ADSORPSI DAN DESORPSI BIRU METILEN PADA MEMBRAN MAKROPORI KITOSAN-KARBOKSIMETIL SELULOSA

DYAHAYU RAHMA DINI, Dr. Dwi Siswanta, M. Eng; Dr. rer. nat. Nurul Hidayat Aprilita, M. Si.

2015 | Skripsi | S1 KIMIA

Telah dilakukan adsorpsi dan desorpsi biru metilen pada membran makropori kitosan-karboksimetil selulosa tertaut silang glutaraldehida dan SiO2 sebagai porogen. Membran makropori diperoleh dengan mencampurkan larutan CMC 0,1% (b/v) dan larutan kitosan 1% (b/v) yang telah diatur pada pH 5. Setelah silika dan glutaraldehida ditambahkan, larutan diuapkan pada suhu 70 derajat Celcius. Membran makropori dikarakterisasi menggunakan FTIR dan SEM. Pada kajian adsorpsi dipelajari pengaruh komposisi membran, waktu kontak, pH, jumlah porogen, kinetika adsorpsi-desorpsi, pola isoterm adsorpsi, kapasitas adsorpsi, dan energi adsorpsi. Pelepasan porogen SiO2 dari membran untuk menghasilkan membran makropori ditunjukkan oleh hilangnya puncak tajam pada daerah serapan 1095 cm^-1 yang merupakan vibrasi ulur asimetri Si-O dari Si-O-Si. Citra SEM membran makropori menunjukkan permukaan kasar dan berpori berbeda dengan permukaan halus pada membran tanpa porogen. Kondisi optimum untuk adsorpsi biru metilen diperoleh pada membran makropori dengan komposisi kitosan:CMC sebesar 30:70, adsorpsi menit ke-30, pH 8, dan jumlah porogen 50%. Adsorpsi biru metilen mengikuti kinetika reaksi orde dua semu dengan pola isoterm Langmuir. Kapasitas adsorpsi maksimum sebesar 158,7 mg g^-1 dan energi adsorpsi sebesar 23,0 kJ mol^-1. Desorpsi maksimum biru metilen menggunakan NaCl 1 M mengikuti kinetika reaksi orde dua semu.

A study on the adsorption and desorption of methylene blue on chitosan-carboxymethyl cellulose macroporous membrane crosslinked by glutaraldehyde and SiO2 as porogen has been conducted. The macroporous membrane had been obtained by mixing a solution of CMC 0,1% (w/v) and chitosan 1% (w/v) which has been set to pH 5. After silica and glutaraldehyde were added, the solution was evaporated at 70 degree of Celcius. The macroporous membranes were characterized using FTIR and SEM. In the adsorption study, the effect of membrane composition, contact time, pH, the amount of porogen, adsorption-desorption kinetics, adsorption isotherms pattern, adsorption capacity, and adsorption energy were examined. The release of SiO2 porogen from the membrane to produce macroporous membrane was indicated by disappearance of a sharp peak absorption area at 1095 cm^-1 which is asymmetric stretching vibration of Si-O from Si-O-Si. SEM image of macroporous membrane showed a rough and porous surface in contrast to smooth surface of non porogen membrane. The optimum conditions for adsorption of methylene blue was obtained on the macroporous membrane with chitosan:CMC composition of 30:70, 30 min adsorption, at pH 8, and the amount of porogen 50%. The adsorption of methylene blue followed the pseudo second order reaction kinetics with the Langmuir isotherm pattern. The adsorption capacity was 158.7 mg g^-1 and the adsorption energy was 23.0 kJ mol^-1. The maximum desorption of methylene blue using NaCl 1 M followed pseudo second order reaction kinetics.

Kata Kunci : membran makropori, biru metilen, adsorpsi, desorpsi, kinetika reaksi