Fabrication Of Superhydrophobic-Superoleophilic Carbon-Based Composites And Its Application In Oil/Water Separation

Offshore oil spills and emission of oily sewage without processing can cause huge damage to the valuable freshwater resources and threaten the survival of marine life and the development of human beings.Therefore,scientists have carried out much research in finding efficient and environmentally friendly oil-water separation materials,which has become a popular area of research in material science.Up until now,the existing oil-water separation materials still have had certain shortcomings,such as low separation efficiency,low life span,high cost,complicated process,easy to cause pollution in the preparation process and so forth.These shortcomings limit the largescale application of oil-water separation materials.To deal with them,the study of this dissertation adopts cheap common cotton textile and melamine foam as raw materials,simple,environmentally friendly and efficient processes to prepare superhydrophobicsuperlipophilic carbon-based composites with high efficiency of oil-water separation and good life span,and systematically studied the oil-water operation performance.The main works are listed as follows:(1)The cotton textile and melamine foams carbonized at high temperature were used as material substrates.The SnO2 nanoparticles were prepared by ultrasonic method and uniformly deposited on carbon fibers.At last,the materials were surface-modified by n-octadecyl mercaptan to obtain superhydrophobic-super lipophilic SnO2@carbon composites.The composites had a water contact angle of 151.3°,and had good flexibility,acid corrosion resistance and structure stability.The oil-water separation efficiency of the composites was 97.5%.(2)A uniform and complete porous SnO2 coating layer was prepared on the prepared carbon fiber by sol-gel method.The superhydrophobic-superlipophilic SnO2@carbon composite was obtained after surface modification of n-octadecyl mercaptan.The water contact angle was 154.2°/153.9°,and the separation efficiency was 97.4%.The composites prepared buy sol-gel method had a better cycle stability than that prepared by ultrasonic method,and still kept separation efficiency of more than 97%after 150 cycles.The material can be applied for simple oil-water separation driven by gravity,or can be connected to the pump to relize continuous oil-water separation.Especially,the composites had unique UV-light corresponding properties.When the composites were irradiated under UV-light for more than 3 h,the material changed from superhydrophobic-superoleophilic to superhydrophilic-superoleophilic.And when the composites were placed in a dark environment,the superhydrophobic property will be restored.Therefore,the reversible conversion between the superhydrophobic-superhydrophilic material can be achieved by UV-light modulation.This study provides a new idea for the design of controllable functional oil-water separation materials.(3)Based on the above researches,we explored carbon textile modified by polydopamine and n-octadecyl mercaptan.The superhydrophobic-superlipophilic polydopamine@carbon textile material had a water contact angle of 158.8°,had acid and alkali corrosion resistance and a good cycle stability.The oil-water separation efficiency is 99.1%.In particular,the wide applicability of polydopamine to different substrates provides important guiding significance for the preparation and engineering application of high performance,acid-alkali resistant oil-water separation materials...