KITOSAN TERCETAK ION UNTUK ADSORPSI SELEKTIF Cu(II), Cd(II) DAN Cr(III); IONIC IMPRINTED CHITOSAN FOR SELECTIVE ADSORPTION OF Cu(II), Cd(II) AND Cr(III) IONS

Shofiyani, Anis, Sri Juari Santosa

2015 | Tesis | FMIPA

Synthesis and characterization of Ionic Imprinted Chitosan (IIC) and Ionic Imprinted Chitosan on Chlorellla Biomass surface (IICCB) with Cu(II), Cd(II) and Cr(II) as imprinting ions have been conducted in this study. The IIC was prepared by interacting hydrogel chitosan with imprinting ions, then coagulating it for beads formation and crosslinking it using epichlorohydrin. The imprinted ions were then leached using 0.1 M solution of HNO3 followed by 0.2 M solution of Na2EDTA to provide specific templates as selective adsorption sites of the adsorbents. The IICCB was prepared through the same procedure as that of IIC with adding biomass after ion imprinting stage. Variables of imprinting ions concentration and weight ratio of chitosan : biomass were optimized to get an optimum condition in the preparation of IIC and IICCB, respectively. Adsorption characteristics of Cu(II), Cd(II) and Cr(IIII) on IIC and IICB were examined to study the effect of initial pH, contact time, concentration of metal ions, selectivity and reusability of the adsorbents. The synthesis of IIC using imprinting ion concentration of 5000 mg/L provided the optimum stability and relative adsorption capacity with the average percentage of ion elution by 80%, while the weight ratio chitosan:biomass = 1:1 provided the optimum results with 95% average percentage of elution on the synthesis of IICCB. The physicochemical characterization of IIC and IICCB indicated the role of –NH2 and –OH as the main sites for adsorption of Cu(II), Cd(II) and Cr(III) and involvement of –COOH groups of biomass in the interaction of chitosan-biomass. The adsorption of Cu(II) and Cd(II) took place optimally at pH 5-6 on IIC and at pH 4-6 on IICCB, while Cr(III) adsorbed optimally at pH 4-5 in both types of adsorbent. The adsorption kinetics of Cu(II), Cd(II), and Cr(III) on both IIC and IICCB followed the pseudo-second order model with the rate constants (k2) of IICCB were 2-3 times greater than those of IIC. The adsorption of Cu(II), Cd(II), and Cr(III) followed the Langmuir isotherms model with the adsorption capacities (Qm) of 48.780 and 61.728 mg/g, 44.44 and 53.763 mg/g, 50.505 and 61.350 mg/g for Cu(II), Cd(II), Cr(III) on IIC and IICB, respectively. These capacities were greater than those of the not-imprinted adsorbents. The selectivity data showed that IIC and IICCB were more selective than non-imprinted chitosans (CLC and Chit-Bio) and they could be re-used for 3 times with more than 80% percentage of adsorbed ions.

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