Adsorption of palladium(II) from aqueous solution using nanosilica modified with imidazoline groups

Nanosilica was functionalized with imidazoline groups and used as a new sorbent to recycle Pd(II) from aqueous solution. The sorbent was investigated by thermogravimetric analysis (TGA), transmission electron microscopy (TEM), fourier transform infrared (FT-IR) and X-ray photoelectron spectroscopy (XPS). The influence of pH, adsorption time and original Pd(II) concentration on recovery was discussed. The optimal pH value for adsorption was 4. The maximum adsorption quantity of Pd(II) was 69.6 mg/g. The coexisting ions exhibit little interference on the Pd(II) separation. The separation process of Pd(II) matches a pseudo-second-order kinetic model. The separation data obeyed best with the Langmuir isotherm model. The adsorbent exhibited good recyclability for Pd(II). Separation of Pd(II) takes place via chelation and ion-exchange. The adsorbent has wide application prospect to selectively capture Pd(II) from aqueous solutions.