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Conventional nanomaterials are met with the bottleneck problem of difficult recycling and reuse when applied to water treatment. Carbon aerogel with three-dimensional structure can effectively solve the problem of recycling, however, the preparation of efficient and recyclable aerogel catalyst is still an urgent technical problem. Here, an NH 2 -MIL-88B(Fe)/agarose carbon aerogel (MGA-x) was synthesized at different calcination temperatures (x = 100, 150, 200 and 300 °C) and their changes in structures and photo-electrochemical properties were investigated. As a photo-Fenton catalyst, the aerogel could efficiently activate H 2 O 2 to ultrafast degrade mitoxantrone in water. Within 2 min, the removal efficiency of mitoxantrone in the MGA-200/H 2 O 2 /Light system was 97.6%, which was 85.3 times greater than that in the agarose aerogel/H 2 O 2 /Light system. Notably, the aerogel catalyst could be directly recovered and recycled without additional treatments, and the microstructure and degradation performance were maintained even after five cycles, demonstrating excellent sustainability for applications in practical aquatic environment. The primary active radicals involved in the photocatalytic degradation process were • OH, h+ and • O 2 -, which were confirmed through free radical quenching experiments and electron paramagnetic resonance analysis. Additionally, possible degradation pathways for mitoxantrone were proposed based on the results of liquid chromatography-mass spectrometry. This study presents a photocatalytic aerogel with highly efficient degradation ability along with recycling and reuse capacity, exhibiting great potential for application in the remediation of water pollution. [Display omitted] • NH 2 -MIL-88B(Fe)/agarose carbon aerogel was prepared by low-temperature calcination. • The photo-Fenton reaction of MGA-200 through degrading MTX was studied. • The MGA-200/H 2 O 2 /Light system could ultrafast remove 97.6% of MTX in 2 min. • MGA-200 can be recovered and recycled directly without additional treatment. • A new pathway for the potential degradation of MTX was proposed. [ABSTRACT FROM AUTHOR]

• BiOBr/BTO heterojunction catalysts were prepared by chemical precipitation method. • The catalyst exhibits highly efficient piezo-photocatalysis for degrading multi-pollutant. • Synergistic piezo-photocatalysis was realized under light illumination and ultrasound. • The catalyst shows favorable cycling stability and applicability for multi-pollutant. Piezo-catalysis is a green and effective method for degrading rich and obstinate molecules in wastewater. Yet, the piezo-catalytic performance of frequently-used barium titanate (BTO) is still limited for practical applications, thus it is crucial to construct high-efficiency BTO-based catalysts. Herein, BiOBr/BTO heterojunction-based piezo-photocatalysts were successfully prepared using the chemical precipitation method, and an internal electric field was established via ultrasound to promote the separation of photogenerated electron-hole pairs through the synergistic effect of piezocatalysis and photocatalysis. Transmission electron microscopy, Raman spectroscopy and X-ray photoelectron spectroscopy were utilized to characterize the heterojunction. The degradation performance of Rhodamine B (RhB) by BiOBr/BTO is the best among various pollutants, giving a reaction rate constant up to 20.839 × 10−2 min−1, exceeding numerous previously reported catalysts. In addition, the piezo-photocatalytic reaction rate of BiOBr/BTO for Methyl Orange was 9.298 × 10−2 min−1, ≈ 3.3 times than those of pure BTO (2.806 × 10−2 min−1), and also ≈ 15.9 times and 3.3 times than those of single photocatalysis (0.585 × 10−2 min−1) or piezocatalysis (2.848 × 10−2 min−1). Importantly, the BiOBr/BTO heterojunction demonstrates excellent catalytic degradation performance for a broad range of pollutants (e.g., dyes and antibiotics) and their mixtures, as well as favorable cycling stability and repeatability with changed environmental conditions, displaying applicability in actual wastewater treatment. The possible degradation pathways of RhB were analyzed by liquid chromatography-mass spectrometry. The present work supplies a feasible strategy for the preparation of high-efficiency piezo-photocatalytic BTO-based heterojunctions, which can guide other composites for environmental remediation. [ABSTRACT FROM AUTHOR]