Sorption behavior and mechanism of indium (III) onto amino methylene phosphonic acid resin

The sorption behavior of amino methylene phosphonic acid resin (APAR) for In(III) was investigated. Experimental results show that In(III) adsorbed on APAR can be elated with 2 mol.L-1 HCl. The apparent rate constant is k(298) = 1.50 x 10(-5) s(-1). The Sorption behavior of APAR for In (III) obeys the Freundlich isotherm. The themodynamic parameters of sorption, enthalpy change H-Delta, H, free energy change (Delta)G and entropy change S-Delta of sorption (APAR) for In (III) are 24.1 kJ.mol(-1), -35.1 kJ.mol(-1) and 200 J.mol(-1).K-1, respectively. The coordination molar ratio of the functional g-roup of APAR to In(III) is 2:1. The sorption mechanism of APAR for In (III)) was examined by IR Spectrometry.