Green Synthesis of De Novo Bioinspired Porous Iron-Tannate Microstructures with Amphoteric Surface Properties

Abstract

Bioinspired porous microstructures of iron-tannate (Fe(III)-TA) coordination polymer framework were synthesized by catenating natural tannic acid with iron(II), using a scalable aqueous synthesis method in ambient conditions. The chemical composition, morphology, physiochemical properties, and colloidal stability of microstructures were elucidated. The surface area (SBET) and the desorption pore volume were measured to be 70.47 m2/g and 0. 44 cm3/g, respectively, and the porous structure was confirmed with an average pore dimension of ~27 nm. Microstructures were thermally stable up to 180 °C, with an initial weight loss of 13.7% at 180 °C. They exhibited high chemical stability with pH-responsive amphoteric properties in aqueous media at pH levels ranging from 2 to 12. Supporting their amphoteric sorption, microstructures exhibited rapid removal of Pb+2 from water, with 99% removal efficiency, yielding a maximum sorption capacity of 166.66 mg/g. Amphoteric microstructures of bioinspired metal–phenolate coordination polymers remain largely unexplored. Additionally, natural polyphenols have seldomly been used as polytopic linkers to construct both porous and pH-responsive amphoteric coordination polymer frameworks with a robust structure in both acidic and basic media. Thus, this de novo porous microstructure of Fe(III)-TA and its physiochemical surface properties have opened new avenues to design thermally and chemically stable, eco-friendly, low-cost amphoteric sorbents with multifunctionality for adsorption, ion exchange, separation, storage, and sensing of both anions and cations present in heterogeneous media.

Mechanistic Understanding of Sieving Lithium Ions Using a Biobased Sorbent Technology for Sustainable Lithium Reclamation and Cleansing Brines

“…As the first bioinspired coordination polymer with a rigid framework synthesized from a polytopic natural polyphenol, the porous Fe(III)-TA sorbent demonstrates the use of biomass building blocks to construct an environmentally benign bioinspired adsorbent using a green synthesis in a large scale under ambient conditions in water (Figure 1). 14 The structural and chemical composition of the sorbent was confirmed by FTIR spectroscopy (Figure S1a) and XPS elemental survey analysis (Figure S1b adsorption highlight Fe(III)-TA's potential utility as an amphoteric sorbent for separation, extraction, and upcycling of anions, cations, toxic heavy metals, valuable minerals, and organic contaminants from water resources. 14 For instance, the physiochemical surface properties of this sorbent provides a greater insight into understanding the interfacial interactions with a variety of impurities present in aqueous solutions, enabling one to use it as an adsorbent for contaminant removal and separation from aqueous environments.…”

“…As the first bioinspired coordination polymer with a rigid framework synthesized from a polytopic natural polyphenol, the porous Fe­(III)-TA sorbent demonstrates the use of biomass building blocks to construct an environmentally benign bioinspired adsorbent using a green synthesis in a large scale under ambient conditions in water (Figure ). The structural and chemical composition of the sorbent was confirmed by FTIR spectroscopy (Figure S1a) and XPS elemental survey analysis (Figure S1b and Table S1). Microporosity, amphoteric surface properties, and colloidal stability in water at a wider range of pH as well as heavy metal adsorption highlight Fe­(III)-TA’s potential utility as an amphoteric sorbent for separation, extraction, and upcycling of anions, cations, toxic heavy metals, valuable minerals, and organic contaminants from water resources .…”

“…14 For instance, the physiochemical surface properties of this sorbent provides a greater insight into understanding the interfacial interactions with a variety of impurities present in aqueous solutions, enabling one to use it as an adsorbent for contaminant removal and separation from aqueous environments. 14 Owing to the amphoteric nature of Fe(III)-TA sorbents, the solid-phase adsorption of Fe(III)-TA could offer a favorable path to extract one class of analytes over another. Favoring the cationic interactions with the sorbent's surface, we conditioned the sorbents with a weak base to reach the pH of the colloidal solution above 5.…”

“…Microporosity, amphoteric surface properties, and colloidal stability in water at a wider range of pH as well as heavy metal adsorption highlight Fe(III)-TA's potential utility as an amphoteric sorbent for separation, extraction, and upcycling of anions, cations, toxic heavy metals, valuable minerals, and organic contaminants from water resources. 14 For instance, the physiochemical surface properties of this sorbent provides a greater insight into understanding the interfacial interactions with a variety of impurities present in aqueous solutions, enabling one to use it as an adsorbent for contaminant removal and separation from aqueous environments. 14 Owing to the amphoteric nature of Fe(III)-TA sorbents, the solid-phase adsorption of Fe(III)-TA could offer a favorable path to extract one class of analytes over another.…”

“…The conventional sorbent-based methods, including ion-exchange techniques, uses large volumes of freshwater during the lithium recovery process and discharges untreated brines to the environment. 3−5 Focusing on the in-depth adsorption studies of our previously developed novel biobased sorbent, iron(III)-tannate (Fe(III)-TA), 14 for lithium, we reveal its feasibility as a platform for a sorbent-based method for lithium capture and refining from brine. The attractiveness of Fe(III)-TA is featured by its origin from a natural polyphenol, a readily available biomass byproduct derived from agricultural waste.…”