Highly efficient and reusable superhydrophobic 3D polyurethane nanocomposite foam for remediation of oil polluted water

The release of oil and organic pollutants into water bodies poses a severe environmental concern because they bioaccumulate and are difficult to degrade. In this study, an alternative polyurethane (PU) composite foam containing hydroxylated multi-walled carbon nanotubes (MWCNTs) and polydimethylsiloxane (PDMS) was prepared using a dip-coating method. Adding MWCNTs and PDMS transformed the hydrophilic pristine PU foam to a superhydrophobic PU/CNT-PDMS, as evidenced by the substantial increase in the water contact angle value. Our work evaluated the performance of the foams containing different MWCNTs loading and PDMS concentrations in the oil-water separation process. The foam comprising of 6.97 wt% MWCNTs and 6.52 wt% PDMS, exhibited the highest absorption performance, with the maximum absorption capacity of 33.83 and 44.98 g/g for engine oil and acetone. The recyclability test showed that the PU/CNT-PDMS hybrid foam retained at least 90% of its initial oil absorption capacity after 10 absorption-desorption cycles. The PU/CNT-PDMS hybrid foam produced showed excellent absorption characteristics and was reusable, confirming its potential as a suitable candidate for efficiently removing oil and organic solvents from water.