694
mechanical extraction, chemical extraction using NaOH solution, mechanical and
chemical extraction, extraction with water at boiling point, natural alkali extraction
using ash from banana stem and retting extraction. Water hyacinth contained
72.17% cell walls which further consisted of 52.63% lignocelluloses. Mechanical
extraction has shown the highest elongation of fibre, whereas chemical extraction
method with 10% NaOH at 37 °C for 1 h was found superior as it was able to generate uniform surface texture with the maximum number of split fibres upon completion of the method.
Cellulose nanofibres from water hyacinth have been isolated by Thiripura
Sundari and Ramesh [83] using different chemical and mechanical treatments.
Bleaching and processing with alkaline and sodium chlorite solution were the
chemical methods employed to separate cellulose, hemicellulose and lignin.
Mechanical methods like ball milling, cryocrushing and ultrasound treatment of
chemically treated fibres were performed to obtain the desired particle size of fibre.
The microfibres have been subjected to cryocrushing using liquid nitrogen to produce nanofibres from stem bundle which were further sonicated for 15 min to form
individual nanofibres. The nanofibres with 20–100 nm diameter as per scanning
electron microscopy and 25 nm as per transmission electron microscopy have been
obtained by this method.
Microwave pre-treatment under acidic conditions led to hydrolysis of hemicellulose into monosaccharide such as xylose, galactose and arabinose, while some
fractions of cellulose and lignin were hydrolysed into glucose and propiolic acid,
respectively [84]. A higher content of cellulose has been obtained after degradation
of lignocellulosic biomass. Microwave pre-treatment of 10 g/L input with 1%
H 2 SO 4 at 140 °C for 15 min and hydrolysis with cellulase enzyme reducing sugar
yield of 48.3 g/100 g WH have been achieved. Hydrolysis of Eichhornia crassipes
into fermentable sugars is desirable for production of clean biofuels (e.g. ethanol
and hydrogen).
Nguyen Thi et al. [85] have employed subcritical water (SCW) pre-treatment for
cellulose recovery from water hyacinth and compared with pre-treatment using
H 2 SO 4 and untreated biomass. Recovery of cellulose, hemicellulose and lignin from
untreated biomass was 25%, 11% and 2.5%, respectively. The SCW pre-treatment
was carried out at 165 °C, 30 min, 50 bar with water to dried biomass ratio of
10:1 mL/g for which cellulose content of 68.2% was obtained. Pre-treatment with
1% H 2 SO 4 under same operating conditions has provided 69.4% cellulose content.
Though the cellulose content was more using H 2 SO 4 pre-treatment, SCW pretreatment is environment-friendly. Cellulose recovery and removal of lignin have
promoted the bioethanol production.
Devi et al. [86] have prepared cellulose nanocrystals (CNCs) by acid hydrolysis
of compost made with water hyacinth (120 kg), cow dung (15 kg) and sawdust
(15 kg). Compost was treated with alkali (NaOH) and bleaching chemicals (H 2 O 2
and NaClO) for gradual removal of hemicellulose and lignin followed by acid
hydrolysis (H 2 SO 4 ) to hydrolyse cellulose and prepare CNCs. CNCs were obtained
with mixed morphology of cone, rectangular with diameter of ~30–50 nm and
length ~200–300 and spherical shaped CNCs with diameter of 20–30 nm.
P. V. Ganorkar et al.
mechanical extraction, chemical extraction using NaOH solution, mechanical and
chemical extraction, extraction with water at boiling point, natural alkali extraction
using ash from banana stem and retting extraction. Water hyacinth contained
72.17% cell walls which further consisted of 52.63% lignocelluloses. Mechanical
extraction has shown the highest elongation of fibre, whereas chemical extraction
method with 10% NaOH at 37 °C for 1 h was found superior as it was able to generate uniform surface texture with the maximum number of split fibres upon completion of the method.
Cellulose nanofibres from water hyacinth have been isolated by Thiripura
Sundari and Ramesh [83] using different chemical and mechanical treatments.
Bleaching and processing with alkaline and sodium chlorite solution were the
chemical methods employed to separate cellulose, hemicellulose and lignin.
Mechanical methods like ball milling, cryocrushing and ultrasound treatment of
chemically treated fibres were performed to obtain the desired particle size of fibre.
The microfibres have been subjected to cryocrushing using liquid nitrogen to produce nanofibres from stem bundle which were further sonicated for 15 min to form
individual nanofibres. The nanofibres with 20–100 nm diameter as per scanning
electron microscopy and 25 nm as per transmission electron microscopy have been
obtained by this method.
Microwave pre-treatment under acidic conditions led to hydrolysis of hemicellulose into monosaccharide such as xylose, galactose and arabinose, while some
fractions of cellulose and lignin were hydrolysed into glucose and propiolic acid,
respectively [84]. A higher content of cellulose has been obtained after degradation
of lignocellulosic biomass. Microwave pre-treatment of 10 g/L input with 1%
H 2 SO 4 at 140 °C for 15 min and hydrolysis with cellulase enzyme reducing sugar
yield of 48.3 g/100 g WH have been achieved. Hydrolysis of Eichhornia crassipes
into fermentable sugars is desirable for production of clean biofuels (e.g. ethanol
and hydrogen).
Nguyen Thi et al. [85] have employed subcritical water (SCW) pre-treatment for
cellulose recovery from water hyacinth and compared with pre-treatment using
H 2 SO 4 and untreated biomass. Recovery of cellulose, hemicellulose and lignin from
untreated biomass was 25%, 11% and 2.5%, respectively. The SCW pre-treatment
was carried out at 165 °C, 30 min, 50 bar with water to dried biomass ratio of
10:1 mL/g for which cellulose content of 68.2% was obtained. Pre-treatment with
1% H 2 SO 4 under same operating conditions has provided 69.4% cellulose content.
Though the cellulose content was more using H 2 SO 4 pre-treatment, SCW pretreatment is environment-friendly. Cellulose recovery and removal of lignin have
promoted the bioethanol production.
Devi et al. [86] have prepared cellulose nanocrystals (CNCs) by acid hydrolysis
of compost made with water hyacinth (120 kg), cow dung (15 kg) and sawdust
(15 kg). Compost was treated with alkali (NaOH) and bleaching chemicals (H 2 O 2
and NaClO) for gradual removal of hemicellulose and lignin followed by acid
hydrolysis (H 2 SO 4 ) to hydrolyse cellulose and prepare CNCs. CNCs were obtained
with mixed morphology of cone, rectangular with diameter of ~30–50 nm and
length ~200–300 and spherical shaped CNCs with diameter of 20–30 nm.
P. V. Ganorkar et al.