| 摘要 | 巯基纤维素作为一种改性纤维素，是良好的固体吸附剂。本论文从巯基纤维素的制备、材料性能、吸附性能、解吸再生性能、吸附机理，到应用于处理甲基汞废水、废气及重金属工业废水进行了系列的研究和探索。
巯基纤维素制备方法：棉花先经过冰醋酸润胀，然后按15g棉花－100mL巯基乙酸－浓硫酸1.0mL的比例，在40℃条件下，反应48小时。制备的巯基纤维素色泽洁白、机械强度较好，碘量法测定巯基含量在1.70%左右。
巯基纤维素化学性质稳定。溶液酸度和温度对巯基纤维素的水解影响很小，日常太阳光照射和大气中的氧气对巯基纤维素的影响也甚微。但巯基纤维素对强氧化剂的稳定性较差，因此巯基纤维素应避免与强氧化剂的直接接触，否则将严重影响其吸附性能。
巯基纤维素对CH3Hg+、Hg2+、Cu2+、Pb2+、Cd2+和Zn2+均具有较好的吸附性能，其吸附饱和容量分别为：55～65、30～35、6～8、24～30、14～20、8～10（mg/g）。吸附性能与pH值之间的关系密切，其对上述离子定量吸附酸度范围分别为：pH2.0~8、2.5mol/L~pH8、pH2.5~8、pH4.5~8、pH5.0~8、pH5.5~8。
巯基纤维素所吸附的上述离子能用一定酸度的盐酸洗脱下来，实现巯基纤维素的再生。洗脱上述离子的盐酸最低酸度（mol/L）分别为：2.00、NaCl饱和的5mol/L HCl、2.00、0.03、0.02、0.01。研究表明巯基纤维素有很强的再生能力，对于再生10次左右的巯基纤维素对上述离子的吸附能力依然在98%以上。
巯基纤维素用于处理含甲基汞废水、废气的工艺流程及工艺条件等。工艺路线为：先用巯基纤维素吸附甲基汞废水或废气，然后用氯化钠饱和的5mol/L盐酸溶液洗脱甲基汞，经紫外光照射迅速分解后，再经铜屑还原，回收金属汞。实验结果表明该工艺对甲基汞的去除率高、操作简单，并且无二次污染。适宜对含大量甲基汞的废水、废气进行深度处理。
研究了巯基纤维素用于处理重金属工业废水的工艺流程及工艺条件等。工艺路线为：前期使用化学沉淀法，去除部分重金属离子；后期调节pH6.0～8.0，然后用巯基纤维素对废水中重金属离子进行吸附。实验结果表明该工艺具有去除率高、操作简单、投资成本低、管理方便等诸多优点。与其它传统工艺相比，优势明显。
总的来说，巯基纤维素对水溶液和大气中的许多离子具有良好的吸附性能。通过对巯基纤维素进行的系列研究表明，巯基纤维素化学性质稳定，不仅仅适用于环境分析检测领域，还适用于对含甲基汞、重金属的废水或废气进行深度处理。巯基纤维素应用前景广阔，我们可以预测随着对巯基改性纤维素的进一步研究，巯基纤维素将在今后的环境检测、物质分析、环境治理等多个行业发挥更为重要的作用。 |
| Abstract | Sulphydryl cellulose fiber (SCF) as a kind of modified cellulose is a kind of excellent solid adsorbent.This thesis systemically expounds its preparation, material properties, adsorption properties, regeneration properties and adsorption mechanism, as well as its applications in the treatment of waste water or gas containing CH3Hg+ and industrial wastewater containing heavy metals.
Preparation method of sulphydryl cellulose: 100mL thioglycolic acid (SHCH2COOH) and 1.0mL concentrated sulfuric acid (H2SO4) react with 15g cotton expanded by ice acetic acid for 48h at the temperature of 40℃. SCF preparated in above method has pure luster and good mechanism strength. The content of sulphydryl group determined by iodimetry is about 1.7%.
SCF has stably chemical properties. The aqua acidity and temperature have little effect on its hydrolyzation extent. The ultraviolet in the sunshine and oxygen in the atmosphere have little effect on its sulphydryl content, too. But SCF has bad stability in the situation strong oxidant exits. So SCF should be avoided touching with those strong oxidants directly, otherwise its adsorption capacity will be terribly worssened.
SCF has excellent adsorption capacity on CH3Hg+, Hg2+, Cu2+, Pb2+, Cd2+ and Zn2+. The saturated adsorption capacity on these ions is respectively 55~65, 30~35, 6~8, 24~30, 14~20, 8~10(mg/g). The adsorption capacity is closely related with the aqua’s pH value. The pH range for quantitative adsorption is respectively pH2.0~8, 2.5mol/L~pH8, pH2.5~8, pH4.5~8, pH5.0~8, pH5.5~8.
The ions adsorbed by SCF can be desorbed by HCl with certain acidity. In this way SCF can be regenerated. The lowest hydrochloric acid acidity (mol/L) for desorption on above ions is respectively 2.00, 5mol/L HCl saturated by NaCl, 2.00, 0.03, 0.02, 0.01. The research result shows that SCF has strong regeneration ability. The adsorption ratio of SCF regenerated about 10 times on these ions is still above 98%.
The process and condition of waste water or gas containing CH3Hg+ treatment with SCF have been probed. The process is as followed: Firstly CH3Hg+ in the waste water or gas is adsorbed with SCF. Secondly it is desorbed with 5mol/L HCl saturated by NaCl. Thirdly CH3Hg+ is disassembled by ultraviolet. At last Hg2+ in the aqua is deoxidized to metal Hg by copper scraps. And then metal Hg can be reclaimed. Experimental result expresses that the process possesses many advantages such as high removal efficiency on CH3Hg+, simple operation method, no secondary pollution. The process is adepted to deeply treat waste water or gas containing quantities of CH3Hg+.
The process and condition of treating industrial wastewater containing heavy metals with SCF have been probed. The process is as followed: In prophase chemical deposition method is used to remove heavy metals partly. In anaphase the rest of heavy metals are adsorbed with SCF effectively in the situation pH value is between 6.0 and 8.0. Experiment result expresses that the process possesses many advantages such as high removal efficiency on heavy metal ions, simple operation, low cost, easy administration, etc. Compared with other traditional processes, the process has obvious advantages.
Taking one with another, SCF has excellent adsorption capacity on plenty of ions in aqua and gas.The researches on SCF in series show that SCF has stably chemical properties. It is adapt to be used not only in environmental analysis and determination realm, but also in the deep treatment of waste water or gas containing CH3Hg+ or heavy metals. SCF has bright application foreground. We can predict that with further researches going on, SCF will play more important role in environmental determination, material analysis and environmental treatment, etc. |
