Removal of Common Heavy Metals from Aqueous Solutions by Waste Salvadora persica L. Branches (Miswak)

Document Type: Original Research Paper


1 Department of Chemistry, Faculty of Arts and Science, Ondokuz Mayýs University, 55139 Kurupelit, Samsun, Turkey

2 Department of Chemistry, Faculty of Arts and Science, Kirikkale University, 71450, Yahşiyan, Kirikkale, Turkey


The adsorption ability of miswak (Salvadora persica L.) waste was investigated for the removal
of common heavy metals; Pb(II), Cu(II), Ni(II) and Cd(II), from aqueous systems. The miswak mainly
consists of saponins, tannins, silica and resin, which are accounted for the removal of heavy metal ions from
aqueous systems. The effects of various parameters, such as solution pH, contact time, initial concentration
of the heavy metal ions and adsorbent dosage were examined. The linear correlation coefficients of Langmuir
and Freundlich isotherms were obtained and the results revealed that the Freundlich isotherm fitted the
experiment results better than Langmuir isotherm (r2=0.974–0.993). The maximum adsorption capacities of
Pb(II), Cd(II), Cu(II) and Ni(II) for per g miswak waste were calculated as 6.84±0.23, 5.91±0.20, 4.56±0.17
and 3.73±0.15 mg, respectively. Five cycles of adsorption-desorption were carried out revealing the strong
reuse potential of this low-cost adsorbent. The results indicate that the miswak waste, which has a very low
economical value, could be used to effectively adsorb common heavy metals from aqueous systems for
environmental cleaning purposes.