Author: Site Editor Publish Time: 2022-10-11 Origin: Site
The solvent is separated from the solution by a semi-permeable membrane that can only pass through the solvent but not the solute molecules. The solvent molecules will spontaneously pass through the membrane from the solvent side to the solution side under the action of osmotic pressure, which is the phenomenon of osmosis, also known as "forward osmosis".
Desalination
The use of FO for desalination is one of the most widely researched areas. Early applications were mainly found in patents, but most of these studies were immature and not very feasible.
Early studies reported the use of FO membranes for the treatment of low concentration heavy metal wastewater, but this was not carried out in depth due to the severe contamination of the RO (reverse osmosis) membranes used and the rapid decline in flux.
The CoffinButte landfill in Corvallis, Oregon, USA, produces (2-4) x 104m3 of waste leachate per year, and in order to meet the water quality standards for land use, the TDS of the effluent must be reduced to less than 100mg/L.
Reverse osmosis is a membrane separation process driven by pressure. In order to generate reverse osmosis pressure in use, a pump is used to apply pressure to the saline solution or waste water to overcome the natural osmotic pressure and the resistance of the membrane so that the water passes through the reverse osmosis membrane, stopping dissolved salts or contaminants in the water on the other side of the membrane.
Water is essential for people to survive and carry out productive activities. Due to the increasing scarcity of fresh water resources, the capacity of reverse osmosis water treatment plants worldwide has reached millions of tonnes per day.
At present, the application of reverse osmosis membranes in the deep treatment of municipal wastewater, especially in secondary effluent reuse and water reuse in wastewater treatment plants, has been highly regarded.
The conventional treatment methods for wastewater containing heavy metal ions are only a pollution transfer, i.e. the dissolved heavy metals in the wastewater are transformed into precipitation or a more manageable form, and their final disposal is often to landfill, while the danger of secondary pollution of groundwater and surface water environment by heavy metals still exists for a long time.
Oily wastewater is a large and extensive industrial wastewater, if discharged directly into the water body, it will produce an oil film on the surface layer of the water body to prevent oxygen from dissolving into the water, thus causing lack of oxygen in the water, biological death and bad smell, and seriously polluting the ecological environment. Oil 3.5mg/L, total organic carbon (TOC) (16~23) mg/L oilfield water treatment to boiler water quality so that the treated water back to the power station boiler feed water.
