Plant Uptake-Assisted Round-the-Clock Photocatalysis for Complete Purification of Aquaculture Wastewater Using Sunlight

Abstract

A novel reactor equipped with solar batteries, Bi₂O₃/TiO₂ film photocatalyst, and celery plant was designed and used for purification of aquaculture wastewater. The Bi₂O₃/TiO₂ film photocatalyst started photocatalytic degradation of organonitrogen compounds under irradiation of sunlight. Meanwhile, the solar batteries absorbed and converted excess sunlight into electric energy and then started UV lamps at night, leading to round-the-clock photocatalysis. Subsequently, the inorganic nitrogen species including NH₄⁺, NO₂^–, and NO₃^– resulting from photocatalytic degradation of the organonitrogen compounds could subsequently be uptaken by the celery plant as the fertilizer to reduce the secondary pollution. It was found that, after 24 h circulation, both organonitrogen compounds and NO₂^– species were completely removed, while NH₄⁺ and NO₃^– contents also decreased by 30% and 50%, respectively. The reactor could be used repetitively, showing a good potential in practical application