Comparative study of various pretreatment reagents on rice husk and structural changes assessment of the optimized pretreated rice husk

Kinetics for enzymatic hydrolysis of rice hulls by the ultrasonic pretreatment with a bio-based basic ionic liquid

“…The increase in crystallinity was due to the removal of ash and Si (Table 1) from the structure of the rice hulls by the action of [Ch][OH] and ultrasound. The previous studies using NaOH or HCl to treat rice hulls also indicated that the increases in the degree of crystallinity were due to the removal of waxes, silica and so on from the surfaces of the fibers [3,27].…”

“…The two spectral profiles of most bands (790, 898, 1043, 1423, 1511, 1637, and 2919 cm −1 ) were rather similar, indicating that RH and CHRH had similar functional groups; but, the bands around 898 cm −1 , which corresponded to C O stretching and C H vibration in the cellulose, were intensified after the pretreatment with [Ch][OH] and ultrasound, showing that the available cellulose exposed for hydrolysis was increased. In addition, the bands, which represent silica bonds (790 cm −1 ), C O stretching vibration in cellulose/hemicellulose (1043 cm −1 ), the aromatic skeletal stretching in lignin (1423 and 1511 cm −1 ), O H bending vibration of adsorbed water molecules (1637 cm −1 ), and C H vibration or stretching in cellulose rich material (∼2919 cm −1 ) [25,27,28], were reduced after the pretreatment with [Ch][OH] and ultrasound, indicating that the pretreatment with [Ch][OH] and ultrasound can effectively remove silica and lignin from RH and destroy their rigid structure, thereby promoting the effect of enzymatic hydrolysis.…”

Removal of Cd (II) from Aqueous Media by Adsorption onto Chemically and Thermally Treated Rice Husk

“…There, an important decrease in the specific surface area value of rice husk chemically treated (4 m 2 /g) in relation to the sample without treatment (13 m 2 /g) can be seen. This change can be attributed to the effects of NaOH on the material either by partial degradation of some components of the rice husk, generating merging of smaller pores (micropores) into large pores (mesopores) [30], or because of the fixing of NaOH on the surface of the material which may cause blockage in the pores.…”

Effects of Pretreatment of Single and Mixed Lignocellulosic Substrates on Production of Endoglucanase by Bacillus aerius S5.2

“…MS was subjected to dilute acid, dilute alkali, hydrothermal, and organic solvent pretreatments with 1% (v/v) H2SO4, 1% (v/v) NaOH, distilled water, and 85% (w/w) Nmethylmorpholine-N-oxide (NMMO), respectively, as pretreatment solvents. Besides the unique effects of each of these pretreatment methods on lignocellulose mentioned earlier, they also represent a fairly diverse range of physicochemical pretreatments commonly applied for rice and oil palm residues (Imman et al 2013;Purwandari et al 2013;Ang et al 2013). MS was suspended in the respective solvents of each pretreatment method in 500 mL bottles to obtain a solid loading of 10% (w/v) on a dry weight basis.…”