Tailoring the heterojunction of TiO2 with multivalence CeO2 nanocrystals - for detection of toxic 2-aminophenol

Visible-light-driven photoelectrochemical sensor based on conjugated microporous polymer-grafted graphene for o-aminophenol detection

The pollutant o-aminophenol (o-AP) presents considerable risk to environmental safety, and its detection is therefore critical. Although various optical and electrochemical methods have been proposed for the detection of o-AP, there are a limited number of detection methods based on photoelectrochemical (PEC) sensors. In this study, a sensitive visible-light-driven PEC sensor was developed for o-AP detection in water. A conjugated microporous polymer (CMP)-coated graphene heterostructure (CMP-rGO) was synthesized and used to develop a PEC sensor. Under optimal conditions, the proposed sensor exhibited a high sensitivity of 0.03 μM with a wide linear range of 0.0034-37.6 μM. The PEC sensor also displayed acceptable repeatability and reproducibility, good long-term stability, and excellent recovery (98-102%). In addition, the binding patterns of CMP to o-AP and o-AP analog molecules were analyzed by molecular docking. Therefore, this study provides a new and feasible PEC sensor-based detection scheme for o-AP detection.

Fabrication and characterization of new Fe3O4@SiO2@TiO2-CPTS-HBAP (FST-CH) nanoparticles for photocatalytic degradation and adsorption removal of rhodamine B dye in the aquatic environment

In this study, Fe3O4@SiO2@TiO2-CPTS-HBAP (FST-CH) nanoparticle was prepared for the simultaneous adsorption and photocatalytic degradation of aromatic chemical pollutants (Rhodamine B dye) in aqueous solution. FST-CH nanoparticle was characterized using scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR), Energy Dispersive X-Ray (EDX) Fluorescence Spectrometer and X-Ray Diffraction (XRD) spectroscopy. The photocatalytic activity of rhodamine B dye (RhB) was evaluated with a Kerman UV 8/18 vertical roller photoreactor. About 56% of RhB in aqueous medium was adsorbed by FST-CH nanoparticles with only 45 min of stirring in the dark, and about 77.01% was degraded or converted to other structures under the photoreactor for 120 min. The photocatalytic degradation of RhB (apparent rate constant: 0.0026 mg dm-3 min-1) occurred by a pseudo-second order reaction. In addition, the recovery of the prepared magnetic FST-CH nanoparticle by an external magnetic field, exhibiting good magnetic response and reusability, shows that the obtained magnetic FST-CH nanoparticle is stable and maintains high degradation ratio and catalyst recovery even after four cycles. Thus, the prepared FST-CH nanoparticle can be highly recommended for its use in potential applications of water decontamination.

Spindle-shaped Cu-Ru mesoporous nanospheres with enhanced enzyme-like activity for visual differentiation of toxic o-/m-aminophenol and recognition mechanisms

To effectively differentiate toxic aminophenol isomers, a kind of spindle-shaped Cu-Ru bimetal mesoporous nanozyme (Cu-Ru MPNZ) with high specific surface was developed by one-pot homogeneous reduction method, directed by hexadecyl trimethyl ammonium bromide (CTAB) in this work. By virtue of the distinctive microstructure, Cu-Ru MPNZ expressed superior bi-functional oxidase- and peroxidase-mimic activity to catalyze the oxidation of 3,3',5,5,'-tetramethylbenzidine (TMB) and 2,2'-azinobis (3-ethylbenzothiazoline-6- sulfonic acid) ammonium salt (ABTS) with low Michaelis-Menten constants and quick reaction rates. Especially, toxic aminophenol isomers could exclusively react with the oxydates of TMB or ABTS to express differentiable signals in color. Under the optimal conditions, Cu-Ru MPNZ was successfully applied for visual differentiation of toxic aminophenol isomers in real aqueous, juices and medicinal samples with low detection limits (1.60 × 10-8 mol/L for o-aminophenol and 3.25 × 10-8 mol/L for m-aminophenol) and satisfactory recoveries (96.6-103.5%). The different recognition mechanisms of Cu-Ru MPNZ to toxic o- and m-aminophenol isomers were proposed for the first time as far as we known. This work will provide a potential way to monitor different organic isomer pollution in future.