【作者】 黄诚；

【导师】 谭世语；

【作者基本信息】 重庆大学 ， 生物化工， 2007， 硕士

【摘要】 稻壳是稻谷加工的剩余物,量大而集中。本课题以稻壳为原料,利用硫酸的催化作用将稻壳中的半纤维素进行水解,从而制备附加值较高的木糖晶体,这方面的研究工作不仅具有重要的学术意义,而且具有重要的经济和社会价值。半纤维素在稀酸的催化条件下可以水解制备木糖,实验进行了如下几个方面研究。首先,确定了对水解实验具有较大影响的条件因素:料液比、水解温度、反应时间和酸浓度。对这些影响因素进行单因素水解实验,考察还原糖和木糖取得较好收率时,那些影响因素的取值范围。其次,通过正交实验优化了水解条件,在料液比1∶6、硫酸浓度3wt%、反应温度120℃、水解时间2小时的条件下,稻壳水解制备木糖的收率在9.1%(按稻壳干料计);而在料液比为1∶6、硫酸浓度为3wt%、反应温度为120℃、水解时间3小时的条件下,还原糖具有较好的产率,半纤维素的利用率也较好。最后,实验对制备的木糖晶体进行熔点测定、红外光谱、高效液相色谱分析,分析的结果表明产生的木糖晶体熔点为140～147℃、具备木糖的红外光谱特征、液相色谱分析其纯度为95.4%。实验产生的木糖渣若不加以利用,大量地堆积会引起环境问题,因此,实验留下的木糖渣必须进行处理,通过单因素实验,分别考察了活化温度、磷酸浓度与活化时间对木糖废渣制备活性碳的影响,确定了制备具有较好脱色力和收率活性碳的实验条件为:活化温度400℃,磷酸浓度40 wt%,反应时间1小时。更多还原

【Abstract】 Paddy hull is the cellulosic residue of paddy processing. In this article, hemicellulose of paddy hull was hydrolyzed into xylose while sulphuric acid was used as the catalyzer. The research was provided with academic, social and economic value.Xylose was produced in hydrolysis of hemicellulose under catalyzing by dilute acid. Some investigations were presented in experiment. Firstly, reaction conditions which performed influence on experiment were confirmed. These influence factors were the ratio of solid to liquid, concentration of sulphuric acid, hydrolysis temperature and reaction time. In order to a maximal yield of deoxidize sugar and xylose, the value range of influence factors was obtained through single factor experiments of hydrolysis. Secondly, on the basis of perpendicular design experiment, the optimal hydrolysis conditions were mass ratio of solid to liquid 1∶6, concentration of sulphuric acid 3.0wt%, hydrolysis temperature 120℃and reaction time 2h. Under the condition, 9.1wt% xylose yield was obtained. When the hydrolysis conditions were mass ratio of solid to liquid 1∶6, concentration of sulphuric acid 3.0wt%, hydrolysis temperature 120℃and reaction time 3h, deoxidize sugar had a maximal yield and hemicellulose had good utilization. Finally, the product produced in experiment was analyzed by melting-point measure, IR and HPLC. As the result, the melting point of xylose crystal was 140～147℃, IR spectrum diagram of xylose produced in experiment was consistent with spectrum diagram of standard xylose, the pure of xylose was 95.4% through HPLC.If the residue of xylose was not utilized and largely stacked in experiment, it would bring environmental problem. Some single factor experiments were carried out to inspect the influence of active temperature, concentration of phosphorous acid and active time. Through these experiments, the conditions were confirmed to active temperature 400℃, concentration of phosphorous acid 40 wt% and active time 1h. The active carbon had excellent discolor power and yield under the condition.更多还原