Adsorption Kinetics, Equilibrium and Radiation Effect Studies Of Radioactive Cesium by Polymer-Based Adsorbent Michael Adekunle Olatunji , 1 Mayeen Uddin Khandaker, 1,2 H.N.M. Ekramul Mahmud 3 1 Department of Physics, University of Malaya, 50603 Kuala Lumpur, Malaysia 2 Center for Radiation Sciences, School of Healthcare and Medical Sciences, Sunway University, 47500 Bandar Sunway, Selangor, Malaysia 3 Department of Chemistry, University of Malaya, 50603 Kuala Lumpur, Malaysia Electroactive polypyrrole has been synthesized by oxi- dative polymerization of pyrrole using ferric chloride hexahydrate as oxidant in the presence of sodium dode- cylbenzene sulfonate (SDBS), and used to remove radio- active cesium from aqueous solution. The SDBS-doped polypyrrole (PPy/SDBS) adsorbent was characterized by Field emission scanning electron microscopy, X-ray dif- fraction and Fourier transform infrared techniques. A rapid and efficient adsorption of 137 Cs radionuclide with a maximum sorption capacity of 26.2 mg/g has been achieved at 313 K. The kinetic data show the best fitting by the pseudo first-order model while the Langmuir model properly reproduced the isotherm data. The ther- modynamics parameters revealed an endothermic and spontaneous nature of the adsorption process. The adsorption efficiency shows only an insignificant variation with the gamma-ray doses of 100 and 200 kGy. Considering the toxicity and nonbiodegradable nature of radioactive cesium, SDBS-doped polypyrrole could be a good adsorbent for the recovery of 137 Cs from radioactive effluents. J. VINYL ADDIT. TECHNOL., 00:000– 000, 2017. V C 2017 Society of Plastics Engineers INTRODUCTION Environmental pollution by radioactive materials emanat- ing from the operation and maintenance of nuclear power plants, nuclear weapon testing, nuclear medicine and various unseen nuclear accidents or unmonitored radioactive waste disposal has been a grave concern from the health point of view [1, 2]. Among the various radionuclides, radioactive 137 Cs is a significant component of nuclear waste and nuclear fallout [3]. It is of a significant concern due to the emission of strong gamma-ray (Eg5 661.9 keV) and long half-life (30.17 years) and hence, its exposure is more destructive to humans [4, 5]. Cesium is highly soluble, making easy for migration through water and other environmental media to both human and animal. Food chain forms the major path- way to the transfer of this radionuclide to human body. Once radioactivity is accumulated in the body tissues, they can pose severe health effects including gene mutation and carci- nogenic effects. Beside this, radioactive cesium decays to barium, forming a secondary route to heavy-metal pollution. Removal of this radionuclide from wastewater before dis- posal is the only way to reduce human exposure by both radioactive and nonradioactive pathways [5]. Several methods have been proposed for the removal of radionuclides and heavy metal ions from aqueous solu- tions [2, 6, 7]. However, adsorption technique is consid- ered the most feasible and affordable in radioactive wastewater treatment due to the abundant of adsorbent materials and ease of operation [8]. Presently, there is a growing demand in developing and optimizing low-cost and effective adsorbents for the removal of radioactive materials from aqueous solutions. With the advent of conducting polymers, much research interests have been generated to realize their applications in various fields such as polymeric batteries, wire, microactua- tors, biological and gas sensors, ion-selective electrodes, and functional membranes [9]. Among them, polypyrrole con- ducting polymer has been widely studied owing to its supe- rior electroactive properties, ease of preparation at low cost in both aqueous and non-aqueous media, reasonable thermal stability and its metal-coordinating properties [7, 10]. Con- versely, polypyrrole conducting polymer has emerged as a low-cost adsorbent or ion-exchanger for heavy metal removal from aqueous solution [11–14]. Polypyrrole con- ducting polymer without or with weak additives shows to exhibit low sorption capacity [15]. Hence, to use polypyrrole conducting polymer as an adsorbent for radionuclides, the choice of dopants, synthesis method and formation period bear a great significance toward high adsorption. Consequent to the very limited efforts, we have explored a new adsorbent for the removal of 137 Cs radionuclide based on polypyrrole conducting polymer doped with sodium dodecylbenzene sulfonate (SDBS), a large size Correspondence to: M. U. Khandaker; e-mail: mu_khandaker@um.edu. my or HNM Ekramul Mahmud; e-mail: ekramul@um.edu.my DOI 10.1002/vnl.21620 Published online in Wiley Online Library (wileyonlinelibrary.com). V C 2017 Society of Plastics Engineers JOURNAL OF VINYL & ADDITIVE TECHNOLOGY—2017