Surface-coating of gamma-assisted reduced graphene oxide (rGO) on natural rubber foam (NRF) for enhanced oil adsorption performance

Oil pollution poses a serious threat to both aquatic and terrestrial ecosystems, necessitating the need for efficient, reusable, and eco-friendly sorbent materials. To address this challenge, the present study investigated the coating of natural rubber foam (NRF) with reduced graphene oxide (rGO) to enhance oil adsorption capacity and mechanical durability, with polylactic acid (PLA) utilized as a binding agent to impro v e interfacial adhesion between NRF and rGO. The sorbents were fabricated by sequentially coating NRF with an optimized 2 % ( w / v ) PLA solution and rGO with varying contents (0–5 % w/v). The rGO was synthesized by gamma irradiation of graphene oxide (GO) at doses ranging from 0 to 65 kGy, in which 45 kGy was identified as the optimal dose for effective removal of oxygen-containing functional groups. The results also demonstrated that PLA coating substantially improved the adhesion of rGO to the foam surface, as evidenced by lower rGO detachment during water immersion and enhanced oil adsorption performance. Furthermore, the rGO-coated NRF samples exhibited increases in oil adsorption capacities—79 % for diesel, 88 % for benzene, 71 % for lubricant, and 57 % for palm oil—compared to pristine NRF, with adsorption performance reaching a plateau and optimal condition at 3 % ( w / v ) rGO. The reusability tests also confirmed the durability of the developed sorbents, with approximately 85 % of the initial adsorption capacity retained over five to six adsorption–desorption cycles. Overall, this study highlighted the potential of gamma-assisted rGO synthesis for the development of high-performance and sustainable oil sorbents for environmental remediation applications. • Highly effective oil sorbents based on NRF coated with PLA and rGO were developed. • 45-kGy gamma irradiation on GO effectively removed oxygens for the synthesis of rGO. • 2 % PLA coating was the optimal content for improved adhesions between rGO and NRF. • Coating 2 % PLA and 3 % rGO on NRF greatly improved oil adsorption capacities. • rGO-coated NRF could be effectively used up to five or six cycles of oil sorption.