Polyamide 6-Organic Montmorillonite Composite Sponge by Large-scale Solution Foaming as Reusable and Efficient Oil and Organic Pollutants Sorbent
Effective removal of oil spills or organic pollutants oils from water is of global significance for environmental protection. However, traditional techniques usually suffer from the limits of low efficiency and high cost. In this study, sponge-like polyamide 6/organic montmorillonite (PA 6/OMMT) composite absorbents were fabricated through a large-scale solution foaming. Sodium carbonate aqueous solution was injected to PA/formic acid solution with well-dispersed nanoclay to generate CO2 and meanwhile initiate the phase separation of PA molecules from solvent. Both mesopores and macropores existed in prepared sponges. The effect of OMMT content on the microstructures and adsorption properties was investigated. Increasing the OMMT fraction in composite sponges, the pore size decreased and the fraction of mesopore increased. Higher adsorption properties were thus obtained. When OMMT nanoplatelets accounted for 10%, the corresponding sponge had an uptake capacity of 12.5-22.1 g/g to diverse oil or organic solvent. Moreover, the composite sponges absorbed oils and organic solvents rapidly and reached saturation in 20 s. When it was coated with methyltrichlorosilane (MTS), static water contact angle on the surface of sponge increased from 88o to 115o. The selective absorption to oil from an oil/water mixture was improved. A great promising approach is provided to make commercial polyamide into highly porous functional materials for the cleanup of large-scale oil spills.