Organotrialkoxysilane-Functionalized Prussian Blue Nanoparticles-Mediated Fluorescence Sensing of Arsenic(III)

Abstract

Prussian blue nanoparticles (PBN) exhibit selective fluorescence quenching behavior with heavy metal ions; in addition, they possess characteristic oxidant properties both for liquid–liquid and liquid–solid interface catalysis. Here, we propose to study the detection and efficient removal of toxic arsenic(III) species by materializing these dual functions of PBN. A sophisticated PBN-sensitized fluorometric switching system for dosage-dependent detection of As3+ along with PBN-integrated SiO2 platforms as a column adsorbent for biphasic oxidation and elimination of As3+ have been developed. Colloidal PBN were obtained by a facile two-step process involving chemical reduction in the presence of 2-(3,4-epoxycyclohexyl)ethyl trimethoxysilane (EETMSi) and cyclohexanone as reducing agents, while heterogeneous systems were formulated via EETMSi, which triggered in situ growth of PBN inside the three-dimensional framework of silica gel and silica nanoparticles (SiO2). PBN-induced quenching of the emission signal was recorded with an As3+ concentration (0.05–1.6 ppm)-dependent fluorometric titration system, owing to the potential excitation window of PBN (at 480–500 nm), which ultimately restricts the radiative energy transfer. The detection limit for this arrangement is estimated around 0.025 ppm. Furthermore, the mesoporous and macroporous PBN-integrated SiO2 arrangements might act as stationary phase in chromatographic studies to significantly remove As3+. Besides physisorption, significant electron exchange between Fe3+/Fe2+ lattice points and As3+ ions enable complete conversion to less toxic As5+ ions with the repeated influx of mobile phase. PBN-integrated SiO2 matrices were successfully restored after segregating the target ions. This study indicates that PBN and PBN-integrated SiO2 platforms may enable straightforward and low-cost removal of arsenic from contaminated water.

Electrochemical Sensing and Removal of Cesium from Water Using Prussian Blue Nanoparticle-Modified Screen-Printed Electrodes

“…A fluorometric method was utilized to understand cesium-mediated fluorescence quenching; the obtained values were compared to those recorded for As(III) as reported earlier [15]. Fluorescein was used as probe molecule (λex = 480 nm, λem= 510 nm).…”

“…The conventional synthesis of PB is followed by agglomeration of nuclei into large particles; this phenomenon is associated with the poor processability of PB into PB filmmodified electrodes [13,14]. Accordingly, we have demonstrated an efficient approach that enables the controlled conversion of the single precursor potassium ferricyanide into PB nanoparticles as shown in TEM images (Figure 2) using small organic reducing agents [13][14][15][16]. We have already demonstrated that the organic reagent tetrahydrofuran in the presence of hydrogen peroxide enabled the conversion of K 3 [Fe(CN) 6 into PB nanoparticles [16].…”

“…We recently demonstrated that PB nanoparticles served as an efficient nanomaterial for sensing and removal of As(III) [15]. In order to understand the utility of PB for sensing and removal of cesium ions, it is important to discriminate the interaction of PB with hydrogen peroxide, arsenic (III), and cesium ions.…”

“…Accordingly, this study involved understanding the electrochemical adsorption and sensing behavior of a PB-modified electrode. It has been previously shown that PB serves as an artificial peroxidase and displays electrochemical behavior as a function of hydrogen peroxide concentration [12][13][14][15][16]. In addition, recent studies indicate that PB can be used for the sensing and screening of As(III) in water [15], which directed us to examine the selectivity, if any, on the interaction dynamics of PB and appropriate analytes (hydrogen peroxide, arsenic (III) ions, and cesium ions) using PB-modified electrodes.…”

“…The controlled synthesis of PB and its mixed metal analogs has been previously evaluated; the processability and nanoscale geometry of this material have been demonstrated [12][13][14][15][16]. It should be noted that PB is a US Food and Drug Administration-approved drug for the treatment of radioactive exposure and has been clinically used for the treatment of 137 Cs-contaminated individuals [17].…”