Candle soot nanoparticle embedded nanofibrous membrane for separation of miscible and immiscible oil/water mixtures

Abstract Candle soot (CS) nanoparticles exhibit excellent superhydrophobic and superoleophilic properties, making them an ideal absorbent for separating oil and oil/water mixtures. Although their cost‐effectiveness is attractive, the challenges associated with recovering soot nanoparticles after oil absorption and producing secondary pollutants have limited their attention. Our study demonstrates the synthesis of CS nanoparticles embedded polystyrene (PS) nanofibrous membranes with excellent stability, surface‐to‐volume ratios, and flexibility. CS‐incorporated composite membrane with a rough surface showed a water contact angle (WCA) of 156° ± 1.5°, about 20% higher than the smooth pristine PS membrane. The CS‐based composite membrane also demonstrated improved performance as an absorbent, owing to its hydrophobic characteristics linked with surface roughness when employed for separating oil from oil/water mixtures. Furthermore, when exposed to four different oils, the CS‐based membrane displayed a higher absorption capacity (up to ≈120 g oil/g membrane) than the pristine membrane. Using a gravity‐assisted continuous oil/water separation setup, we measured the oil permeate flux using nanofiber mats as a membrane. Compared to the original membrane, the modified membrane showed enhanced oil permeate flux of ~2873 ± 122 L m⁻² h⁻¹ and separation efficiency of over 99%.