Highly-efficient isolation of cellulose microfiber from rice straw via gentle low-temperature phase transition

Lignocellulose is an important biomass resource. Its main components cellulose, hemicellulose, and lignin can be used as important energy and chemical raw materials. The special 3-D stereoscopic structure of lignocellulose makes it difficult to separate its components efficiently, limiting large-scale industrial applications. In this work, a novel one-pot and low-temperature phase transition (LTPT) method with no oxidant was applied to efficiently isolate rice straw cellulose microfibers (CMF) from rice straw (RS), with the cellulose content of the CMF reaching 85.4%. The LTPT method can also change the crystal structure of cellulose in RS from cellulose I to cellulose II. Furthermore, experimental results show that CMF can be isolated from RS at a low concentration (3 wt%) of NaOH solution. Graphic abstract In this work, we used the one-pot and low-temperature phase transition method to prepare rice straw cellulose microfibers (CMF) in NaOH solution. The diameter of CMF is about 4.32 μm, and its cellulose content can reach 85%.