| Growing shortage of resources and increasingly prominent environmental issues have become serious issues in today’s world. China faces serious challenges in coal and petroleum-based energy and chemical structure. Per capita resources of energy are insufficient. Environmental and ecological pressure was significant. Energy saving and emission reduction are arduous task. Solutions to environmental problems is no longer a simple treatment of pollutants, but how to extract useful resources from the waste, turning waste into wealth and achieve sustainable development.Polyethylene Glycol (PEG) has excellent properties and extremely widespread application in many industries, especially in solar and semiconductor industries. It has been calculated that producing1ton of PEG indirectly consumed8.6tons of oil. Therefore, recovering the PEG from wastewater can not only reduce pollution greatly but also conserve resources. However, PEG’s good solubility in water and good compatibility with a number of organic groups make it difficult to recycle by traditional methods of separation. Pyrolysis or hydrolysis also makes it hard to treat. Existing methods of PEG waste water treatment can reduce the pollution, but waste the recyclable resources, and also involve a lot of energy consumption. Therefore, it is especially important to find a low-cost and effective method to recover PEG.Forward osmosis (FO) is a novel membrane process that using the osmotic pressure gradient across a semi-permeable membrane as driving force, with high energy Efficiency and low membrane fouling. Nowadays, FO has potential value in many fields, such as desalinating seawater, industrial wastewater treatment, potable reuse in life support systems, liquid foods treatment, aerospace and power generation. However, few publications on the use of forward osmosis (FO) for PEG concentration appear in the literature.In this paper, three typical draw solution (DS):CaCl2, NaCl and sucrose solution were chosen to evaluate the performance of PEG concentration using forward osmosis, and the effect of types of draw solution, liquid flow rate (pump speed), feed solution (FS) concentration and membrane orientation were Investigated. Experiments showed that FO can be used for PEG concentration. We can achieve better permeability when the active layer face towards the feed solution. With2M CaCl2solution, PEG can be concentrated from3wt%to30wt%with a short time. Sucrose solution can be used as raw materials of fermentation, so to eliminate the subsequent reverse osmosis treatment. After a simple analysis of energy consumption, this method has its feasibility. |
