The present investigation deals with the adsorptive removal of crude petroleum oil from the water surface using coconut oil-modified pinewood biochar. Biochar generated at higher pyrolysis temperature (700 °C) revealed higher fatty acid-binding efficiency responsible for the excellent hydrophobicity of the biochar. Fatty acids composition attached to the biochar produced at 700 °C was (mg g−1 BC) lauric acid (9.024), myristic acid (5.065), palmitic acid (2.769), capric acid (1.639), oleic acid (1.362), stearic acid (1.114), and linoleic acid (0.130). Simulation of the experimental adsorption data of pristine and modified pinewood biochar generated at 700 °C offered the best fit to pseudo-first-order kinetics (R2 > 0.97) and Langmuir isotherm model (R2 > 0.99) based on the highest regression coefficients. Consequently, the adsorption process was mainly driven by surface hydrophobic interactions including π-π electron-donor-acceptor between electron-rich (π-donor) polycyclic aromatic hydrocarbons from the crude oil and biochar (π-acceptor). A maximum adsorption capacity (Qmax) of 5.315 g g−1 was achieved by modified floating biochar within 60 min. Whereas the reusability testing revealed 49.39% and 51.40% was the adsorption efficiency of pristine and modified biochar at the fifth adsorption-desorption cycle.
This research was supported by the C1 Gas Refinery Program through the National Research Foundation of Korea (NRF), funded by the Ministry of Science and ICT (2015M3D3A1A01064882) and Research Program to solve social issues of the National Research Foundation of Korea (NRF) funded by the Ministry of Science and ICT, South Korea (2017M3A9E4077234). This work was also supported by the National Research Foundation of Korea (NRF) [NRF-2019R1F1A1058805 and NRF-2019M3E6A1103979]. The authors would like to acknowledge Prof. Sunghwan Kim (Kyungpook National University, South Korea) and Prof. Kyoung-Soon Jang (Korea Basic Science Institute, South Korea) for providing crude petroleum oil samples.
