An Integrating Platform of Ratiometric Fluorescent Adsorbent for Unconventional Real-Time Removing and Monitoring of Copper Ions

Abstract

Nondegradable heavy metals have caused great dangers to the environment and human health. Combining stimuli-responsive materials with conventional MOF-based adsorbents has been considered an effective method to generate intelligent adsorbents for superior control over the adsorption process. Herein, a smart MOF-based ratiometric fluorescent adsorbent was designed to accurately monitor the progression of the removal of copper ions with dual-emitting fluorescence signal. Unlike the traditional difunctional materials, this delicately designed platform overcomes the huge energy gap to achieve two functions simultaneously. This unconventional platform provides a reliable fluorescent response toward Cu2+ during the removing process, changing linearly related to the degree of the adsorption process, which holds extreme promise in effectively monitoring the adsorption process. The underlying relationship of the adsorption and fluorescence response process toward copper was investigated by density functional theory (DFT) calculations. In particular, because of the favorable ion binding affinity of ZIF-8 and self-calibrating effect of RhB, the as-prepared smart adsorbent demonstrates a superior adsorption performance of 608 mg g–1, broad response range (0.05–200 ppm, 2.07 × 10–7to 8.29 × 10–4 M), ultrahigh sensitivity (0.04 ppm, 1.91 × 10–7 M) toward Cu2+ and strong anti-interference ability. This smart adsorbent opens an intelligent pathway to promote substantial advancements in the fields of environmental monitoring and industrial waste management.

N-alkylation briefly constructs tunable multifunctional sensor materials: Multianalyte detection and reversible adsorption

“…SPBI-c (28.5% alkylation) and SPBI-g (65.0% alkylation) could also discern Cu 2+ and Fe 3+ but with different sensitivities (Figures S27-S39 and further discussions can be seen in the SI). The signals of SPBI-c were more sensitive to Cu 2+ than those of SPBI-g, and its sensitivity was also better than those of some reported metal ion sensors (Table S6) (Kim et al, 2013;Zhang et al, 2020a;Du et al, 2020). For Fe 3+ , the sensitivity of SPBI-c was also higher than that of SPBI-g as well as those of some reported Fe 3+ sensors (Table S7) (Li et al, 2019a(Li et al, , 2019bFan et al, 2020;Cui et al, 2020;Zheng et al, 2020;Shia et al, 2020;Jia et al, 2020;Sun et al, 2020).…”

Preparation of Large Conjugated Polybenzimidazole Fluorescent Materials and Their Application in Metal Ion Detection

“…According to the calculation method reported in the literature [ 47 , 48 , 49 ], the fluorescence detection limit of sensor CPBI 2 for Cu 2+ and Zn 2+ can be calculated as 5.98 × 10 −9 M and 6.02 × 10 −9 M, respectively ( Figure 5 b,d). Compared with the data reported before, the results indicate that sensor CPBI 2 is more sensitive than most known Cu 2+ and Zn 2+ sensors [ 50 , 51 , 52 , 53 , 54 ] (more comparisons can be seen in Tables S5 and S6 ).…”

“…According to the calculation method reported in the literature [47][48][49], the fluorescence detection limit of sensor CPBI 2 for Cu 2+ and Zn 2+ can be calculated as 5.98 × 10 −9 M and 6.02 × 10 −9 M, respectively (Figure 5b,d). Compared with the data reported before, the results indicate that sensor CPBI 2 is more sensitive than most known Cu 2+ and Zn 2+ sensors [50][51][52][53][54] (more comparisons can be seen in Tables S5 and S6). In addition, as a "turn-off" fluorescence sensor, the fluorescence-quenching proces of CPBI2 can be determined by Stern-Volmer (S-V) constant (Ksv), whose calculation formula is: I0/I = 1+Ksv[Q] (Figure 6).…”

Applications of MOFs as Luminescent Sensors for Environmental Pollutants

“…Zhou and Wang et al reported a ratiometric luminescent RhB@ZIF-8, which was prepared through encapsulating dye molecule Rhodamine B (RhB) into ZIF-8. [75] ): Compared with the above mentioned heavy metal ions, Cr(VI) species, as toxic anions, is more widely detected using LMOF-based sensors. Our group reported a 3D heterometallic Dy-Zn MOF by 4,4′-dicarboxylate-2,2′-dipyridine anion ligand.…”