Self-supporting rGO/BiOBr composite on loofah-sponge as a floating monolithic photocatalyst for efficient microcystis aeruginosa inactivation

Abstract

• An innovative design of using agricultural waste for algae inactivation is proposed. • High-efficient monolithic photocatalyst supporting on loofah sponge is fabricated. • rGO improves the adhesive of BiOBr on loofah sponge, but also facilitates charge separation. • rGO/BiOBr@LF shows high efficient algae killing activity and long term operation stability. Photocatalysis has long been considered as a promising way for water purification, however the practical application of it has been strictly hindered by the difficulty in photocatalyst recyclability. In this work we report the first use of agricultural waste of loofah sponge as catalyst host to support photocatalyst, forming a floating monolithic-like structure for algae contaminated wastewater treatment. Taking BiOBr as an example, a series of floating monolithic photocatalysts of rGO/BiOBr supporting on loofah sponge (rGO/BiOBr@LF) are fabricated, exhibiting remarkable photocatalytic activities toward microcystis aeruginosa inactivation. Among them, rGO/BiOBr@LF with rGO loading content of 1.5 wt% (rGO/BiOBr@LF-2) shows the highest photocatalytic algae degradation performance, where more than 90% of microcystis aeruginosa can be removed with the TOC removal of algae reaching 74% within 3 h photocatalysis. Furthermore, the as-prepared rGO/BiOBr@LF-2 could be simply recycled by taking the material out of the solution, while without obvious catalytic activity loss. This work offers a new insight in designing recyclable and floating monolithic photocatalyst for high-efficient practical algae wastewater treatment.