title: Anion selective pTSA doped polyaniline@graphene oxide-multiwalled carbon nanotube composite for Cr(VI) and Congo red adsorption.
abstract: Multiwalled carbon nanotube (CNT)-graphene oxide (GO) composite was combined with polyaniline (Pani) using an oxidative polymerisation technique. The resulting Pani@GO-CNT was later doped with para toluene sulphonic acid (pTSA) to generate additional functionality. The functional groups exposed on the GO, Pani and pTSA were expected to impart a high degree of functionality to the pTSA-Pani@GO-CNT composite system. The composite was characterised by scanning electron microscopy, transmission electron microscopy, X-ray diffraction, and X-ray photoelectron spectroscopy. The characterisation results revealed the characteristics of Pani, GO, CNT, and pTSA, and suggested the successful formation of the pTSA-Pani@GO-CNT composite system. The composite was utilised successfully for the adsorptive removal of Cr(IV) and Congo red (CR) dye and the adsorption of both pollutants was found to be strongly dependent on the solution pH, adsorbate concentration, contact time, and reaction temperature. The maximum adsorption of Cr(IV) and CR was observed in an acidic medium at 30°C. The kinetics for Cr(IV) and CR adsorption was studied using pseudo-first order, pseudo-second order, and intraparticle diffusion models. The adsorption equilibrium data were also fitted to the Langmuir and Freundlich isotherm models. The thermodynamic results showed that the adsorption process was exothermic in nature. The present study provides a new methodology for the preparation of a highly functionalised Pani-based nanocomposite system and its potential applications to the adsorptive removal of a multicomponent pollutant system from an aqueous solution.
authors.affiliation: Center of Nanotechnology, King Abdulaziz University, Jeddah 21589, Saudi Arabia; School of Chemical Engineering, Yeungnam University, Gyeongsan-si, Gyeongbuk 712-749, South Korea.
authors.forename: Mohammad Omaish
authors.initials: MO
authors.lastname: Ansari
authors.affiliation: Department of Environmental Sciences, Faculty of Meteorology, Environment and Arid Land Agriculture, King Abdulaziz University, Jeddah 21589, Saudi Arabia. Electronic address: olifiaraju@gmail.com.
authors.forename: Rajeev
authors.initials: R
authors.lastname: Kumar
authors.affiliation: School of Chemical Engineering, Yeungnam University, Gyeongsan-si, Gyeongbuk 712-749, South Korea.
authors.forename: Sajid Ali
authors.initials: SA
authors.lastname: Ansari
authors.affiliation: Department of Applied Chemistry, Faculty of Engineering and Technology, Aligarh Muslim University, Aligarh 202002, India.
authors.forename: Shahid Pervez
authors.initials: SP
authors.lastname: Ansari
authors.affiliation: Department of Environmental Sciences, Faculty of Meteorology, Environment and Arid Land Agriculture, King Abdulaziz University, Jeddah 21589, Saudi Arabia; Central Metallurgical R & D Institute, Helwan 11421, Cairo, Egypt.
authors.forename: M A
authors.initials: MA
authors.lastname: Barakat
authors.affiliation: Center of Nanotechnology, King Abdulaziz University, Jeddah 21589, Saudi Arabia; Physics Department, Faculty of Science, King Abdulaziz University, Jeddah, Saudi Arabia.
authors.forename: Ahmed
authors.initials: A
authors.lastname: Alshahrie
authors.affiliation: School of Chemical Engineering, Yeungnam University, Gyeongsan-si, Gyeongbuk 712-749, South Korea. Electronic address: mhcho@ynu.ac.kr.
authors.forename: Moo Hwan
authors.initials: MH
authors.lastname: Cho
keywords: Adsorption; Dye adsorption; Graphene oxide; Heavy metals removal; Polyaniline