Solar photocatalytic degradation of carbendazim in water using TiO2 particle- and sol-gel dip-coating filters

Carbendazim degradation with TiO2 photocatalysis under sunlight irradiation using particle- and sol-gel coating filters was studied. For particle coating, an appropriate concentration of Degussa P25, namely 0.3, 0.5, and 1% w/v, and binder types, namely Duramax B1000, PEG1000, PEG2000, PEG4000, and PEG6000 were investigated. It was found that 0.5% w/v of P25 and 1 wt% of PEG6000 yielded the highest efficiency of 89-91% from triplicate runs. The best kinetic rate constant was 0.048 min-1. For sol-gel coating, different anatase to rutile (A/ R) ratio were compared for efficiency. The synergistic effect from photocatalysis and sorption due to the honeycomb-like coating surface was observed. The efficiency of 98-99.5% in 10 min were obtained from PEG4000-6000. Zeta potential analysis revealed that the TiO2 from both coatings and carbendazim had negative charge, which was the same as that of the TiO2, then the sorption was not due to the opposite charge attraction.