Multifunctional recycled wet wipe with negatively charged coating for durable separation of oil/water emulsion via interface charge demulsification

Plastic pollution and oily wastewater discharge are the main factors which threaten the ecological environment, and the controlling of the two kinds of pollution consumes a lot of resources. From the perspectives of pollution treatment and saving resources, using solid waste (plastic waste) to treat liquid waste (emulsion) may have economic and environmental protection benefits. Here, a negatively charged hydrogel-coated recycled wet wipe (RWW-NH) is prepared by spraying and crosslinking process, which will be applied in cationic surfactant-contained oily wastewater treatment. The negatively charged hydrogel coating can absorb CTAB molecules, and the recycled wet wipe serving as the porous architecture can promote the coalescence of oil droplets. The obtained composite membrane has superior separation performance for CTAB stabilized emulsion, and the membrane with double layers can continuously separate 4000 mL emulsion with a permeation flux of 3057 L m −2 h −1 . Besides, RWW-NH can absorb cationic dyes and heavy metal ions, due to the negative charges and high-density phosphate groups of the coating, respectively. The as-prepared composite membrane with low cost and simple preparation process has both environmental and economic values, which provides a prospective application in environmental treatment.