Walnut shells as a potential biosorbent for Cu(II), Pb(II) and As(III)/(V) ions removal from river waters

In this study, the potential of the walnut shell as a biosorbent for biosorption of Cu(II), Pb(II), and As(III)/(V) ions from river water samples was investigated. The effects of various conditions of water samples such as the initial ion concentration, sample pH, and contact time at a constant temperature and biosorbent dosage, on biosorption of Cu(II), Pb(II), and As(III)/(V) were investigated. Walnut shells, as the material with a high potential for removal of investigated ions, have biosorption efficiency of up to 99.6%, under the applied experimental conditions. The best adsorption time was obtained at 4 h for Cu(II), Pb(II), and As(III)/(V) ions. The maximum removal of 97.6% (Cu(II)), 82.9% (Pb(II)), and 99.6% (As(III)/(V)) was obtained at pH=4.43, pH=8.55, and pH=7.84, respectively. Hence, the walnut shell shows potential of a cost-effective biosorbent that could be used for the treatment of contaminated rivers. However, further investigation is needed to fully explore this potential.