Adsorption studies on Citrus reticulata (fruit peel of orange): removal and recovery of Ni(II) from electroplating wastewater.

The ability of fruit peel of orange to remove Zn, Ni, Cu, Pb and Cr from aqueous solution by adsorption was studied. The adsorption was in the order of Ni(II)>Cu(II)>Pb(II)>Zn(II)>Cr(II). The extent of removal of Ni(II) was found to be dependent on sorbent dose, initial concentration, pH and temperature. The adsorption follows first-order kinetics. The process is endothermic showing monolayer adsorption of Ni(II), with a maximum adsorption of 96% at 50 degrees C for an initial concentration of 50 mg l(-1) at pH 6. Thermodynamic parameters were also evaluated. Desorption was possible with 0.05 M HCl and was found to be 95.83% in column and 76% in batch process, respectively. The spent adsorbent was regenerated and recycled thrice. The removal and recovery was also done in wastewater and was found to be 89% and 93.33%, respectively.