A393 P11 by NAYLI AMANI BTE MUHAMED NOR https://padlet.com/200172701/f83nluz4o0yy3vf4 Made with big dreams en-us 2022-01-27 04:37:10 UTC 2024-10-14 23:46:54 UTC hello@padlet.com Membrane distillation 200172701 https://padlet.com/200172701/f83nluz4o0yy3vf4/wish/2015061928 - A separation process where a micro-porous hydrophobic membrane separates two aqueous solutions at different temp]]> 2022-01-27 04:38:47 UTC https://padlet.com/200172701/f83nluz4o0yy3vf4/wish/2015061928 Desalination 200111911 https://padlet.com/200172701/f83nluz4o0yy3vf4/wish/2015061933 2022-01-27 04:38:47 UTC https://padlet.com/200172701/f83nluz4o0yy3vf4/wish/2015061933 a review of partial pressure zahir13july https://padlet.com/200172701/f83nluz4o0yy3vf4/wish/2015065828 partial pressure of gas is pressure exerted by each type of gas in a gas mixture.
The formula can be expressed in components of partial pressure or the moles of the component. 
Pi = Xi * P  ---------- 1 
Xi = Pi/P = ni/n      -------- 2 

Where:   
xi = mole fraction of any individual gas component in a gas mixture 
pi = partial pressure of any individual gas component in a gas mixture 
ni = moles of any individual gas component in a gas mixture 
n = total moles of the gas mixture 
p = total pressure of the gas mixture
]]> 2022-01-27 04:42:08 UTC https://padlet.com/200172701/f83nluz4o0yy3vf4/wish/2015065828 Vapour pressure 200172701 https://padlet.com/200172701/f83nluz4o0yy3vf4/wish/2015067377 Water vapour: Liquid

Vapour pressure increases exponentially when temperature increases

Vapour pressure difference --> driving force
Vapour molecules will transport through the pores of the membrane from the high vapour pressure side to the low vapour pressure side]]> 2022-01-27 04:43:25 UTC https://padlet.com/200172701/f83nluz4o0yy3vf4/wish/2015067377 Temperature 200172701 https://padlet.com/200172701/f83nluz4o0yy3vf4/wish/2015067605 Higher temperature, higher average energy of particles --> more particles have sufficient energy to escape from the surface of liquid --> increases saturated vapor pressure

Higher temperature = higher vapor pressure]]> 2022-01-27 04:43:37 UTC https://padlet.com/200172701/f83nluz4o0yy3vf4/wish/2015067605 Selectivity zahir13july https://padlet.com/200172701/f83nluz4o0yy3vf4/wish/2015068292 The membrane in the distillation process acts as a vapour gap that allows vapour to pass through. 

Hydrophobic and porous membrane 

hydrophobic membrane will not let water pass through as if it does the air gap will become flooded with water affecting the pathway of the vapour.

porous membrane - will ensure vapour to pass through the membrane to the cooler side. 

How is selectivity achieved ?
The volatility of the vapour, the vapour with a higher volatility will be able to pass through the membrane first hence by collecting the more volatile vapour first then collecting what comes next selectivity can be achieved.  ( volatility calculated with vapour pressure, Antoine equation, higher vapour pressure more Volatile)

In some cases only one parameter will be passing through such as salt water, where salt will not be able to evaporate into vapour but water will hence only water vapour will be passing through. ]]> 2022-01-27 04:44:15 UTC https://padlet.com/200172701/f83nluz4o0yy3vf4/wish/2015068292 Hydrophobicity 200111911 https://padlet.com/200172701/f83nluz4o0yy3vf4/wish/2015068712 Avoid constriction of pores from which block vapors from permeating]]> 2022-01-27 04:44:39 UTC https://padlet.com/200172701/f83nluz4o0yy3vf4/wish/2015068712 Flux 20019303 https://padlet.com/200172701/f83nluz4o0yy3vf4/wish/2015068929 Flux force relationship
vapor flux = membrane based parameter * pressure difference between warm feed and cold permeate

- the higher the difference in pressure between the feed and permeate sides -> the greater the flux rate will be]]> 2022-01-27 04:44:50 UTC https://padlet.com/200172701/f83nluz4o0yy3vf4/wish/2015068929 Applications 200172701 https://padlet.com/200172701/f83nluz4o0yy3vf4/wish/2015069071 2022-01-27 04:44:54 UTC https://padlet.com/200172701/f83nluz4o0yy3vf4/wish/2015069071 Evaporation of sea water 200111911 https://padlet.com/200172701/f83nluz4o0yy3vf4/wish/2015071553 Uses heat to separate vapor from liquid water which is then put through a membrane to separate the aqueous solution]]> 2022-01-27 04:46:41 UTC https://padlet.com/200172701/f83nluz4o0yy3vf4/wish/2015071553 Reverse Osmosis (P08) 200111911 https://padlet.com/200172701/f83nluz4o0yy3vf4/wish/2015072005 Uses pumping systems to create pressure for osmosis to occur through membranes]]> 2022-01-27 04:47:05 UTC https://padlet.com/200172701/f83nluz4o0yy3vf4/wish/2015072005 Desalination methods 200111911 https://padlet.com/200172701/f83nluz4o0yy3vf4/wish/2015074536 2022-01-27 04:49:15 UTC https://padlet.com/200172701/f83nluz4o0yy3vf4/wish/2015074536 To separate liquid water from water vapour 200111911 https://padlet.com/200172701/f83nluz4o0yy3vf4/wish/2015081199 This is to allow water vapour to condense on a cooler surface in order to recover the desalinated water]]> 2022-01-27 04:55:00 UTC https://padlet.com/200172701/f83nluz4o0yy3vf4/wish/2015081199 Desalination in high solar radiation countiries 200111911 https://padlet.com/200172701/f83nluz4o0yy3vf4/wish/2015086991 2022-01-27 04:59:29 UTC https://padlet.com/200172701/f83nluz4o0yy3vf4/wish/2015086991 Desalination in countries with geothermal energy 200111911 https://padlet.com/200172701/f83nluz4o0yy3vf4/wish/2015087407 2022-01-27 04:59:49 UTC https://padlet.com/200172701/f83nluz4o0yy3vf4/wish/2015087407 note zahir13july https://padlet.com/200172701/f83nluz4o0yy3vf4/wish/2015092450 from the formula, 
a change in partial pressure of the component can be caused by a change in mole fraction ( removal or addition of gas ) and a change in total pressure ]]> 2022-01-27 05:04:03 UTC https://padlet.com/200172701/f83nluz4o0yy3vf4/wish/2015092450 Porosity of membrane 200172701 https://padlet.com/200172701/f83nluz4o0yy3vf4/wish/2015098315 Ensures separation of liquid particles ]]> 2022-01-27 05:08:56 UTC https://padlet.com/200172701/f83nluz4o0yy3vf4/wish/2015098315 Challenges faced 20019303 https://padlet.com/200172701/f83nluz4o0yy3vf4/wish/2015110137 - scaling will occur due to salt water over time
- heating of the cold permeate: when temp at the permeate increases, the driving force is affected -> Δpi will be smaller, hence lower flux is obtained. This is known as temperature polarisation ]]> 2022-01-27 05:18:47 UTC https://padlet.com/200172701/f83nluz4o0yy3vf4/wish/2015110137 Solution 20019303 https://padlet.com/200172701/f83nluz4o0yy3vf4/wish/2015134753 Heat transfer due to conduction
- to slow down the heat transfer rate from the feed side to the permeate side, a thicker membrane should be used ]]> 2022-01-27 05:42:21 UTC https://padlet.com/200172701/f83nluz4o0yy3vf4/wish/2015134753