Preparation, characterization and performance of acetylated cellulignin membranes obtained by green methods from biomass

Abstract

The main objective of this work was the preparation, characterization and evaluation of membranes made from agave bagasse biomass through environmental friendly techniques. An Ethanosolv pretreatment (with four factors: temperature, ethanol, catalyst and residence time) was performed to recuperate cellulose using a central composite design 2k+2k, k=4 obtaining a response surface equation. The biomass obtained at maximal cellulose recovery was further acetylated by a Fisher process, in which the biomass reacted primarily with acetic acid. Afterwards, acetylated cellulignin membranes were produced by an evaporation-precipitation method. The resulting membranes (ABM) were characterized by SEM, AFM, FTIR, TGA and DMA, comparing with a CTA membrane obtained in the same conditions. Other membranes from cellulose obtained by acid-alkaline (AA), thermal (AT) and organosolv (AC) pretreatments were prepared. A comparison was made in terms of flux, fluoride rejection and acetylation yields. ABM achieved lower fluxes than AA, AT and AC. Only ABM rejected fluoride (98% removal for a 406ppm solution). Afterwards, removal of the main cations and anions was assessed using ABM, from well water (Chihuahua, Mexico) which was as high as 99.99%. Biofouling was presented after 20days of continuous operation.Agave bagasse, evaporation-precipitation method, acetylated cellulignin membranes, ion removal.