Buoyant calcium stearate modified sorbent based on Rhizoclonium hookeri derived activated carbon for facile oil spill...

The development of marine algae-derived oil sorbents is an emerging field with potential to offer a promising solution to mitigate catastrophic impact of oil spills. Herein, a highly buoyant, hydrophobic and magnetically separable oil sorbent "calcium stearate-modified magnetic activated carbon" (CS@MAC) was fabricated by anchoring magnetite over algal biocarbon derived from Rhizoclonium hookeri and by subsequent surface coating with calcium stearate. Characterization studies using FTIR, SEM, XRD, and TG evidenced that surface modifications of algal biomass were effective in bringing concomitant changes in its properties, rendering it suitable for oil spill clean-up applications. SEM results verified even distribution of magnetite spheres (~50 nm) over biocarbon's surface, and the presence of CS in the resultant sorbent was established by FTIR and TG, which leads to buoyancy and hydrophobicity. Our engineered CS@MAC demonstrated excellent oil sequestration efficiency exceeding 90% and fast kinetics (30 min) using a low dose in synthetic sea water matrices. Compared with magnetic biochar and magnetic activated carbon, the CS@MAC not only reached up to a higher oil uptake efficiency but also remained buoyant, validating its suitability for oil spill clean-up. Furthermore, CS@MAC demonstrated robust performance with removal efficiency of 93% in 1st to 74% in 5th cycle, indicating its potential for practical applications. These combined findings show that our designed sorbent is an eco-friendly, affordable, and buoyant material with improved hydrophobicity, signifying a viable solution for facile oil spill clean-up.