purification residual section

例句：

1. 1. The process of purification involves removing impurities from a substance.
   净化过程涉及从物质中去除杂质。
2. 2.The purification of water is essential for drinking and cooking.
   水的净化对于饮用水和烹饪至关重要。
3. 3.The research team has conducted purification experiments on the sample.
   研究小组对样本进行了净化实验。