Photooxidative Degradation of Dye Pollutants Accumulated in Self‐Assembled Natural Polyelectrolyte Microshells under Visible Radiation

Abstract

A novel route to facilitate the degradation of dye pollutants, a class of well-known recalcitrant organic pollutants, is reported. This new approach is based on a natural polyelectrolyte microshell that was preformed by the alternate adsorption of the anionic alginate sodium (ALG) and the cationic chitosan (CHI) onto weakly cross-linked melamine formaldehyde (MF) colloidal particles, and the subsequent sacrifice of MF templates in 0.1 M HCl. The as-prepared microshells could accumulate rhodamine B (RhB) and fluorescein (Flu) efficiently in water under ordinary conditions by means of a simple mixing process. The photodegradation of the accumulated RhB and Flu was examined in the presence of Fe3+ and H2O2 under visible radiation. The accumulated RhB and Flu are rapidly degraded and the assembled shells maintain their intact spherical shape throughout the photoreaction process. Results of recycling degradation experiments and the photochemical behavior of the shells, as demonstrated by confocal laser scanning microscopy (CLSM), UV-visible spectroscopy, and scanning force microscopy (SFM), further suggest that the constructed shells may be used as environmentally friendly microcontainers for the elimination of dyes in wastewater.