Biosorption of cadmium (II) from aqueous solutions by natural and modified non-living leaves of Posidonia oceanica

Abstract

Natural, HCl-treated, and formaldehyde-treated non-living leaves of Posidonia oceanica, a marine plant, were investigated as potential biosorbents to remove Cd from aqueous solutions. The studied biosorbents were characterized by elemental analysis and Fourier transform infrared spectroscopy (FTIR) and it was observed that the adsorption capacity of the biosorbents strongly depended on the pH, increasing as the pH rises. The adsorption process was fast. The adsorption kinetic was analyzed using five kinetic models: pseudo-first order, pseudo-second order, Elovich, intraparticle diffusion, and Bangham models. The adsorption isotherms were analyzed by the Langmuir, Freundlich, Dubinin-Radushkevich, Sips, Redlich-Peterson, and Toth models. The maximum biosorption capacity was attained by the biosorbent treated with HCl (1.11 mmol g). The distribution equilibrium constant and the Gibbs free energy change were calculated. The effects of the presence of Na, K, Mg, and Ca ions in the solution on Cd uptake were studied. Results indicate that non-living leaves of P. oceanica, natural or treated, can be considered as effective and low-cost biosorbents for the removal of cadmium from aqueous solutions.

How Serratia marcescens HB-4 absorbs cadmium and its implication on phytoremediation

“…As shown in Figure 1b, the naturally dead cells exhibited a high Cd removal yield of 86.1 ± 0.68%, while the live cells removed 97.12 ± 0.02% Cd. Higher than other strains reported so far [Chao et al, 2016;Meseguer et al, 2016]. The Cd removal yield dropped significantly to lower than 50% when the cells were autoclaved or ultrasonicated, which could attribute to destroying cell structure.…”

Removal of cationic pollutants from water by xanthated corn cob: optimization, kinetics, thermodynamics, and prediction of purification process

“…The kinetic sorption constants were determined in terms of pseudo-first order, pseudosecond order, intraparticle diffusion and Chrastil's kinetic models. The first-order rate expression of Lagergren states that the rate of occupation of sorption sites should be proportional to the number of unoccupied sites (Meseguer et al 2016). The nonlinear form of this equation is:…”

Non-linear adsorption characteristics of modified pine wood sawdust optimised for adsorption of Cd(II) from aqueous systems

“…As a consequence, the removal of heavy metals from water systems has attracted significant attention, which has increased in recent years, with a growing understanding of the toxicity of these species towards human health, aquatic life, flora and fauna [1]. Cadmium has been identified as a major heavy metal pollutant, with a proven high degree of toxicity at very low exposure levels, which can result in acute disorders and various chronic diseases by accumulation in living organisms [2]. This metal is discharged from central industries, like the mining, oil refineries, metal plating, batteries, alloy industries, smelting, phosphate fertilisers and pigments [3][4][5], resulting in cadmium contaminated water courses.…”