbed Pb(2+) on the various adsorbents. Delta H (o) for Pb/Ca exchange was endothermic in nature for K-O-Ca adsorbent and K-TPP-Ca adsorbents. However, it was exothermic for K-Ca adsorbent. Delta G (o) for Pb/Ca exchange on modified adsorbents was nonspontaneous but was spontaneous for K-Ca adsorbent. With increasing temperature, Delta G (o) for the ion exchange reaction became more spontaneous for all adsorbents. Conclusions Pb/Ca ion exchange on phosphate-modified kaolinite clay adsorbents is endothermic in nature and nonspontaneous. However, with increase in temperature, spontaneity of the ion exchange reaction increased. This study suggests that liming of kaolinitic soils will decrease strongly the adsorption capacity of the soil for Pb(2+), especially when they have initially adsorbed phosphates. |
| 收录类别 | SCI |
| WOS关键词 | AQUEOUS-SOLUTIONS ; CADMIUM IONS ; ADSORPTION ; LEAD ; CALCIUM ; THERMODYNAMICS ; MONTMORILLONITE ; REMOVAL |
| WOS研究方向 | Geology ; Agriculture |
| WOS类目 | Geosciences, Multidisciplinary ; Soil Science |
| 语种 | 英语 |
| WOS记录号 | WOS:000280845300011 |
| 出版者 | SPRINGER HEIDELBERG |
| URI标识 | http://www.irgrid.ac.cn/handle/1471x/2558827 |
| 专题 | 南京土壤研究所 |
| 通讯作者 | Unuabonah, Emmanuel I. |
| 作者单位 | 1.Redeemers Univ, Coll Nat Sci, Dept Chem Sci, Redemption City, Ogun State, Nigeria 2.Univ Ibadan, Dept Chem, Ibadan, Nigeria 3.Adekunle Ajasin Univ, Dept Chem, Akoko Akungba, Nigeria 4.Univ Benin, Dept Chem, Benin, Nigeria 5.Acad Sinica, Inst Soil Sci, Nanjing, Peoples R China |
| 推荐引用方式 GB/T 7714 | Unuabonah, Emmanuel I.,Olu-Owolabi, Bamidele I.,Oladoja, Abiola N.,et al. Pb/Ca ion exchange on kaolinite clay modified with phosphates[J]. JOURNAL OF SOILS AND SEDIMENTS,2010,10(6):1103-1114. |
| APA | Unuabonah, Emmanuel I.,Olu-Owolabi, Bamidele I.,Oladoja, Abiola N.,Ofomaja, Augustine E.,&Yang, Zhang L..(2010).Pb/Ca ion exchange on kaolinite clay modified with phosphates.JOURNAL OF SOILS AND SEDIMENTS,10(6),1103-1114. |
| MLA | Unuabonah, Emmanuel I.,et al."Pb/Ca ion exchange on kaolinite clay modified with phosphates".JOURNAL OF SOILS AND SEDIMENTS 10.6(2010):1103-1114. |
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来源：南京土壤研究所
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