As a by-product of lignocellulosic depolymerization for furfural production, furfural residue (FR) is composed of residual cellulose, lignin, humic acid, and other small amounts of materials, which have high reuse value. However, due to the limitation of furfural production scale and production technology, the treatment of FR has many problems such as high yield, concentrated stacking, strong acidity, and difficult degradation. This leads to the limited treatment methods and high treatment cost of furfural residue. At present, most of the furfural enterprises can only be piled up at will, buried in soil, or directly burned. The air, soil, and rivers are polluted and the ecological balance is destroyed. Therefore, how to deal with furfural residue reasonably needs to be solved. In this review, value-added products for furfural residue conversion are described in detail in the fields of soil culture, catalytic hydrolysis, thermal decomposition, and porous adsorption. The future studies reporting the FR to convert value-added products could find guidance from this review to achieve specific goals.

Corn stover (CS), as a major agricultural residue in Northeast China, suffers from inefficient anaerobic digestion (AD) due to its rigid lignocellulosic structure and the generation of inhibitory phenolic compounds during pretreatment. Alkaline hydrogen peroxide (AHP) disrupts lignocellulosic structures while generating methanogenesis-inhibiting phenolic compounds. Current pretreatments only resolve either lignocellulosic rigidity or phenolic toxicity, with no integrated method to mitigate both simultaneously. This work investigated a combined strategy of AHP pretreatment coupled with MnO₂ amendment to improve methane production from CS using laboratory-scale batch AD. Results demonstrated that 3% AHP pretreatment induced structural modifications and altered lignin-related functional groups, while the subsequent addition of 1.0 g MnO₂ significantly (p < 0.05) removed up to 28.4% of the generated total phenolic equivalents and alleviated volatile fatty acid (VFA) accumulation. The Mn-AHP group achieved the highest cumulative methane production of 449.28 ± 13.25 mL/g VS, representing a 14.6% increase compared to the control and a 3.24% improvement over the AHP-only group. Microbial analysis revealed increased relative abundance of acidogenic bacteria (e.g., Synergistota) and a compositional shift in the archaeal community toward a structure dominated by Methanobacterium and Methanothrix. These findings indicate that coupling AHP with MnO₂ is a promising approach to address the dual challenges of lignocellulosic recalcitrance and phenolic inhibition, providing a feasible pathway for agricultural waste valorization.