Gravity Filtration and Vacuum Filtration

The first laboratory technique that we will learn together is a very simple one, filtration. This is how we separate a mixture of liquids and solids. There are two common ways a chemist will perform filtration, those being gravity filtration and vacuum filtration. These are very easy to understand and perform, but there are some tricks involving the setup and execution that one must understand in order to be successful with them. Let's go through these techniques together now!

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[me]

I would add something about vacuum filtration. Either use gravity filtration or a very weak vacuum if your desired product has delicate crystals. Example: making metallic aerogel blocks

[Allestya]

I love you Dave! You have been an indescribably amazing help in my journey to become a biochemist or potentially biologist. I love science in ever form, and it all excites me, and I'm not entirely sure what I want to progress to and your tutorials on nearly all fields help me gain a grasp on all of them. It's all so awesome but I have to make a decision soon because I return to college soon.
Also how is everyone not just blown away by the existence of the natural world and the fact that we know so much (and simultaneous next to nothing) about it.

[Dinnye]

Wow. TF sponsorship! You really made it!

I am very happy that you are being sponsored by the big manufacturers, which is a direct acknowledgement of your work.

[Ensaima]

Even thought chemistry isnt my favorite science, you make it interesting. I would love for every teacher to be like you!

[vangkhach]

For vacuum filtering, normally we have an intermediate glass bottle between the filtering set and the pump. If some liquid is sucked in the pipe, it will remain in the intermediate bottle and won't damage the pump.

[zmarssojourner]

Is there a specific lab kit that we can use to follow and perform along with the videos?

[jdmfh]

I would imagine a funnel with a longer end protruding past the vacuum intake would prevent the vacuum from sucking up the filtrate. Seems like an important step.

[Rryan]

This is actually a topic I learned about the other day, perfect timing for this video. I don’t know why but I’m always seeing vids about topics after I learn them. Just yesterday I learned about the MPLA from school, got on YouTube and seen a video about Bo2’s MPLA mission

[archivist]

Thanks, Dave! I'd not done vacuum filtration at school.

[TheHyponeoriteChannel]

So far I've only performed vacuum filtrations using a faucet, and in these cases we're always taught to, when we're done, first pull the hose out, and close the faucet only after that. Otherwise, some liquid might flow back to the flask due to the change in pressure.
I'm not sure that's also the case with the device being shown here.

[nikkiralaniakea]

Your channel is amazing, you have a video on everything I need 🙏

[martinarenzi]

Thanks Professor Dave!
Could you speak various types of spectroscopy such as IR UV vis and spectrometry such as MS NMR ICP?

[mortimertobarius]

These were incredibly helpful for the National Chemistry Olympiad.

[ameen]

could you please tell me the mixture that you tried in filtering in this video? the one in the vacuum filtration experiment part

[JudithTheROSE]

Could you do a video on soxhlet apparatus extracting

[demo]

Thank you Why use a Buchner instead of a sintered sand core funnel with a thick porous filter?

[diverdannavyvet]

Gravity AND Vacuum mentioned in the same video? Oh boy. Flerfs aren't going to like this. 🤣😝

[andrewjones]

Hi, Dave. This will be a fun series. Just curious though, what compound is your friend separating?

[lostfan]

This guy knows a lot about the science stuff

[yepyep]

Filtração simples

usada para separar misturas heterogêneas sólido+líquido
usa a força gravitacional para remover as impurezas, queremos isolar (obter) o líquido filtrado
passo a passo:
dobramos o papel de filtro (podendo dubrá-lo em 1/4 ou 1/8, sendo o 1/8 uma técnica maia rápida)
colocamos a argola no suporte universal e nela colocamos o filtro. Dentro do vidro, colocamos o papel de filtro, o qual molhamos com o mesmo líquido solvente da mistura para que ele adira ao vidro, sem deixar pontos secos ou bolhas
garantimos que a mistura está "bem misturada" e despejamos ela lentamente no filtro
notas:
não tenha pressa! a mistura não pode passar da altura do papel de filtro, pois pode contaminar o líquido filtrado
deixe o funil próximo do frasco coletor e com sua ponta tocando as paredes internas do recipiente (para que o líquido filtrado não goteje)
para garantir que toda mistura foi separada, lavamos o recipiente em que estava a mistura com o solvente dela, para extrair os restos de soluto

Filtração à Vácuo

destinada para grandes volumes de mistura, por ser mais rápida
obtenção do sólido (e também do liquido, mas o sólido é o principal)
usamos um kitassato conectado à uma bomba à vácuo, pois a pressão causada pela remoção do ar
puxa o líquido através do filtro, acelerando o processo
usamos também um funil de buchner, o qual cobrimos com um papel de filtro (que deve ter exatamente o tamanho do funil, sem sobrar nem deixar de cobrir os buraquinhos)
aperte o funil contra o kitassato para garantir a pressão adequada
para que o papel adira ao funil, molhe-o com o solvente da mistura
teste o funcionamento do sistema
despeje sua mistura no filtro
deixe a bomba ligada por um tempinho para "secar" o sólido obtido
remova o papel de filtro com uma pinça

notas:
não deixe o vácuo muito intenso, isso pode rasgar o papel de filtro e resultar em contaminação
não faça com que o líquido no kitassato atinja a parte em que o frasco é conectado com a bomba, ou o líquido será sugado pela máquina