Penetration and accumulation modes of the dominant degraded compounds in acidic lignocellulosic hydrolysate during electrodialysis separation

Abstract

The lignocellulosic hydrolysate must be separated to obtain the products xylose and xylo-oligosaccharide. As a low energy consumption and selective separation technology, electrodialysis has a good application prospect. Separation of hydrolysate using electrodialysis can recover the acid from the pretreatment process while obtaining the product, which greatly saves the cost of lignocellulose utilization. However, the complex degradation products of lignocellulose can lead to membrane clogging and reduce electrolysis efficiency. Here, through the penetration and accumulation of the simulated liquid with dominant degraded compounds, varied aromatic compounds are demonstrated to be key membrane pollutants. Only <10 % of the aromatic compounds penetrated to the acid chamber, and 33.39 % to 78.72 % were deposited on membrane. Aromatic compounds with more carbon atoms were more likely to accumulate on the membrane and those with fewer oxygen atoms under the same carbon atom conditions were more likely to accumulate, and the elution rule was reversed. In addition, the penetration and accumulation models of aromatic compounds were studied. These provide support for the enhancement of acid recovery from lignocellulosic hydrolysate, the extension of electrodialysis membrane life, and the acceleration of self-providing acid pretreatment technology.