Preparation And Properties Of Superhydrophobic And High Elastic Melamine-based Foams For Oil Absorption

The leakage of oil contaminations caused serious effect on the ecological environments.Physical absorption is considered as the most important approach for removal of these pollutions,so an ideal adsorbent attracted great attention,which required high absorption capacity,excellent selectivity,superior recyclability,and low cost.Most of the existing oil adsorbents were hydrophobic,they absorbed water inevitably which weakened their adsorption selectivity and adsorption efficiency properties.Many superhydrophobic materials were not high elastic and were recycled in an expensive way.Only a minority of superhydrophobic and high elastic adsorbents were reported.However,their had noticeable faults such as complicated preparation process and poor controllability or low oil absorption.Based on this,the following two works were performed in this dissertation.1)A superhydrophobic and superoleophilic melamine/graphene/carbon black sponge(M/G/CS)was prepared through a three-step procedure.Firstly,the graphene oxide(GO)sheets were anchored on the skeletons of melamine sponge by a dip-coating step,then the GO on MS was reduced to hydrophobic graphene by a low-temperature thermal reduction method.After that,the hydrophobic N330 particles were adhered on the surface of graphene,generating a deep black composite sponge,Graphene wrapped the skeletons of the sponge tightly by ?-? stacking between the graphene sheets,and the N330 could anchor in the graphene surface by?-? stacking between them similarly.To the best of our knowledge,the carbon black particles have not been used to increase the nanoscale roughness of materials.FT-IR,XPS,Raman and TGA were applied to verify the reduction of graphite oxide sheets in the sponges and the addition of N330.Water contact angle(CA)of M/G/CS was 1670 and oil contact angle of it was 0°,indicting its superhydrophobicity and superoleophilicity.What's more,the composite sponge inherited the excellent elasticity and could restore the original shape even after 1000 compression cycles.This is the first superhydrophobic graphene-based foam with high elasticity.With the excellent elasticity,the M/G/CS could be regenerated by absorption-squeezing.The composite sponge played the synergy of the three and it showed high absorption capacity for common oils and organic solvents up to 50-140 g/g,excellent recyclability and high selectivity for oils/water.In addition,its preparation protocol was simple,scalable,and cost effective.Therefore,the resulting composite sponge was an excellent absorbent for practical oil-absorption and removal of organic solvents.2)Superhydrophobic and superoleophilic melamine/polyvinylidene fluoride sponge(M/PS)was fabricated by a dip-coating method.PVDF films were coated on the skeletons of melamine sponge,and numerous nanoscale particles were generated on the micron-sized skeleton of sponge in the film-formation process.Compared with the complicated chemical modification approach,the physical coating method possess characters of easy preparation and environmentally friendly.Water contact angle(CA)of M/PS was 155° and oil contact angle of it was 0°,indicting its superhydrophobicity and superoleophilicity.The composite sponges inherited the excellent elasticity and could restore the original shape even after 1000 compression cycles.The M/PS showed an absorption capacity of 60-160 g/g for common oils and organic solvents.Meanwhile it had excellent regenerative ability and high oil-water selectivity.In addition,its fabrication procedure was facile and cost effective which can be easily scaled up.Thus M/PS displayed a promising application prospect in the field of absorption of oil contamination and organic solvents.