Ultrasensitive photoelectrochemical determination of chromium(VI) in water samples by ion-imprinted/formate anion-incorporated graphitic carbon nitride nanostructured hybrid

Abstract

A rapid and highly sensitive photoelectrochemical (PEC) method has been proposed for the determination of trace amounts of chromium in water samples under visible-light irradiation. Here, a unique nanostructured hybrid of formate anion incorporated graphitic carbon nitride (F-g-C3N4) is smartly integrated with a Cr(VI) ion-imprinted polymer (IIP) as a photoactive electrode (denoted as IIP@F-g-C3N4). The nanohybrid of F-g-C3N4 exhibits an enhanced charge separation with substantially improved PEC responses versus g-C3N4. The newly designed IIP@F-g-C3N4 PEC sensor exhibits high sensitivity and selectivity for the determination of Cr(VI) because it offers efficient photogenerated electron reduction toward Cr(VI). The PEC analysis is highly linear over Cr(VI) concentrations ranging from 0.01 to 100.00ppb with a detection limit of 0.006ppb (S/N=3). Our approach can be used to detect Cr(VI), Cr(III) and the total chromium level in aqueous solution through oxidation of Cr(III) to Cr(VI) and the determination of the total chromium as Cr(VI). In practical applications, this low-cost and sensitive assay has been successfully applied for speciation determination of chromium in environmental water samples.

Host–Guest Recognition on 2D Graphitic Carbon Nitride for Nanosensing

“…with a Cr 6+ -imprinted polymer (IIP) (IIP@F-g-C 3 N 4 ). [59] Compared with g-C 3 N 4 , the nanocomposite exhibits enhanced charge separation and substantially improved PEC responses. The results prove that the IIP@F-g-C 3 N 4 PEC sensor offers high sensitivity and selectivity for the detection of Cr 6+ , and IIP@F-g-C 3 N 4 analysis provides competent photogenerated electrons for the reduction of Cr 6+ (Figure 2g).…”

“…[63] Copyright 2016, Royal Society of Chemistry; (g) Reproduced with permission. [59] Copyright 2016, Elsevier B.V.; (h) Reproduced with permission. [61] Copyright 2017, Elsevier B.V.; (i, j) Reproduced with permission.…”

Recent Advances in Electrochemical Monitoring of Chromium

“…A nanostructured photoelectrochemical sensing element based on the use of Cr(VI) ion imprinted polymer and formate ion incorporated graphitic carbon nitride has been explored by the Tian Fang group [ 78 ] for Cr(VI) measurement in different water samples with good recovery of 89.8–105% at 0.006 µg·L −1 . The designed sensor exhibits high selectivity and sensitivity towards Cr(VI) owing to the efficient photogenerated electron reduction offered toward Cr(VI).…”

“…In another study, a PEC sensor based upon the combination of Cr(VI) ion imprinted polymer and formate anion incorporated graphitic carbon nitride (IIP@F-g-C 3 N 4 ) was developed and destined to Cr(VI) detection. The constructed sensor could also be used for total chromium quantification and that after the oxidation of Cr(III) by the use of hydrogen peroxide (H 2 O 2 ) whereas Cr(III) content was calculated by subtracting the Cr(VI) concentration from total Cr [ 78 ]. Another research group has developed a specific sensor for chromium determination at ppt level [ 43 ].…”

Ion-imprinted modified molecular sieves show the efficient selective adsorption of chromium(vi) from aqueous solutions

“…In 1972, Wulff et al 17 proposed molecule imprinting polymers, which have been shown to be an effective way to remove heavy metal ions from industrial wastewater with good selectivity. [18][19][20] Furthermore, the surface ion imprinting polymer technology (IIP) was studied because the traditional IIP have innate limitations such as heterogeneous distribution of the binding sites, incomplete template removal, and slow mass transfer for the target ions. Until now, numerous IIP studies have focused on Cr(VI) adsorption.…”