pH-responsive nonwoven fabric with reversibly wettability for controllable oil-water separation and heavy metal removal

Removal of organic solvents and heavy metals in effluents is of great significance to environmental pollution control and ecological civilization construction. pH-responsive materials have unique advantages in treating complicated oily wastewater. In this work, an intelligent pH-responsive nonwoven fabric with excellent reversible wettability was prepared. The pH-sensitive polymer was synthesized by free radical polymerization (FRP) technique, then dipped with SiO2 on PP fabric. The particular molecular structure of poly (dimethylaminoethyl methacrylate) (PDMAEMA) enabled the fabric surface to switch wettability rapidly between hydrophilic/underwater oleophobic and oleophobic/hydrophobic under pH stimulus and exhibit controllable selective separation of various oil/water mixtures. Furthermore, the fabric removed Pb2+ efficiently under a wide pH range. The experimetal results showed that the separation flux reached 19,229 +/- 1656.43 L-h(-1)-m(-2) for water and 19,342 +/- 1796.77 L-m(-2)-h(-1) for n-hexane. Besides, the obtained fabric effectively realized the separation and collection process of complex ternary mixtures. The fabric removed Pb2+ in solutions with efficiency up to 90.83%. After immersing in acid and alkali solutions for 24 h, no significant damage to the surface wettability. This economical and intelligent fabric is able to meet the different separation purposes of industrial wastewaters with complex compositions.