Bioremoval of Malachite green from water sample by forestry waste mixture as potential biosorbent Fatih Deniz a, ⁎, Remziye Aysun Kepekci b a Department of Environmental Engineering, Faculty of Engineering and Architecture, Sinop University, 57000 Sinop, Turkey b Department of Food Processing, Vocational High School of Technical Sciences, Gaziantep University, 27310 Gaziantep, Turkey abstract article info Article history: Received 2 November 2016 Received in revised form 17 January 2017 Accepted 21 January 2017 Available online 23 January 2017 Application of cetyltrimethylammonium bromide (CTAB) modified multi-component biosorbent composed of pine, oak, hornbeam and fir sawdust biomasses was investigated to remove Malachite green (MG) as a model pollutant from aqueous solution. The effects of pH, dye concentration, biosorbent amount and contact time on the biosorption performance were explored in a batch biosorption system. The biosorption isotherm data were analyzed using Freundlich, Langmuir, Sips and Dubinin-Radushkevich models while the kinetic data of biosorption were modeled with the pseudo-first-order, pseudo-second-order, Elovich, logistic and intra-particle diffusion models. These studies showed that Sips isotherm and logistic model fitted well to the dye biosorption data. The maximum biosorption capacity of biosorbent was calculated to be 52.610 mg g -1 at the optimized conditions. Thus, the CTAB modified multi-component sawdust biomass can be employed as cost effective and ecological friendly biosorbent in the treatment of industrial effluents containing such unsafe pollutants. © 2017 Elsevier B.V. All rights reserved. Keywords: Phytosorbents Sawdust Biosorption Synthetic dyes 1. Introduction Synthetic dyes are widely used in many areas such as paper, textile, food, cosmetic, leather, plastic and pharmaceutical industries. An im- portant amount of these pollutants are commonly present in the efflu- ents of above industries [1]. Unless properly treated, synthetic dyes may affect aesthetic condition of water bodies and compromise many water uses. Also, they may pose serious risks to aquatic life and human health [2,3]. Therefore, the effluents containing synthetic dyes need to be treated to minimize their threat to the environment. One of the most used synthetic dyes is Malachite green (MG). MG, a triarylmethane dye, is widely used for different purposes in various in- dustrial fields such as textile, food, paper and other biological fields. However, MG presented many adverse characteristics because of its high toxicity, as well as teratogenic, carcinogenic, and mutagenic prop- erties. Although different authorities all over the world have applied re- strictions for the usage of MG, it is still used in many countries due to its low cost and availability [4–6]. Many different types of treatment processes including ion exchange, coagulation, flocculation, membrane filtration and chemical oxidation have been used to remove such synthetic unsafe dyes from polluted ef- fluents. These methods have some disadvantages such as incomplete re- moval, high reagent and energy requirements, and generation of toxic sludge or other waste products that require disposal [7,8]. Hence, the re- moval of hazardous dyes to an environmentally safe level in a cost effec- tive and environmentally friendly manner assumes great importance. Among the emerging remediation technologies for dye impurity, biosorption of synthetic dyes using natural biomasses or agro-industrial wastes and by-products is known to be a feasible and efficient alterna- tive considering numerous biosorbent sources, low operational costs, high removal efficiency and low secondary pollution risk [9–11]. As a natural waste biomass, sawdust generated in abundance from forestry and agricultural activities in particular has various important advan- tages in terms of cost, quantity, renewability and biodegradability. It mainly consists of cellulose, hemicellulose and lignin. These properties make sawdust a suitable biomass for pollutant biosorption. Many biosorption studies involving different unwanted materials and saw- dust residues have been performed earlier [12–15]. However, to the best of our knowledge, performance of different types of sawdust bio- mass in biosorption system has been evaluated individually. Besides, current studies have focused on applying different modification agents to improve biosorption capacities of biosorbents, and this operation showed a great improvement [16,17]. Hence, cetyltrimethylammonium bromide (CTAB) as a model modification agent was first applied to modify a novel multi-component biosorbent composed of pine, oak, hornbeam and fir sawdust biomasses, aiming to obtain an effective biosorbent for MG dye in this study. Different process variables were evaluated for optimal biosorption conditions. Performance estimation of batch biosorption system was achieved by appropriate mathematical modeling. Microchemical Journal 132 (2017) 172–178 ⁎ Corresponding author. E-mail address: f_deniz@outlook.com (F. Deniz). http://dx.doi.org/10.1016/j.microc.2017.01.015 0026-265X/© 2017 Elsevier B.V. All rights reserved. Contents lists available at ScienceDirect Microchemical Journal journal homepage: www.elsevier.com/locate/microc