The valorization of lignocellulosic biomass into value-added chemicals like furans and anhydrosugars is pivotal for sustainable biorefineries, yet conventional pretreatment methods remain energy-intensive and environmentally unsustainable. This study introduces a closed-loop paradigm leveraging water microdroplets to generate hydrogen peroxide in situ on oxygen-rich biomass surfaces, enabling autonomous oxidative pretreatment. By spraying water microdroplets onto woodchips, interfacial reactions with surface oxygen-containing functional groups spontaneously yielded hydrogen peroxide, achieving concentrations of 72.2 mM/m2 (geometric surface area of woodchips) after 120 spraying cycles. Surface engineering such as air plasma and alkaline ethanol treatments enriched surface oxygen content by 16% and hydroxyl/ether groups by 64%, amplifying hydrogen peroxide production 10.2-fold compared to untreated biomass. Subsequent pyrolysis of the resulting hydrogen peroxide pretreated biomass at 400 °C produced bio-oil with remarkably enhanced formation of furans and anhydrosugars. Typically, the production of 5-hydroxymethylfurfural (HMF) and levoglucosan (LG) increased 2.1-fold and 17.2-fold compared to untreated biomass, respectively. This self-sustaining system eliminates reliance on external hydrogen peroxide supply and hazardous reagents, offering a cost-effective and energy-efficient pathway for sustainable biorefineries. The integration of microdroplet chemistry and biomass surface engineering establishes a green framework for autonomous biomass valorization.
Pan et al. (Mon,) studied this question.