Lignocellulosic adsorbent from carrot pomace for enhancing the performance of polylactide-based membranes in the removal of cationic dyes

A composite membrane of polylactide (PLA) with a lignocellulosic adsorbent derived from carrot pomace (CP) was prepared by non-solvent induced phase separation. CP was treated with NaOH (tCP) under mild conditions to improve the adsorption capacity of the lignocellulosic biomass. The tCP removed 95% of the methylene blue (MB) with an adsorption capacity of 310 mg/g using a dosage of 0.3 g/L at an initial MB concentration (C 0 ) of 100 mg/L. The effects of different contents of tCP on the properties of the PLA-based membrane were investigated. The optimum tCP content was 30 wt%. The water flux of the PLA/tCP30 membrane was 870 L/m 2 ⋅h with 99% of MB removal while the PLA membrane removed only 30% with lower water flux of 337 L/m 2 ⋅h. Furthermore, the PLA/tCP30 membrane maintained this high MB removal efficiency over ten consecutive cycles. In single and binary dye systems, the membrane separated cationic dyes from water and allowed an anionic dye to pass through the membrane, demonstrating the negative charge of the membrane. The simple conversion of food waste into a functional filler could not only enhance the dye removal performance of a PLA membrane but also reduce food waste.