Simultaneous Adsorption of Multicomponent Lanthanide Ions on Pectin Encapsulated Zeolite A

In this study, pectin encapsulated Na-zeolite A particles (P-ZA) was synthesized using the impregnation method and it was used as an adsorbent for adsorption of multicomponent lanthanides ions. The Na-zeolite A (zeolite A) was prepared from natural kaolin by the hydrothermal method, while pectin was isolated from white pith of citrus maxima fruits. Scanning electron microscope (SEM) images suggested that P-ZA composite adopts a nest-like shaped surface morphology occupied by zeolite A particles or pectin encapsulated skeleton system of zeolite A particles. The size of P-ZA particles was approximately 125 μm. The highest adsorption capacity of La3+, Ce3+, Nd3+, Sm3+, and Dy3+ on P-ZA composite is 4.81×10‒5 M, 4.65×10‒5 M, 6.19×10‒5 M, 6.04×10‒5 M, and 6.03×10‒5 M, respectively, at the contact time of 60 mins. The lanthanides ions are adsorbed on the P-ZA surfaces through either ion exchange with Na-zeolite A or coordination with the functional groups of pectin, and are further stabilized by their hydrolysis on the P-ZA surfaces. The results suggest that P-ZA composite has the potential to be utilized as an adsorbent for the initial step of separation and purification of lanthanides after leaching from the metallurgical ores