Table 3
Dilute acid pretreatment of waste paper with different acid concentrations.
Acid concentration (N) TRS (g/l) Xylose (g/l) Phenolics (%)
0.005 0.088 ± 0.004 0.048 ± 0.002 0.011 ± 0.001
0.01 0.104 ± 0.007 0.062 ± 0.002 0.012 ± 0.001
0.05 0.789 ± 0.042 0.400 ± 0.012 0.016 ± 0.001
0.10 2.542 ± 0.118 1.213 ± 0.034 0.022 ± 0.001
0.50 12.422 ± 0.792 8.680 ± 0.223 0.120 ± 0.004
1.00 14.456 ± 0.859 8.809 ± 0.267 0.129 ± 0.004
A.K. Dubey et al. / Carbohydrate Polymers 88 (2012) 825–829 827
Fig. 1. WAXD of untreated waste paper.
3. Results and discussion
3.1. Waste paper compositional analysis
The oven dried waste paper dust (60 mesh size) was found
to contain holocellulose (70.12 ± 4.88%) comprising -cellulose
(61.5 ± 3.49%), pentosans (7.42 ± 0.36%), lignin (16.33 ± 0.96%),
ash (12.50 ± 0.33%) and moisture (8.28 ± 0.63%). The presence
of 70.12 ± 4.88% of total carbohydrates (holocellulose) makes
waste paper a prospective and renewable biomass for bioethanol
production.
3.2. Dilute acid pretreatment
The dilute acid pretreatment of waste paper was carried out
with different solid/liquid ratios (1:8–1:14), different reaction time
(01–06 h) and different sulfuric acid concentrations (0.005–1.00 N)
at 120 ◦C temperature in an autoclave.
3.2.1. Effect ofdifferent bath ratio
Pretreatment with different bath ratios (1:8–1:14) was carried
out with sulfuric acid concentration 0.10 N for 02 h at 120 ◦C temperature. The maximum total reducing sugars yield obtained was
Fig. 2. WAXD of acid pretreated waste paper.
828 A.K. Dubey et al. / Carbohydrate Polymers 88 (2012) 825–829
03.27 ± 0.162 g/l at 1:10 bath ratio (Table 1 ). The biomass when
treated with 1:12 and 1:14 there was slightly decrease in concentration of total reducing sugars, xylose and phenolics.