258
S. Chatterjee et al.
some works on ionic liquids demonstrated higher yield of RS (Φ g ); however, higher
costs made the overall process economically unattractive (Rinaldi et al. 2008; Zhang
and Zhao 2009).
To overcome these difficulties, many researchers have shown much interest in the
application of heterogeneous solid acid catalysts for LB hydrolysis (Suganuma et al.
2008). Recently, Meena et al. (2015) used Amberlyst 15 as solid acid catalyst for
rice straw hydrolysis, but owing to higher mass transfer resistance between insoluble
cellulose and solid acid, this method demonstrated poor hydrolysis efficiency.
In the last decade, microwave irradiation was applied to hasten the LB hydrolysis for RS synthesis (Vani et al. 2012; Chakraborty and Sahu 2014). Nonetheless,
the yield was relatively low (20–45%) using HY zeolite in a microwave reactor
(400 W) for 4 min (Zhang and Zhao 2009). Vani et al. (2012) reported a maximum
Φ g of 0.495 g/g applying 300 W power input for 6 min (108 kJ). Notably, highpressure pretreatment (180 °C, 100 rpm for 45 min) repeated for 5 times, consumed
approximately 540 kJ energy.
Recent work has exhibited the energy-efficient and time-saving application of
infrared radiation (IRR) to intensify the trans-esterification reaction of waste tallow to
produce ecologically benign cost-effective biodiesel (Chakraborty and Sahu 2014).
Notably, no scientific report is available on the application of IRR especially for
intensification of hydrolysis of WPS for production of RS.
Taguchi L 9 orthogonal array has been used to evaluate the optimal process
conditions to achieve maximum Φ g (Chakraborty and RoyChowdhury 2013).
This article reports the synthesis of RS by hydrolysis of pretreated WPS (PWPS)
using commercial Amberlyst 15 catalyst in an infrared radiated batch reactor
(IRRBR). The pretreatment of WPS, traditional Ammonia fiber explosion (AFEX)
pretreatment has been modified through the application of IRR. Taguchi orthogonal experimental matrix (TOEM) was employed to evaluate the effects of four
process factors, viz., PWPS to catalyst ratio(w/w), IRRBR Temperature (°C), water
to PWPS ratio(w/w), and reaction time (min) and to evaluate the optimal factorial
values corresponding to maximum Φ g .
2 Materials and Methods
2.1 Materials
The WPS was collected from a local market and analytical reagent (AR) grade
chemicals, viz., DNS (di-nitro salicylic acid) and aq. NH 4 OH (25 wt%) were procured
from Merck (India); Amberlyst 15 catalyst was sourced from SIGMA-ALDRICH.
S. Chatterjee et al.
some works on ionic liquids demonstrated higher yield of RS (Φ g ); however, higher
costs made the overall process economically unattractive (Rinaldi et al. 2008; Zhang
and Zhao 2009).
To overcome these difficulties, many researchers have shown much interest in the
application of heterogeneous solid acid catalysts for LB hydrolysis (Suganuma et al.
2008). Recently, Meena et al. (2015) used Amberlyst 15 as solid acid catalyst for
rice straw hydrolysis, but owing to higher mass transfer resistance between insoluble
cellulose and solid acid, this method demonstrated poor hydrolysis efficiency.
In the last decade, microwave irradiation was applied to hasten the LB hydrolysis for RS synthesis (Vani et al. 2012; Chakraborty and Sahu 2014). Nonetheless,
the yield was relatively low (20–45%) using HY zeolite in a microwave reactor
(400 W) for 4 min (Zhang and Zhao 2009). Vani et al. (2012) reported a maximum
Φ g of 0.495 g/g applying 300 W power input for 6 min (108 kJ). Notably, highpressure pretreatment (180 °C, 100 rpm for 45 min) repeated for 5 times, consumed
approximately 540 kJ energy.
Recent work has exhibited the energy-efficient and time-saving application of
infrared radiation (IRR) to intensify the trans-esterification reaction of waste tallow to
produce ecologically benign cost-effective biodiesel (Chakraborty and Sahu 2014).
Notably, no scientific report is available on the application of IRR especially for
intensification of hydrolysis of WPS for production of RS.
Taguchi L 9 orthogonal array has been used to evaluate the optimal process
conditions to achieve maximum Φ g (Chakraborty and RoyChowdhury 2013).
This article reports the synthesis of RS by hydrolysis of pretreated WPS (PWPS)
using commercial Amberlyst 15 catalyst in an infrared radiated batch reactor
(IRRBR). The pretreatment of WPS, traditional Ammonia fiber explosion (AFEX)
pretreatment has been modified through the application of IRR. Taguchi orthogonal experimental matrix (TOEM) was employed to evaluate the effects of four
process factors, viz., PWPS to catalyst ratio(w/w), IRRBR Temperature (°C), water
to PWPS ratio(w/w), and reaction time (min) and to evaluate the optimal factorial
values corresponding to maximum Φ g .
2 Materials and Methods
2.1 Materials
The WPS was collected from a local market and analytical reagent (AR) grade
chemicals, viz., DNS (di-nitro salicylic acid) and aq. NH 4 OH (25 wt%) were procured
from Merck (India); Amberlyst 15 catalyst was sourced from SIGMA-ALDRICH.