Next Article in Journal
Volcanic Plumes: Impacts on the Atmosphere and Insights into Volcanic Processes
Next Article in Special Issue
Selected Metal Content and Binding Behaviour in Riverbed Sediments of the Kavala–Philippi Area (Northern Greece)
Previous Article in Journal
Major Strike-Slip Faults Identified Using Satellite Data in Central Borneo, SE Asia
Previous Article in Special Issue
Total and Bioaccessible Soil Arsenic and Lead Levels and Plant Uptake in Three Urban Community Gardens in Puerto Rico
Article Menu
Issue 5 (May) cover image

Export Article

Open AccessArticle
Geosciences 2018, 8(5), 157;

Adsorption of Pb and Cu from Aqueous Solutions by Raw and Heat-Treated Attapulgite Clay

Department of Geology & Geoenvironment, National and Kapodistrian University of Athens, Panepistimiopolis Zographou, 15784 Athens, Greece
Edafomichaniki S.A., Em. Papadaki 19, N. Iraklio, 14121 Athens, Greece
Author to whom correspondence should be addressed.
Received: 31 March 2018 / Revised: 21 April 2018 / Accepted: 25 April 2018 / Published: 27 April 2018
Full-Text   |   PDF [3011 KB, uploaded 15 May 2018]   |  


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 g·L−1 to 15 g·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. View Full-Text
Keywords: lead; copper; attapulgite clay; palygorskite clay; adsorption efficiency lead; copper; attapulgite clay; palygorskite clay; adsorption efficiency

Figure 1

This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited (CC BY 4.0).

Share & Cite This Article

MDPI and ACS Style

Pyrgaki, K.; Messini, P.; Zotiadis, V. Adsorption of Pb and Cu from Aqueous Solutions by Raw and Heat-Treated Attapulgite Clay. Geosciences 2018, 8, 157.

Show more citation formats Show less citations formats

Note that from the first issue of 2016, MDPI journals use article numbers instead of page numbers. See further details here.

Related Articles

Article Metrics

Article Access Statistics



[Return to top]
Geosciences EISSN 2076-3263 Published by MDPI AG, Basel, Switzerland RSS E-Mail Table of Contents Alert
Back to Top