Laser-assisted synthesis of graphene-based paper for both oil/water mixtures and emulsions separation

Nowadays, dealing with the complex oil/water contamination that contains both oil/water mixtures and emulsions with desirable performance remains a huge challenge. Complicated fabrication procedures, low flux, and efficiency are shortcomings of the known materials. Herein, a facile and effective laser-assisted strategy is proposed to prepare super-hydrophobic graphene/PDMS paper (L-G-P), which perfectly takes advantage of both naturally strong capillary of paper tissue and high-quality graphene. Specifically, graphene is obtained by reducing graphene oxide via laser irradiation, which avoids introducing chemical reducing agents that are either hazardous or hard to separate. Meanwhile, the super-intensive instantaneous energy would create abundant defects on graphene sheets, thus the specific surface area increased by 25%. As for oil/water mixtures, the efficient sorption/separation can realize over 99.99% deep clean, meanwhile showing excellent durability after repeated cycles. As for water-in-oil emulsions, the high separation flux of surfactant-stabilized emulsions could reach 4421 L m⁻² h⁻¹ with an efficiency up to 99.85%. Moreover, the mechanical property of the composite was 80.50% stronger than uncoated paper tissue. The proposed L-G-P with durable and efficient oil/water separation performance is a promising material for practical applications for treating oil-contaminated wastewater in harsh environments.