【作者】 高阳俊；

【导师】 奚旦立；

【作者基本信息】 东华大学 ， 环境工程， 2006， 博士

【摘要】 目前，全球的对苯二甲酸（TA）生产不能满足日益增长的消费需求，而海岛纤维开纤剥离废水中高浓度的TA和难降解的低聚物及各种助剂等使得海岛纤维开纤剥离废水成为纺织印染行业污染大、难处理的新型废水。本文主要研究从海岛纤维废水中回收TA资源，探讨不同的回收技术，将TA资源化利用，对各个工艺技术回收得到的TA品质等相关指标进行了探讨。得出主要的研究结论：从海岛纤维开纤剥离废水产生的过程中，研究了在不同的开纤剥离工艺情况下，纤维的失重率、废水中COD含量、TA含量的变化情况，为最佳的开纤剥离工艺找到废水中主要污染物的含量及其变化，研究认为水溶性聚酯和聚酯（COPET／PET）型海岛纤维开纤剥离工艺最佳条件为：温度为90℃、碱溶液浓度为3％、开纤时间30min，此时，纤维海成分已完全溶解，纤维的失重率为30～35％，岛成分清晰可见。开纤剥离废水中主要的污染物是TA钠盐和乙二醇（EG），废水水质和水量随开纤剥离工艺条件的变化而变化，大部分废水COD为25000mg／L，TA为18000mg／L，实验室模拟废水与工厂实际废水监测结果相符合。对开纤剥离废水进行酸析，酸析过程大致可分为三个阶段：酸析开始段、快速酸析段和酸析结束段。当pH＜3.47时，TA酸化趋于稳定，统一控制酸析pH为3。酸析过程中，随着温度的升高，沉淀比阻降低，随着加酸浓度升高，沉淀比阻增大，加酸速度太小，反应时间长，在加热搅拌过程中，溶剂水挥发很快，过长的反应时间，使溶剂损失太多，增加溶质过饱和度，产生大量微晶，适当增加搅拌强度，可以降低过饱和度，同时使大粒晶体摩擦、撞击而破碎。通过试验得出在温度为70℃左右，加酸速度在5～8ml／min，酸浓度为10～20％，搅拌速度为260～390r／min的条件下TA粒径大于45μm，容易沉淀过滤。酸析单因素对回收TA品质的影响趋势研究得出，温度升高，灰分减小，340mm透过率升高；回收TA的灰分、340nm透过率随酸浓度的升高而变差，当加酸浓度为10％时，灰分较低，340nm透过率较高；加酸速度在5ml／min时，TA在340nm处的透过率较低，灰分较高；当搅拌速度为390r／min时，回收的TA性能良好，此时回收的TA灰分为1000×10^-6，340nm透过率为86.7％。通过正交实验得出酸析最佳的控制条件是温度为70℃，酸浓度10％、加酸速度4ml／min和搅拌速度为390r／min回收得到的TA品质较好。活性炭对开纤剥离废水回收的TA有很好的吸附净化效果，对TA的吸附符合Langrnuir和Freundlich等温吸附方程。Langmuir等温吸附方程为：1／q=0.0037+0.7165／Ce，相关系数R²为0.9348；Freundlich等温吸附方程为q=4.67Ce^0.6167，相关系数R²为0.9308。活性炭用量对TA品质有重要的影响。对于高浓度废水来说，当活性炭用量过小时，除杂作用有限，用量过大，回收率低。为了既能充分发挥吸附净化的作用又不使TA损失过多，高浓度废水的活性炭用量最佳在6g／L左右，在适宜的炭量范围内，吸附振荡时间对净化的效果影响很大，必须在适当的时间后，杂质的去除才能饱和，高浓度废水的最佳振荡时间在60min。废水水质改变时，活性炭的用量和吸附时间对回收TA的品质有同样的影响趋势。对于自制废水，由于COD、TA浓度低、含杂量较少，最佳的使用炭量、振荡时间为4g／L和30min。工厂废水最佳的活性炭用量、振荡时间为6g／L和90min。采用由最佳酸析工艺和活性炭吸附工艺相联合的处理工艺后，可以明显改善回收TA的质量，但仅通过一种净化方法，回收的TA还会残留一些杂质，不能达到实际使用的要求，通过采用联合处理过程，将各种净化方法相结合处理后回收的TA的质量大幅提高，其中，TA灰分含量比直接酸析、优化酸析和活性炭吸附分别提高了64％，52％和43％，340nm处的透过率分别提高了25％，24％和23％，总酸含量可达到97％，酸值达到670.5mg KOH／g，部分指标甚至已达到了工业TA的标准。从废弃资源再利用的角度，分不同用途要求，研究回收再利用的TA指标，主要提出了TA的外观、纯度、总酸含量、酸值、灰分、色泽和光密度等指标，为TA资源化提供一些参考。从环境、经济和社会三个方面分析了从海岛纤维废水中回收TA的效益，研究指出回收TA符合循环经济和可持续发展的方针。更多还原

【Abstract】 The island-sea fabric alkali hydrolysis process wastewater is a kind of the populartextile industrial wastewater in China due to its high concentration of terephthalie acid （TA）and the poorly biodegradable polyester oligomer and chemical promoters. And nowadays, theglobal TA production can not be satisfied with the industrial needs, The recovery of TA fromisland-sea fabric alkali-hydrolysis process wastewater, as well as different recoverytechnologies and TA reuse criterion factors were investigated in this article. The results wereshowed in the following.Basing on wastewater from the island-sea fabric alkali-hydrolysis process, fiberweightlessness rate, COD concentration, TA concentration and other pollutants wereinvestigated. The optimal hydrolysis process condition was temperature 90^C, alkali solutionconcentration 3 percent, hydrolysis time 30min. In the condition, the sea component has beendissolved completely. The fiber weightlessness rater was from 30 to 35 percent. Islandcomponent can be seen dearly. The main pollutants in wastewater were TA and ethyleneglycol （EG）. The quality and quantity of wastewater changed with different hydrolysiscondition. COD and TA concentration in most amount wastewater was 25000 mg/L and18000 mg/L. The lab experiment results were same with the factory monitoring.The wastewater from island-sea fabric alkali-hydrolysis process was acidified withsulfuric acid. The acidification process included three progress which were starting progress,quick acidification progress and ending progress. TA concentration was stable when pH wasno more than 3.47, so the acidification pH was controlled to 3. During the acidification, thedeposition risistance decreased with temperature increase and improved with the sulfuric acid concentration. The adding velocity was slowly, the more time was needed to acidify. Duringthe stirring progress, solvent will volatilize. The more time will reduce the solvent. Thedegree of supersaturation will increase with the acidification time. The smaller particle willbe produced. The optimal condition was temperature 70^C, adding sulfuric acid velocity wasfrom 5 to 8ml per minute, sulfuric acid concentration was from 10 to 20 percent, the stirringvelocity was from 260 to 390 r per minute. In this condition, TA particle diameter could bemore than 45urn and it was easy to be deposited.Basing on the effect of single acidification factor on the characters of TA, the researchwas showed in the following. The TA ash content decreased with the temperatureimprovement and increased with the sulfuric acid concentration. The 34Ohm transmittanceincreased with temperature improvement and decreased with the sulfuric acid concentration.When sulfuric acid concentration was 10 percent, the TA ash content was small, TA 340nmtransmittance was high. When sulfuric acid velocity was 5ml/min, the TA ash content washigh and 340nm transmittance was small. When stirring velocity was 390r/min, the ashcontent was good. The value of ash content was 1000×10^-6, value of 340nm transmittancewas 86.7%. The optimal acidification condition was temperature 70℃, adding sulfuric acidvelocity was 4ml/min, sulfuric acid concentration was 10 percent, the stirring velocity wasfrom 260 to 390 r per minute. In this condition, TA characters were good.Active carbon was good to adsorb TA in wastewater from island-sea fabricalkali-hydrolysis process. The adsorption could be characterized by Langmuir wasothermand Freundlieh wasotherm. The equations were showed in the following. Langmuir,1/q=0.0037+0.7165/Ce, correlation coefficient was 0.9348, Freundlich q=4.67Ce^<sup>0.6167,correlation coefficient was 0.9308. The active carbon amount had much effect on TAcharacters. To high concentration wastewater, when active carbon amount was small, theeffect on decrease impurities was small, and when the amount was too high, the recovery rateof TA was too small. In order to make the effect maximization, the amount of active carbonwas from 3 to 5 g per liter. During the optimal active carbon amount, the adsorption time alsohad effect on the TA characters. Only in the optimal adsorption time, the impurities could bepurified. The optimal adsorption time was 60 minute. When wastewater quality changed, theamount of active carbon and the adsorption time had the same effect on the TA characters. When the COD and TA concentration was less than 15000 mg per liter and 8000 mg per liter,the amount of active carbon and the adsorption time were 3g per liter and 30min.When theCOD and TA coneentration was more than 15000 mg per liter and 8000 mg per liter, theamount of active carbon and the adsorption time were 5.5 g per liter and 90min.When wastewater from island-sea fabric alkali-hydrolysis process was treated with thecombined technology by optimal acidification technology and active carbon adsorption, TAcharacters were improved. But treated by a single technology, TA character can not besatisfied the actual use criterion. The impurities stored in the sample. Used by the combinedtechnology, comparing with the directed acidification technology, optimal acidificationtechnology and active carbon adsorption, the TA ash content was increased 64, 52 and 43percent, the 340nm transmittance was improved 25, 24 and 23 percent. The total acidcontent reached to 97%, the acid value reach to 670.2 nag KOH/g. Some factor had beenreached the fiber grade.Basing on the recovery waste material and reuse, from different use criterion, the TAreuse factors were brought out. The main factors were appearance, purity, total acid content,the acid value, colour and 340nm transmittance. This will give some information to TArecovery and reuse.Environmental benefit, economic benefit and social benefit were discussed in theresearch. TA recovery and reuse were satisfied with the circular economy and sustainabledevelopment stratagem.更多还原