Optimasi Suhu Kalsinasi Terhadap Sintesis Nanostruktur Zno Sebagai Fotokatalis Dengan Memanfaatkan Buah Nanas Sebagai Pengkelat

Abstract

Abstrak ZnO telah disintesis dengan metode sol-gel menggunakan pengkelat dari ekstrak buah nanas sebagai solusi agar dapat mengurangi penggunaan zat kimia. Buah nanas yang digunakan yaitu nanas madu dan nanas batu yang memiliki kandungan kadar gula total berbeda. Pada nanostruktur ZnO yang menggunakan pengkelat nanas madu disintesis pada suhu kalsinasi 500, 600, 700, 800, dan 900˚C. Nanostruktur ZnO yang menggunakan pengkelat nanas batu berhasil disintesis pada suhu kalsinasi 700 dan 800˚C. Dalam eksperimen ini dipelajari efek suhu kalsinasi terhadap hasil nanostruktur ZnO serta pengaruhnya saat diaplikasikan sebagai fotokatalis untuk mendegradasi methylene blue. Hasil karakterisasi morfologi dengan SEM sampel menggunakan pengkelat nanas madu di suhu kalsinasi 800˚C diketahui bahwa ukuran partikel berada pada rentang 0,540 – 3,614 μm dengan rata-rata 1,858 μm, hasil yang masih besar diperkirakan terjadi karena adanya aglomerasi. Karakterisasi terhadap sifat kristal dengan menggunakan XRD di dapatkan ukuran kristal pada sampel menggunakan pengkelat nanas madu di suhu kalsinasi 800˚C dengan rata-rata 35,10 nm sementara pengkelat nanas madu di suhu kalsinasi 700˚C, ukuran kristalit yaitu dengan rata-rata 30.90 nm. Kedua sampel yang dikarakterisasi sifat kristalnya dengan menggunakan XRD memiliki struktur kristal wurtzite berbentuk heksagonal yang berukuran a = 3,25 x 10 −10 m dan c = 5,21 x 10 −10 m. Kata kunci : ZnO, green synthesis, metode sol-gel, degradasi metilen biru, suhu kalsinasi Abstract ZnO has been synthesized by the sol-gel method with chelate from pineapple (Ananas comosus (L.)) extract, as a solution to reduce the chemical substances. Pineapple extract is used as a chelate because it has high total sugar content. ZnO nanostructure that has been synthesized with cayenne pineapple chelate was synthesized at calcination temperatures of 500, 600, 700, 800 and 900 ˚C, whereas ZnO nanostructure that has been synthesized with queen pineapple chelate was synthesized at calcination temperatures of 700 and 800 ˚C. The morphology of ZnO nanostructure has been checked by Scanning Electron Microscopy (SEM). ZnO nanostructure that has been synthesized with cayenne pineapple chelate at calcination temperature of 800 ˚C showed particle size average of 1,858 μm, these result was still too large and occurred due to agglomeration. The crystallite structure of calcined powders were analyzed using XRD. The average size of zno nanostructure crystallite was synthesized with cayenne pineapple chelate at 800 ˚C calcination temperature, which was 35,10 nm while at calcination temperature 700 ˚C the average size of crystallite was 30.90 nm. The diffraction peaks can be indexed as hexagonal wurtzite structure of ZnO (a = 3,25 x 10 −10 m, c = 5,21 x 10 −10 m) and diffraction data were in good agreement with the JCPDS card for ZnO (JCPDS 36-1451). The photocatalytic activity of ZnO catalysts obtained by modified sol-gel method at different calcination was valuated for the photo degradation of methylene blue under UV light. The most effective degradation occurred in Zno nanostructure which was synthesized with cayenne pineapple as chelate at 700 ˚C calcination temperature during UV irradiation for 240 minutes, the degradation rate was 55,87% at a concentration of 10 ppm MB solution. Keywords: ZnO, green synthesis, sol-gel method, degradation of methylene blue, calcination temperature