In-situ construction of stable and efficient superhydrophobic MOFs-based cellulose paper for oil–water separation

In recent years, separating oil-water mixed pollutants has emerged as an increasingly significant part of sustainable development due to oil-containing wastewater discharged and offshore oil spills. Therefore, developing stable and efficient materials for the separation of oily wastewater has garnered significant attention in current research. Herein, a novel superhydrophobic functionalized MOFs-based cellulose paper (PDMS/UiO-66-NH2@CP) was successfully synthesized by integrating cellulose paper (CP) with UiO-66-NH2 via solvothermal method and further modifying with polydimethylsiloxane (PDMS), which was used as an oil-water separation material to purify oily wastewater. The reaction procedure is facile and simple, and the preparation method is efficient. Notably, the as-synthesized PDMS/UiO-66-NH2@CP showed excellent superhydrophobicity/superlipophilicity, with a water contact angle up to 162° and an oil contact angle (OCA) of approximately 0º, and it can still maintain superhydrophobic stability under strong acid or alkali conditions. Furthermore, the surface of superhydrophobic paper cannot been adhered by dye solution and powder, indicating its good self-cleaning and anti-fouling ability. Moreover, the composite paper displayed exceptional UV blocking property with the ability to block 99% ultraviolet. Attributed to these characteristics, PDMS/UiO-66-NH2@CP as an oil-water separator demonstrated exceptional performance in separating oil-water mixtures and emulsions, achieving efficiencies exceeding 98% and fluxes in the range of 105.26−412.14 L·m-2·h-1. More importantly, it displayed remarkable recyclability and its separation efficiency was still above 98% after 50 cycles. This study not only develops a facile and effective strategy for preparing superhydrophobic papers, but also provides innovative and instructive guidance for developing efficient oil-water separation materials.