【作者】 李扬杰；

【导师】 李德良；

【作者基本信息】 中南林业科技大学 ， 环境科学， 2008， 硕士

【摘要】 木质素作为造纸工业的副产品,由于没有得到有效的利用,不仅对环境造成了严重的污染,而且使得大量的木质素被白白的浪费。本论文通过酸析法从造纸黑液提取木质素,然后用甲醛对木质素进行改性,再用于吸附Cu2+,Ni2+、Zn2+、pb2+、Cd2+五种重金属离子,探索木质素用于制备重金属吸附剂上的可行性,主要研究结果如下：1、对木质素提取过程的影响因素进行分析,结果显示pH值对木质素提取得率的影响最明显,温度、加热时间和沉淀时间对木质素提取得率的影响较小,较适宜的酸化pH值、加热温度、加热时间、沉淀时间分别为3.0、50℃、45min和60min。2、对木质素改性的影响因素进分析,结果表明木质素和甲醛反应时,温度是影响木质素接枝率的最主要因素,反应时间和反应pH值是第二因素,甲醛投加量是第三因素,催化剂的投加量对接枝率的影响最小。在单因素实验得较适宜的反应温度、反应时间、反应pH值、甲醛投加量和催化剂投加量分别为100℃、180min、7.0、0.9mol和1.0g。3、对木质素改性物进行耐酸碱性实验,结果显示木质素改性物难溶于酸性溶液中,易溶于碱性溶液中。对改性前后的木质素进行电子显微镜分析,结果显示改性后的木质素表面出现更多的孔隙结构,经计算,木质素改性物的比表面积达到56.11 m2/g,比未改性前的24.50m2/g增加了31.61m2/g4、对改性前后的木质素进行红外光谱分析,比较改性前后的木质素红外光谱图可以发现,木质素改性物的0-H基团的吸收峰明显增宽,在1219 cm-1附近的C-0基团吸收峰基本消失。5、对影响木质素改性物吸附重金属离子的因素进行分析,结果显示吸附时间是影响木质素吸附过程首要因素,pH值是第二因素,而重金属初始浓度是第三因素,吸附温度对吸附过程的影响最小。对影响木质素改性物吸附的因素进行单因素分析,结果显示较适宜的吸附时间、pH值、吸附温度分别是120min、7.0和25℃。6、对改性前后的木质素吸附容量进行测定,结果显示改性后的木质素对重金属的吸附有明显的提高,其中对重金属Pb2+的吸附容量最大,可达55.47mg/g,对重金属Ni2+的吸附容量最小,只有25.14mg/g,而对Cu2+、Zn2+、Cd2+的吸附容量分别为35.41mg/g、30.35mg/g、40.37mg/g。7、对木质素改性物吸附的重金属进行解吸实验,结果表明当HCl浓度达到1.5mol/L时,重金属离子的解吸接近平衡。对木质素改性物进行连续四次的吸附—解吸重金属离子的实验,结果显示对五种重金属离子的第四次吸附量只比第一次的吸附量分别减少3.71mg、3.34mg、5.35mg、4.81mg、5.35mg,说明木质素改性物的连续使用稳定性比较高。同时,木质素改性物的解吸率也比较高,达到90%以上。更多还原

【Abstract】 Lignin was the by-product of papermaking industry. Because it had not be applicated effectively,it not only became one of pollution,but also wasted a lot of lignin resource.This thesis extracted lignin from black liquor by acid, then modificated it with formaldehyde,Finally, used it to adsorped heavy metal ions Cu2+,Ni2+、Zn2+、Pb2+ and Cd2+ for exploring the possibility to prepare heavy metal absorbent from lignin,the result showed that:1. Analysised influential factors on lignin extracted process,the result showed that pH is the most obvious influential factor on lignin obtained rate.The heating temperature and time, precipitation time were relatively less influential on it. The best acidification condition followed:the pH, heated temperature and time, precipitation time were respectively 3.0,50℃,45min and 60min.2. Analysised on influential factors on lignin modification, the result showed when lignin reacted with formaldehyde, temperature was the first important influential factor on lignin grafting, reaction time and pH was the second important influential factor, formaldehyde quantity was the third important influential factor, catalyst quantity had a little effect on lignin grafting rate. Through single factor which was effective on lignin grafted experiment,drawed out the best modification condition:the Heated temperature and time, pH, formaldehyde quantity and catalyst quantity were respectively 100℃,180min,7.0 and 1.0g.3. Research on the acid and alkaline resisting ability of lignin modification, the result showed that it was difficult to dissolve in acidic solution and easy to dissolve in alkalic solution.Compared between lignin and lignin modification by electron microscope scanning, the surface of lignin modification had more porous appearance. Based on caculated,surface area of modification was 56.11 m·g-1,31.61 m·g-1 bigger than the 24.50 m2·g-1 of unmodificated lignin.4. Compared between lignin and lignin modification on infrared spectrum found the speak of lignin’s O-H group broadened obviously and C-O group near 1219 cm-1 disappeared. 5. Analysised on the factors on which effected lignin modification adsorped heavy metal, the result showed adsorption time was the first influential factor on adsorption process, pH was the second factor, original concentration of heavy metal was third factor and adsorption temperature had little influential.Analysised on single factor which influenced adsorption of lignin modification, the result showed the best adsorption condition were respectively 120min,7.0,25℃.6. By determination the adsorption capacity of lignin and its modification conduction, discovered the adsorption capacity of modification conduct was obviously enh-anced.The adsorping capacity for Pb2+ was maximum and reached 55.47m2·g-1,the adsorping capacity for Ni2+ was minimum and only was 25.14m2·g-1,and the adsorping capacity for Cu2+、Zn2+、Cd2+ wre respectively 35.41 m2·g-1,30.35m2·g-1 and 40.37 m2·g-17. Accorded to the result of desorption experiment that adsorping heavy metal with lignin modification, the desorption of heavy metal approached equilibrium when HCl concentration was 1.5mol·L-1. on the continuous four experiment that lignin modification adsorped heavy metal, result showed that the fourth capacity of five heavy metals only decreased respectively 3.71mg,3.34mg,5.35mg、4.81mg,5.35mg.It showed that lignin modificatial conduct had high stability on utilization and the heavy metal desorption rate of lignin modification were high, much than 90%.更多还原