IMOBILISASI ASAM HUMAT PADA KITOSAN MENGGUNAKAN METODE PENGIKAT-SILANG TERPROTEKSI DAN APLIKASINYA SEBAGAI ADSORBEN Cd(II) DAN Zn(II)

Immobilization of humic acid (HA) on chitosan using protected crosslinking method and its application as adsorbent of Cd(II) and Zn(II) have been done. This research was done by isolating HA from peat moss soil from Rawa Pening, Ambarawa, Central Java, protected with Cd(II) ion and cross-linking with chitosan using glutaraldehyde as a cross-linking agent. Then, Cd(II) ion is removed using EDTA. Adsorbent product resulted from humic acid immobilization on chitosan was characterized using FTIR spectrophotometer and used to adsorb Cd(II) ion by analyzing effect of acidity on adsorption, rate constant of adsorption, identification of functional group playing its important role in adsorption, and effect of another metal, Zn(II). Isolated HA has ash level of 0.86%. Chitosan deacetylation level was determined with base line a method of 76.37% and base line b of 83.57%. The results showed that optimum adsorption occurs in pH 6. The adsorption of Cd(II) ion by the adsorbent follows Ho�s pseudo second-order kinetic model with adsorption rate constant of 3.5879x10-1 g/mg min. Functional groups playing its important role in adsorption process are �COOH and �OH. Adsorption study at the presence of other metal indicates that the resulted adsorbent did not form template and adsorption follows HSAB rule with Zn(II) ion is predominantly adsorbed by the adsorbent rather than Cd(II) ion. Keywords: immobilization, cross-linking, humic acid, chitosan, adsorptio