| Summary: | 碩士 === 逢甲大學 === 化學工程學所 === 97 === In this study, the microwave irradiation was used to promote the hydrolysis of cellulosic material (cryptomeria, rice straw, and bagasse) in various acid solutions (hydrochloric acid, sulfuric acid, phosphoric acid). One- and two-stage (preatreatment with alkaline solution) hydrolyses were investigated to obtain the optimal operation condition. Sequentially, the hydrolysate obtained under the optimum conditions was used as the feedstock to produce H2 in a batch experiment.
For one-stage microwave hydrolysis, the optimum hydrolysis conditions for cryptomeria were 0.49% sulfuric acid (pH 1.0) at a solid/liquid ratio of 15/100, 180℃ for 20 min, and addition of 7 g/l NaCl. The yields of total sugar and reducing sugar were 0.227 and 0.226 g/g cryptomeria, respectively. For rice straw, the optimum hydrolysis conditions were 0.49% sulfuric acid at a solid/liquid ratio of 15/100, 180℃ for 5 min, and without NaCl addition. The yields of total sugar and reducing sugar were 0.334 and 0.332 g/g rice straw, respectively. The optimum hydrolysis conditions for bagasse were 0.49% sulfuric acid at a solid/liquid ratio of 10/100, 150℃ for 20 min, and without NaCl addition. The yields of total sugar and reducing sugar were 0.409 and 0.385 g/g bagasse, respectively.
For two-stage microwave hydrolysis, cryptomeria was pretreated using microwave irradiation (solid/liquid ratio 15/100 and 180℃ for 30 min) in 0.2% NaOH solution; afterward the pretreated cryptomeria proceeded microwave sulfuric acid hydrolysis (solid/liquid ratio 10/100 and 180℃ for 20 min). The results showed that the yields of total sugar and reducing sugar were 0.255 and 0.220 g/g cryptomeria, respectively. For rice straw, the yields of total sugar and reducing sugar were 0.320 and 0.319 g/g rice straw, respectively, with two-stage microwave hydrolysis (in H2SO4 solution, solid/liquid ratio 10/100, and 180℃ for 5 min).
In biohydrogen production experiment, hydrolysate from one-stage microwave-acid hydrolysis via overliming treatment could be transform into hydrogen efficiently. The hydrolysates of cryptomeria and bagasse with phosphoric acid hydrolysis obtained the maximum hydrogen yield of 5.22 and 4.91 mmol H2/g total sugar, respectively. For rice straw, the hydrolysate with hydrochloric acid hydrolysis got the maximum hydrogen yield of 4.02 mmol H2/g total sugar. For hydrogen production from hydrolysate with two-stage microwave-acid hydrolysis and overliming treatment, cryptomeria and rice straw hydrolysates gained a yield of 5.51 and 5.56 mmol H2/g total sugar, respectively.
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