Photocatalytic degradation of malachite green by a novel CeO₂ loaded alkali-activated steel slag-based nanocomposite

ABSTRACT

A new CeO₂ loaded alkali-activated steel slag-based nanocomposite (CeO₂-ASSN) for photocatalytic degradation of malachite green dye was firstly synthetized via incipient wetness impregnation method. The XRD and SEM results indicated that calcium silicate hydrate (CSH) was mainly mineral phase in the alkali-activated steel slag-based nanocomposite specimens, and the loaded CeO₂ particles with particle size about 15 nm were highly dispersed on the surface of photocatalyst carrier. Photoluminescence intensity of the CeO₂ loaded specimens was obviously decreased and the 8wt% CeO₂ loaded nanocomposite specimen showed the weakest photoluminescence intensity. The CeO₂ loaded specimens exhibited high photocatalytic degradation efficiency of malachite green dye under UV light irradiation for 80 min, and the maximum degradation rate of the 8wt% CeO₂ loaded nanocomposite specimen could reach 100%. It was ascribed to the co-action of CeO₂ active component and FeO in the carrier. The formation of the coupled semiconductors could promote the high efficiency separation of the photogenerated electron-hole pairs. The photocatalytic degradation belongs to the first-order reaction kinetics.

KEYWORDS:

• Alkali-activated steel slag-based nanocomposite
• CeO₂
• photocatalysis
• malachite green
• reaction kinetics

Funding

This study was financially supported by National Natural Science Foundation of China (No. 21346011 and No. 21676209), the Key Project of Natural Science foundation Research Plan of Shaanxi Province (No. 2013JZ014), and the Key Scientific Research Project of Natural Science in Education Department of Shaanxi Province (No.16JS055).