从超纤碱减量废水中回收对苯二甲酸并制备DOTP低毒增塑剂

Preparation of Low-Toxic DOTP Plasticizer by Using Terephthalic Acid Recovered from Microfibers Alkali Weight-Reduction Wastewater

摘要: 定岛超细纤维在碱减量过程中会产生大量含对苯二甲酸盐的废水，直接排放不仅会给环境带来严重负担，同时会造成对苯二甲酸资源浪费。鉴于此，本论文采用抽滤、混凝、吸附三步法去除定岛超细纤维碱减量废水中杂质，再通过酸析将废水中对苯二甲酸盐沉淀析出，最后探索以回收对苯二甲酸为原料制备对苯二甲酸二(2-乙基己基)酯(DOTP)低毒增塑剂的可行性。结果表明，采用上述技术路线能有效去除定岛超细纤维碱减量废水中纤维碎屑、胶体微粒及重金属等杂质，回收的对苯二甲酸纯度超过99%，所制备DOTP满足聚氯乙烯增塑剂行业标准。本论文实验结果为定岛超细纤维碱减量废水处理及资源化利用提供了借鉴与参考。

Abstract: Huge quantities of waste water containing terephthalic acid were generated during the alkali weight-reduction process of microfiber production, which not only causes a serious burden on the environment, but also leads to a tremendous waste of terephthalic acid if directly discharged. Herein, a three-step process, including filtration, coagulation, and adsorption, is employed to remove impurities in microfibers alkali weight-reduction wastewater, followed by exploring the feasibility of synthesizing bis-(2-ethylhexyl) terephthalate (DOTP) plasticizer by using terephthalic acid recovered from the wastewater via acidification. The results demonstrate that impurities such as fiber debris, colloidal particles and heavy metals can be effectively removed from the microfibers alkali weight-reduction wastewater by using the above three-step process, and the recovered terephthalic acid has high purity, while the synthesized DOTP meets the industry standard for PVC plasticizers. The present effort may provide guidance for the treatment and resource utilization of microfibers alkali weight-reduction wastewater.