Ecological Engineering 60 (2013) 99–107 Contents lists available at ScienceDirect Ecological Engineering journa l h om epage: www.elsevier.com/locate/ecoleng Biosorption of chromium onto native and immobilized sugarcane bagasse waste biomass Ihsan Ullah, Raziya Nadeem ∗ , Munawar Iqbal ∗ , Qaisar Manzoor ∗ Department of Chemistry and Biochemistry, University of Agriculture, Faisalabad 38040, Pakistan a r t i c l e i n f o Article history: Received 28 March 2013 Received in revised form 12 June 2013 Accepted 5 July 2013 Available online 14 August 2013 Keywords: Heavy metals Kinetics Isotherms Tannery wastewater SEM EDX analysis a b s t r a c t Adsorption experiments were carried out using sugarcane bagasse native and immobilized biomasses as a function of initial concentration, biomass dose, pH and contact time for the removal of Cr(III) and Cr(VI) form simulated and tannery wastewater stream. The equilibrium biosorption data was analyzed using pseudo-first order and pseudo-second order kinetic models and Langmuir and Freundlich isotherm models. The immobilized biomass furnished considerably high adsorption capacity of both chromium ions versus native biomass. Maximum uptake of 80.6% and 41.5% was observed for Cr(VI) and Cr(III) onto immobilized biomass and at optimized conditions, up to 73% chromium adsorption was observed onto immobilized sugarcane bagasse biomass. The sorption capacity of sugarcane bagasse biomass varies greatly with initial pH, biosorbent dose, initial metal ions concentration and contact time. Langmuir model fitted well to the data and the pseudo-second order could best describe the biosorption kinetics. © 2013 Published by Elsevier B.V. 1. Introduction Heavy metals are discharged into environment from various sources such as textile, pigments, plastics, mining, electroplating and metallurgical processes (Han et al., 2006; Iyer et al., 2005), and are considered persistent environmental contaminants, because they cannot degraded naturally (Montazer-Rahmati et al., 2011). Due to their toxic effect and accumulation tendency throughout the food chain, the heavy metals pollution represents an important problem with serious ecological and human health consequences (Bulgariu and Bulgariu, 2011). The chromium enters into water bodies due to indiscrimi- nate disposal of wastes from the industries (Lakshmanraj et al., 2009). A survey report published by Pakistan Council of Research in Water Resources revealed that 23 major cities groundwater of Pakistan has been contaminated with chromium. Various authors individually reported that the chromium concentration has been exceeds the safe limits of WHO standards (0.05 mg/L). Analysis of drinking water samples from the residential area of Kasur, Khy- ber Pukhtoonkhwa, Lahore, Gujarat, Sialkot and Karachi showed chromium concentration beyond the permissible limits in drink- ing water. The reason of elevated concentration of chromium in water is the leather and tanneries industries located in these ∗ Corresponding authors. Tel.: +92 41 41 9200161 67x3310. E-mail addresses: raziyaanalyst@yahoo.com (R. Nadeem), bosalvee@yahoo.com (M. Iqbal), qaisar263@yahoo.com (Q. Manzoor). areas (Azizullah et al., 2011). While studying the concentration of chromium in effluents of tanneries, soil and drinking water in Sialkot District, Pakistan, the concentration of total chromium was found to be in the range of 16.12–36.83 mg/L, 1.0483–3.1824 mg/L and 3.45–11.43 mg/kg, respectively (Mahmood, 2010). Due to toxic nature and environmental impacts of chromium, there are growing concern for the removal of this metal from wastewaters (Bulgariu and Bulgariu, 2011; Chaisuwan et al., 2011). Various methods have been used for heavy metal removal, including chemical precipitation, neutralization, membrane filtra- tion and adsorption. Among these techniques, biosorption using agricultural waste has gained considerable attention because of high efficiency, low cost, more availability and ease of handling (Chaisuwan et al., 2011). Biosorption utilizes biological materi- als as adsorbents and this method has been studied by several researchers as an alternative to conventional methods for the removal of heavy metals from wastewater (Bhatti and Amin, 2013; Inyang et al., 2012; Omorogie et al., 2012; Saqib et al., 2013; Zuo et al., 2012). The use of non-living biomaterial containing metal-binding functional groups would have the advantage of not requiring utmost care and maintenance as well as being useful in remediating areas with high levels of heavy metal contamination (Iqbal et al., 2013; Vijayaraghavan et al., 2012; Witek-Krowiak et al., 2011). Sugarcane bagasse (Saccharum officinarum L.) is the fibrous material left after the crushing of the cane stalk and juice extracting. Structurally, sugarcane is composed of an outer rind and inner pith. The majority of sucrose together with bundles of small fibers is 0925-8574/$ – see front matter © 2013 Published by Elsevier B.V. http://dx.doi.org/10.1016/j.ecoleng.2013.07.028