Multicomponent isotherm for biosorption of Zn(II), CO(II) and Cd(II) from ternary mixture onto pretreated dried Aspergillus niger biomass Zahra Hajahmadi a , Habibollah Younesi a,n , Nader Bahramifar a , Hossein Khakpour b , Kasra Pirzadeh c a Department of Environmental Science, Faculty of Natural Resources, Tarbiat Modares University, Imam Reza Street, P.O. Box 64414-356, Noor, Iran b Department of Chemical Engineering, Ayatollah Amoli Branch, Islamic Azad University, Amol, Iran c Chemical Engineering Department, Babol University of Technology, Shariati Street, Babol, Iran article info Article history: Received 11 September 2014 Received in revised form 2 June 2015 Accepted 14 July 2015 Keywords: Multicomponent biosorption A. niger Genetic algorithm Isotherms Kinetics abstract In the present study, multicomponent competitive biosorption of heavy metal from aqueous solution onto pretreated dried Aspergillus niger in batch system was investigated. The adsorption data were fitted to the multicomponent Langmuir, Freundlich, Temkin and Sips equations. We used the genetic algorithm of bio- sorption in ternary mixture to evaluate the potential effects of each metal in the removal of other metals. In order to take both mechanisms of the cell-surface binding and intra-particle diffusion into account, an alternative model was investigated by combining the pseudo-second-order kinetics model and the intra- particle diffusion model. A model describing the process of biosorption by a single-stage batch design was developed and verified based on the Temkin isotherm model. Fundamentally, the outlook from these ob- servations of the experiments that the pretreated dried biomass is a suitable absorbent for the removal of significant amounts of the heavy metal from the effluents of industrial wastewater is promising. & 2015 Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/). 1. Introduction The high degree of industrialization and urbanization has re- sulted in environmental pollution. The wastewaters discharged from chemical industries which may contain heavy metal ions have toxic effect on all living organisms. Besides the toxic and harmful effects to a variety of living species [1], heavy metals also accumulate throughout the food chain even in relatively low concentrations and may affect human beings. Zn(II) is an essential element and a potential gastrointestinal toxicity exists because of an over accumulation of this metal in the human body. Zn(II), one of the most important metals often found in effluents discharged from industries involved in acid mine drainage, galvanizing plants, natural ores and municipal wastewater treat- ment plants, is not biodegradable and travels through the food chain via bioaccumulation [2]. Industrial exploitation of Co(II) in alloy manufacturing, electroplating, generation of gas turbines and pet- rochemical industries results in discharge of cobalt into the aquatic environment leading to a variety of toxic effects on all living plants and animals including microorganisms [3]. Co(II) has both beneficial and harmful effects on human being as it is a part of vitamin B 12 , which is essential for human health. It causes neurotoxicological disorders and genotoxicity in human beings and in chronic cases may cause cancer. Cd(II) is a nonessential element for organisms and its high toxicity for humans has been recognized. Pollution by Cd(II) usually comes from several industrial processes such as electro- plating, plastics manufacturing, nickel–cadmium batteries, fertili- zers, pigments, mining and metallurgical processing. Cd(II) toxicity may be observed by a variety of syndromes and its effects include renal dysfunction, hypertension, hepatic injury, lung damage and teratogenic effects [4]. Consequently, there is significant interest regarding Zn(II), Co(II) and Cd(II) removal from wastewaters. The most widely used methods for removing heavy metals from wastewaters include ion-exchange, coagulation, chemical precipitation, reverse osmosis, evaporation, membrane filtration, biological adsorption treatment. Conventional methods have some disadvantages such as incomplete removal, high reagent and en- ergy requirements, and generation of toxic sludge or other waste products that require disposal. Therefore, removal of toxic heavy metals to an environmentally safe level in a cost effective and environmentally friendly manner assumes great importance. Microorganisms including bacteria, algae, fungi and yeast are found to be capable of efficiently accumulating heavy metals [5]. Among the main strains, fungi biomass offers the advantage of having a high percentage of cell wall material that shows excellent metal-binding properties. Aspergillus niger, a filamentous fungus, is not only utilized in the industrial production of citric acid and Contents lists available at ScienceDirect journal homepage: www.elsevier.com/locate/wri Water Resources and Industry http://dx.doi.org/10.1016/j.wri.2015.07.003 2212-3717/& 2015 Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/). n Corresponding author. E-mail addresses: hunesi@modares.ac.ir, hunesi@yahoo.com (H. Younesi). Water Resources and Industry 11 (2015) 71–80