Advanced oxidation processes in the treatment of corn stalks

Abstract

The depletion of fossil fuel reserves and severe environmental damage, resulting in climate change and global warming lead to a necessary shift to alternative renewable resources. Lignocellulose is a valuable feedstock for biorefineries, but its conversion is hindered by the limitations of conventional pretreatments lacking selectivity. This step should also be cost-effective and sustainable. In this paper, combined advanced oxidation techniques were applied for the treatment of corn stalks as a pretreatment for enzymatic hydrolysis. Their effect on delignification and cellulose digestibility was monitored. The combined non-thermal plasma/Fenton treatment appears to be suitable for breaking the complex lignocellulose structure, with a lignin content decrease of 39%. This treatment enhanced carbohydrate hydrolysis, resulting in 2.25 times increase in hexose yield, compared to the untreated sample. Long-term plasma treatment positively affected the textural properties, total porosity, and pore size diameter, of lignocellulose biomass. It enables the creation of materials with a stable system of pores and channels, for the unhindered diffusion of large organic molecules such as enzymes. Additionally, a combination of plasma treatment with Fenton reaction increased selectivity towards lignin degradation in comparison to independently applied Fenton treatment. This could be a significant advantage for a bottleneck in the current valorization of biomass.