A research team at the Shanxi Institute of Coal Chemistry (part of the Chinese Academy of Sciences—CAS) have developed a technique in order to address the challenges in treating wastewater, specifically with oil-water separation.
Currently, the technology of membrane separation provides an effective and encouraging option for treating wastewater, especially with its low energy consumption. But it remains a challenge to find affordable, environmentally-friendly, powerful, and composite membranes that have the potential to obtain a high level of separation.
The research team’s novel process enables them to achieve membrane materials for oil–water separation that are “all cellulose” (cellulose with two or more various crystal forms). As described in their study outcomes, reported in the KeAi journal Green Energy & Environment, their membrane is kind to its surroundings.
“Oil-water separation membrane materials that have been widely used in recent years include vinylidene fluoride (PVDF), polypropylene (PP), polyacrylonitrile (PAN), nylon or their composites. However, these polymers are non-biodegradable and put further pressure on the environment” said Tiansheng Deng, Study Corresponding Author and Professor, Institute of Coal Chemistry, Chinese Academy of Sciences.
Professor Deng and his group selected degradable cellulose that is derived from plants as raw material and combined it with commercial cellulose filter paper, which is affordable and porous. They discovered that numerous nanopores appear in the altered cellulose filter paper, which enhances the barrier against oil droplets of the membrane. When their separation membrane is in touch with the water, a cellulose hydrogel has been developed that, in an efficient manner, isolates oil in water emulsion and oil–water mixture.
“Cellulose chains are tightly bonded by a hydrogen bond, with few defects, and the mechanical properties of the material are greatly improved. The high dry and wet mechanical properties of the membrane extend the ways in which it can be applied and help it to remain stable when used in water. We believe this is an important step forward in the treatment of pollution” added Deng.