Magnetically separable sorbent based on activated carbon derived from a new precursor Rhizoclonium hookeri for facile oil spill clean-up

Abstract

A huge quantity of synthetic toxic materials ends-up in water bodies causing long-lasting environmental and economic impacts due to catastrophic oil spill. Exploring marine algae as sorbent materials for oil spill remediation is a relatively new area and holds great potential. Herein, macroalgae Rhizoclonium hookeri (RH) derived magnetically recoverable activated carbon (RHAC@Fe₃O₄) composite has been proposed as an innovative and robust strategy for oil spill clean-up. The oil uptake efficiency of RHAC@Fe₃O₄ was probed using unused and used motor oil in synthetic seawater matrices by conducting batch wise experiments. Optimal conditions for the designed sorption system were met by varying time (10–60 min), dosage (0.2–1 g) and temperature (20, 30, 40 °C). Characterization studies showed that KOH-based activation played a vital role in developing pore structure and surface functionalities in the algal biochar. Batch experiments demonstrated over 90 % oil removal efficiency of RHAC@Fe₃O₄ from simulated oil spill after 30 min using 0.8 g of composite. Moreover, Fe₃O₄ loading onto carbon material allowed magnetic separation as a convenient alternative to filtration for the recovery of oil laden composite. Apart from superior oil removal ability, synthesized composite demonstrated robust performance up to five cycles in synthetic sea water matrices. Additionally, comparative study revealed better oil sequestration efficiency of the fabricated RHAC@Fe₃O₄ composite (93 %) as compared to its precursors, i.e. algal biochar (71 %) and AC (88 %). Based on these findings, it is advocated that designed RHAC@Fe₃O₄ composite being eco-friendly, economical and readily recoverable with enhanced oil uptake ability could potentially be an innovative platform for oil spill clean-up applications.