ARTICLE IN PRESS JID: JTICE [m5G;March 9, 2017;11:43] Journal of the Taiwan Institute of Chemical Engineers 000 (2017) 1–9 Contents lists available at ScienceDirect Journal of the Taiwan Institute of Chemical Engineers journal homepage: www.elsevier.com/locate/jtice Nanoporous activated carbon prepared from karanj (Pongamia pinnata) fruit hulls for methylene blue adsorption Md. Azharul Islam a,b , S. Sabar c , A. Benhouria d , W.A. Khanday a , M. Asif e , B.H. Hameed a,∗ a School of Chemical Engineering, Universiti Sains Malaysia, Engineering Campus, 14300 Nibong Tebal, Penang, Malaysia b Forestry and Wood Technology Discipline, Khulna University, Khulna 9208, Bangladesh c Chemistry Section, School of Distance Education, Universiti Sains Malaysia, 11800 Minden, Penang, Malaysia d Laboratoire de Génie des Procédés Chimiques (LGPC), Faculté de Technologie, Université Ferhat Abbas Sétif-1, 19000 Sétif, Algerie e Chemical Engineering Department, College of Engineering, King Saud University, P.O. Box 800, Riyadh 11421, Saudi Arabia a r t i c l e i n f o Article history: Received 24 April 2016 Revised 1 January 2017 Accepted 20 January 2017 Available online xxx Keywords: Activated carbon Adsorption Dye KOH activation Karanj a b s t r a c t In this study, karanj (Pongamia pinnata) fruit hulls were used as a precursor to prepare low-cost activated carbon with a large surface area through KOH activation. The prepared activated carbon (KFHAC) was characterized through pore structural analysis, scanning electron microscopy, and Fourier transform in- frared spectroscopy. KFHAC presents a BET surface area of 828.30 m 2 /g, a micropore volume of 0.36 cm 3 /g, and an average pore size of 19.92 ˚ A The adsorption performance of KFHAC was evaluated using methy- lene blue (MB) as the model adsorbate. Adsorption experiments indicated that the pseudo-second-order kinetic and Langmuir adsorption isotherm models can accurately describe the adsorption process. The maximum adsorption capacities (q m ) of MB were 154.8, 203.4, and 239.4 mg/g at 30 °C, 40 °C, and 50 °C, respectively. This study indicates that karanj fruit hull is a promising precursor for the production of low-cost and efficient activated carbon with a large surface area. © 2017 Taiwan Institute of Chemical Engineers. Published by Elsevier B.V. All rights reserved. 1. Introduction Dye-containing effluents discharged by textile, paint, paper, plastic, cosmetic, and food processing industries have become a major concern. These industries produce more than 700 000 tons of dyes yearly, of which 50% is absorbed in surface waters [1]. Ac- cumulation of untreated dyes in water sources may result in ad- verse effects to human health and the environment because these dyes exhibit a complex molecular structure with variable toxicity, carcinogenic, mutagenic, and allergenic properties. As untreated dyes are highly active and stable toward chemical, photochemical, and biological degradation, adsorption has emerged as a practical and effective technique to produce high-quality dye effluents. Different types of fibrous adsorbents like chitosan [2,3] and polypropylene [4] have been developed in recent years for the adsorption of dyes. Activated carbon is a common and efficient adsorbent used to remove dyes from wastewaters because of its large surface area, high adsorption capacity, and diverse func- tional groups [5]. Nevertheless, large-scale application of activated carbon is hindered because this material is non-renewable and requires expensive precursors [6]. Thus, production of activated ∗ Corresponding author. E-mail address: chbassim@usm.my (B.H. Hameed). carbon from cheap and renewable precursors has been an inter- esting research subject. Lignocellulosic biomasses, such as Albizia lebbeck seed pod [6], rattan sawdust [7], rice husks [8], waste tea [9], biodiesel industry solid reside [10], cotton stalk [11], durian shell [12], oil palm ash [13], Iranian milk vetch [14], Soy meal hull [15], olive stone [16], rambutan peel [17], macadamia nut endocarp [18], peach stone [19], coffee ground [20], Posidonia oceanica fiber [21] and apricot stones [22], have been explored as possible pre- cursors for the production of activated carbon. Karanj (Pongamia pinnata) or Karanja is an evergreen, drought- resistant, nitrogen-fixing tree that belongs to the Leguminaceae family [23]. This fast-growing tree is commonly found in tropical and sub-tropical countries, such as Malaysia, India, Thailand, Viet- nam, Philippines, China, Japan, Australia, New Zealand, and USA. Karanj is famous for its seeds, which contain 25–50 wt% of oil [24]. The seeds, which are kidney shaped and brownish red, can be eas- ily collected from the fruits by using a hammer. The fruits are nat- urally flat and elliptic, with a length of 7.5 cm [25]. Each fruit con- tains one to two seeds, and a single tree can produce 9–90 kg of seeds with 25–40 wt% of oil [24]. With these properties, karanj has been recognized as an invaluable non-edible source of bio-oil for medical purposes and as a new feedstock for biodiesel production. As the demand for karanj bio-oil is predicted to increase in the near future, residual waste generated from oil extraction remains a major problem. During seed collection, large amounts of karanj http://dx.doi.org/10.1016/j.jtice.2017.01.016 1876-1070/© 2017 Taiwan Institute of Chemical Engineers. Published by Elsevier B.V. All rights reserved. Please cite this article as: Md.A. Islam et al., Nanoporous activated carbon prepared from karanj (Pongamia pinnata) fruit hulls for methy- lene blue adsorption, Journal of the Taiwan Institute of Chemical Engineers (2017), http://dx.doi.org/10.1016/j.jtice.2017.01.016