Hydrous titania nanosheets constructed hierarchical hollow microspheres as a highly efficient dual-use decontaminant for elimination of heavy metal ions and organic pollutants

Abstract

The development of high-performance dual-use decontaminants is of practical significance to alleviate the serious environmental problems led by both heavy metal ions and organic pollutants in wastewater. Herein, novel hierarchical hollow microspheres well-organized by hydrous titania nanosheets (hhHTO) were synthesized via a simple one-pot template-free hydrothermal route. The formation process of hhHTO was investigated and a possible growth mechanism was also proposed. Owing to the integrated features (i.e., large surface area (156.4 m2 g−1), abundant surface Ti–OH groups, and highly open structure), the as-synthesized hhHTO exhibited a remarkable adsorption capacity (up to 459.04 mg g−1) and a very fast adsorption kinetics (within 10 min) for Pb2+ removal, which can be hardly achieved simultaneously in previous investigations. Moreover, this hierarchical hollow adsorbent showed almost unchanged removal efficiency after six-time reuse. In H2O2-assisted photocatalytic processes, the hhHTO could act as catalytic microreactors which was characterized by strong enrichment capacity for H2O2 and high shell permeability, thereby exhibiting significantly higher photocatalytic efficiency than commercial titania (P25) on the degradation of rhodamine B. Besides, these microreactors were also demonstrated to be highly efficient for catalytic degradation of other recalcitrant organic pollutants and exhibited an excellent reusability during cyclic operation.