Sequestering potential of peach nut shells as an efficient sorbent for some toxic metal ions from aqueous media: a kinetic and thermodynamic study.

Muhammad Ashraf Shaheen; Rehana Akram; Abdul-Karim; Tahir Mehmood; Robina Farooq; Shahid Iqbal; Mudassir Iqbal

Muhammad Ashraf Shaheen Department of Chemistry, University of Sargodha, Sargodha, Pakistan

Rehana Akram Department of Chemistry, University of Sargodha, Sargodha, Pakistan

Abdul-Karim Department of Chemistry, University of Sargodha, Sargodha, Pakistan

Tahir Mehmood Department of Chemistry, University of Sargodha, Sargodha, Pakistan

Robina Farooq Department of Chemical Engineering, COMSATS Institute of Information Technology (CIIT), Lahore, Pakistan

Shahid Iqbal Department of Chemistry, University of Sargodha, Sargodha, Pakistan

Mudassir Iqbal Department of Chemistry, University of Fribourg, Chemin du Musee 9, Fribourg 1700, Switzerland; Department of Chemistry, School of Natural Sciences, National University of Sciences and Technology NUST, H-12, Islamabad, Pakistan

The peach nut shells potential as a low cost biosorbent for separation of certain metal ions from aqueous media was investigated. The effects of different parameters such as pH, shaking speed, initial metal ions concentration and their contact time with adsorbent on sorption efficiency of biosorbent was investigated to optimize the parameters for maximum sorption. The biosorbent was characterized by FT-IR spectroscopy and a significant increase in sorption was noted with rise in pH of metal ions solution and maximum sorption was observed at pH 6. The isothermal data was fitted to Langmuir, Dubinin–Radushkevich (D–R) and Freundlich isotherms. The equilibrium process was best fitted to Langmuir isotherm. The removal efficiency of chemically activated samples was found to be ~35 to 45% greater than raw sample. These results showed that peach nut shell was an effective biosorbent for remediation of contaminated water with lead (II), Nickle (II) and Chromium (III) ions. Being low cost material, PNS has a potential to be exploited in waste water treatment technologies. This study shows that even at very low concentration of sorbent, the activated PNS exhibited appreciable sorption for Pb, Cr and Ni metals ions (97%, 95% and 94%) respectively from aqueous solution. The chemical and thermal activation of peach nut shells enhances the removal efficiency for all metal ions. From reported data; it was found that the adsorption ability of Pb ions is greater than nickel and chromium.