The influence of orange peel-cetyltrimethylammonium bromide (CTAB) modification to increase ZnO photocatalyst ability for methyl orange degradation

Methyl Orange (MO) is one of the dyestuffs that are often used in the textile industry. MO itself has non-biodegradable anionic properties and has the potential to cause hypersensitivity allergies, thus it potentially been dangerous, especially for aquatic environment. One of the methods which often used is photodegradation method. Photodegradation was a method that was easy to implement and relatively affordable. Additionally, dyes could be more easily decomposed into simpler components with the intention that being safer for the environment. This research aimed to degrade MO using ZnO composited with orange peel (OP) which had been modified with cetyltrimethylammonium bromide (CTAB) addition. CTAB itself served as template to increase surface area of the ZnO material, thereby increasing their photocatalytic activities. ZnO, ZnO/OP, and ZnO/OP-CTAB were characterized using FTIR, XRD, SEM-EDX, BET and DR-UV. The results showed that ZnO/OP-CTAB degraded MO more than both ZnO/OP and ZnO. It was achieved optimum condition for without UV irradiation method in 40 minutes treatment, where ZnO/OP-CTAB was able to degrade MO by 48% whereas ZnO/OP and ZnO were only by 40% and 28%, respectively. In with UV irradiation method the optimum condition was achieved for 50 minutes, which ZnO/OP-CTAB succeeded in degrading MO by 78% while ZnO/OP was 74%. This treatment gave different results for ZnO, which ZnO gave optimum performance with %removal of 40% for 40 minutes treatment. Based on the reaction kinetics, it was known that the photodegradation reaction of MO by ZnO, ZnO/OP, and ZnO/OP-CTAB followed the pseudo-second-order reaction kinetics model.