Piezoelectric polarization coupled with photoinduced catalytic oxidation technology for environmental pollution control: Recent advances and future prospects.

Energy scarcity and environmental pollution concerns have become substantial impediments to sustainable global economic development. The advent of semiconductor photocatalysis technology provides a potential possibility for effectively alleviating excessive energy consumption and maintaining the long-term stability of the aqueous ecosystem. However, the inefficient transmission efficiency of charge carriers and the high recombination rate of photogenerated electron-hole pairs will culminate in the mediocre catalytic performance observed in conventional semiconductor materials. Fortunately, the piezo-photocatalysis ingeniously integrates the piezoelectric properties of piezoelectric crystals with the optoelectronic properties of semiconductors, thus building a theoretical system of photo-electric-chemical three-phase coupled catalysis. Currently, the photo-mechanical energy synergistic catalytic oxidation degradation process, as a cutting-edge technology based on clean renewable energy, has been perceived as a promising environmental remediation strategy. Herein, a critical review of the application of piezo-photocatalysis in environmental pollution control was delivered. We undertook a comprehensive analysis to elucidate the underlying enhancement mechanism of the piezoelectric effect on photocatalysis in terms of charge migration dynamics and pertinent energy band bending phenomena. In addition, we meticulously summarized diverse innovative methods for introducing vibration energy in piezo-photocatalytic degradation systems (ultrasound, fluid mechanical energy, airflow, self-assembled reactors, etc.). Then, state-of-the-art research advances in the field of environmental pollution control and the corresponding environmental decontamination mechanisms were elaborated based on various integration modes of catalysts (single component, noble metal deposition, heterojunction, coupled substrate materials, etc.). Eventually, an in-depth assessment of current limitations and development trends of piezo-photocatalytic degradation technology has been proposed, along with proactive strategies aimed at surmounting the existing challenges.

Activated persulfate by iron-carbon micro electrolysis used for refractory organics degradation in wastewater: a review.

With the rapid economic development, the discharge of industrial wastewater and municipal wastewater containing many refractory organic pollutants is increasing, so there is an urgent need for processes that can treat refractory organics in wastewater. Iron-carbon micro electrolysis and advanced oxidation based on persulfate radicals (SO4-·) have received much attention in the field of organic wastewater treatment. Iron-carbon micro electrolysis activated persulfate (Fe-C/PS) treatment of wastewater is characterized by high oxidation efficiency and no secondary pollution. This paper reviews the mechanism and process of Fe-C/PS, degradation of organics in different wastewater, and the influencing factors. In addition, the degradation efficiency and optimal reaction conditions (oxidant concentration, catalyst concentration, iron-carbon material, and pH) of Fe-C/PS in the treatment of refractory organics in wastewater are summarized. Moreover, the important factors affecting the degradation of organics by Fe-C/PS are presented. Finally, we analyzed the challenges and the prospects for the future of Fe-C/PS in application, and concluded that the main future directions are to improve the degradation efficiency and cost by synthesizing stable and efficient catalysts, optimizing process parameters, and expanding the application scope.