Removal of heavy metals by adsorption on Pleurotus ostreatus Amna Javaid a , Rukhsana Bajwa a , Umer Shafique b, *, Jamil Anwar b a Institute of Plant Pathology, University of the Punjab, Quaid e Azam Campus, Lahore, Pakistan b Institute of Chemistry, University of the Punjab, Quaid e Azam Campus, Lahore, Pakistan article info Article history: Received 23 October 2010 Received in revised form 11 November 2010 Accepted 22 December 2010 Available online 13 January 2011 Keywords: Biosorption Electroplating effluents Heavy metals Macro-fungus Pleurotus ostreatus abstract The present study explores the adsorption potential of Pleurotus ostreatus (a macro-fungus) to remove copper, nickel, zinc and chromium from water all together. Different operational parameters such as the effect of pH, biomass dose, equilibrium time, stirring intensity, temperature and initial metal ion concentrations were studied. Maximum adsorption of Ni (II), Cu(II) and Zn(II) took place in the pH range 4.5e5.0, whereas for Cr(VI) ion, best results were achieved at pH 2.5. Nearly 150 min are required to gain sorption equilibrium. Temperature has no significant effect on biosorption in the range of 20e45  C. The maximum biosorption capacity of fungus was 8.06, 20.40, 3.22 and 10.75 mg g 1 for Cu(II), Ni(II), Zn(II) and Cr(VI) in that order. FTIR analysis pointed out the involvement of amine (eNH 2 ) and carboxylic (eCOOH) groups in the adsorption process. Simple and adjusted Langmuir and Freundlich isotherm models were used to explain the sorption phenom- enon. For real effluents of electroplating, biosorption capacities were 2.73, 8.45, 0.88 and 4.45 mg g 1 for Cu(II), Ni(II), Zn(II) and Cr(VI) ions, respectively. Moreover, used P. ostreatus was recycled repeatedly and used many times to evaluate the adsorption efficacy on reuse, but findings pointed out that capacity decreased, to some extent, on recycling. ª 2010 Elsevier Ltd. All rights reserved. 1. Introduction The critical environmental challenge for industry is the safe disposal of wastewater. Among the various industries, elec- troplating units are the most important because of their lucrative applications. In contrast to other industries, the electroplating units use less water, thus produce small volume of wastewater. However, it is highly toxic in nature because of the presence of hazardous metals such as Ni(II), Cr (III/IV) and Cd(II). To reduce the toxicity of heavy metals, several physicochemical methods are being used worldwide [1e4] but these are inherently problematic in their application to metal bearing waste streams [5]. Chemical precipitation, lime coagulation, ion exchange, reverse osmosis and solvent extraction are the common methods of removal of metals from water. Nevertheless, disadvantages like incomplete removal, high reagent cost and energy needs, generation of toxic waste products that need careful disposal have made it imperative to find out a new cost-effective treatment method that is capable of removing heavy metals from effluents [6]. Adsorption is an excellent alternative to above-mentioned techniques. Around the world, scientists are trying to evaluate adsorption capacities of different materials to find out more efficient and economic adsorbents. Attentions have been focused on the microbial biomasses (dead or living), which can bind the heavy metals even from dilute solutions [7]. In the past few years, “macromycetes” have appeared as potential materials for the remediation of wastewater con- taining toxic metal ions. Macromycetes are macro-fungi that belong to division “basidiomycota” and are characterized by the formation of visible fruiting bodies. Various basidiomy- cetes have shown good potential for removal of heavy metals * Corresponding author. Tel.: þ92 321 4990904. E-mail address: umer0101@hotmail.com (U. Shafique). Available at www.sciencedirect.com http://www.elsevier.com/locate/biombioe biomass and bioenergy 35 (2011) 1675 e1682 0961-9534/$ e see front matter ª 2010 Elsevier Ltd. All rights reserved. doi:10.1016/j.biombioe.2010.12.035