3. Results and discussion
3.1. Lignocellulosic composition and structural property of regenerated
samples
The structure swelling of the water hyacinth was observed during
the pretreatment, and the high number of particles evidenced
disruption and exhibited loose structure. Amount of smaller molecules
such as fructose, oligosaccharide and lignin were produced
and dissolved in ionic liquid solutions during the pretreatment
process. In general, 27.1–60.4% of the initial lignin was removed
and the mass loss of water hyacinth was 4.9–25.1% as compared
with the unpretreated sample (Table 1). Although the addition of
DMSO and DMAC could reduce the viscosity of ionic liquid and increase
the flowability of the system, DMAC weakened the delignification
capability of both [Bmim]Cl and [Emim]Cl. The result
indicates that the dissolving and delignification capability of the
solvents studied for pretreatment of water hyacinth follows the
order: [Emim]Ac > [Emim]Ac/DMSO [Bmim]Cl/DMSO > [Bmim]-
Cl DMSO > [Emim]Ac/DMAC [Bmim]Cl/DMACDMAC.
The pretreatments make the surface of water hyacinth more
porous, and [Emim]Ac showed better ability of crystallinity
reduction than [Bmim]Cl. Moreover, the formation of aggregates
could be observed in pretreated water hyacinth, especially in
the samples pretreated at 140 C for 120 min or at 120 C for