ORIGINAL PAPER Competitive adsorption isotherm modelling of heterocyclic nitrogenous compounds, pyridine and quinoline, onto granular activated carbon and bagasse fly ash D. Rameshraja 1 • Vimal Chandra Srivastava 1 • Jai Prakash Kushwaha 2 • Indra Deo Mall 1 Received: 3 June 2017 / Accepted: 10 October 2017 Ó Institute of Chemistry, Slovak Academy of Sciences 2017 Abstract In the present study, simultaneous adsorption of quinoline and pyridine onto adsorbents such as granular activated carbon (GAC) and bagasse fly ash (BFA) from pyridine–quinoline binary aqueous solution was studied at various temperatures (288–318 K). Gathered equilibrium adsorption data were further analysed using various mul- ticomponent competitive isotherm models such as non- modified and modified competitive Langmuir isotherms, extended-Langmuir isotherm, extended-Freundlich model, Sheindorf–Rebuhn–Sheintuch (SRS) model, and non- modified and modified competitive Redlich–Peterson iso- therm model. It was observed that increase in pyridine concentration decreased the total adsorption yield and the individual adsorption yield for both the quinoline and pyridine for both the adsorbents GAC and BFA at all the temperatures studied. Identical trend was observed dur- ing the equilibrium uptake of pyridine on to GAC and BFA with an increase in quinoline concentration. The extended- Freundlich model satisfactorily represented the binary adsorption equilibrium data of quinoline and pyridine onto GAC and BFA. Keywords Quinoline Á Pyridine Á Binary adsorption Á Granular activated carbon Á Bagasse fly ash List of symbols a ij Competition coefficients of component i by component j, dimensionless a R Constant of Redlich–Peterson isotherm, L/mg C 0,i Initial concentration of each component in solution, mg/L K i Individual extended-Langmuir isotherm constant of each component, L/mg n m Number of measurements n p Number of parameters N Number of data points q e,i Equilibrium solid phase concentration of each component in binary mixture, mg/g q e;cal Calculated value of solid phase concentration of adsorbate at equilibrium, mg/g q e;exp Experimental value of solid phase concentration of adsorbate at equilibrium, mg/g q max Max adsorption capacity x i , y i , z i Constants in the extended-Freundlich isotherm b i Constant in SRS model for each component, dimensionless g L,i Multi-component (competitive) Langmuir adsorption constant of each component, dimensionless g R,i Multi-component (competitive) R–P adsorption constant of each component, dimensionless GAC Granular activated carbon BFA Bagasse fly ash AC Activated carbon Electronic supplementary material The online version of this article (doi:10.1007/s11696-017-0321-6) contains supplementary material, which is available to authorized users. & Vimal Chandra Srivastava vimalcsr@yahoo.co.in D. Rameshraja ram.vbr@gmail.com Jai Prakash Kushwaha jps_kag@yahoo.co.in Indra Deo Mall id_mall2000@yahoo.co.in 1 Department of Chemical Engineering, Indian Institute of Technology, Roorkee, Roorkee, Uttarakhand 247667, India 2 Department of Chemical Engineering, Thapar University, Patiala, Punjab, India 123 Chem. Pap. DOI 10.1007/s11696-017-0321-6