Incorporating Co3O4/C modified MnOx/SiO2 into tailored sponge for bifunctional photothermal water evaporation and pollutant degradation

In this study, cobalt-incorporated polydopamine coating onto Mn-modified mesoporous silica and successive graphitization treatment make the resulting composite afford abundant porosity, multiple metal active species, polar N sites, and excellent light-to-heat conversion ability. The controlled graphitization temperature was optimized to improve the activity state of metal species. The results reveal that Co₃O₄ nanoparticles incorporated thin-layer carbon formed onto the Mn-confined mesoporous silica, and more Co(II) and Mn(III) were generated in the MS-Co-500N₂ compared to MS-Co-500Air, which could cause the accelerated reaction cycles in the potassium peroxymonosulfate complex salt (PMS) activation. The degradation experiments demonstrated that the catalyst almost completely degraded biphenol A within 10 min with the reaction rate constant of 0.56 min⁻¹, nearly 205 times enhancement compared to the MS-Co-500Air. The free radicals trapping and quenching control demonstrated the dominant role of ¹O₂ and ·O₂ in the degradation process. Due to the efficient incorporation of Co₃O₄ nanoparticles and thin-layer carbon, the photothermal conversion properties were explored and utilized for solar-driving interface water evaporation and cleanwater recovery. To explore the practical application possibility in treating complicated polluted wastewater, the MS-Co-500N₂ materials were fixed on the melamine sponge by Ca ions-trigger alginate crosslinking strategy, and the integrated monolith evaporator shows an excellent water evaporation performance (1.52 kg·m⁻²·h⁻¹) and synchronous pollutant removal in biphenol A (94%, 10 min), carbamazepine (92%, 10 min), oxytetracycline (84%, 20 min) and norfloxacin (84%, 20 min).

Graphical abstract