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Alvarez-Galvan Y, Minofar B, Futera Z, Francoeur M, Jean-Marius C, Brehm N, Yacou C, Jauregui-Haza UJ, Gaspard S. Adsorption of Hexavalent Chromium Using Activated Carbon Produced from Sargassum ssp.: Comparison between Lab Experiments and Molecular Dynamics Simulations. Molecules 2022; 27:6040. [PMID: 36144787 PMCID: PMC9503432 DOI: 10.3390/molecules27186040] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2022] [Revised: 09/06/2022] [Accepted: 09/10/2022] [Indexed: 12/04/2022] Open
Abstract
Adsorption is one of the most successful physicochemical approaches for removing heavy metal contaminants from polluted water. The use of residual biomass for the production of adsorbents has attracted a lot of attention due to its cheap price and environmentally friendly approach. The transformation of Sargassum-an invasive brown macroalga-into activated carbon (AC) via phosphoric acid thermochemical activation was explored in an effort to increase the value of Sargassum seaweed biomass. Several techniques (nitrogen adsorption, pHPZC, Boehm titration, FTIR and XPS) were used to characterize the physicochemical properties of the activated carbons. The SAC600 3/1 was predominantly microporous and mesoporous (39.6% and 60.4%, respectively) and revealed a high specific surface area (1695 m2·g-1). To serve as a comparison element, a commercial reference activated carbon with a large specific surface area (1900 m2·g-1) was also investigated. The influence of several parameters on the adsorption capacity of AC was studied: solution pH, solution temperature, contact time and Cr(VI) concentration. The best adsorption capacities were found at very acid (pH 2) solution pH and at lower temperatures. The adsorption kinetics of SAC600 3/1 fitted well a pseudo-second-order type 1 model and the adsorption isotherm was better described by a Jovanovic-Freundlich isotherm model. Molecular dynamics (MD) simulations confirmed the experimental results and determined that hydroxyl and carboxylate groups are the most influential functional groups in the adsorption process of chromium anions. MD simulations also showed that the addition of MgCl2 to the activated carbon surface before adsorption experiments, slightly increases the adsorption of HCrO4- and CrO42- anions. Finally, this theoretical study was experimentally validated obtaining an increase of 5.6% in chromium uptake.
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Affiliation(s)
- Yeray Alvarez-Galvan
- Laboratoire COVACHIM-M2E, EA 3592, Campus de Fouillole, Université des Antilles, 97157 Pointe à Pitre, France
- NBC SARL Company, 8, Rue Saint Cyr, Résidence Océane—Apt no. 5, 97300 Cayenne, France
| | - Babak Minofar
- Laboratory of Structural Biology and Bioinformatics, Institute of Microbiology of the Czech Academy of Sciences, Zamek 136, 37333 Nové Hrady, Czech Republic
| | - Zdeněk Futera
- Faculty of Science, University of South Bohemia České Budějovice, Branišovská 1760/31a, 37005 České Budějovice, Czech Republic
| | - Marckens Francoeur
- Laboratoire COVACHIM-M2E, EA 3592, Campus de Fouillole, Université des Antilles, 97157 Pointe à Pitre, France
| | - Corine Jean-Marius
- Laboratoire COVACHIM-M2E, EA 3592, Campus de Fouillole, Université des Antilles, 97157 Pointe à Pitre, France
| | - Nicolas Brehm
- NBC SARL Company, 8, Rue Saint Cyr, Résidence Océane—Apt no. 5, 97300 Cayenne, France
| | - Christelle Yacou
- Laboratoire COVACHIM-M2E, EA 3592, Campus de Fouillole, Université des Antilles, 97157 Pointe à Pitre, France
| | | | - Sarra Gaspard
- Laboratoire COVACHIM-M2E, EA 3592, Campus de Fouillole, Université des Antilles, 97157 Pointe à Pitre, France
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Koya ADA, Qhubu MC, Moyo M, Pakade VE. Scavenging of hexavalent chromium from aqueous solution by Macadamia nutshell biomass modified with diethylenetriamine and maleic anhydride. ENVIRONMENTAL RESEARCH 2022; 212:113445. [PMID: 35609653 DOI: 10.1016/j.envres.2022.113445] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/05/2021] [Revised: 03/08/2022] [Accepted: 05/05/2022] [Indexed: 06/15/2023]
Abstract
Based on the premise that aqueous anions of hexavalent chromium (Cr(VI)) are capable of electrostatic interaction with cationic and polar active sites, acid-washed Madacamia nutshell biomass was sequentially treated with diethylenetriamine (DETA) and maleic anhydride (MA) to graft poly(diethylenetriamine-co-maleic anhydride). By displaying a new peak at 1685 cm-1 ascribed to amide CO stretching vibrations, Fourier transform infrared spectroscopy highlighted the formation of amide groups through reaction of DETA with carboxyl groups on the biomass surface. Scanning electron microscopic images of the MA-modified biomass displayed polymeric growths attributed to copolymerization of DETA with MA. The polar and ionizable amide and amine groups of the grafted copolymer endowed the adsorbent with Cr(VI) removal capabilities over a wide pH range demonstrated by removal efficiencies between 70.9% and 81.7% in the pH 1.6 to pH 10.0 range for the treatment of 20 mL solutions containing 100 mg L-1 Cr(VI) with 200 mg of adsorbent. Conformity of the adsorption isotherm data to the Freundlich model revealed the heterogeneous nature of the adsorbent surface, which comprised a variety of functional groups capable of interaction with Cr(VI) species in solution. The Sips isotherm model provided the best fit to the equilibrium experimental data, and the adsorption capacity was 779.1 mg g-1 at pH 1.6, room temperature and an adsorbent dosage of 5.0 g L-1. The findings indicate that Cr(VI) adsorption onto diethylenetriamine and maleic anhydride modified Madacamia nutshell biomass is a promising option for Cr(VI) removal from aqueous solutions.
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Affiliation(s)
| | - Mpho Cynthia Qhubu
- Department of Chemistry, Vaal University of Technology, Vanderbijlpark, 1911, South Africa
| | - Malvin Moyo
- Department of Chemistry, Vaal University of Technology, Vanderbijlpark, 1911, South Africa; Department of Applied Chemistry, National University of Science and Technology, Bulawayo, Zimbabwe.
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