698
contains different fluxing agents such as K 2 O, Fe 2 O 3 , CaO, MgO and TiO 2 which
reduce firing temperature required for brick production. Porosity of brick increased
with more inclusion of water hyacinth. Water absorption capacity of brick increases
with higher porosity. Brick with 10% inclusion of water hyacinth absorbed less than
25% of water. Therefore, water hyacinth blended brick can be used as a moderate
weather resistant.
5 Biorefinery Approach
For extraction of various value-added compounds such as sterols, organic and fatty
acids and polyphenols from water hyacinth, different extraction methods like supercritical fluid extraction (SFE) [40, 41], solvent extraction [44] and ultrasound
assisted extraction (USAE) [43] have been employed. Sterols have been extracted
from water hyacinth by SFE using CO 2 as a solvent which is eco-friendly solvent.
With some possible modifications in solubilization capacity of supercritical CO 2 , it
is possible to extract a variety of useful constituents with very high degree of separation from solvent without the issue of residual solvent [93], thereby making SFE
a green extraction process. Using USAE, shikimic acid has been successfully
extracted. USAE is based on cavitation phenomenon in which due to collapse of
cavitation bubbles high thermal energy and pressure are released, thereby generating micro jets and shock waves that affect the cell morphology. Hence, cell structure
experiences the damage which enhances the extraction efficiency by increasing the
solvent diffusion rate. The use of sonication, due to intensification in aqueous
media, reduction in extraction time and low energy consumption, makes the process
a greener one [93]. In solvent extraction, water has been used as a solvent making
the process sustainable. By pyrolysis process, biochar and bio-oil have been made
from Eichhornia crassipes. Adsorbents like biochar have effectively removed heavy
metals like Cd (II) [59] and dyes. After removing lignocelluloses, water hyacinth
has been utilized to produce bioethanol and biogas. Minimization of waste like
water hyacinth by utilizing it for production of renewable energy source may assist
in creating self-sufficient system. Three stages such as pre-treatment, hydrolysis
and fermentation are involved in producing bioethanol from Eichhornia crassipes
[10]. Biogas was produced by pre-treatment (acid/alkali/microbial) followed by
methanogenesis.
Water hyacinth grows rapidly, and to control growth of this invasive weed is not
economically viable. Instead of control, sensible utilization of water hyacinth as
feedstock for various value-added products minimizes the dependency on fossil
fuels. The integrated biorefinery concept can be successfully implemented to water
hyacinth upon incorporating extraction of phytochemicals followed by production
of lignocellulose materials and finally biofuel production. Phase II biorefinery can
be implemented for water hyacinth biomass valorization. The complete utilization
of water hyacinth feedstock supports financial and ecological advantages. The
P. V. Ganorkar et al.
contains different fluxing agents such as K 2 O, Fe 2 O 3 , CaO, MgO and TiO 2 which
reduce firing temperature required for brick production. Porosity of brick increased
with more inclusion of water hyacinth. Water absorption capacity of brick increases
with higher porosity. Brick with 10% inclusion of water hyacinth absorbed less than
25% of water. Therefore, water hyacinth blended brick can be used as a moderate
weather resistant.
5 Biorefinery Approach
For extraction of various value-added compounds such as sterols, organic and fatty
acids and polyphenols from water hyacinth, different extraction methods like supercritical fluid extraction (SFE) [40, 41], solvent extraction [44] and ultrasound
assisted extraction (USAE) [43] have been employed. Sterols have been extracted
from water hyacinth by SFE using CO 2 as a solvent which is eco-friendly solvent.
With some possible modifications in solubilization capacity of supercritical CO 2 , it
is possible to extract a variety of useful constituents with very high degree of separation from solvent without the issue of residual solvent [93], thereby making SFE
a green extraction process. Using USAE, shikimic acid has been successfully
extracted. USAE is based on cavitation phenomenon in which due to collapse of
cavitation bubbles high thermal energy and pressure are released, thereby generating micro jets and shock waves that affect the cell morphology. Hence, cell structure
experiences the damage which enhances the extraction efficiency by increasing the
solvent diffusion rate. The use of sonication, due to intensification in aqueous
media, reduction in extraction time and low energy consumption, makes the process
a greener one [93]. In solvent extraction, water has been used as a solvent making
the process sustainable. By pyrolysis process, biochar and bio-oil have been made
from Eichhornia crassipes. Adsorbents like biochar have effectively removed heavy
metals like Cd (II) [59] and dyes. After removing lignocelluloses, water hyacinth
has been utilized to produce bioethanol and biogas. Minimization of waste like
water hyacinth by utilizing it for production of renewable energy source may assist
in creating self-sufficient system. Three stages such as pre-treatment, hydrolysis
and fermentation are involved in producing bioethanol from Eichhornia crassipes
[10]. Biogas was produced by pre-treatment (acid/alkali/microbial) followed by
methanogenesis.
Water hyacinth grows rapidly, and to control growth of this invasive weed is not
economically viable. Instead of control, sensible utilization of water hyacinth as
feedstock for various value-added products minimizes the dependency on fossil
fuels. The integrated biorefinery concept can be successfully implemented to water
hyacinth upon incorporating extraction of phytochemicals followed by production
of lignocellulose materials and finally biofuel production. Phase II biorefinery can
be implemented for water hyacinth biomass valorization. The complete utilization
of water hyacinth feedstock supports financial and ecological advantages. The
P. V. Ganorkar et al.