醇热法处理电子废弃物高分子材料中阻燃剂的研究
文献类型：学位论文
| 作者 | 张聪聪 |
| 学位类别 | 博士后 |
| 答辩日期 | 2014-05 |
| 授予单位 | 中国科学院研究生院 |
| 授予地点 | 北京 |
| 导师 | 陈卫平，张付申 |
| 关键词 | 醇热 电子废弃物 高分子材料 阻燃剂 化学回收 脱溴 Alcohol thermal treatment E-waste Polymeric materials Flame retardants Chemical recycling Debromination |
| 其他题名 | Disposal of flame retardants in polymeric materials from electronic waste under alcohol thermal condition |
| 学位专业 | 生态学 |
| 中文摘要 | 阻燃剂的无害化处理一直是制约电子废弃物中高分子材料和有价资源回收的主要瓶颈，开发高效安全的阻燃剂处理技术对于电子废弃物回收过程中的污染控制具有重要意义。本研究以电子电器设备塑料外壳中添加型四溴双酚A（TBBPA）、印刷线路板（PCBs）中添加型磷酸三苯酯（TPPO）和PCBs中反应型溴化环氧树脂（BERs）为研究目标，开展了醇热法处理电子废弃物高分子材料中阻燃剂的系统研究，并定向调控优化工艺参数，实现电子废弃物中高分子材料和有价资源的回收，为规模化循环利用电子废弃物中的高分子材料提供理论基础和技术支撑。 采用醇热法处理电子废弃物高分子材料中添加型阻燃剂，重点探讨了醇热法对电子电器设备塑料外壳中TBBPA和PCBs中TPPO的提取回收效果，同时评估了电子电器设备塑料外壳和PCBs有价资源回收利用的可行性。结果表明：含有TBBPA的电子电器产品塑料外壳经过醇热处理后，TBBPA转移至液相之中，经旋转蒸发后，可得到淡黄色的TBBPA，与纯品TBBPA结构基本保持一致，回收率达到78.9%。含有添加型TPPO的废弃PCBs经过醇热处理后，TPPO转移至液相之中，经旋转蒸发后，所得TPPO与纯品TPPO结构基本保持一致，回收率达到84.4%。PCBs脱磷率达到97.3%，同时保留了无机金属组分，实现有价资源的绿色分离回收。 采用碱-醇热法处理含BERs的PCBs，重点探讨了碱-醇热处理对PCBs中BERs的催化降解过程，同时评估了PCBs中金属和玻璃纤维分离回收的可行性，结果表明：处理温度、时间及NaOH添加量是影响BERs脱溴率和产物中溴分布的主要影响因素，当处理温度、时间、PCBs与NaOH比值分别为180 ℃，10 h和1.0 g：0.3 g时，BERs的脱溴率高达98.3%。对降解过程的解析发现，BERs首先发生解聚，由于溴化苯环上相对薄弱的醚键，一部分生成TBBPA，TBBPA通过逐步脱溴最终生成双酚A，双酚A和无机溴是主要脱溴产物。PCBs中BERs在碱-醇热体系中降解后，产物按照形态划分，可分为：油相和固体残渣。油相主要为聚乙二醇及BERs降解产物，固体残渣包括金属组分（主要是铜）和非金属组分（玻璃纤维）。固体残渣粉末可通过水选分离，水选分离后铜在金属组分中的含量为97.8%，回收率为86.8%。条状PCBs经碱-醇热处理后，线路板中作为粘结剂的BERs被降解，线路板中金属铜箔层和非金属玻璃纤维层可自动分离，铜箔纯度为96.5%，回收率为97.8%。因此，采用碱-醇热法处理含BERs的PCBs能够有效的实现BERs无害化，同时回收有价金属组分和玻璃纤维。 |
| 英文摘要 | The treatment and disposal of flame retardants contained in polymeric materials of electronic waste (E-waste) has received worldwide concerns, which restricts the ecovery of polymeric materials and valuable resources. Development of novel safe and efficient treatment technologies for flame retardants is of great significance for pollution control in the course of recycling E-waste. Taking additive tetrabromobisphenol A (TBBPA) in computer housing plastic, additive triphenyl phosphate (TPPO) and reactive brominated epoxy resins (BERs) in printed circuit boards (PCBs) as the study subject, this study conduct the disposal of of flame retardants in polymeric materials from E-waste under alcohol thermal condition and optimize the system parameters of alcohol thermal processes to ensure the recovery efficiency of polymeric materials and valuable resources, which will lay the scientific foundation and provide powerful technical support for large scale resource recovery of polymeric materials from E-waste. As for additive flame retardants contained in polymeric materials of E-waste,TBBPA from computer housing plastic and TPPO contained in PCBs were tentatively subjected to alcohol thermal treatment in order for efficient recycling of additive flame retardants and recovery of valuable resources contained in computer housing plastic and PCBs. Experimental results demonstrated that TBBPA was transferred to solvent phase after alcohol thermal treatment. When the solvent phases were evaporated to dryness, the structure of the recycled TBBPA was in good agreement with TBBPA standard material and the recovery efficiency reached 78.9%. Moreover, TPPO was transferred into the solvents after alcohol thermal treatment and solid TPPO powder was easily recovered through vacuum rotary evaporation. The recovery efficiency of TPPO reached 84.4%. Dephosphorization efficiency of waste PCBs reached 97.3% and the inorganic metal components were remained, which could be separated for recovery of valuable resources. Typical BERs contained in PCBs were tentatively subjected to alkali-alcohol thermal treatment using poly(ethylene glycol) (PEG200)/sodium hydroxide (NaOH)catalytic system in order to detoxify BERs and obtain bromine-free resources. The variation of debromination efficiency and bromine distribution of BERs degradation products with temperature, time and PCBs /NaOH ratio were studied. It was found that BERs were quickly degraded under alkali-alcohol thermal condition and the debromination efficiency of BERs reached 98.3% by controlling the temperature, time and PCBs/NaOH ratio at 180 ℃, 10 h and 1.0 g: 0.3 g, respectively. BERs were quickly depolymerized and the degradation process started from the formation of TBBPA due to the break of relative weak ether bond on the brominated benzene ring.TBBPA might be transformed into tribromobisphenol A, dibromobisphenol, monobromobisphenol A and finally bisphenol A and inorganic bromine are main debromination products. According to morphology of the products, the degradation products of PCBs could be divided as oil phase and solid residue. Oil phase was mainly composed of PEG200 and BERs degradation products, while solid residue was composed of metal (mainly copper) and nonmetallic components (glass fibres). Solid residue powder could be easily separated by gravity separation and the recovered metallic component contained 97.8% of copper with the recovery efficiency of 86.8%. As for PCBs bulk after alkali-alcohol thermal treatment, the bonding agent of BERs were degraded. The copper foil layer and glass fiber layer were separated automatically. The recovery efficiency of copper component in the copper foil reached 97.8% in a purity of 96.5%. Alkali-alcohol thermal treatment provides a clean and applicable process for degradation of BERs and simultaneous recovery of high value metal components and glass fibers. |
| 公开日期 | 2015-06-16 |
| 源URL | [http://ir.rcees.ac.cn/handle/311016/13488]  |
| 专题 | 生态环境研究中心_城市与区域生态国家重点实验室 |
| 推荐引用方式 GB/T 7714 | 张聪聪. 醇热法处理电子废弃物高分子材料中阻燃剂的研究[D]. 北京. 中国科学院研究生院. 2014. |
入库方式： OAI收割
来源：生态环境研究中心
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