Polymer sequestrants for biological and environmental applications

Abstract

Toxic contaminates have profound consequences on both health and the environment. Consequently, effective approaches for addressing the effects of these toxicants are paramount. Here, we review recent progress in developing polymeric sequestrants for biological toxins, heavy metals and organic micropollutants. Polymers have several advantages as sequestration materials, including relatively low cost and high affinity for target compounds. As a result a number of polymer-based toxin-mitigation applications have been investigated. Naturally occurring toxins may be neutralized with polymers capable of binding and eliminating them from the body. Heavy metal contamination from mining operations, energy and industrial sources may also be mitigated with appropriate chelating polymers, both for environmental remediation and in chelation therapy for metal poisoning. Micropollutants such as pesticides from agriculture and polycyclic aromatic hydrocarbons from combustion processes may also be isolated using polymeric materials. Each of these applications illustrates the capabilities of polymers for eliminating toxic contaminants, thereby facilitating greater health and sustainability.

Exploring the role of polymer hydrophobicity in polymer–metal binding thermodynamics

“…Several such approaches (e.g., polymer-enhanced ultrafiltration) use metal-chelating polymers to selectively bind and extract REEs. 3,4 Thus, quantifying metal binding thermodynamics in aqueous solution is critical, but the interactions among metal-ion, polymer, and water are complex. [5][6][7] To probe these complexities, the thermodynamics (DG, DH, and DS) of the polymer-metal interaction have been studied: Binding is entropy driven, suggesting the critical role of water in REE chelation.…”

Synthesis and Rare-Earth-Element Chelation Properties of Linear Poly(ethylenimine methylenephosphonate)

“…Rare-earth elements (REEs: La–Lu, Y, and Sc) are critical components in electronics, clean-energy technologies, catalysts, and other applications. − However, conventional sources of REEs are increasingly insufficient to keep pace with world demand and often have adverse effects on the environment. − For example, common solvent extraction processes for separating REEs require high volumes of organic extractants and strong acids, leading to negative environmental impacts . Consequently, effective technologies for the extraction and purification of REEs, particularly from waste streams or other unconventional sources, are of great interest. − …”

Effect of Copolymer Structure on Rare‐Earth‐Element Chelation Thermodynamics

“…[6][7][8] One approach for extracting and purifying REEs is to employ polymeric chelators-polymers containing ligands that can selectivity bind REEs in solution-in conjunction with polymer enhanced ultrafiltration (PEUF). [9,10] In PEUF, water-soluble, high-molecular-weight polymer chelators bind to the desired metal ion in solution. [11] After binding, the polymer-metal ion complex is rejected by an ultrafiltration membrane.…”