In-situ synthesis of La2O3/sepiolite composite with promoted visible-light driven photocatalytic decomposition for tetracycline

A series of La 2 O 3 /sepiolite (La 2 O 3 /SEP) composites were synthesized by a one-step ammonia precipitation method for photocatalytic degrading tetracycline (TC) in simulated wastewater. The chemical compositions , microstructural morphologies, and surface physicochemical properties were characterized, and various factors' impact on TC degradation has also been investigated. The results showed that the La 2 O 3 /SEP composites exhibited good photocatalytic activity for TC solution under visible light. The ideal ratio of La 2 O 3 and sepiolite was 30 % in La 2 O 3 /SEP composite due to its higher TC degradation efficiency (94.1 % in 120 min) than other samples. Besides, the reaction rate constant of La 2 O 3 /SEP (0.01825 min −1 ) was about 4 times that of pure La 2 O 3 (0.00443 min −1 ). The improved photocatalytic performance was primarily attributed to the dispersion of La 2 O 3 nanoparticles on the surface of sepiolite nanofibers , which reduced the agglomeration phenomenon of La 2 O 3 and enhanced the specific surface area , thus exposing more adsorption and catalysis reaction active sites. Furthermore, the composite exhibited good reusability and stability. The free radical trapping experiment revealed that h + was the dominant active species in the TC degradation process. Based on the results of HPLC-MS, the possible degradation pathways of TC were proposed. It can be concluded that La 2 O 3 /SEP composite is a promising photocatalyst with great potential for application in antibiotic wastewater treatment . • La 2 O 3 /sepiolite photocatalyst was synthesized via simple precipitation method. • La 2 O 3 /sepiolite exhibited the outstanding TC adsorption and degradation performance. • Sepiolite played a key role in enhancing photocatalytic activity of La 2 O 3 .