Photocatalytic Degradation of Methylene Blue by Schiff-base Cobalt Modified CoCr Layered Double Hydroxides

Abstract

A series new material of cobalt (Ⅱ) with Schiff-base intercalated cobalt-chromium layered double hydroxides (CoCr/SBCo-LDHs) were successfully prepared via coprecipitation. Their structure and property of the CoCr-LDHs and CoCr/SBCo-LDHs materials were thoroughly characterized by X-ray powder diffraction (XRD), UV-Vis DRS, scanning electron microscope (SEM), transmission electrons microscope (TEM) and energy dispersive X-ray spectroscope (EDX), X-ray photoelectron spectroscope, and specific surface area analyzer. Using H2O2 as photocatalytic additive, the effects of different intercalation amount, catalyst dosage and initial concentration of methylene blue (MB) solution on photocatalytic activity were investigated, and the kinetics and main active groups of photocatalytic degradation process were explored. Experimental results show that H2O2 can improve the photocatalytic performance of hydrotalcite materials. Under the condition of the Xenon lamp simulated sunlight and MB initial concentration of 25 mg/L, the photocatalytic degradation rate of MB by 20 mg CoCr/SBCo0.5-LDHs and H2O2 was 99%. The photodegradation process of MB conforms to the quasi-first-order kinetic model, and the active groups playing major role are h+ and •OH.