Synergetic removal of Cr(VI) and dibutyl phthalate mixed pollutants on MoS2 sheet inserted in TiO2 nanotube under visible light

The challenge of developing stable and efficient photocatalysts for the simultaneous removal of heavy metals and organic pollution persists. Herein, molybdenum sulfide (MoS2) sheet inserted in porous-walled titanium dioxide nanotube arrays (TNTAs) with Z-scheme heterojunctions were synthesized via anodic oxidation and hydro-thermal methods. The MoS2@p-TNTAs possess a robust response to visible light, with a large specific surface area and tight inter-semiconductor bonding. Notably, MoS2@p-TNTAs exhibited superior removal efficiencies in treating Cr(VI)-DBP mixed pollutants solution compared to individual pollutants. The degradation kinetic constants of Cr(VI) and DBP in the mixed pollutants were 8.3 and 3.3 times higher than those of single pollutants, respectively. The photodegradation efficiency of MoS2@p-TNTAs for DBP has consistently remained above 85 % even after undergoing 20 cycles, while the morphological structure remained stable, demonstrating outstanding structural stability and reusability. Mechanistic analysis revealed that the composites with Z-scheme hetero-junctions exhibit a robust redox capability, while DBP and Cr were synergistically removed by consuming holes and electrons, respectively. Consequently, this study offers valuable insights into the potential application of TNTAs in wastewater treatment.

Automated summary

In this study, stable and efficient photocatalysts, MoS2@p-TNTAs, were synthesized for the simultaneous removal of heavy metals and organic pollutants. The material exhibited strong response to visible light, with a large specific surface area and tight inter-semiconductor bonding. It showed superior removal efficiency in treating mixed pollutants compared to individual pollutants. The material also demonstrated outstanding structural stability and reusability.