A comparative study of modified and unmodified maize tassels for removal of selected trace metals in contaminated water |
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Authors: | Isaac W Mwangi Jonathan O Okonkwo |
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Institution: | 1. Department of Chemical Technology , University of Johannesburg, Doornfontein Campus , P.O Box 17011, Doornfontein 2028, Johannesburg, South Africa;2. School of Chemistry, University of KwaZulu-Natal , P/Bag X45001, Westville, Durban 4000, South Africa;3. Department of Environmental, Water &4. Earth Science, Faculty of Sciences , Tshwane University of Technology , P/Bag X680, Pretoria 0001, South Africa |
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Abstract: | Powdered maize tassels were studied and found to exhibit metal sorption properties due to the availability of functional groups. The tassels have a high amount of soluble organic substances that can dissolve in aqueous media, contributing to secondary pollution during a water treatment process. A chelating agent was chemically attached on the maize tassels with a view to increase the sorption capacity, minimize leaching, and enhance the tassels’ stability. Thermogravimetric analysis confirmed that modification improved their thermal stability to withstand temperatures above 600°C as well as reduced the “secondary pollution”. The modified sorbent was employed for the sorption of lead, copper, and cadmium ions in both the model solutions and the real samples. The contact time and pH were optimized after which Langmuir and Freundlich isotherms were applied to the data. The sorption capacities for Cu2+, Cd2+, and Pb2+ improved from 3.4, 0.8, and 1.7?g?kg?1, respectively, to 6.3, 2.6, and 2.6?g?kg?1 in the same order. The sorbent was shown to remove up to 95% of the metals in less than 10 min. This study has a potential application for the remediation of polluted waters. |
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Keywords: | metal sorption waste water maize tassels modified sorbent ethylenediamine |
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