Study of the Interaction Mechanism in the Biosorption of Copper(II) Ions onto Posidonia oceanica and Peat

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 (qmax) 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(NO3)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, CH2, and CH3 in aliphatic structures, COO− and COOH groups and unsaturated aromatic structures on the surface of both biosorbents, as well as peaks corresponding to SiO 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.

Removal of Cu(II), Cr(III), and Cr(VI) from Aqueous Solution using a Novel Agricultural Waste Adsorbent

“…These shifts suggested that chemical coordination takes place on the surface of the biomass between ionizable functional groups and metal ions. These ideas have already been incorporated by other authors in more recent papers (12,(41)(42)(43).…”

Processing of PLA nanocomposites with cellulose nanocrystals extracted from Posidonia oceanica waste: Innovative reuse of coastal plant

“…2d). The spectral bands at 3175-3490 cm −1 are assigned to O H stretching intra-molecular hydrogen bonds for cellulose I, 2850-2970 cm −1 to C H stretching and the signal at 1511 cm −1 is associated to the aromatic ring present in lignin (Cocozza et al, 2011;Coletti et al, 2013;Izquierdo et al, 2012;Salapare Iii et al, 2013). The FT-IR spectra of bleached fibres and CNC from P. oceanica confirmed the results already observed in the thermogravimetric analysis: after chemical treatment, the band at 1511 cm −1 was absent, confirming the removal of the lignin fraction.…”

Removal of Vanadium(III) and Molybdenum(V) from Wastewater Using Posidonia oceanica (Tracheophyta) Biomass

“…These proteins have the capacity to bind heavy metals through the thiol groups, which are also known as sulfhydryl groups (R-SH), and amino groups (R-NH 2 ) of its cysteine residues [24], [25]. Other studies have investigated the biosorption of heavy metals such as copper, lead, and chromium, and the removal of dyes from textile waters using P. oceanica biomass [21], [26]–[30].…”