Adsorption of Pb and Cu from Aqueous Solutions by Raw and Heat-Treated Attapulgite Clay
The main objective of the present study is the investigation of the adsorption efficiency of raw and heat-treated attapulgite clay for removing Pb and Cu from aqueous solutions. The removal of each metal was studied separately with the use of one-substance solutions. The effect of certain factors, i...
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MDPI AG
2018-04-01
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| Series: | Geosciences |
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| Online Access: | http://www.mdpi.com/2076-3263/8/5/157 |
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| author | Konstantina Pyrgaki Panagiota Messini Vasilis Zotiadis |
| author_facet | Konstantina Pyrgaki Panagiota Messini Vasilis Zotiadis |
| author_sort | Konstantina Pyrgaki |
| collection | DOAJ |
| description | The main objective of the present study is the investigation of the adsorption efficiency of raw and heat-treated attapulgite clay for removing Pb and Cu from aqueous solutions. The removal of each metal was studied separately with the use of one-substance solutions. The effect of certain factors, including solution pH and ionic strength, contact time, adsorbent concentration, temperature of treatment of the adsorbent, and initial metal concentration, was studied. In alkaline conditions, pH > 8.0, precipitation of Pb(OH)2 and Cu(OH)2 takes place, whereas at pH range 4.0–8.0 removal of metals is probably due to adsorption processes. Metal removal increases by 20% for Pb and by 80% for Cu with the increase of attapulgite content from 2 mg·L−1 to 15 mg·L−1. The removal of metals decreases with increasing solution ionic strength due to competition of Na with Pb and Cu for the available sites. Significant changes in the adsorption capacity of the used attapulgite clay occur after calcination in temperatures >550 °C due to destruction of the crystal lattice of the material and nano-porosity change. Finally, Pb adsorption is described well by both Langmuir and Freundlich isotherm models. According to the Langmuir model, the maximum adsorption capacity for Pb is 30 mg·g−1 and 4.41 mg·g−1 for Cu. The Freundlich model fitted better the experimental data of Cu. |
| first_indexed | 2024-12-13T02:58:00Z |
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| issn | 2076-3263 |
| language | English |
| last_indexed | 2024-12-13T02:58:00Z |
| publishDate | 2018-04-01 |
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| spelling | doaj.art-5e58ce673af349bbb707659c558cfa332022-12-22T00:01:54ZengMDPI AGGeosciences2076-32632018-04-018515710.3390/geosciences8050157geosciences8050157Adsorption of Pb and Cu from Aqueous Solutions by Raw and Heat-Treated Attapulgite ClayKonstantina Pyrgaki0Panagiota Messini1Vasilis Zotiadis2Department of Geology & Geoenvironment, National and Kapodistrian University of Athens, Panepistimiopolis Zographou, 15784 Athens, GreeceDepartment of Geology & Geoenvironment, National and Kapodistrian University of Athens, Panepistimiopolis Zographou, 15784 Athens, GreeceEdafomichaniki S.A., Em. Papadaki 19, N. Iraklio, 14121 Athens, GreeceThe main objective of the present study is the investigation of the adsorption efficiency of raw and heat-treated attapulgite clay for removing Pb and Cu from aqueous solutions. The removal of each metal was studied separately with the use of one-substance solutions. The effect of certain factors, including solution pH and ionic strength, contact time, adsorbent concentration, temperature of treatment of the adsorbent, and initial metal concentration, was studied. In alkaline conditions, pH > 8.0, precipitation of Pb(OH)2 and Cu(OH)2 takes place, whereas at pH range 4.0–8.0 removal of metals is probably due to adsorption processes. Metal removal increases by 20% for Pb and by 80% for Cu with the increase of attapulgite content from 2 mg·L−1 to 15 mg·L−1. The removal of metals decreases with increasing solution ionic strength due to competition of Na with Pb and Cu for the available sites. Significant changes in the adsorption capacity of the used attapulgite clay occur after calcination in temperatures >550 °C due to destruction of the crystal lattice of the material and nano-porosity change. Finally, Pb adsorption is described well by both Langmuir and Freundlich isotherm models. According to the Langmuir model, the maximum adsorption capacity for Pb is 30 mg·g−1 and 4.41 mg·g−1 for Cu. The Freundlich model fitted better the experimental data of Cu.http://www.mdpi.com/2076-3263/8/5/157leadcopperattapulgite claypalygorskite clayadsorption efficiency |
| spellingShingle | Konstantina Pyrgaki Panagiota Messini Vasilis Zotiadis Adsorption of Pb and Cu from Aqueous Solutions by Raw and Heat-Treated Attapulgite Clay Geosciences lead copper attapulgite clay palygorskite clay adsorption efficiency |
| title | Adsorption of Pb and Cu from Aqueous Solutions by Raw and Heat-Treated Attapulgite Clay |
| title_full | Adsorption of Pb and Cu from Aqueous Solutions by Raw and Heat-Treated Attapulgite Clay |
| title_fullStr | Adsorption of Pb and Cu from Aqueous Solutions by Raw and Heat-Treated Attapulgite Clay |
| title_full_unstemmed | Adsorption of Pb and Cu from Aqueous Solutions by Raw and Heat-Treated Attapulgite Clay |
| title_short | Adsorption of Pb and Cu from Aqueous Solutions by Raw and Heat-Treated Attapulgite Clay |
| title_sort | adsorption of pb and cu from aqueous solutions by raw and heat treated attapulgite clay |
| topic | lead copper attapulgite clay palygorskite clay adsorption efficiency |
| url | http://www.mdpi.com/2076-3263/8/5/157 |
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