Pemangkin ZnO/Degussa TiO2 dipasangkan dengan pelbagai dos ZnO (0.25-1.0 % berat) telah berjaya dihasilkan. Sampel yang terhasil telah dicirikan oleh pembelauan sinar-X (XRD), mikroskop imbasan electron (SEM), serakan sinar-X (EDX), ciri-ciri permukaan dan spektrum UV-vis pantulan. Keputusan XRD menunjukkan penambahan beban ZnO di dalam penyediaan pemangkin tidak memberi puncak yang nyata mungkin disebabkan oleh kandungan ZnO terlalu sedikit daripada Degussa TiO2 semasa penyediaan. Prestasi fotomangkin bagi sample yang telah disediakan dinilai dengan memantau kepekatan degradasi metilena biru. Ujian fotomangkin mendedahkan 0.75 % berat pemangkin memberikan kecekapan penyingkiran tertinggi. Tiga pembolehubah proses telah dikaji; kesan beban pemangkin (0.25-0.5 g/L),, kesan kepekatan awal metilena biru (5-40 mg/L) dan kesan larutan pH (3-10). Keadaan-keadan teroptimum adalah berikut: beban pemangkin 1.0 g/L, kepekatan awal metilena biru 10 mg/L dan larutan pH 10. Kinetik bagi degradasi metilena biru turut dikaji. Keputusan menunjukkan bahawa kinetic bagi reaksi ini mematuhi kinetic bagi pseudo-pertama dengan nilai kapp ialah 0.0193 min-1. Pemangkin yang tersedia juga menunjukkan bahawa aktiviti fotopemangkin bagi fotomangkin ZnO/Degussa TiO2 menunjukkan kebolehulangan dan boleh digunakan untuk beberapa kitaran.
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ZnO/Degussa TiO2 catalyst coupled with various ZnO dosages (0.25 -1.0 wt %) were successfully prepared by solid-state method. The prepared samples were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), energy dispersive X-ray (EDX), surface characteristics and UV-vis reflectance spectra. XRD result showed that the addition of ZnO loading in catalyst preparation did not give any intense peak of ZnO possibly because of the amount of ZnO was very less than Degussa TiO2 during preparation. The photocatalytic performance of the prepared samples was evaluated by monitoring the degradation of methylene blue concentration. Photocatalytic test revealed that 0.75 wt% of prepared catalyst gave the highest removal efficiency. Three process variables were studied; effect of catalyst loading (0.25-0.5 g/L), effect of initial methylene blue concentration (5-40 mg/L) and effect of solution pH (3-10). The optimum conditions as followed: catalyst loading 1.0 g/L, initial concentration of methylene blue 10 mg/L and solution pH 10. Kinetic for degradation of methylene blue also has been studied. Result showed that the reaction kinetic for this study followed pseudo-first order kinetic with kapp was 0.0193 min-1. The prepared catalyst also showed that the photocatalytic activity of ZnO/Degussa TiO2 catalyst displayed repeatability and can be used for a number of cycles.
Photodegradation of methylene blue using ZnOdegussa TiO2 catalyst / Noor Izzati Md Rosli