Liquefaction of metal-contaminated giant reed biomass in acidified ethylene glycol system: Batch experiments

GUO Zhao-hui(郭朝晖), LIU Ya-nan(刘亚男), WANG Feng-yong(王凤永), XIAO Xi-yuan(肖细元)

(School of Metallurgy and Environment, Central South University, Changsha 410083, China)

Abstract:Giant reed is a suitable pioneer plant for metal-contaminated soil phytoremediation, however, it is imperative to dispose the metal-contaminated biomass after harvesting. The liquefaction of metal-contaminated giant reed biomass in ethylene glycol system with sulfuric acid as catalyst for the precursors of polyurethane compounds was studied. The results show that giant reed biomass from metal-contaminated soil is potentially liquefied and significantly affected by solvent/solid ratio, liquefaction temperature and liquefaction time (P<0.05). The liquefaction rate of biomass in acidified ethylene glycol system can reach 85.2% with optimized conditions of 60 min, 170 °C, 3% sulfuric acid and solvent/biomass ratio of 5:1. The hydroxyl value of liquefied products is of 481 mg KOH/g while reactive hydroxyl groups of them are abundant, which is promised as potential precursors for polyurethane compounds. The solvent liquefaction is a potential method to dispose the metal-contaminated biomass, however, the containing-metal liquefied products should be studied deeply in order to get the suitable precursors in future.

Key words:Arundo donax L.; metal-contaminated biomass; solvent liquefaction; phytoremediation