UJI KEMAMPUAN ADSORPSI PATI BERAS C4 TERHADAP METILEN BIRU DAN METIL ORANYE

FIRDA AINUN NISAH, Sri Sudiono, S.Si, M.Si.

2014 | Skripsi | KIMIA

Uji kemampuan adsorpsi pati beras C4 terhadap metilen biru dan metil oranye telah dipelajari. Pati beras dikarakterisasi menggunakan Surface Area Analyzer (SAA) dan Scanning Electron Microscope (SEM). Proses adsorpsi metilen biru dan metil oranye dilakukan dengan cara mecampurkan 0,1 g pati dengan 20 mL zat warna sambil digojog dalam shaker selama 2 jam. Variasi pH dilakukan pada rentang pH 5-8. Variasi konsentrasi awal zat warna sebesar 1, 5, 10, 20, 30, 40, 50, 80, dan 100 ppm. Hasil yang berupa filtrat dianalisis menggunakan spektrofotometer UV-Vis. Endapan dikeringkan dengan oven dibawah temperatur 45 oC selama 24 jam. Hasil analisis SEM menunjukkan bahwa setiap granula pati terdiri atas molekul-molekul pati yang tersusun rapat memiliki ukuran 3-7 μm dan berbentuk polihedral. Karakterisasi dengan penggunaan SAA diketahui pati mempunyai luas permukaan 1,10 m2/g, volume total pori 3,571×10-3 cc/g, dan diameter pori 6,42423×10-1 Å. Hasil proses adsorpsi menunjukkan bahwa semakin besar nilai pH semakin besar metilen biru yang teradsorpsi. Berlawanan dengan, semakin rendahnya bedah semakin besar metil oranye yang teradsorpsi. Variasi konsentrasi awal zat warna adsorpsi oleh pati menunjukkan bahwa adsorpsi zat warna akan semakin besar dengan meningkatkan konsentrasi. Adsorpsi metilen biru dan metil oranye oleh pati beras C4 mengikuti isoterm adsorpsi Freundlich. Kapasitas adsorpsi pati beras terhadap metilen biru dan metil oranye adalah 4,596×10-7 mol/g dan 0,403×10-7 mol/g.

Assessment of C4 rice starch adsorptivity towards methylene blue and methyl orange had been studied. The rice starch was characterized by Surface Area Analyzer (SAA) and Scanning Electron Microscope (SEM). Methylene blue and methyl orange adsorption were performed by adding and shaking 0.1 g adsorbent into 20 mL dye for 2 h. The variations was done under pH 5-8. Dye initial concentration was also varied at 1, 5, 10, 20, 30, 40, 50, 80, and 100 ppm. The filtrate was analyzed using UV-Vis spectrophotometer to determine the unadsorbed dye concentration. The precipitate was then dried in oven under temperature of 45 oC for 24 h. The SEM image showed that the starch consisted of compact molecules, with mean diameter of 3-7 μm and having a polyhedral shape. The SAA characterization showed that the starch had a surface area of 1.10 m2/g, pore volume of 3.571×10-3 cc/g, and a pore diameter of 6.42423×10-1 Å. The adsorption test showed that by increasing the pH value of the solution caused the increase of methylene blue adsorption. In contrast, by decreasing the pH value of the solution caused an increase in methyl orange adsorption. The increase of dye initial concentration also caused an increase in the adsorbed dye. The adsorption of methylene blue and methyl orange by rice starch followed the Freundlich adsorption isotherm. The adsorption capacity of the starch toward methylene blue and methyl orange were 4.596×10-7 mole/g and 0.403×10-7 mole/g.

Kata Kunci : adsorpsi, pati beras C4, metilen biru, metil oranye