Enhanced tribocatalytic degradation performance of organic pollutants by Cu1.8S/CuCo2S4 p-n junction

Enhanced Tribodegradation of a Tetracycline Antibiotic by Rare-Earth-Modified Zinc Oxide

Tribocatalysis is an emerging advanced oxidation process that utilizes the triboelectric effect, based on friction between dissimilar materials to produce charges that can initiate various catalytic reactions. In this study, pure and rare-earth-modified ZnO powders (La2O3, Eu2O3, 2 mol %) were demonstrated as efficient tribocatalysts for the removal of the tetracycline antibiotic doxycycline (DC). While the pure ZnO samples achieved 49% DC removal within 24 h at a stirring rate of 100 rpm, the addition of Eu2O3 increased the removal efficiency to 67%, and La2O3-modified ZnO powder exhibited the highest removal efficiency, reaching 80% at the same stirring rate. Additionally, increasing the stirring rate to 300 and 500 rpm led to 100% DC removal in the ZnO/La case within 18 h, with the pronounced effect of the stirring rate confirming the tribocatalytic effect. All tribocatalysts exhibited excellent recycling properties, with less than a 3% loss of activity over three cycles. Furthermore, a scavenger assay confirmed the importance of superoxide radical generation for the overall reaction rate. The results of this investigation indicate that the rare-earth-modified ZnO tribocatalysts can effectively utilize mechanical energy to decompose pollutants in contaminated water.

Environmental remediation approaches by nanoscale zero valent iron (nZVI) based on its reductivity: a review

The fast rise of organic and metallic pollution has brought significant risks to human health and the ecological environment. Consequently, the remediation of wastewater is in extremely urgent demand and has received increasing attention. Nanoscale zero valent iron (nZVI) possesses a high specific surface area and distinctive reactive interfaces, which offer plentiful active sites for the reduction, oxidation, and adsorption of contaminants. Given these abundant functionalities of nZVI, it has undergone significant and extensive studies on environmental remediation, linking to various mechanisms, such as reduction, oxidation, surface complexation, and coprecipitation, which have shown great promise for application in wastewater treatment. Among these functionalities of nZVI, reductivity is particularly important and widely adopted in dehalogenation, and reduction of nitrate, nitro compounds, and metal ions. The following review comprises a short survey of the most recent reports on the applications of nZVI based on its reductivity. It contains five sections, an introduction to the theme, chemical reduction applications, electrolysis-assisted reduction applications, bacterium-assisted reduction applications, and conclusions about the reported research with perspectives for future developments. Review and elaboration of the recent reductivity-dependent applications of nZVI may not only facilitate the development of more effective and sustainable nZVI materials and the protocols for comprehensive utilization of nZVI, but may also promote the exploration of innovative remediation approaches based on its reductivity.

High Tribocatalytic Performance of FeOOH Nanorods for Degrading Organic Dyes and Antibiotics

Tribocatalysis is vitally important for electrochemistry, energy conservation, and water treatment. Exploring eco-friendly and low-cost tribocatalysts with high performance is crucial for practical applications. Here, the highly efficient tribocatalytic performance of FeOOH nanorods is reported. The factors related to the tribocatalytic activity such as nanorod diameter, surface area, and surface roughness are investigated, and the diameter of the FeOOH nanorods is found to have a significant effect on their tribocatalytic performance. As a result, under ultrasonic excitation, the optimized FeOOH nanorods exhibit superior tribocatalytic degradation toward rhodamine B (RhB), acid orange 7, methylene blue, methyl orange dyes, and their mixture. The RhB and mixed dyes are effectively degraded within 20 min (k = 0.179 min-1 ) and 35 min (k = 0.089 min-1 ), respectively, with the FeOOH nanorods showing excellent reusability. Moreover, antibiotics, such as tetracycline hydrochloride, phenol, and bisphenol A are efficiently degraded. Investigation of the catalytic mechanism reveals that the friction-generated h+ as well as these yielded •OH and •O2 - active radicals participate in the catalytic reaction. This work not only shed light on the design of high-performance tribocatalyst but also demonstrates that by harvesting mechanical energy, the FeOOH nanorods are promising materials for removing organic contaminants in wastewater.