Preparation And Application Of Hydrophobic Composite Based On MOFs Modification

Superhydrophobic materials have wide prospects in the applications of oil-water separation,surface self-cleaning,self-healing,anti-icing,and anti-biological adhesion.In this paper,based on sponge/non-woven fabric,two new hydrophobic composites were prepared by in situ growth of MOFs nanoparticles and co-modification of low surface energy compounds,and their applications in oil-water separation and heavy metal adsorption were further studied.The main research contents are as follows:(1)Polydopamine-assisted surface coating of MIL-53 and dodecanethiol on a melamine sponge for oil-water separation:A superhydrophobic and superoleophilic porous composite was successfully prepared via a polydopamine-assisted surface coating of MIL-53(Fe)and 1-dodecanethiol(DDT)on a melamine formaldehyde(MF)sponge.The as-prepared sponge composite(MIL-DDT@MF)has a high water contact angle(WCA)of 151.8°,which is probably attributed to both the rough surface derived from in situ growth of MIL-53 nanocrystals and the low surface energy due to grafting of hydrophobic 1-dodecanethiol.The MIL-DDT@MF sponge can effectively absorb oil or organic solvent with an absorption capacity of up to 54.1(for petroleum)to 120.2(for chloroform)times its own weight.In addition,the MIL-DDT@MF sponge retained a high absorption capacity and maintained approximately 78%of its original value after 50 cycles of reuse.Moreover,the MIL-DDT@MF composite can selectively absorb the oil/organic solvent from water and achieve continuous oil-water separation,the separation efficiency can reach above 95%.The superhydrophobic and superoleophilic MIL-DDT@MF sponge has potential as a promising absorbent for treatment of oily wastewater.(2)A mercapto-functionalized PCN-222/non-woven fabric composite for the removal of oils and heavy metal ions from water:A hydrophobic composite(PDMS/PCN-222@NWF)was successfully prepared via surface modification of PDMS and in situ growth of the mercapto functionalized Zr-MOF(PCN-222)on the surface of the polyester non-woven fabric(NWF).The as-prepared composite has a water contact angle(WCA)of 141.7°,which is probably attributed to both the rough surface derived from in situ growth of PCN-222 crystals and the low surface energy due to coating of hydrophobic PDMS.The PDMS/PCN-222@NWF composite can effectively separate oil-water mixture,with a maximum separation efficiency about98.6%,and after 5 cycles of reuse,the separation efficiency can still reach above 94%.In addition,PDMS/PCN-222@NWF composite can also selectively removal of Hg²⁺ions from water,with a maximum adsorption capacity of 294.44 mg/g,due to the loading of mercapto functionalized PCN-222 crystals on the surface of non-woven fabric.