_____________________________________________________________________________________________________ *Corresponding author: E-mail: giwa1010@gmail.com, aoibrahim2016@gmail.com; Current Journal of Applied Science and Technology 22(5): 1-13, 2017; Article no.CJAST.34196 Previously known as British Journal of Applied Science & Technology ISSN: 2231-0843, NLM ID: 101664541 Biosorption of Nitrophenol from Aqueous Mixture of Phenolic Compounds Using Sawdust of Parkia biglobosa Deborah Olubunmi Aderibigbe 1 , Abdur-Rahim Adebisi Giwa 1* , Asiata Omotayo Ibrahim 1* and Isah Adewale Bello 1 1 Department of Pure and Applied Chemistry, Ladoke Akintola University of Technology, Ogbomoso, Oyo State, Nigeria. Authors’ contributions This work was carried out in collaboration between all authors. Author ARAG designed and supervised the study while Author DOA managed the analyses of the study and wrote the first draft of the manuscript. Author IAB handled the Kinetics and thermodynamics aspects of the study, and Author AOI managed the literature searches and wrote the second draft of the manuscript. All authors read and approved the final manuscript. Article Information DOI: 10.9734/CJAST/2017/34196 Editor(s): (1) Jon S. Gold, Dept. of Chemistry, East Stroudsburg University, East Stroudsburg, PA, USA. Reviewers: (1) Julian Cruz-Olivares, Autonomous University of State of Mexico, Mexico. (2) José Ismael Acosta Rodríguez, Universidad Autónoma de San Luis Potosí Inicio, Mexico. (3) Jelena Kiurski, University Business Academy in Novi Sad, Serbia. Complete Peer review History: http://www.sciencedomain.org/review-history/20221 Received 18 th May 2017 Accepted 4 th July 2017 Published 26 th July 2017 ABSTRACT The present study investigated the potential of sawdust of Parkia biglobosa, an agroforestry by- product, for the removal of 4-Nitrophenol (4NP), from its aqueous solutions (singly) and in combination with phenol (binary) and chlorophenol (ternary). The effects of sawdust dose, initial concentration of phenolics and pH of the solution on the adsorption were investigated through batch adsorption experiments. Five isotherm models were employed to describe the equilibrium experimental data. The adsorption kinetics and thermodynamics were also studied. The equilibrium time for the sorption was observed to be 720 min, while the optimum dose was 0.500 g. The kinetics of the adsorption could be best described by the pseudo-second order model, while Freundlich isotherm gave the best fit in all the systems studied. The thermodynamics of the adsorption revealed that the process was not spontaneous at low temperatures as ∆G was positive; but it was endothermic in the single, binary and ternary systems. Original Research Article