A self-supported CuO/Cu nanowire electrode (CuO/CuNWE), which was prepared by annealing Cu nanowires to form a porous Cu nanowire electrode (CuNWE) and then anodizing the as-prepared CuNWE in alkaline medium to generate Cu(OH)₂ nanowires followed by calcination, was employed for chemical oxygen demand (COD) determination using cyclic voltammetry (CV). The structure and electrochemical behavior of the CuO/CuNWE were investigated by scanning electron microscopy, X-ray diffraction, and CV. The results indicated that the as-synthesized CuO/CuNWE, in which CuO nanowires with a length of several micrometers and a diameter of 100 to 300 nm could be found, was stable in alkaline medium and more electrocatalytically active for oxidizing a wide range of organic compounds in comparison with the CuNWE. Under optimized alkaline concentration and scan rate, the CuO/CuNWE exhibited a good performance for COD measurement, with a linear range of 5 to 1153 mg L⁻¹, a sensitivity of 2.46× 10⁻² mA /(mg L⁻¹), and a detection limit of about 2.3 mg L⁻¹. In addition, an excellent correlation was observed in COD values obtained by our method and the classic dichromate method (r = 0.9995, p < 0.01, n = 11). Finally, our method was successfully used to measure the COD values in real water samples, showing great potential for practical application in water pollution control.

In recent years, antibiotics (such as levofloxacin (LEV)) have been detected widely in the environment. Semiconductor photocatalysis has been recognized as a promising technology for removing pollutants in the environment. In this work, nitrogen and carbon codoped titanium dioxide nano-catalyst (NCD-TiO₂) was immobilized in polyvinyl alcohol (PVA) matrix to form PVA/NCD-TiO₂ films through solution casting and thermal treatment, which exhibited good photocatalytic efficiency for LEV degradation. The results showed that about 42% LEV can be degraded after 2 h in the presence of PVA/NCD-TiO₂ nanocomposite film (the weight ratio of NCD-TiO₂ to PVA is 8% and thermal treatment is 120 °C) under visible light. Moreover, possible pathways of photocatalytic degradation of LEV according to the detected intermediates are proposed, which provide insight into the degradation mechanism of LEV by using PVA/NCD-TiO₂ photocatalytic films. Finally, the synthesized PVA/NCD-TiO₂ films exhibited excellent reusability and stability in photocatalysis. This work provides fundamental support for the design of a high-stability, excellent photocatalyst for practical application.

The adsorption behavior of pharmaceuticals and personal care product, Bisphenol-A (BPA), according to four coal-based and four wood-based granular activated carbons modified using outgassing treatment, acidic treatment or alkaline treatment was studied. The adsorption isotherm results indicated that carbon surface acidity played a very important role in the adsorption of BPA. It was found that increasing surface acidity would increase the hydrogen bonding effects and increase adsorption of BPA on activated carbon. The acidic modified sample (F600-A and OLC-A) represented the best adsorption capacity, and the equilibrium adsorption amounts reached 346.42 and 338.55 mg/g, respectively. Further, effects of surface charge and surface basicity were examined. It was found that the adsorbed amount of BPA decreased with the increase of surface charge. Finally, there appeared to be a significant oligomerization phenomenon with BPA molecules onto the surface of activated carbon. OLC and OLC-OG, which have higher micropore percentages, are very effective in hampering the oligomerization of BPA under oxic conditions.

A titanate nanotube catalyst for ozonation was synthesized with a simple one-step NaOH hydrothermal treatment without energy-consuming calcination. The synthesized titania catalysts were characterized by X-ray diffraction (XRD), Raman, porosimetry analysis, high-resolution transmission electron microscopy (HR-TEM), Fourier transformed infrared (FTIR), and electron paramagnetic resonance (EPR) analysis. The catalyst treated with a higher concentration of NaOH was found to be more catalytically active for phenol removal due to its higher titanate content that would facilitate more OH groups on its surface. Furthermore, the main active oxidizing species of the catalytic ozonation process were recognized as singlet oxygen and superoxide radical, while the hydroxyl radical may only play a minor role. This work provides further support for the correlation between the properties of titania and catalytic performance, which is significant for understanding the mechanism of catalytic ozonation with titania-based materials.