High‐Performance, Superparamagnetic, Nanoparticle‐Based Heavy Metal Sorbents for Removal of Contaminants from Natural Waters

Abstract

We describe the synthesis and characterization of high-performance, superparamagnetic, iron oxide nanoparticle-based, heavy metal sorbents, which demonstrate excellent affinity for the separation of heavy metals in contaminated water systems (i.e., spiked Columbia River water). The magnetic nanoparticle sorbents were prepared from an easy-to-synthesize iron oxide precursor, followed by a simple, one-step ligand exchange reaction to introduce an affinity ligand to the nanoparticle surface that is specific to a heavy metal or class of heavy metal contaminants. The engineered magnetic nanoparticle sorbents have inherently high active surface areas, allowing for increased binding capacities. To demonstrate the performance of the nanoparticle sorbents, river water was spiked with specific metals and exposed to low concentrations of the functionalized nanoparticles. In almost all cases, the nanoparticles were found to be superior to commercially available sorbent materials as well as the unfunctionalized iron oxide nanoparticles.

The role of nanomaterials as effective adsorbents and their applications in wastewater treatment

“…Many reports discussed the influence of different parameters on the removal of metal ions by Fe 3 O 4 magnetic nanoparticles [47,123]. For example, the adsorption efficiency of Ni(II), Cu(II), Cd(II) and Cr(VI) ions by Fe 3 O 4 nanoparticles was strongly dependent on pH, temperature, amount of the adsorbent and the incubation time [124][125][126][127]. Further, a higher removal efficiency of these metal ions at a 3.5 mg mL [124][125][126][127].…”

“…For example, the adsorption efficiency of Ni(II), Cu(II), Cd(II) and Cr(VI) ions by Fe 3 O 4 nanoparticles was strongly dependent on pH, temperature, amount of the adsorbent and the incubation time [124][125][126][127]. Further, a higher removal efficiency of these metal ions at a 3.5 mg mL [124][125][126][127]. Singh et al [46] reported the removal of toxic metal ions from wastewater using carboxyl-, amine-and thiol-functionalized Fe 3 O 4 nanoparticles (succinic acid, ethylenediamine and 2,3-dimercaptosuccinic acid, respectively).…”

“…It has been reported that these surface-engineered Fe 3 O 4 nanoparticles have a strong affinity for the simultaneous adsorption of [45,47,48,51,68,118,[123][124][125][126]. In addition, the adsorption process was found to be highly dependent on the amount, surface functionality and pH of the medium, which caused these nanoparticles to selectively adsorb metal ions [125][126][127]. An almost 100% removal rate of Cr(III), Co(II), Ni(II), Cu(II), Cd(II) and Pb(II) ions from water was reported at pH [ 8 by these functionalized nanoparticles [124][125][126][127].…”

Recovery of Phosphate from Mixed Solutions Using Surface Modified Maghemite Nano-Adsorbents

“…Dimercaptosuccinic acid (DMSA) is one surface coating that has been studied because of its stable molecular structure across a wide pH range and ability to prevent particle aggregation at high ionic strengths [21]. Secondary molecules can also be bound to the carboxylates on the DMSA molecule once adsorbed to the γ-Fe 2 O 3 nanoparticles.Coating Fe 3 O 4 nanoparticles with DMSA increased copper adsorption in synthetic groundwater and river water from 3.45 mgCu(II)/g to 36.49 mgCu(II)/g and 23.82 mgCu(II)/g, respectively [19,20]. Warner et al found that DMSA-coated γ-Fe 2 O 3 nanoparticles having a diameter of 7.2 nm adsorbed 23.8 mg Cu(II)/g compared to 3.5 mg Cu(II)/g for bare γ-Fe 2 O 3 nanoparticles of equal diameter [19].…”

“…This characteristic is particularly attractive as it affords the possibility of separating the adsorbent/adsorbate complex from solution without the need for clarification or filtration processes [16]. For these reasons they have become the focus of a large body of research on using magnetic nanoparticle for metal recovery from solution [14,[17][18][19][20]. γ-Fe 2 O 3 nanoparticles can adsorb metals in both a bare or surface modified state.…”