Neodymium Recovery by Chitosan/Iron(III) Hydroxide [ChiFer(III)] Sorbent Material: Batch and Column Systems

Abstract

A low cost composite material was synthesized for neodymium recovery from dilute aqueous solutions. The in-situ production of the composite containing chitosan and iron(III) hydroxide (ChiFer(III)) was improved and the results were compared with raw chitosan particles. The sorbent was characterized using Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy-energy dispersive X-ray analyses (SEM-EDX). The equilibrium studies were performed using firstly a batch system, and secondly a continuous system. The sorption isotherms were fitted with the Langmuir, Freundlich, and Sips models; experimental data was better described with the Langmuir equation and the maximum sorption capacity was 13.8 mg·g−1 at pH 4. The introduction of iron into the biopolymer matrix increases by four times the sorption uptake of the chitosan; the individual sorption capacity of iron (into the composite) was calculated as 30.9 mg Nd/g Fe. The experimental results of the columns were fitted adequately using the Thomas model. As an approach to Nd-Fe-B permanent magnets effluents, a synthetic dilute effluent was simulated at pH 4, in order to evaluate the selectivity of the sorbent material; the overshooting of boron in the column system confirmed the higher selectivity toward neodymium ions. The elution step was carried out using MilliQ-water with the pH set to 3.5 (dilute HCl solution).

A Study on the Removal of Copper (II) from Aqueous Solution Using Lime Sand Bricks

“…On the other hand, a higher residence time allows Cu(II) to diffuse and reach the active sites of the sorbent. The finding is in agreement with the results obtained by Demey et al on neodymium removal using the low cost composite material of chitosan/Iron(III) hydroxide [ChiFer(III)] [46], who conclude that the external film diffusion reduced under the higher superficial velocity, thus, resulting in a faster breakthrough. The Cu(II) adsorption capacity was 59.65, 84.98 and 98.16 mg/kg with the increasing residence times for 8, 10 and 12 min, respectively.…”

“…This may be due to the fact that the adsorption is particularly active in the dilute concentrations. Demey et al and Kleinübing et al also observed a higher sorption capacity obtained from the batch experiment than from the column experiments [46,47]. The fact was explained by the resistance to the film diffusion active in the low concentrations which are similar to the present study.…”

The Use of Chalcedonite as a Biosorption Bed in the Treatment of Groundwater

“…The creation of biofilms and the formation of manganese oxide coatings on the surface of chalcedonite causes the deposit to work continuously (does not run out). For that very reason, the Thomas model commonly applied to describe the continuous column system [30] may not be used.…”

“…Using a continuous sorption system allows a better approach to real industrial applications. A few models that can describe these processes have been reported in the literature [22,30]. However, only a limited number of references exist on the modelling of the combined and simultaneous removal of the above pollutants [6,9].…”

Support materials of fixed biofilm based on solid plastic wastes for domestic wastewater treatment

“…The developing of cheap and easy-to-operate wastewater treatment methods are crucial in order to surpass the low economies issues and maintain the sanitation. Among the most used methods to wastewater treatment are biological processes, as they are economically viable compared to other processes such as advanced oxidation or precipitation [2][3][4][5][6]i.e. vehicle operating costs and speeds are also allowed to vary over time.…”