International Journal of Latest Technology in Engineering, Management & Applied Science (IJLTEMAS) Volume VI, Issue IV, April 2017 | ISSN 2278-2540 www.ijltemas.in Page 13 Application of Response Surface Methodology for Biosorption of Reactive Dyes from Textile Effluent Using Dead Fungal Biomass of Rhizopus Arrhizus NCIM 997 *Sukhada Saraf and Varsha K. Vaidya The Institute of Science, 15, Madam Cama Road, Mumbai 400 032, Maharashtra, India. *Corresponding Author: Sukhada Saraf Abstract: - Response Surface Methodology was employed for studying the biosorption of reactive dyes from textile effluent by utilization of dead biomass of Rhizopus arrhizus in a batch system. Central Composite Design at the specified combinations of four variables (pH, biosorbent dosage, speed of agitation, contact time) was adopted to achieve maximum biosorption. The fitted quadratic model (P<0.0001) was used to arrive at the best operating conditions. Under the following optimum conditions i.e., pH 2.0; biosorbent dosage 3 g /L; speed of agitation 80 rpm and contact time 60 min, 99.60% of the dyes were removed from the wastewater. The mechanism of biosorption was elucidated by FTIR, XRD and BET analysis. This work demonstrated the feasibility of employing Rhizopus arrhizus as an effective and economical fungal biosorbent for the removal of dyes from the textile effluent. Keywords: Biosorption, Textile effluent, Response surface methodology, Rhizopus arrhizus, I. INTRODUCTION extile industry extensively uses reactive dyes, owing to their technical attributes and easy availability of raw materials [1].The effluent generated by reactive dyeing processes contains hydrolyzed dyes amounting to 20-30% of the dyes used; recalcitrant organics; surfactants, sizing, coating and finishing agents, which are responsible for the high COD and BOD of the effluents; textile fibres (60-100 g/L); electrolytes, essentially NaCl and Na 2 CO 3 , which contribute to the high salinity of the wastewater [1-6]. Thus, release of textile effluents in the ecosystem has raised a great concern due to the aesthetic considerations as well as their recalcitrant nature; potential toxicity, carcinogenicity and mutagenicity to animals and humans [7-9]. Reactive dyes because of their complex aromatic molecular structure tend to pass through the conventional physical and chemical processes while inhibiting the conventional biological wastewater treatment processes [7, 10-14]. This has given an impetus to use eco-friendly techniques such as adsorption because of ease of design, effectiveness, simplicity of operation, insensitivity to noxious materials and capacity to treat the dyes in a more concentrated form [15]. One of the most extensively used adsorbents is activated carbon because of its very good adsorption capacity for organic pollutants. However, its commercial application is limited due to high expenses, difficulty in regeneration and problems with respect to its ultimate disposal [16-18]. Hence, low-cost biosorbent materials such as natural waste materials originated from agriculture and industry (i.e. corncob, pinewood, rice husk, bagasse, chitosan, etc.) as well as biosorbents produced from microbial biomass have gained increase in attention due to reduction the adsorbent dose and minimization of the disposal problem [4,19-21]. Among the various types of biomasses, the inactivated fungal biomass is particularly attractive due to its constant and cheap supply from industrial fermentation processes, selectivity, high removal rates, ease of storage and regeneration. The effectiveness of the biosorption by some fungi under equilibrium conditions has been shown to be superior to the traditional ion-exchange resins and activated carbon for reactive azo dyes [4,19, 22, 23]. The majority of wastewater treatment processes are multi-variable and optimization of the process by statistical approaches such as Response Surface Methodology (RSM), offers advantages such as closer confirmation of the output response to normal, lower process variability, reduced development time and costs. RSM helps to optimize operational variables, to build models, to scrutinize the interactions between the variables while minimizing the empiricism of trial-and-error techniques [24,25]. Recently, several wastewater treatment processes including; textile, tannery, palm oil mill and industrial paint effluents, landfill leachate, etc. have been optimized via RSM [26,27]. The current work focuses on the application of RSM in studying the usability and effectiveness of the biosorbent made from the dead biomass of Rhizopus arrhizus in optimization of textile wastewater treatment and modeling the process parameters. The kinetics data were used to identify the T