Utilization of Ziziphus lotus Fruit as a Potential Biosorbent for Lead(II) and Cadmium(II) Ion Removal from Aqueous Solution

Abstract

The removal of cadmium (II) and lead (II) ions from aqueous solutions by the Ziziphus lotus fruits powder, as inexpensive and eco-friendly biosorbent, was studied in batch mode. Fruits powder (FP) revealed the highest uptake rate at pH=8 and pH=7 for Cd(II) and Pb(II) consecutively. The best metal adsorption rate is obtained with a temperature ranging from 25 to 30 °C, a contact time of 90 min, an initial ionic concentration of 100 mg/L, and a biosorbent dosage ranging from 3.5 to 5 g/L.The experimental kinetic data of the biosorption process for both heavy metal ions were fitted by the pseudo second order model. The equilibrium data fitted very well to the Langmuir model. The maximum monolayer biosorption capacities were 33.94 mg/g and 69.06 mg/g for Cd(II) and Pb(II) respectively. The main chemical groups which are involved in the trapping of Cd(II) and Pb(II) and which have been revealed by FTIR spectral analysis are: N–C, O=C, H-O, H-C, and O–C. The present research confirms that Z. lotus fruits could be exploited as a low-cost and an effective biosorbent for the elimination of Cd(II) and Pb(II) ions from aqueous solution.