Equilibrium, kinetic, and thermodynamic studies of lead ion and zinc ion adsorption from aqueous solution onto activated carbon prepared from palm oil mill effluent Ganiyu Abimbola Adebisi a , Zaira Zaman Chowdhury a, ** , Peter Adeniyi Alaba b, * a Nanotechnology & Catalysis Research centre (NANOCAT), University of Malaya, IPS Building, 50603 Kuala Lumpur, Malaysia b Department of Chemical Engineering, University of Malaya, 50603 Kuala Lumpur, Malaysia article info Article history: Received 19 November 2016 Received in revised form 6 February 2017 Accepted 6 February 2017 Available online 8 February 2017 Keywords: Activated carbon Adsorption POME Equilibrium Isotherm Thermodynamic abstract An efficient activated carbon was prepared using palm oil mill effluent as a precursor. The adsorption capacity of activated carbon for lead ion and zinc ion from aqueous media was investigated under equilibrium conditions between 303.15 and 353.15 K. The activated carbon was analyzed using fourier transform infrared spectroscopy, field emission scanning electron microscope, energy dispersive X-Ray, and Nitrogen adsorption-desorption analysis. The adsorption capacity of activated carbon was studied by varying adsorbent dosage, contact time, and temperature. The equilibrium time was attained after 50 min for both ions. The data analysis was performed with different isotherm and kinetic models. Pseudo-second-order kinetic rather than pseudo first-order model is best fitted for both lead ion and zinc ion removal from wastewater. Further, the rate-determining step for both metal ions is chemisorption based on the suitability of the Elovich equation. Langmuir model provides the best fit for both removal of lead ion and zinc ion. The thermodynamic parameters shows the feasibility of adsorption of both ions is endothermic. © 2017 Elsevier Ltd. All rights reserved. 1. Introduction Heavy metals are discharged into water bodies through various industrial activities especially in the manufacturing and mining industries. They are highly toxic and usually constitute health hazards when consumed beyond the permissible and bearable amount. Heavy metal pollutants have been removed from waste- waters using various technologies ranging from precipitation, reverse osmosis, membrane filtration and ion exchange (Baccar et al., 2009). However, these technologies have several disadvan- tages such as requirement of expensive equipment and the need of chemicals, which may in turn pollute the water. Due to these lim- itations, there is vital need for a more environmentally benign and cost effective method. Several efforts were geared towards the use of adsorption process. The use of adsorbents in heavy metal removal from wastewaters has not only been found to be superior to other conventional methods, but it has equally been found to be cost-effective, simple in design, easy to operate and much more environmentally benign (Naje et al., 2016). In view of this, sub- stantial attention has been given to development of cheap adsor- bents such as kaolin (Alaba et al., 2016a), bentonite, fly ash blast furnace slag and activated carbon for removal of the different heavy metals at low concentration (Mishra and Patel, 2009). Palm oil is one of the most significant vegetable oils globally with Malaysia being the largest producer and exporter (Sani et al., 2015). During palm oil processing, several products and by- products generated include palm oil, palm kernel, palm oil mill effluent (POME), shell, empty fruit bunch (EFB) and fiber (Sani et al., 2015). The palm oil mill industry is said to be the major source of industrial pollution in Malaysia (Phang, 1990). They discharges more than 15million ton of POME from more than 110 processing mill (Board, 2003) into the environment, thereby constituting a serious environmental pollution especially in the waterways (Phang and Kim-Chong, 1988). The discharge of POME, either un- treated or poorly treated, into the environment can lead to serious hazards ranging from pollution of groundwater, release of methane into the atmosphere to release of unpleasant odor to the environ- ment (Chavalparit, 2006). Several methods have been adopted to treat POME before the discharge including sedimentation, filtration * Corresponding author. ** Corresponding author. E-mail addresses: adebisi@siswa.um.edu.my (G.A. Adebisi), dr.zaira. chowdhury@um.edu.my (Z.Z. Chowdhury), adeniyipee@live.com (P.A. Alaba). Contents lists available at ScienceDirect Journal of Cleaner Production journal homepage: www.elsevier.com/locate/jclepro http://dx.doi.org/10.1016/j.jclepro.2017.02.047 0959-6526/© 2017 Elsevier Ltd. All rights reserved. Journal of Cleaner Production 148 (2017) 958e968