Adsorption of Zn(II) ions on Calcium Silicate Precipitation Tube (CaSPT) produced through ‘silica garden’ route

Zn(II) adsorption in aqueous medium has been reported on Calcium Silicate Precipitation Tube (CaSPT), grown by ‘silica garden route’. Adsorption varies nonlinearly with adsorbent dose and initial adsorbate concentration. Adsorption data fit better with Langmuir isotherm model which returns Zn(II) loading capacity of 229.6mgg−1 at 0.01g CaSPT. Adsorption kinetics follows pseudo-second order rate equation with activation energy of 8.56kJmol−1, typical for a physisorption process. The adsorption process is endothermic and spontaneous. CaSPT was successfully tested with regard to Zn(II) removal on a real life effluent sample collected from an electroplating industry.