ADSORPSI ZAT WARNA KRISTAL VIOLET MENGGUNAKAN LIMBAH KULIT SINGKONG (Manihot esculenta)
HENI IRAWATI, 1. Dr. rer. nat. Nurul Hidayat Aprilita, M.Si.; Dr. Eko Sugiharto, DEA
2016 | Tesis | S2 Ilmu KimiaTelah dilakukan penelitian tentang pemanfaatan limbah kulit singkong sebagai biosorben untuk mengadsorpsi zat warna kristal violet dengan sistem batch. Penelitian diawali dengan pembuatan biosorben kulit singkong yang dikarakterisasi dengan spektrofotometer Fourier Transform Infrared (FTIR) untuk mengetahui gugus fungsi, Scanning Electron Microscope (SEM) untuk mempelajari morfologi permukaan biosorben dan Surface Area Analyzer (SAA) untuk mengetahui luas permukaan. Uji kemampuan adsorpsi biosorben kulit singkong terhadap zat warna kristal violet dilakukan pada berbagai variasi massa biosorben, pH larutan, waktu kontak dan konsentrasi awal kristal violet. Selanjutnya dilakukan studi kinetika, isoterm dan energi adsorpsi. Hasil karakterisasi FTIR sebelum adsorpsi zat warna kristal violet menunjukkan adanya gugus C-H, O-H, C-O dan C=O dari lignoselulosa yang terkandung dalam kulit singkong. Terdapat pergeseran bilangan gelombang setelah terjadinya adsorpsi pada gugus O-H dan C-O serta munculnya puncak baru gugus C-N dari zat warna kristal violet yang mengindikasikan adanya interaksi antara biosorben dengan zat warna kristal violet. Karakterisasi SEM menunjukkan morfologi permukaan biosorben yang heterogen dan memiliki luas permukaan 0,85 m2 g-1. Pada konsentrasi awal zat warna kristal violet 100 mg L-1 sebanyak 20 mL diperoleh keadaan optimum massa biosorben 0,10 g, pH 7 dan waktu kontak 210 menit dengan kapasitas adsorpsi 19,41 mg g-1. Kinetika adsorpsi zat warna kristal violet pada biosorben kulit singkong mengikuti persamaan kinetika orde dua semu dengan laju reaksi sebesar 2,26 x 10-2 g mg-1 menit-1. Tipe isoterm yang sesuai yaitu tipe isoterm Freundlich dan berlangsung secara kemisorpsi dengan energi adsorpsi sebesar 22,38 kJ mol-1.
Adsorption of crystal violet dye using cassava peel waste under batch system had been done. Biosorbent was prepared from cassava peel. The biosorbent was characterized by spectrophotometer FTIR to determine the functional group. SEM and SAA were respectively performed to study surface morphology of biosorbent and the surface area. The assay of adsorption of cassava peel biosorbent toward crystal violet dye was performed at various mass of biosorbent, pH solution, contact time and the initial concentration of crystal violet dye. The study of kinetics, isoterm and adsorption energy were then carried out. The FTIR spectra showed that the biosorbent had the functional groups of C-H, O-H, C-O and C=O from lignocellulose contained in cassava peel before contacting with the crystal violet dye . The chemical shift of O-H and C-O and the presence of new peak of C-N happened due to the interaction between biosorbent and crystal violet dye. The characterization of SEM showed that the surface morphology of biosorbent was heterogen with the surface area of 0.85 m2 g-1. The optimum adsorption of crystal violet dye by cassava peel waste was obtained at pH of 7, biosorbent mass of 0.10 g and contact time at 210 min with the adsorption capacity of 19.41 mg g-1 at its initial concentration of 100 mg L-1 and its volume of 20 mL. The adsorption kinetics was in good agreement with pseudo-second-order kinetic model with the reaction rate of 2.26 x 10-2 g mg-1 min-1. The equilibrium data was best fitted to the Freundlich isoterm with adsorption energy was 22.38 kJ/mol, indicating the chemisorption was carried out.
Kata Kunci : limbah kulit singkong, kristal violet, adsorpsi/ cassava peel waste, crystal violet, adsorption
