吴鹏　韩宇超　白佳鑫　华笑非　赵金明

摘要 [目的]优化水热处理玉米秸秆提取腐植酸的工艺条件。[方法]以氢氧化钠溶液为溶剂水热处理玉米秸秆。利用单因素试验探究水热时间、温度、氢氧化钠浓度、固液比等对腐植酸产率的影响，并用正交试验优化制备条件;采用紫外可见光谱和重铬酸钾滴定法测定腐植酸的含量，用傅里叶红外光谱对制备的腐植酸基团结构进行了表征。[结果]优化的工艺条件如下：水热时间5 h，水热温度为200 ℃，固液比1∶10，氢氧化钠溶液浓度0.75  mol/L;在此条件下腐植酸的提取量高达0.48 g/g。傅立叶转换红外线光谱（FTIR）分析结果表明，提取样品中除存在芳香环结构外，还含有大量的醇羟基、醛基、羧基、羰基等酸性结构。[结论]该工艺研究为从玉米秸秆中制备腐植酸提供了技术方案和理论支持，为玉米秸秆的资源化利用提供了新途径。

关键词 玉米秸秆;水热法;腐植酸;工艺优化

中图分类号 S216文献标识码 A

文章编号 0517-6611（2020）11-0190-04

Abstract [Objective]To optimum the process conditions for extraction of humic acid from corn straw by hydrothermal treatment. [Method]The corn straw was treated by hydrothermal method using sodium hydroxide solution as solvent， and the content of humic acid was determined by UVVis and potassium dichromate titration， respectively. The effects of hydrothermal time， temperature， sodium hydroxide concentration， and solidliquid ratio on the yield of humic acid were explored by single factor experiments， and the process conditions were optimized via orthogonal experiment. Then， the group structure of the humic acid was determined by FTIR. [Result]Orthogonal experimental results showed that the optimum conditions were as follows： hydrothermal time was 5 h， hydrothermal temperature was 200 ℃， solidliquid ratio was 1∶10， and sodium hydroxide solution concentration was 0.75 mol/L. Under the optimal conditions， the extraction quality of humic acid was as high as 0.48 g/g corn stalks. The results of FTIR characterization showed that the aromatic ring structure， alcohol hydroxyl， phenolic hydroxyl， aldehyde， carboxyl， carbonyl， and other acidic structures were presenced in the humic acid. [Conclusion]The process research provided technical scheme and theoretical support for the preparation of humic acid from corn stalk， and provided a new way for the resource utilization of corn stalk.

Key words Corn stalk;Hydrothermal method;Humic acid;Optimization of pcrocess conditions

我国是粮食玉米种植大国，玉米秸秆年产量高达7亿t[1]。近年来，随着经济的发展，農民已经逐渐放弃采用秸秆作为生活燃料，因而造成了大量的玉米秸秆堆置或被露天焚烧，造成了严重的环境污染[2]。为解决这一问题，我国政府鼓励玉米秸秆的综合利用。目前对玉米秸秆的主要资源化处理方式有秸秆气化[3]、秸秆发酵制乙醇[4]、秸秆饲料加工等[5]，这些处理方式有的投资大或者工艺过程复杂，探索新的处理和利用方式是玉米秸秆资源化利用的必然趋势。……