MODIFIKASI KITOSAN DENGAN PENAUTSILANGAN, PENCANGKOKAN DAN PENCETAKAN ION SERTA APLIKASINYA SEBAGAI ADSORBEN ION LOGAM BERAT; MODIFICATION OF CHITOSAN THROUGH CROSSLINKING, GRAFTING AND ION IMPRINTING AND THE APPLICATION AS ADSORBEN HEAVY METAL ION

Masykur, Abu, Sri Juari Santosa

2015 | Tesis | FMIPA

The aim of the study was to modify chitosan to obtain adsorben with good stability towards acid solution, high ability to adsorp metal ion and goodselectivity on specific ion. Modification was done through processes of crosslinking, grafting and ion imprinting. Chitosan crosslinking was aimed to form an acid-insoluble adsorben using three various crosslinking agents of ethylene glycol diglycidyl ether (EGDE), diethylene glycol diglycidyl ether (DEGDE) and bisphenol A diglycidyl ether (BADGE). Succinic anhydride and chloroacetic acid were used for the grafting of the crosslinked chitosan. Ion imprinting technique used was Pb(II) that was templated on carboxymethyl chitosan using BADGE crosslinker. Adsorben was characterized using FTIR to identify the functional groups, XRD, DTA-TGA, 13C NMR spectrometer, SEMEDX, surface area analysis (SAA) and elemental analysis (EA). The adsorben properties studied by pH influence, contact times, concentration metals ion, selectivity and mechanism of the adsorption were also performed. Crosslinking of chitosan showed that adsorbent formed was insoluble in the acid solution. At pH 5 was optimum pH reached for the adsorption of Pb(II), Cu(II) and Cd(II) ions. Adsorption ability of the adsorbent was influenced by crosslinking agents used with BADGE > DEGDE > EGDE sequence. Adsorption ability was also influenced by grafter agent, in which chloroacetic acid was better than succinic anhydride. Adsorption kinetic of Pb(II) on the all adsorbents followed a kinetic of the pseudo second order. Pb(II) adsorption of chitosan obeyed the adsorption isotherm of Langmuir, but other adsorbents obeyed adsorption isotherm of Freundlich. Adsorption capacity of chloroacetic acidgrafted chitosan was Pb(II) > Cu(II) > Cd(II). Energy of Pb(II) adsorption was -21 - -28 kJ/mole. Interaction ion Pb(II) on chitosan were trapping, ion exchange, hydrogen bonding and covalent bonding. Chloroacetic acid grafted adsorbent was mostly hydrogen bonding. Grafting with chloroacetic acid improved the selectivity of of Pb(II) ion over Cu(II), Cd(II), Zn(II) and Ni(II) ions. Ion imprinted adsorbent (Pb-IIP) had better adsorption ability on Pb(II) ion than NIP. Selectivity of Pb-IIP adsorbent was depend on the size of counterion.

Kata Kunci : chitosan; crosslinking; grafting; ion templating; adsorption; metal ion.