The preparation process comprises the following steps: 1), preparing tannin solution at a mass-volume concentration of 3 to 20 percent with distilled water;

其制备过程包括如下步骤：1）用蒸馏水配制质量体积比为3-20%浓度的单宁溶液；

youdao

The preparation process comprises the following steps: 1), preparing tannin solution at a mass-volume concentration of 3 to 20 percent with distilled water;

其制备过程包括如下步骤：1）用蒸馏水配制质量体积比为3-20%浓度的单宁溶液；

youdao