电镀含铬废水资源化治理及新型螯合纤维制备研究

发布时间：2018-05-12 05:10

本文选题：离子交换纤维 + 聚丙烯纤维　；参考：《郑州大学》2015年博士论文

【摘要】：随着全球工业化进程快速发展,重金属水污染对人类的健康及环境造成严重威胁。其中,六价铬是一种具有高度致癌性和氧化性的重金属离子,铬污染已成为世界各国普遍关注的环境问题。目前工业中对六价铬废水的处理方法主要是将六价铬还原为低毒三价铬,然后以Cr(OH)3沉淀形式除去。此法产生的固体沉淀容易形成新的污染,并且不能实现铬离子的资源回收。因此,针对六价铬废水的处理开发一种操作简单、成本经济的资源化治理工艺具有良好的应用价值。离子交换纤维(IEF)是继离子交换树脂之后出现的一种新型吸附分离材料,其活性位点包括酸性、碱性以及螯合等化学官能团。其中,螯合纤维可以利用结构中含孤对电子的原子(N、O、P、S等)与金属离子形成配位键,构成与小分子螯合物类似的稳定结构,具有良好的吸附选择性。近年来,螯合纤维在深度净化有害物质、痕量元素分离以及有害气体防护等领域取得了广泛的应用。本文围绕离子交换纤维资源化治理电镀含铬废水以及新型螯合纤维制备的研究,主要工作内容如下:(1)以聚丙烯腈基多胺(PAN-TETA)离子交换纤维为基体,考察了PAN-TETA多胺纤维静态吸附六价铬性能。系统研究了纤维型式、六价铬浓度、溶液p H等因素对纤维吸附六价铬性能的影响,采用SEM-EDS等手段分析纤维吸附六价铬的过程中特征元素(C、N、O、Cr)的含量及分布情况。结果表明,Cl-型PAN-TETA纤维对六价铬的吸附量及再生性能均优于OH-型纤维,且溶液p H为2~3有利于纤维吸附六价铬。PAN-TETA纤维对六价铬的吸附量最高可达425.1mg/g,吸附过程符合准二级动力学模型(R20.999)。通过表面及断面SEM-EDS分析,PAN-TETA纤维表面及内部的胺基均参与了对六价铬吸附,且六价铬分布均匀。PAN-TETA纤维经100次静态循环吸附工业含铬废水,铬离子去除率可达91.0%以上,保持良好的吸附再生性能。(2)在静态吸附实验研究的基础上,考察了多胺纤维柱吸附六价铬性能。PAN-TETA纤维对六价铬的穿透吸附量及饱和吸附量最高分别可达291.2mg/g、426.3mg/g,并且柱吸附过程Thomas模型(R20.9)。硫酸根的存在对PAN-TETA纤维吸附六价铬造成一定的影响,但随着吸附时间的延长,纤维上部分的硫酸根可以被溶液中的六价铬取代,最终达到吸附平衡。氢氧化钠溶液可快速、有效的洗脱PAN-TETA纤维中的六价铬,洗脱过程前半段流出液基本呈中性,OH-得到充分利用;后半段流出液呈碱性,含大量可被循环利用的OH-。PAN-TETA纤维经80次再生吸附混合含铬废水,其饱和吸附量为230.1mg/g~180.9mg/g,性能较为稳定。PAN-TETA纤维经5次循环吸附镀铬漂洗废水,饱和吸附量可达320mg/g以上,并且纤维循环使用过程中对六价铬的处理能力无明显降低。由此可见,该材料可满足于循环治理含铬废水,尤其适合处理镀铬漂洗废水。(3)在以上研究工作的基础上,设计一种多柱串联吸附-分步洗脱的工艺对镀铬漂洗废水进行处理。PAN-TETA纤维经5次再生吸附镀铬漂洗废水,其饱和吸附量基本在228.4mg/g~324.6mg/g范围内波动。延长吸附时间对PAN-TETA纤维中Cr6+、SO42-、Cl-的离子分布有重要影响,可以使纤维中六价铬的离子纯度得到明显提高。经该工艺洗脱、回收的六价铬浓度可达30g/L以上,并且可以回用于电镀行业。(4)以聚丙烯接枝苯乙烯(PP-St)纤维为骨架,经混酸硝化、氯化亚锡还原制得PP-St-NH2功能纤维。硝化反应过程中,混酸比例VH2SO4/VHNO3对硝化增重率的影响最大,反应时间t次之,混酸体积Vmixed acid影响最小,苯环上单硝基取代的转化率接近100%。还原反应过程中,胺基交换容量最高为5.78mmol/g,硝基还原率可达92%以上。制备得到的PP-St-NH2纤维在300℃以下没有发生分解,具有良好的热稳定性。(5)以PP-St-NH2功能纤维为基体,分别与氯乙酸钠、亚磷酸、水杨醛反应,得到3种螯合纤维PP-St-IDA、PP-St-PAA、PP-St-SCB,初步考察这三种螯合纤维对Ni2+的选择性吸附性能。PP-St-NH维分别成功引入亚胺二乙酸、氨基膦酸以及席夫碱螯合结构,氨基转化率可达90%以上。PP-St-IDA、PP-St-PAA、PP-St-SCB螯合纤维对镍离子的静态吸附量最高分别为102.6mg/g、51.6mg/g以及44.1mg/g。在镍离子与钙离子共存体系中,PP-St-IDA、PP-St-PAA、PP-St-SCB纤维对镍离子的吸附选择性为PP-St-IDAPP-St-PAA≈PP-St-SCB。通过对比实验,PP-St-IDA纤维对镍离子的吸附量及选择性明显优于传统的PAN-COONa纤维,该纤维可望有效用于含镍废水处理及回收。
[Abstract]:With the rapid development of the global industrialization process, heavy metal water pollution poses a serious threat to human health and environment. Among them, six valence chromium is a heavy metal ion with high carcinogenicity and oxidation, and chromium pollution has become a widespread environmental problem in the world. At present, the treatment methods of six valent chromium waste water are mainly to be treated in the industry. Six valence chromium is reduced to low toxic trivalent chromium, and then removed in the form of Cr (OH) 3 precipitation. The solid precipitation produced by this method is easy to form new pollution and can not recover the resource of chromium ion. Therefore, a simple operation, cost economical treatment process for the treatment of six valent chromium wastewater is of good application value. Fiber (IEF) is a new type of adsorptive separation material after ion-exchange resin. Its active sites include acidic, alkaline and chelating chemical functional groups. In this, chelating fibers can form coordination bonds with metal ions in the structure of atoms containing isolated electrons (N, O, P, S, etc.) in the structure to form a similar stability to small molecule chelates. In recent years, chelating fibers have been widely used in the fields of deep purification of harmful substances, separation of trace elements and the protection of harmful gases. In this paper, the research on the treatment of electroplated chromium containing wastewater and the preparation of new chelating fiber by ion exchange fiber resources is studied in this paper. The main contents are as follows: (1) The polyacrylonitrile base polyamine (PAN-TETA) ion exchange fiber was used as the matrix to investigate the static adsorption properties of PAN-TETA polyamine fibers for six valent chromium. The effects of fiber type, six valence chromium concentration, P H on the adsorption of six valence chromium on the fiber were systematically studied. SEM-EDS and other means were used to analyze the characteristic elements (C, N, O, C) in the process of adsorption of six valence chromium. The content and distribution of R) showed that the adsorption capacity and regeneration performance of Cl- PAN-TETA fiber for six valence chromium were better than that of OH- fiber, and P H of the solution was 2~3 beneficial to the adsorption of six valence chromium on the adsorption of six valence chromium.PAN-TETA fiber, and the adsorption process conforming to the quasi two class kinetics model (R20.999). Cross section SEM-EDS analysis, the surface of PAN-TETA fiber and the internal amine group are all involved in the adsorption of six valence chromium, and the distribution of six valence chromium is evenly distributed by.PAN-TETA fiber through 100 static cycles to adsorb industrial chromium containing wastewater. The removal rate of chromium ion can reach more than 91%. (2) on the basis of the static adsorption experimental study, a lot of investigation has been made. The absorption of six valence chromium by an amine fiber column, the maximum penetration and saturation adsorption of six valence chromium.PAN-TETA fibers can reach 291.2mg/g, 426.3mg/g, and Thomas model of column adsorption (R20.9). The existence of sulphate root causes a certain effect on the adsorption of six valence chromium on the PAN-TETA fiber, but with the prolongation of the adsorption time, the sulfur on the fiber part of the fiber. The acid root can be replaced by six valence chromium in the solution and finally reach the adsorption equilibrium. Sodium hydroxide solution can quickly and effectively elute six valence chromium in PAN-TETA fiber. The effluent of the first half of the elution process is basically neutral and OH- is fully utilized; the latter half of the effluent is alkaline, and the OH-.PAN-TETA fiber containing a large amount can be recycled for 80 times. The adsorbed mixed chromium containing wastewater has a saturated adsorption capacity of 230.1mg/g~180.9mg/g, and the performance is more stable. The performance of the wastewater is more stable than that of.PAN-TETA. The adsorption capacity of the wastewater is more than 320mg/g by 5 cycles, and the treatment capacity of the six valence chromium in the process of fiber recycling is not obviously reduced. Thus, this material can be satisfied with the recycling treatment. Chromium wastewater, especially suitable for treatment of chromium plating wastewater. (3) on the basis of the above research work, a multi column series adsorption and stepwise elution process was designed for the treatment of chromium plating wastewater. The.PAN-TETA fiber was treated with 5 regenerated adsorption chromium plating wastewater. The saturated adsorption capacity of the wastewater was fluctuated in the range of 228.4mg/g~324.6mg/g. The ion distribution of Cr6+, SO42-, Cl- in PAN-TETA fiber has an important influence on the ion purity of the six valence chromium in the fiber. After the elution process, the concentration of six valence chromium can be above 30g/L and can be reused in the electroplating industry. (4) polypropylene graft styrene (PP-St) fiber as the skeleton, nitrification and chlorination through mixed acid. In the process of nitrification, the effect of the mixed acid ratio VH2SO4/VHNO3 on the nitrification increase rate is the most, the reaction time is t, the mixed acid volume Vmixed acid has the smallest effect. The conversion rate of the mono nitro substitution on the benzene ring is close to the 100%. reduction reaction, and the highest amino exchange capacity is 5.78mmol/g, and the reduction rate of the nitro group is. Up to 92%. The prepared PP-St-NH2 fibers were not decomposed below 300 C and had good thermal stability. (5) PP-St-NH2 functional fibers were used as matrix, respectively, with sodium chloroacetate, phosphoric acid and salicylaldehyde, and 3 kinds of chelating fibers, PP-St-IDA, PP-St-PAA, PP-St-SCB, were obtained, and the selectivity of these three chelate fibers to Ni2+ was preliminarily investigated. The adsorption properties of.PP-St-NH dimension were successfully introduced to imide two acetic acid, amino phosphonic acid and Schiff base chelating structure. The amino conversion rate could reach more than 90%.PP-St-IDA. The highest static adsorption capacity of PP-St-PAA and PP-St-SCB chelating fibers for nickel ions was 102.6mg/g, 51.6mg/g and 44.1mg /g. in the coexistence system of nickel ions and calcium ions, PP-St-IDA, P. P-St-PAA, the adsorption selectivity of PP-St-SCB fiber to nickel ion is PP-St-IDAPP-St-PAA PP-St-SCB. through comparison experiment. The adsorption quantity and selectivity of PP-St-IDA fiber to nickel ion is obviously superior to that of the traditional PAN-COONa fiber. The fiber is expected to be effectively used in the treatment and recovery of nickel containing wastewater.

【学位授予单位】：郑州大学
【学位级别】：博士
【学位授予年份】：2015
【分类号】：X781.1

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