Authors: Ali Ahmadpour; Tahereh Rohani Bastami; Masumeh Tahmasbi; Mohammad Zabihi
Addresses: Department of Chemical Engineering, Faculty of Engineering, Ferdowsi University of Mashhad, P.O. Box 9177948944-1111, Mashhad, Iran. ' Department of Chemistry, Faculty of Sciences, Ferdowsi University of Mashhad, University Campus, P.O. Box 9177948944, Mashhad, Iran. ' Department of Chemistry, Faculty of Sciences, Ferdowsi University of Mashhad, University Campus, P.O. Box 9177948944, Mashhad, Iran. ' School of Chemical and Petroleum Engineering, Sharif University of Technology, P.O. Box 11155-9465, Azadi Ave., Tehran, Iran
Abstract: In the present investigation, different agricultural solid wastes namely: eggplant hull (EH), almond green hull (AGH), and walnut shell (WS), that are introduced as low cost adsorbents, were used for the removal of heavy metals (cobalt, strontium and mercury ions) from aqueous solutions. Activation process and/or chemical treatments using H2O2 and NH3 were performed on these raw materials to increase their adsorption performances. The effectiveness of these adsorbents was studied in batch adsorption mode under a variety of experimental conditions such as: different chemical treatments, various amounts of adsorbents, initial metal-ion concentrations, pH of solutions, contact times, and solution temperatures. High metal adsorption efficiencies were achieved for all cases only in the first two to three minutes of adsorbents' contact time. Maximum adsorption capacity of AGH sorbent for cobalt and EH for mercury were found to be 45.5 mg/g and 147.06 mg/g, respectively. The adsorption capacity of mercury for WS was also obtained as 151.5 and 100.9 mg/g for two different treated sorbents.
Keywords: environmental pollution; heavy metals; heavy metal removal; low cost adsorbents; aqueous solutions; agricultural solid waste; eggplant hulls; almond green hulls; walnut shells; cobalt; strontium; mercury; water quality; water pollution; adsorption.
International Journal of Global Environmental Issues, 2012 Vol.12 No.2/3/4, pp.318 - 331
Received: 15 Apr 2011
Accepted: 29 Aug 2011
Published online: 02 Oct 2012 *