Vacuum Filtration - Science@Waikato

Summary

This video tutorial demonstrates the process of vacuum filtration, a method where a liquid is drawn through a filter by applying a vacuum. Key equipment includes a booster flask, vacuum hose, clamp, booster funnel, and filter paper. The video explains how to set up the filtration system, wet the filter paper with the fluid, and collect the crude product. It also covers washing the product to remove soluble impurities and ensures that the correct filter paper size is used. The final product can be collected directly from the filter paper or scraped off once dry.

Takeaways

• 😀 Vacuum filtration is a process where liquid is drawn through a filter by applying a vacuum to collect solid products.
• 😀 You'll need a booster flask (vacuum flask), a clamp, a vacuum hose, a vacuum source, a booster funnel, and filter paper to carry out the filtration.
• 😀 Ensure the vacuum hose is thick-walled and not too flexible to prevent leaks.
• 😀 Securely clamp the booster flask to the workbench or a retort stand before beginning the process.
• 😀 The filter paper should fit snugly inside the booster funnel, covering all holes to create a vacuum seal with the flask.
• 😀 Attach a rubber cone to the bottom of the booster funnel to form a tight seal with the booster flask.
• 😀 Wet the filter paper with the liquid being filtered to ensure it sits properly in the funnel.
• 😀 Once the vacuum is applied, pour the fluid into the booster funnel, allowing the solid product to be collected in the filter.
• 😀 To remove soluble impurities, wash the solid product with a washing liquid and reapply the vacuum to help it settle.
• 😀 The washing process may not always show obvious effects, but the change in color of impurities can indicate success.
• 😀 The finished product can be removed directly from the filter paper or scraped off once dried.

Q & A

What is vacuum filtration?

Vacuum filtration is a filtration process where a liquid is drawn through a filter using vacuum pressure. This method is typically used to collect a solid product.

What equipment is needed for vacuum filtration?

The equipment required includes a booster flask, clamp, vacuum hose, vacuum source (like a vacuum tap or aspirator), booster funnel, and filter paper.

Why is the vacuum hose used in this process?

The vacuum hose is used to connect the booster flask to the vacuum source, allowing the vacuum pressure to draw the liquid through the filter.

How should the booster flask be set up for the filtration?

The booster flask should be securely clamped to the workbench or a retort stand, with the vacuum hose connected to the flask's short tube and the other end attached to the vacuum source.

How do you ensure the filter paper fits correctly in the booster funnel?

The filter paper should be the correct size to fit snugly at the bottom of the funnel, covering all holes to create a proper vacuum seal with the booster flask.

What is the purpose of the rubber cone in vacuum filtration?

The rubber cone is used to form a seal between the booster funnel and the booster flask, ensuring that the vacuum pressure is applied effectively.

Why should the filter paper be wetted with the fluid being filtered?

Wetting the filter paper ensures it sits correctly in the funnel, improving the vacuum seal and the filtration process.

What should be done if the product in the funnel contains soluble impurities?

If soluble impurities are present, the product should be washed by adding a washing liquid to the funnel, mixing it with the product, and reapplying the vacuum.

How can the effect of washing be observed?

In some cases, the impurities will be a different color from the product, making the effect of washing visible as the impurities are removed.

What should be done with the finished product after filtration?

The finished product can either be removed from the filter paper or, if left to dry, can be scraped off the paper.