Ethylenediaminetriacetic Acid-Functionalized Activated Carbon for the Adsorption of Rare Earths from Aqueous Solutions

Abstract

A novel and low-cost EDTA-functionalized activated carbon (EDTA-AC) was synthesized by anchoring N- [(3-trimethoxysilyl)propyl]ethylenediamine triacetic acid (TMS-EDTA) to oxidized activated carbon (AC). Material characterization was done by FTIR and Raman spectroscopy, TGA, N 2 physisorption, SEM and the Boehm titration method, the latter being used to determine the amount and type of oxygen functional groups present in carbon samples. EDTA-AC was tested for the adsorption and separation of rare-earth ions from aqueous solutions, in order to evaluate the feasibility of using this material for the recovery of rare earths from industrial residues and electronic waste, like batteries, magnets and lamp phosphors. The maximum adsorption capacity of EDTA-AC was derived for Nd(III) by constructing an adsorption isotherm and fitting the data to the Langmuir adsorption model. A kinetic and thermodynamic study were performed by varying the contact time and the temperature and plotting the corresponding adsorption data to the pseudo-second-order kinetic model and the Van 't Hoff equation, respectively. The affinity of EDTA-AC for each of the lanthanide ions was determined and from binary mixtures of La/Ni, Sm/Co and Eu/Y, the highest selectivity was observed for the rare earths. The adsorbed metal ions could be recovered and the adsorbent regenerated by treatment with a dilute solution of HCl, thus showing the (large-scale) potential of EDTA-functionalized AC for the recovery of rare earths from aqueous waste streams.

Poly(styrene‐alt‐maleic anhydride) ionic salt functionalized reduced graphene oxide doped with rare earth ions for anti‐corrosion performance enhancement

“…The similar oxygen functionalities with binding energy around 286.2 eV (Chetero of imidazolium groups in Is) and 288.2 eV corresponding to OCO from the SMA were also found in the spectra of SMA‐Is/rGO (Figure 5(e)), La 3+ / SMA‐Is/ rGO (Figure 5(f)), Ce 3+ / SMA‐Is/ rGO (Figure 5(g)) and Pr 3+ / SMA‐Is/ rGO (Figure 5(h)), but the intensities happened to change in comparison to those observed for rGO, indicating that the rGO maintains its original structure during the synthesis process 36 . Moreover, the peaks of oxygen functionalities from Re 3+ / SMA‐Is/ rGO composite had slightly shifted to higher energy compared with SMA‐Is/rGOs and rGO, because rare earth ions might change the chemical environment of Re 3+ / SMA‐Is/ rGO 37 . The binding energy 851 and 884 eV correspond to La 3d and Ce 3d orbits, which meant the trivalent oxidation states of La, Ce and Pr in Re 3+ / SMA‐Is/ rGO composite in Figure 6(a‐b) 38 …”

Cellulose citrate: a convenient and reusable bio-adsorbent for effective removal of methylene blue dye from artificially contaminated water

“…For this reason, we assume that the adsorption of MB on cellulose citrate takes place through different forces, including: electrostatic interactions, hydrogen bond, proton exchange, and hydrophobic interactions. [82][83][84][85] We reported a schematic depiction of methylene blue adsorbed on cellulose-citrate (Scheme 1).…”

Extraction of Rare Earth Metals by Solid-Phase Extractants from Phosphoric Acid Solution

“…Novel and inexpensive activated carbon impregnated with EDTA (EDTA-AC) was synthesized by Babu et al [3] by adding N-[ (3-trimethoxysilyl) propyl] ethylenediaminetriacetic acid (TMS-EDTA) to oxidized activated carbon (AC). The affinity of EDTA-AC for each of the lanthanide ions was determined, and from binary mixtures La/Ni, Sm/Co, Eu/Y and Dy/Nd, the highest selectivity was observed for heavy rare earth elements (REE).…”