Enhanced Photocatalytic Degradation of 4-chlorophenol using Lanthanum Oxide Nano-particles under UVC/Vis Irradiation

ABSTRACTPhotocatalytic oxidation using novel photo-catalysts has been considered as an effective method for destruction of recalcitrant organics. In this study, photocatalytic degradation of 4-chlorophenol (4-CP) using lanthanum Oxide nanoparticles (LONPs) was investigated under UVC/Vis irradiation. Effect of operational parameters including pH (2 – 11), catalyst content (250-3000 mg L-1), contact time (20 - 180 min) 4-CP concentration (25- 400 mgL-1) were investigated according to one factor at the time experimental procedure. Highest removal efficiency of 4-CP was observed at pH =7. Result was indicated that the removal of 4-CP was increased from 76% to 92%, with increasing catalyst dosage from 0.25 to 1 g L-1. Then, a decrease was observed in 4-CP removal with an enhancement in catalyst dosage from 1 to 3 g L-1. Highest 4-CP removal (98%) was observed at the initial concentration of 25 mg L-1. At the contact time from 20 to 60 min, removal efficiency of 4-CP was increased from 24% to 64%, respectively. The contact time was increased to 120 min, removal efficiency of 4-CP was increased to 100%. Therefore, the optimal reaction time was 100 min. The AOS indices was showed an increasing trend of mineralization. In other words, the process of degradation of 4-CP was improved with photocatalytic degradation by UVC-La2O3. Among the kinetic models, the pseudo-first order model due to the highest correlation coefficient of R2 = 0.991 for the La2O3-UVC process.