Fabrication of Organic Probe Decorated Water-Soluble Polymer Chains on Natural Fibers for Selective Detection and Efficient Removal of Hg²⁺ Ions in Pure Aqueous Media

Abstract

Developing dual-functional materials that can simultaneously detect and remove toxic heavy metal ions is of practical importance but still remains a challenging task. Herein, an ionrecognizable material, MA−SAPQA@NFs, was facilely fabricated through covalent grafting of salicylaldehyde-containing polymeric quaternary ammonium (SAPQA) chains onto the lotus seedpodderived natural fibers (NFs), followed by decoration with 2mercaptoaniline (MA). Several remarkable features for MA− SAPQA@NFs, which could rarely be achieved in previous studies, were integration of good hydrophilicity, high content of organic probe units, and specific visual recognition ability toward Hg 2+ , making it an excellent candidate as a dual-functional platform for simultaneous detection and removal of Hg 2+ under completely aqueous conditions. The distinctive color change as result of Hg 2+ binding to MA−SAPQA@NFs could be detected easily by the naked eye and allowed quantitative determination of Hg 2+ in simulated and real water samples with the assistance of a smartphone. Meanwhile, the MA−SAPQA@NFs was demonstrated to be highly efficient in removal of Hg 2+ , exhibiting a very high adsorption capacity (218.21 mg g −1 ), strong anti-interference ability, rapid kinetics, and satisfying reusability. Furthermore, characterization analysis in combination with theoretical calculations revealed the possible binding mechanism behind the detection and adsorption processes. All these findings indicate that the MA−SAPQA@NFs is highly promising for applications in assessment and remediation of heavy metal pollution.

A Selenone-Functionalized Polyhedral Oligomeric Silsesquioxane for Selective Detection and Adsorption of Hg2+ ions in Aqueous Solutions

“…Moreover, POSS-Se was determined to have a capacity of 952 mg g −1 of Hg 2+ (the capacity of POSS-Se (HCl) is 907 mg g −1 , which was determined under the same method to that of POSS-Se). This value is higher than most reported Hg 2+ adsorbents, such as NH 2 -MIL-53(Al) (153.85 mg g −1 ) [42], MA−SAPQA@NFs (218.21 mg g −1 ) [43], sulfur-doped porous reduced graphene oxide (829.27 mg g −1 ) [47], SiO 2 -G0-SA∼SiO 2 -G2.0-SA (363.07 mg g −1 ) [51], and TAPB-BMTTPA-COF (734 mg g −1 ) [53], although some of them have lower LODs compared to that of POSS-Se (HCl) ( Table 1). experiment was performed by adsorbing Hg 2+ ions (1000 ppm) using POSS-Se and the acid product POSS-Se (HCl) as the adsorbents as suspension in water (1 mg mL −1 ).…”

“…POSS-Se (HCl) exhibits a high sensitivity towards Hg 2+ with a low LOD of 8.48 ppb (Figure 4c). The acquired value is comparable to or higher than many reported sensors [39], such as Fe 3 O 4 @TiO 2 -L (L=2,6-bis(2-thienyl)pyridine, 1.40 ppm) [40], thioether-based fluorescent covalent organic framework (COF-LZU8, 25.0 ppb) [41], metal-organic framework (NH 2 -MIL-53(Al), 30.13 ppb (0.15 µM)) [42], nature fibers modified by polymer chains (MA−SAPQA@NFs, 16.72 ppb (0.08 µM)) [43], silica modified by an anthracene excimer (SiO 2 @PBATPA, 37 ppb) [44], and vesicular chemical sensor (10.64 ppb (53.0 nM)) [45], but lower than some sensors such as rhodamine B selenolactone (4.62 ppb (53.0 nM)) [37], fluorescent phosphane selenide (0.18 ppb) [46], and sulfur-doped porous reduced graphene oxide [47] ( Table 1). The lower performance may be due to the heterogenous detection by POSS-Se (HCl), which is insoluble in water, in contrast to the homogenous detection by most sensors, which are commonly soluble in water.…”

Magnetic Activated Carbon from ZnCl2 and FeCl3 Coactivation of Lotus Seedpod: One-Pot Preparation, Characterization, and Catalytic Activity towards Robust Degradation of Acid Orange 10

“…It was suggested that the initial natural porous structure of LSP for ZnCl 2 and FeCl 3 loading played an important role in the morphology of Fe- and Zn-based products. LSP contains natural cellulose fibers [ 84 ]. Wire-like morphology may, therefore, result from crystallization in an extremely narrow fibrous matrix.…”

Bifunctional Porous Organic Polymers Based on Postfunctionalization of the Ketone-Based Polymers

“…The saturation adsorption ( q max ) of the precursor polymers varied from 128 to 216 mg/g, while the final polymers showed a much higher q max of 374–425 mg/g, which was comparable to some reported polymers (Table ). ,− The much higher Hg 2+ capacities of the MA-based polymers should be from the fact that they had much higher V micro and N content. TPE–PMDA–MA possessed the highest Hg 2+ uptake of 425 mg/g at 298 K. Its highest S BET , V micro , and abundant N groups should give great positive contributions.…”