Selective adsorption of Pb(II) ion on amine-rich functionalized rice husk magnetic nanoparticle biocomposites in aqueous solution

Abstract

Amine group on rice husk magnetic nanoparticle bicomposites (RHB-MH) was synthesized by one-step solvothermal method. The new finding of biocomposites is utilization of rice husk cellulose as a support which produced high amine content on surface of magnetic nanoparticle (MNPs). The rice husk cellulose (RH-D), iron(III) chloride hexahydrate, Na-acetate anhydrate were mixed in ethylene glycol, then kept at ±200 °C for 6 h. Amine modified MNPs was constructed by addition of 1,6-hexanediamine in mixture before the reaction. The MNPs was growth on surface of RH-D then formed biocomposites. The Fe content about 93.11 % and the magnetic nanoparticle structure was proved by specific peaks at 36°, 43°, 63° for magnetite. The magnetic saturation value of biocomposites about 16.4 emu/g. The thermal stability of biocomposites showed up to 200 oC with less than 10 % of mass degradation. Higher amine content of 12.3 mmol/g on biocomposites was achieved after addition of 7 mL of 1,6-hexanediamine (RBH-MH2). Amine functional group on biocomposites exhibited the resonance bands at 1645 cm−1 and 1050 cm−1. The adsorption of Pb(II) ion on RBH-MH2 follows pseudo 1 st order kinetic and well-fitted by Langmuir adsorption isotherm model which have maximum capacity of 680.19 mg/g at room temperature and pHe∼5. The RBH-MH2 have significant effect to capture Pb(II) ion due to electrostatic interaction and showed 3.6-fold higher adsorption capacity than rice husk biocomposites without modification. The amine-rich on biocomposites does not only provide an easy retrievable from aqueous solution but also potential candidate for effective green adsorbent.