Removal of arsenic and mercury species from water by covalent triazine framework encapsulated γ-Fe2O3 nanoparticles

Abstract

The covalent triazine framework, CTF-1, served as host material for the in situ synthesis of FeO nanoparticles. The composite material consisted of 20 ± 2 m% iron, mainly in γ-FeO phase. The resulting γ-FeO@CTF-1 was examined for the adsorption of As, As and Hg from synthetic solutions and real surface-, ground- and wastewater. The material shows excellent removal efficiencies, independent from the presence of Ca, Mg or natural organic matter and only limited dependency on the presence of phosphate ions. Its adsorption capacity towards arsenite (198.0 mg g), arsenate (102.3 mg g) and divalent mercury (165.8 mg g) belongs amongst the best-known adsorbents, including many other iron-based materials. Regeneration of the adsorbent can be achieved for use over multiple cycles without a decrease in performance by elution at 70 °C with 0.1 M NaOH, followed by a stirring step in a 5 m% HO solution for As or 0.1 M thiourea and 0.001 M HCl for Hg. In highly contaminated water (100 μg L), the adsorbent polishes the water quality to well below the current WHO limits.

Emerging Functional Porous Polymeric and Carbonaceous Materials for Environmental Treatment and Energy Storage

“…In addition to the thiol functionalization, [149] other functional groups like S heteroatom ring, [72] N heteroatom, [73,80] perfluorous group, [78] ferrocene, [75] carboxyl and phenolate [178] groups have also been selected as chelating sites for the removal of other ions like Pb 2+ , [70,178,200] Au 3+ , [74] Nd 3+ , [148] and others. [201] Liu et al introduced an easy-to-make porous conjugated polymer (TMBPT), which consisted of a triazine ring bonded to three 3,5-dimethylpyrazole moieties. [79] The TMBPT can selectively bind and separate Ag(I) ions from base metal ions (e.g., Figure 6.…”

The interfacial reactivity of arsenic species with green rust sulfate (GRSO4)

“…have been shown to have little or no effect on As adsorption (Asere et al, 2017;Guo and Chen, 2005;Gupta et al, 2009). Common aqueous groundwater ions can compete for the available active surface sites on GR SO4 (Folens et al, 2016;Leus et al, 2018). We tested the effect of relevant dissolved potentially interfering ions in the water matrix through competitive adsorption experiments with Ca 2+ (100 mg L −1 ), Mg 2+ (50 mg L −1 ) or PO 4 3− (10 mg L −1 ) and As (10 mg L −1 ) to the GR SO4 suspension at pH 8.…”

Geogenic arsenic removal through core–shell based functionalized nanoparticles: Groundwater in-situ treatment perspective in the post–COVID anthropocene

“…It has been very well–known that As is naturally present in the groudwater, which is considered to be one of the significant drinking water sources in the contemporary time, along with the other common geogenic cationic (i.e., Ca 2+ , Mg 2+ and Fe 2+ ) and anionic (i.e., F – , Cl – , SO 4 2– , NO 3 – , PO 4 3– , CO 3 2– and SiO 4 4– ) species ( Leus et al, 2018 ). These differently charged species (anions/cations) may have synergistic and/or antagonistic effects on the adsorption of As.…”

“…In previous studies authors tried to directly coat iron oxide NPs with alginate biopolymer, however it could not prevent aggregation of iron NPs mainly because alginate polymeric backbone is more conformationally limited ( Sreeram et al, 2004 ; Ma et al, 2007 ). Hence, recently extensive organic groups containing materials, also known as covalent organic frameworks (COFs) have been applied for the functionalization of the iron based NPs ( Liu et al, 2017 ; Leus et al, 2018 ). However, several associated challenges such as, complex fabrication/synthesis procedure, less stability and generation of anonymous toxic breakdown products restrict their applications for the groundwater purification.…”