化工进展 ›› 2018, Vol. 37 ›› Issue (12): 4939-4947.DOI: 10.16085/j.issn.1000-6613.2018-0655

• 资源与环境化工 • 上一篇    下一篇

不同pH下涂装废水中沉淀物形成的计算模拟预测及验证

付海娟1, 池勇志1, 赵建海1, 曹凌云1, 田秉晖2, 费学宁1, 付翠莲1,3   

  1. 1 天津城建大学环境与市政工程学院, 天津市水质科学与技术重点实验室, 天津 300384;
    2 中国科学院生态环境研究中心环境水质学国家重点实验室, 北京 100085;
    3 天津城建大学建筑设计研究院, 天津 300384
  • 收稿日期:2018-03-30 修回日期:2018-05-08 出版日期:2018-12-05 发布日期:2018-12-05
  • 通讯作者: 付翠莲,高级工程师,废水处理研究与设计。
  • 作者简介:付海娟(1992-),女,硕士研究生,研究方向为水处理。E-mail:hjf2378@163.com。
  • 基金资助:
    天津市科技计划(16YFXTSF00390)及国家水体污染控制与治理科技重大专项(2017ZX07107)项目。

Prediction and verification of precipitate formation in the coating wastewater under different pH

FU Haijuan1, CHI Yongzhi1, ZHAO Jianhai1, CAO Lingyun1, TIAN Binghui2, FEI Xuening1, FU Cuilian1,3   

  1. 1 Tianjin Key Laboratory of Water Quality Science and Technology, School of Environmental and Municipal Engineering, Tianjin Chengjian University, Tianjin 300384, China;
    2 State Key Laboratory of Environmental Aquatic Chemistry, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China;
    3 Architectural Design and Research Institute of Tianjin Chengjian University, Tianjin 300384, China
  • Received:2018-03-30 Revised:2018-05-08 Online:2018-12-05 Published:2018-12-05

摘要: 采用中和沉淀法处理涂装废水,在不同pH(4~12)下研究了涂装废水中总磷、硫酸根等阴离子和总铁、总铅、总铬等主要的阳离子去除效果,并利用修正后的热力学方程Gibbs函数△G=RTln(Qc/K°sp)对pH调节过程中沉淀形成机制进行讨论。结果表明,pH=2.18~10时离子强度I在0.10mol/L左右,pH=12时离子强度I为0.59mol/L;考虑离子强度I影响时沉淀产物的活度积K°sp与溶度积Ksp相比最大,可相差15个数量级,对于涂装废水沉淀产物生成预测时应采用活度积K°sp进行判定;pH对弱酸弱碱各型体的存在浓度影响很大,pH=4~8时形成的沉淀产物主要为磷酸盐,pH=10~12时氢氧化物沉淀种类增加,pH=12时形成的沉淀产物种类最多。

关键词: 涂装废水, 热力学模型, 沉淀形成, 模拟预测

Abstract: The coating wastewater was treated by neutralization and precipitation. Removal effect of negative ions such as total phosphorus, sulfate radical and positive ions such as total iron, total lead and total chromium in the coating wastewater was studied under different pH (4-12). The mechanism of precipitation formation during the process of pH adjustment was discussed by using the modified Gibbs function of thermodynamic equation △G=RTln(Qc/K°sp). The results showed that when pH value was 2.18-10, the ionic strength (I) was around 0.10mol/L. When pH was 12, the ionic strength (I) was 0.59mol/L. When considering the influence of ionic strength I, the active equilibrium constant K°sp can be up to 15 orders of magnitude compared with that of the solubility product Ksp. The Gibbis function calculation should be performed by the active equilibrium constant K°sp. pH had a great influence on the concentration of various forms of existence of weak acid and alkali. When pH=4-8, the precipitates formed were mainly phosphate. When pH=10-12, the types of hydroxide precipitate increased. At pH=12, the precipitates were the most abundant.

Key words: the coating wastewater, thermodynamic equation, formation of precipitate, simulation and prediction

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