Effects of Cu(II) on the Adsorption Behaviors of Cr(III) and Cr(VI) onto Kaolin
The adsorption of Cr(III) or Cr(VI) in the absence and presence of Cu(II) onto kaolin was investigated under pH 2.0–7.0. Results indicated that the adsorption rate was not necessarily proportional to the adsorption capacity. The solutions’ pH values played a key role in kaolin zeta potential (ζ), es...
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| Format: | Article |
| Language: | English |
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Wiley
2016-01-01
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| Series: | Journal of Chemistry |
| Online Access: | http://dx.doi.org/10.1155/2016/3069754 |
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| author | Juanjuan Liu Xiaolong Wu Yandi Hu Chong Dai Qin Peng Dongli Liang |
| author_facet | Juanjuan Liu Xiaolong Wu Yandi Hu Chong Dai Qin Peng Dongli Liang |
| author_sort | Juanjuan Liu |
| collection | DOAJ |
| description | The adsorption of Cr(III) or Cr(VI) in the absence and presence of Cu(II) onto kaolin was investigated under pH 2.0–7.0. Results indicated that the adsorption rate was not necessarily proportional to the adsorption capacity. The solutions’ pH values played a key role in kaolin zeta potential (ζ), especially the hydrolysis behavior and saturation index of heavy metal ions. In the presence of Cu(II), qmixCr(III) reached the maximum adsorption capacity of 0.73 mg·g−1 at pH 6.0, while the maximum adsorption capacity for the mixed Cr(VI) and Cu(II) system (qmixCr(VI)) was observed at pH 2.0 (0.38 mg·g−1). Comparing the adsorption behaviors and mechanisms, we found that kaolin prefers to adsorb hydrolyzed products of Cr(III) instead of Cr3+ ion, while adsorption sites of kaolin surface were occupied primarily by Cu(II) through surface complexation, leading to Cu(II) inhibited Cr(VI) adsorption. Moreover, Cr(III) and Cr(VI) removal efficiency had a positive correlation with distribution coefficient Kd. Cr(III) and Cr(VI) removal efficiency had a positive correlation with distribution coefficient Kd and that of adsorption affinities of Cr(III) or Cr(VI) on kaolin was found to be Kd Cr(III) < Kd Cr(III)-Cu(II) and Kd Cr(VI) > Kd Cr(VI)-Cu(II). |
| format | Article |
| id | doaj-art-2a67f109a7174b658d743f047bbbc6e7 |
| institution | Kabale University |
| issn | 2090-9063 2090-9071 |
| language | English |
| publishDate | 2016-01-01 |
| publisher | Wiley |
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| series | Journal of Chemistry |
| spelling | doaj-art-2a67f109a7174b658d743f047bbbc6e72025-02-03T01:22:51ZengWileyJournal of Chemistry2090-90632090-90712016-01-01201610.1155/2016/30697543069754Effects of Cu(II) on the Adsorption Behaviors of Cr(III) and Cr(VI) onto KaolinJuanjuan Liu0Xiaolong Wu1Yandi Hu2Chong Dai3Qin Peng4Dongli Liang5College of Natural Resources and Environment, Northwest A&F University, Yangling, Shaanxi 712100, ChinaCollege of Natural Resources and Environment, Northwest A&F University, Yangling, Shaanxi 712100, ChinaDepartment of Civil & Environmental Engineering, University of Houston, Houston, TX 77004, USADepartment of Civil & Environmental Engineering, University of Houston, Houston, TX 77004, USACollege of Natural Resources and Environment, Northwest A&F University, Yangling, Shaanxi 712100, ChinaCollege of Natural Resources and Environment, Northwest A&F University, Yangling, Shaanxi 712100, ChinaThe adsorption of Cr(III) or Cr(VI) in the absence and presence of Cu(II) onto kaolin was investigated under pH 2.0–7.0. Results indicated that the adsorption rate was not necessarily proportional to the adsorption capacity. The solutions’ pH values played a key role in kaolin zeta potential (ζ), especially the hydrolysis behavior and saturation index of heavy metal ions. In the presence of Cu(II), qmixCr(III) reached the maximum adsorption capacity of 0.73 mg·g−1 at pH 6.0, while the maximum adsorption capacity for the mixed Cr(VI) and Cu(II) system (qmixCr(VI)) was observed at pH 2.0 (0.38 mg·g−1). Comparing the adsorption behaviors and mechanisms, we found that kaolin prefers to adsorb hydrolyzed products of Cr(III) instead of Cr3+ ion, while adsorption sites of kaolin surface were occupied primarily by Cu(II) through surface complexation, leading to Cu(II) inhibited Cr(VI) adsorption. Moreover, Cr(III) and Cr(VI) removal efficiency had a positive correlation with distribution coefficient Kd. Cr(III) and Cr(VI) removal efficiency had a positive correlation with distribution coefficient Kd and that of adsorption affinities of Cr(III) or Cr(VI) on kaolin was found to be Kd Cr(III) < Kd Cr(III)-Cu(II) and Kd Cr(VI) > Kd Cr(VI)-Cu(II).http://dx.doi.org/10.1155/2016/3069754 |
| spellingShingle | Juanjuan Liu Xiaolong Wu Yandi Hu Chong Dai Qin Peng Dongli Liang Effects of Cu(II) on the Adsorption Behaviors of Cr(III) and Cr(VI) onto Kaolin Journal of Chemistry |
| title | Effects of Cu(II) on the Adsorption Behaviors of Cr(III) and Cr(VI) onto Kaolin |
| title_full | Effects of Cu(II) on the Adsorption Behaviors of Cr(III) and Cr(VI) onto Kaolin |
| title_fullStr | Effects of Cu(II) on the Adsorption Behaviors of Cr(III) and Cr(VI) onto Kaolin |
| title_full_unstemmed | Effects of Cu(II) on the Adsorption Behaviors of Cr(III) and Cr(VI) onto Kaolin |
| title_short | Effects of Cu(II) on the Adsorption Behaviors of Cr(III) and Cr(VI) onto Kaolin |
| title_sort | effects of cu ii on the adsorption behaviors of cr iii and cr vi onto kaolin |
| url | http://dx.doi.org/10.1155/2016/3069754 |
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