Facile Fabrication of Ag/g-C3N4 Photocatalyst with Visible Light Responsive Efficiency for Cr(VI) Reduction in Presence of EDTA

In order to enhance photocatalytic Cr(VI) reduction from aqueous solution, g-C3N4 was fabricated by Ag to synthesize Ag/g-C3N4 composite via a simple one-step calcination method from urea and AgNO3. The properties of the as-synthesized Ag/g-C3N4 were examined by a series of characterization techniques. The obtained Ag/g-C3N4 composite exhibited apparently improved charge separation efficacy and optical absorption. Additionally, the influence of operating parameters, including Ag quantity in the composite, calcination temperature and time, amount of catalyst, initial Cr(VI) concentration, ethylenediaminetetraacetic acid (EDTA) concentration, and pH was studied to find an optimized condition for Cr(VI) reduction. The Ag/g-C3N4 composite containing 22 wt% of Ag displays 96% photocatalytic Cr(VI) reduction within 30 min in the presence of EDTA. The photocatalytic Cr(VI) reduction could follow pseudo-first-order kinetics, and the rate constant using the Ag/g-C3N4 composite (0.1054 min(-1)) was 6 times higher than that using g-C3N4 (0.0177 min(-1)) in the presence of EDTA. Furthermore, the composite showed high recyclability up to the fourth cycle. Highlights center dot A facile one-step calcination process is used to fabricate Ag/g-C3N4 photocatalyst. center dot Prepared Ag/g-C3N4 composite exhibited excellent performance for Cr(VI) reduction. center dot Fabricating Ag on the g-C3N4 surface decreases electron hole-pair recombination. center dot The addition of EDTA improved the photocatalytic reduction of Cr(VI).