Facile synthesis of CaWO4 nanoparticles incorporated on porous carbons with improved photocatalytic degradation of tetracycline

The construction of an efficient and recyclable photocatalyst for the degradation of antibiotics is still a challenge. In this work, we successfully synthesized porous carbon-supported CaWO4 nanoparticles (CaWO4 @C) by solidifying sodium alginate (SA) mixed with Na2WO4 by Ca2+ ions and subsequent high-temperature carbonization. The introduction of porous carbon significantly reduced the size of CaWO4 particles, increased the specific surface area for mass transport, and improved visible light utilization. The influence factors of photocatalytic activity were extensively explored through photocatalytic degradation of tetracycline (TC). As a result, the optimized CaWO4 @C exhibited excellent photocatalytic performance with the TC degradation rate of 94.56% after 60-min visible light irradiation. The TC photodegradation rate constant was calculated to be 0.051 min−1, which was 30.19-time higher than the pristine CaWO4. Besides, the photocatalytic reaction mechanism for degradation of TC was revealed in terms of free radical trapping experiments and electron spin resonance (ESR) techniques.