The 21st century has brought upon the global textile industry, the urgent need to reduce the water wastage, pertaining to the manufacturing process. This need has been further pressed by the fact that regulations on the discharge of effluent have been tightened all across the globe. Textile as an industry expels humongous amounts of water as waste, which makes it essential for it to find out some feasible production techniques, which in turn helps the industry meet the regulatory standards.
Thankfully enough, membrane filtration, and specifically nano-filtration is coming up as a potential solution for the long standing problems of this industry. Nano filtration not only helps the manufacturers substantially reduce the amount of waste water but also creates an extensive possibility of recovering dyes and colorants, in order for them to be reused. This technique will thus aid in considerable cost cutting as well as decrease in the overall ecological footprint of the industry.
While it may be new to the textile sector, membrane filtration has found application in numerous other industries, wherein it is used to concentrate, separate and even fractionate various liquids with remarkable efficiency, that too on a molecular level. This technique has always been widely used in reverse osmosis for purification purposes of potable water as well as the desalination of saltwater. In fact, membrane filtration also allows the harvest of numerous valuable products of the like of whey protein. It also aids the purification and reuse of liquids, as in the case of electro-coat paint in the automotive segment. Nano-filtration is a technique that by far, seems to be the most fitting solution in terms of processing of the waste water and recovery of raw materials. Nano-filtration is nothing but reverse osmosis carried out at lower pressure, and is found to be extremely cost efficient especially of conducted under a properly maintained set-up, with the requisite pre-treatments.
There are quite a few liquids that form a substantial percentage of the waste streams expelled out by textile mills, and nano-filtration has been found to be helpful in the case of all of these. The first one being PVA or polyvinyl alcohol, that is majorly used to smoothen and strengthen the fibres. This chemical is innate to the production of modern textiles, but sadly, is highly toxic. Hence, it’s recovery as aided by the nano-filtration membrane is expedient, both economically as well as environmentally. The next product that goes as waste is the dye. Again, nano-filtration has come to the rescue in this regard, by aiding the recovery of the unused dyes as well as salts and sulphides from the wastewater. Not only does this operation help in improving the quality of the expelled water, but also helps in the reuse of dyes.
It can be thus concluded that the nano-filtration technique has a great potential in terms of reducing the ecological footprint of the textile industry by allowing the reuse of chemicals that are not only valuable in terms of money, but are also indispensable with respect to the process of manufacturing!