浸出和提取的区别

Leaching vs Extraction

The difference between leaching and extraction can be explained in terms of the chemical principles used in these two processes. Both leaching and extraction refer to the isolation of one or severalcompounds来自混合物that they are originally present in. When a solid mixture is brought in contact with asolventin order to separate the components that are soluble, the process is called leaching. When compounds in a mixture, in one chemical phase, are being separated out to another, it is referred to as extraction.

What is Leaching?

Leaching is将组件与固体混合物分开的过程by bringing that mixture in contact与一个liquid solventin which these components are soluble. There are three important factors that are required for leaching to occur. They are acompound mixture, a solute, and a solvent. When a liquid or solvent is applied or brought in contact with a compound mixture, the components which are soluble in the solvent starts to dissolve while other components remain in a slurry. These components that dissolve are called ‘solutes.’ Therefore, upon the application of the solvent in excess, the solutes can be removed from the initial compound mixture. Even though it is expected only for the solutes to be present in the solvent, it only happens under ideal conditions. Therefore, the solvent usually contains other impurities from the slurry. Leaching is a type of‘solid-liquid’ extraction.

This method is commonly used in industries when solid materials are to be separated from a solid mixture. Some common examples include separation ofsugarfrom sugar beet with hot water, separation ofmetal从金属矿石中使用酸等。在自然界中，浸出重金属和其他土壤污染物进入地下水。

什么是提取？

提取也是将分量与化合物混合物分离的过程，但是在这里，一个化学阶段中的化合物正在分离到另一个阶段。通常extraction takes place between two immiscible solvents,明确称为‘solvent-solvent’ extraction. A compound mixture can be separated into components among two immiscible solvents depending on the affinities of the various components to each solvent used. The affinity mentioned above is usually due to the polarity of the compounds and the respective solvents. Some common solvent systems used are water: ethyl acetate, water: methylene chloride, water/methanol mixture: methylene chloride, water/methanol mixture: ethyl acetate, etc.

This technique is often used under technical chemical laboratory conditions where organic compounds are generated or which, as a part of a mixture, needs to be separated out. Hence, extraction into organic solvents are performed. The process of extraction of a given compound in one phase to another phase is governed by the “分区理论.” Once a compound or several compounds have been separated out from their initial mixture into a second solvent, the compounds can be isolated through the evaporation of the excess solvent. An instrument called the ‘rotary evaporator’用于此目的。

还有其他类型的提取solid phase extraction. Some modern variations include super critical carbon dioxide extraction, ultrasonic extraction, microwave-assisted extraction, etc.

浸出和提取有什么区别？

•浸出和提取的定义：

•浸出是通过将混合物中的固体材料溶解在合适的溶剂中的过程中。

• In extraction, a given compound is separated from one chemical phase to another due to the polarity differences.

• Chemical Principle:

• Leaching occurs via a concentration gradient for soluble components.

• Extraction is governed by the Partition theory.

• 应用：

• Leaching, which is simpler in approach, is commonly applied at industrial scale.

• Extraction is often used in laboratory level.

图像提供：

1. Iron leaching通过Wikicommons（公共领域）
2. Separatory funnelbyPRHaney(CC BY-SA 3.0)