Toward a Circular Economy: Decontamination and Valorization of Postconsumer Waste Wood Using the ionoSolv Process

Abstract

Postconsumer waste wood is one of the most highly generated and yet overlooked waste streams that are typically sent to landfills or hazardous incineration facilities. This study presents the valorization of real postconsumer metal-contaminated waste wood as viable biorefinery feedstock using the ionoSolv process. Waste wood characterization showed high levels of heavy metal contamination originating from preservatives, paints, and pigments. Several ionic liquids (ILs) were screened to investigate their effectiveness in fractionating waste wood quantified by lignin and hemicellulose removal, glucan recovery, enzymatic saccharification yield, and their effectiveness in extracting the heavy metals from the biomass. 1-Methylimidazolium chloride [H1Cim]Cl IL was shown to be the most effective in fractionating the waste wood, achieving quantitative glucose yield, while simultaneously extracting 84–96% of heavy metals under optimum conditions. The effect of increasing the solid loading on pretreatment fractionation efficiency also was investigated, as well as on heavy metal extractions, with 74–95% extractions being achieved at solid to solvent loadings of 1:2 g g–1. Electrodeposition of Pb was also demonstrated at low overpotentials. This is the first example of turning hazardous waste wood that has low to negative value to its producers into value-added products in a biorefinery scheme.

Evaluating the Role of Water as a Cosolvent and an Antisolvent in [HSO4]-Based Protic Ionic Liquid Pretreatment

“…Glucan recovery for waste wood seemed to remain unaffected by the changes in the water concentration in the pretreatment medium. The independence of the pretreatment outcomes (delignification, glucan recovery, and hemicellulose removal) of postconsumer waste wood under various pretreatment conditions of different severities was communicated in detail in a recent study . Similar trends are observed in this study, where delignification, hemicellulose removal, and glucan recovery remain highly unchanged when varying the concentrations of water.…”

Biocatalysis in ionic liquids: state-of-the-union

“…189,190 In the ionoSolv process, 191 deconstruction of lignocellulose is conducted in low-cost (ca. $ 1-2 / kg) PILs, exemplified by 1-methylimidazolium chloride, [hmim][Cl], 192 [Et 3 NH][HSO 4 ], 193,194,195,196 198 at elevated temperatures, affording a cellulose rich pulp. In contrast, when low-cost tetramethylguanidinium (TMG) hydrogen sulfate was used, the biomass completely dissolved and the cellulose was precipitated with ethanol.…”

Evaluating the potential of a novel hardwood biomass using a superbase ionic liquid

“…45 The extent of hemicellulose and lignin removal was estimated from the compositional data relative to the amounts in the original biomass using relevant formulae that have been taken from the literature. 46,47 For the complete outcome of pretreatment in terms of lignin recovery/removal, hemicellulose removal and CRM recovery, see Table S1 (ESI). † At 100 C, the data show a very gradual decrease in the lignin content of biomass as a function of time.…”