Photocatalytic conversion of ethylenediaminetetraacetic acid dissolved in real electroplating wastewater to hydrogen in a solar light-responsive system.

Abstract

A sustainable and multifunctional photocatalysis-based technology has been established herein for simultaneous hydrogen generation and oxidation of ethylenediaminetetraacetic acid (EDTA) in real electroplating wastewater. When the photocatalyst concentration was 4 g/L and electroplating wastewater pH was 6, optimal adsorptions of EDTA2-, H+, and H2O were observed, while hydrogen generation efficiency reached 305 µmol/(h g). Owing to EDTA oxidation and occupation of the active sites of the photocatalyst by Ni ions or Ni-EDTA chelates, the charge separation and adsorptions of H+ and H2O decreased, reducing hydrogen generation efficiency with time. The lower EDTA and Ni concentrations in treated wastewater showed that photocatalytic conversion of EDTA in real electroplating wastewater to enhance hydrogen generation efficiency can be a practical alternative energy production technology. This study provided a novel idea to enhance the value of electroplating wastewater, to build a hydrogen generation route with no consumption of a valuable resource, and to reduce EDTA and Ni concentrations in electroplating wastewater.