Electrospun lignin-based composite nanofiber membrane as high-performance absorbent for water purification

An alkali lignin/poly (vinyl alcohol) (lignin/PVA) composite nanofiber membrane was fabricated by electrospinning and tested as an adsorbent for efficient Safranine T (ST) adsorption. Effect of lignin/PVA ratios on the morphology and chemical properties of the prepared composite membranes were studied. The influence of initial dye pH, time and temperature on the adsorption performance of composite membranes were investigated, and further evaluated the desorption and recycling behavior. The results showed that strong intermolecular hydrogen bonds were formed between the hydroxyl groups of PVA and lignin. The diameter of fiber displayed decreasing tendency to the increase in lignin content and the carbonization process. The excellent bead-free membranes were produced with the lignin content as high as 50 wt%. Further study found that the adsorption capacity increased with increasing the initial dye pH and temperature. The results of adsorption indicated that the absorption behavior of composite membranes was better consistent with the Langmuir isotherm and pseudo-second-order kinetic models. The adsorbent exhibited the excellent desorption behavior with an optimal desorption time of 4 h and constant recycling performance. Overall, these results indicate that lignin/PVA composite nanofiber membrane can be applied as a cost-efficient absorbent for removal of dyes from wastewater.