大学化学 >> 2022, Vol. 37 >> Issue (5): 2110049.doi: 10.3866/PKU.DXHX202110049

所属专题： 第2届全国大学生化学实验创新设计竞赛

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多技术融合-创新设计沉淀重量法测定钡含量的实验

孟哲(), 宋伟明, 马晓虎, 李峪安, 罗期允   

  • 收稿日期:2021-10-15 录用日期:2021-11-04 发布日期:2022-03-22
  • 通讯作者: 孟哲 E-mail:meng_z@nxu.edu.cn
  • 作者简介:孟哲, Email: meng_z@nxu.edu.cn
  • 基金资助:
    国家自然科学基金(21768003);国家自然科学基金(21966024)

Multi-Technology Fusion and the Innovative Experiment of Determination of Barium Content Using the Precipitation Gravimetric Method

Zhe Meng(), Weiming Song, Xiaohu Ma, Yuan Li, Qiyun Luo   

  • Received:2021-10-15 Accepted:2021-11-04 Published:2022-03-22
  • Contact: Zhe Meng E-mail:meng_z@nxu.edu.cn

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摘要：

在现行沉淀重量法测定钡含量的实验基础上，本实验依据晶型沉淀生长的热力学理论，通过晶核形成过程的速率决定于形成和生长两个因素的动力学分析，针对沉淀制备过程中耗时长的陈化过程，创新性地引入微波技术，制备出形貌完整、粒径粗大(10 μm左右)的BaSO4晶型沉淀。采用响应面法设计，优化微波输出功率300 W，微波陈化时间5 min，静置陈化时间15 min的连续二次微波陈化条件，总陈化时间仅需25 min。采用多种可视化微观表征技术将抽象的理论与基础的实验教学充分融合，有助于提升本科实验教学的前沿性和高阶性。在实验教学中(4学时)，本实验的改进更加贴合现代化学实验教学的发展，为学生的科研和创新能力打下良好基础。

关键词: 沉淀重量法, 微波陈化, 钡含量测定, 创新设计

Abstract:

In the current experiment for barium content determination by using the precipitation gravimetric method, the precipitation aging process is found to be time consuming. Depending on the thermodynamic theory of crystal precipitation growth, the microwave technology is innovatively introduced to shorten the precipitation aging process through an improved experiment. Kinetic analysis reveals that crystal nucleus formation is governed by two factors: nucleus formation rate and growth. After response surface method optimization, two consecutive microwave irradiation cycles are conducted for 5 min at 300 W; the standing interval is 15 min. Finally, a coarse BaSO4 precipitate with a complete morphology and large particle size distribution (~10 μm) can be successfully prepared. The total time for the precipitation aging process through this improved experiment is only 25 min. The sufficient integration between the metaphysical principles and basic experimental teaching by various visual micro-representation techniques will help to enhance the frontier and high-order characteristic of undergraduate experimental teaching. From the experimental teaching perspective (4 class hours), the improved experiment is more in line with modern chemistry experiment teaching and lays a good foundation for students' scientific research and innovation abilities.

Key words: Gravimetric method by precipitation, Microwave aging, Determination of barium content, Innovative design