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Study of the Interaction Mechanism in the Biosorption of Copper(II) Ions onto Posidonia oceanica and Peat
Author(s) -
Izquierdo Marta,
Marzal Paula,
Gabaldón Carmen,
Silvetti Margherita,
Castaldi Paola
Publication year - 2012
Publication title -
clean – soil, air, water
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.444
H-Index - 66
eISSN - 1863-0669
pISSN - 1863-0650
DOI - 10.1002/clen.201100303
Subject(s) - sorption , copper , biosorption , desorption , chemistry , fourier transform infrared spectroscopy , adsorption , nuclear chemistry , langmuir , inorganic chemistry , chemical engineering , organic chemistry , engineering
Abstract A systematic approach was used to characterize the biosorption of copper(II) onto two biosorbents, Posidonia oceanica and peat, focusing on the interaction mechanisms, the copper(II) sorption–desorption process and the thermal behavior of the biosorbents. Sorption isotherms at pH 4–6 were obtained and the experimental data were fitted to the Langmuir model with a maximum uptake ( q max ) at pH 6 of 85.78 and 49.69 mg g −1 , for P. oceanica and peat, respectively. A sequential desorption (SD) with water, Ca(NO 3 ) 2 , and EDTA was applied to copper‐saturated biosorbents. Around 65–70% copper(II) were desorbed with EDTA, indicating that this heavy metal was strongly bound. The reversibility of copper(II) sorption was obtained by desorption with HCl and SD. Fourier transform IR spectroscopy (FTIR) analysis detected the presence of peaks associated with OH groups in aromatic and aliphatic structures, CH, CH 2 , and CH 3 in aliphatic structures, COO − and COOH groups and unsaturated aromatic structures on the surface of both biosorbents, as well as peaks corresponding to SiO groups on the surface of peat. The results of SEM‐EDX and FTIR analysis of copper‐saturated samples demonstrated that ion exchange was one of the mechanisms involved in copper(II) retention. Thermal analysis of biosorbent samples showed that copper(II) sorption–desorption processes affected the thermal stability of the biosorbents.