Self-Assembly of Poly(ethyleneimine)-Modified g-C₃N₄ Nanosheets with Lysozyme Fibrils for Chromium Detoxification

Abstract

We disclose a straightforward approach to fabricate nanocomposites for efficient capture of Cr­(VI) from an aqueous solution through the self-assembly of poly­(ethyleneimine)-modified graphitic carbon nitride nanosheets (PEI-g-C3N4 NSs) and lysozyme fibrils (LFs). The as-made PEI-g-C3N4 NSs@LFs exhibited mesoporous structures with a high specific surface area of 39.6 m2 g–1, a large pore volume of 0.25 cm3 g–1, several functional groups (e.g., −N, −NH, −NH2, and −COOH), and a zero-point charge at pH 9.1. These merits allow the PEI-g-C3N4 NSs@LFs to further enhance their physical adsorption and electrostatic attraction with the negatively charged Cr­(VI) species of HCrO4 – and CrO4 2–, which is beneficial for the uptake of Cr­(VI), >80%, from an aqueous solution in a wide pH range. Interestingly, X-ray photoelectron spectra indicate that the PEI-g-C3N4 NSs@LFs converted Cr­(VI) to Cr­(III) through visible-light-induced photoreduction. The adsorption of Cr­(VI) on the surface of PEI-g-C3N4 NSs@LFs was found to obey the Freundlich isotherm model, signifying that they have a heterogeneous surface for the multilayer uptake of Cr­(VI). In contrast, the PEI-g-C3N4 NSs and LFs as Cr­(VI) adsorbents followed the Langmuir isotherm model. Adsorption kinetic studies showed that the uptake of Cr­(VI) through the PEI-g-C3N4 NSs@LFs was highly correlated with a pseudo-first-order model, suggesting that physisorption dominates the interaction of Cr­(VI) and the PEI-g-C3N4 NSs@LFs. In real-life applications, the PEI-g-C3N4 NSs@LFs were used for the detoxification of the total chromium in the industrial effluent and sludge samples.

Covalent Organic Framework Nanosheets as an Enhancer for Light-Responsive Oxidase-like Nanozymes: Multifunctional Applications in Colorimetric Sensing, Antibiotic Degradation, and Antibacterial Agents

“…The resulting mixture was then transferred to a silica crucible and heated under N 2 gas at 550 °C for 5 h. The products were cooled at room temperature and then crushed into a very fine powder. The as-prepared COF powder (0.5 g) was dispersed in HCl (2.0 M, 100 mL) and then ultrasonicated at ambient temperature for 9 h. The resulting products were centrifuged (45 min, 5000 rpm) and filtered to yield exfoliated COF NSs . Following the incubation of the obtained COF NSs with PEI (10% v/v, 10 mL) for 5 h under sonication, the unbound PEI molecules were removed by multiple washes with Milli-Q water.…”

RecJf exonuclease-assisted signal amplification for the sensitive detection of di(2-ethylhexyl)phthalate by a Pd@Au NB labeled electrochemical aptasensor based on Au@Ni-CoHNB/PEI-g-C3N4

“…† PEI-g-C 3 N 4 was prepared according to a previous report. 36 5 mg of the prepared g-C 3 N 4 was dispersed in 5 mL of water, and then 100 mL of PEI (2%, 20 mg mL À1 ) was added and stirred at 400 rpm at 25 1C overnight. The mixture was centrifuged to remove unreacted PEI, and the obtained PEI-g-C 3 N 4 was redispersed in 5 mL of distilled water.…”

“…Through the Au–N bonds, numerous Au@Ni-CoHNBs will be attached, providing more binding sites for Apt. 36 However, the application of g-C 3 N 4 in electrochemical sensors is limited due to poor conductivity. Therefore, g-C 3 N 4 was functionalized by polyethyleneimine (PEI) which is a water-soluble macromolecular polymer with good electrical conductivity to increase the electron transfer rate and improve the electrode performance.…”

Synergistic Generation of Radicals by Formic Acid/H2O2/g-C3N4 Nanosheets for Ultra-efficient Oxidative Photodegradation of Rhodamine B

“…26,27 In particular, g-C 3 N 4 , a non-metallic conjugated visible-light sensitive photocatalyst, has received extensive interest since its first development in 2009 28 due to its great potential in various photocatalytic applications, including H 2 /O 2 evolution in water splitting, 29−33 H 2 O 2 production, 23,34,35 CO 2 reduction, 22,36 and pollutant photodegradation. 2,7,37 Tremendous efforts have been devoted to improve the energy harvesting of g-C 3 N 4 based on the photocatalytic process, which typically involves four steps: light-induced generation of electron−hole pairs, separation and migration of charge carriers, reduction or oxidation reaction with electrons or holes, and recombination of charge carriers. First, rational morphological or topological design of g-C 3 N 4 might enhance its solar energy harvest.…”

“…Semiconductor photocatalysts have been developed to construct expeditious solar energy conversion systems for photocatalysis, ,, such as TiO 2, , ZnO, , perovskites, graphite carbon nitride (g-C 3 N 4 ), − and metal–organic frameworks. , In particular, g-C 3 N 4 , a non-metallic conjugated visible-light sensitive photocatalyst, has received extensive interest since its first development in 2009 due to its great potential in various photocatalytic applications, including H 2 /O 2 evolution in water splitting, − H 2 O 2 production, ,, CO 2 reduction, , and pollutant photodegradation. ,, …”