ARTICLE IN PRESS JID: JTICE [m5G;December 4, 2018;16:43] Journal of the Taiwan Institute of Chemical Engineers xxx (xxxx) xxx Contents lists available at ScienceDirect Journal of the Taiwan Institute of Chemical Engineers journal homepage: www.elsevier.com/locate/jtice Efficient removal of textile dye using nanosized fly ash derived zeolite-x: Kinetics and process optimization study Sivamani Sivalingam, Sujit Sen ∗ Catalysis Research Laboratory, Department of Chemical Engineering, National Institute of Technology, Rourkela, Odisha 769008, India a r t i c l e i n f o Article history: Received 31 July 2018 Revised 6 October 2018 Accepted 13 October 2018 Available online xxx Keywords: Adsorption Nanocrystalline zeolite X Crystal violet Response surface methodology Equilibrium study Kinetics a b s t r a c t A novel nanocrystalline zeolite X (nZX) was synthesized using coal fly ash of eastern India for adsorptive removal of a textile dye—crystal violet (CV) from aqueous solution. nZX was characterized by TEM, XRF, FESEM, XRD, FTIR, and BET. The nZX has a surface area, an average crystal size, an average particle size, crystallinity, and product yield of 651.34 m 2 /g, 16.28 nm, 27.28 nm, 82% and 91% respectively. A maxi- mum of 99.52% CV was removed at optimized condition of pH 9, 60 min contact time, 50 °C temperature, 100 mg/L initial dye concentration and 1.0 g/L adsorbent mass. A high correlation coefficient (R 2 = 0.998) good agreement between the predicted and experimental values. The maximum Langmuir adsorption ca- pacity of 234.57 mg/g was obtained. The adsorption of CV followed a pseudo-second order kinetic model. The synthesized nZX was also found to be very efficient up to five regenerative cycle in removing the dye. Therefore, the synthesized nZX could be utilized for efficient removal of CV dye in real wastewater. © 2018 Taiwan Institute of Chemical Engineers. Published by Elsevier B.V. All rights reserved. 1. Introduction Industrial effluent contains different dyes discharged from dif- ferent industries such as textile, food, leather, cosmetics, rubber, plastic, paint and paper printing [1]. Synthetic textile dyes are highly toxic material. Crystal violet (CV) is a one such dye that has been used in bloody fingerprints, veterinary and animal medicine as a biological stain. This water soluble dye may cause ingestion, skin disease, severe eye irritation, inhalation issues and even can- cer on account of its toxic nature in environment and human health [2–4]. Therefore, it is highly desirable to remove the CV dye from wastewater before its recycle and reuse. In literature, various methods were reported for removal of dyes like CV from wastewater based on physical, chemical, and biolog- ical treatments methods such as biosorption [5], coagulation and flocculation [6], electrochemical remediation [7], adsorption [8], and fungal decolonization [9]. Among these methods, adsorption is the most effective, advanced and low cost technique for removal of dye molecule [10]. Recently researchers have formulated low cost and effective adsorbents for dye removal such as clay [11], agri- cultural waste [12], magnetic nanoparticles [13], fly ash [14], rice husk [15], and zeolite [16]. Utilization of many industrial waste has also become an emerging research area [17]. Activated carbon is a well-known adsorbent for its high surface area but it has its ∗ Corresponding author. E-mail address: sensujit@nitrkl.ac.in (S. Sen). limited application due to high cost and regeneration process. There is therefore a need of alternative low cost adsorbent with high efficiency and economically feasible method of preparation. This study aimed at synthesis of nanosized zeolite from indus- trial waste material and testing the performance in removal of a cationic dye viz. crystal violet. Zeolites have been widely used for dye removal because of their high surface area, high adsorption capacity and reusability char- acteristic [16,18,19]. The coal fly ash (CFA) is a by-product of coal based thermal power plants and it consist of high silica and alu- mina material along with some trace elements. Zeolites are crys- talline hydrated alumina-silicate materials. Hence CFA can be con- verted to zeolite following a proper method [20]. There are a few studies on removal of dye using different zeolites like nano ZSM- 5 [21], natural zeolite [22], and so on. Nano zeolite is having high sorption capacity for textile dye [23]. For the first time, nanocrys- talline zeolite X (nZX) from coal fly ash was being used as an effi- cient adsorbent for removal of CV dye. For optimization of the cru- cial parameters, Response Surface Methodology (RSM) combined with central composite design (CCD) has been utilized and then re- sponses were maximized by setting desired criterion with the help of Desirability Function (DF) [24,25]. In this paper, nanocrystalline zeolite X was synthesized from coal fly ash, which was abundantly available in eastern India. As- synthesized nZX was characterized by means of various techniques such as X-Ray Diffraction (XRD) analysis, Transmission Electron Mi- croscopy (TEM), Field Emission Scanning Electron Microscopy (FE- SEM), Fourier Transform Infrared (FT-IR) spectroscopy along with https://doi.org/10.1016/j.jtice.2018.10.032 1876-1070/© 2018 Taiwan Institute of Chemical Engineers. Published by Elsevier B.V. All rights reserved. Please cite this article as: S. Sivalingam and S. Sen, Efficient removal of textile dye using nanosized fly ash derived zeolite-x: Kinetics and process optimization study, Journal of the Taiwan Institute of Chemical Engineers, https://doi.org/10.1016/j.jtice.2018.10.032