Re-use of waste cotton textile as an ultrafiltration membrane

Textile industry produces millions of tons of waste annually, which is predominantly incinerated or landfilled. Cotton textile comprises a quarter of total textile production, and although being renewable, its production is highly chemical-and water-intensive, rising the need for effective waste cotton textile recycling. This study presents an investigation whether it is possible to utilize waste cotton textile as a cellulose source for the fabrication of cellulose membranes. The effect of casting thickness and cellulose concentration on the prepared membranes' performance was studied. Membranes cast from 2 wt% casting solutions exhibited the highest permeabilities of 1.11 and 3.09 m3/(m(2)center dot s center dot Pa) for 300 and 150 mu m casting thickness, respectively, but poor adhesion stability and low retention. Membranes cast from solutions of higher concentrations (5, 6, and 7 wt%) resulted in membranes with more stable performance. The permeability values for 300 mu m membranes were in the range of 0.27 - 0.39 m(3)/(m(2)center dot s center dot Pa) and for 150 mu m 0.51 - 0.67 m(3)/(m(2)center dot s center dot Pa). The retention values of these six membranes were relatively close to each other, showing 80 - 92% retention of polyethylene glycol (PEG) 35 kDa. Three most promising membranes (5, 6, and 7 wt% cast at 150 mu m) were additionally characterized, showing negative zeta potential within-23 --35 mV range at pH 7 and contact angles of very hydrophilic material (14 - 16 degrees). Overall, the results showed that very hydrophilic ultrafiltration membranes having attractive permeability and retention properties can be made from textile waste. 1 m2 of cotton bed linen is enough to produce approximately 20 m2 of cellulose membrane.

Automated summary

The textile industry generates millions of tons of waste annually, with waste cotton textile being explored as a potential cellulose membrane material. Studies have shown that increasing solution concentration can improve membrane stability and performance.