0.05N H2SO4

Check this: It can be expressed in M or N -read further:

H2SO4 releases two hydrogen ions into solution.

Therefore its N ormality is twice its M olarity.

Sulphuric acid (Is what you dilute)

H2SO4, FW = 98.08, Density = 1.8

1M = 56mls = 2N

250ml 0.05M = 0.7ml = 0.1N

1 liter 0.05M = 2.8ml = 0.1N (use 3 mls)- still double of what you need

1 liter 0.025M=1.4ml=0.05N (this is your dilution)

USE 1.5 ml = milliliter per liter water. hope this helps. D

This is also a ready available dilution, used for tests. Laboratory chemicals suppliers might have it. I agree. For only one liter the 0.1 ml might stick in the pipet.

I didn't want to assume W/W, that is not clear in his post either. I specified the concentration and the density, and we seem to agree on that one. We prefer to handle small bottle pure concentrations in the acid handler box in our lab. I didn't notice the start from 20% diluted. Are you sure it is no ready made battery acid? We never bought 20% solutions. But at the end we end up with 2 different outcomes. what do you assume about that? Where are the Chemists? Respectfully. D

Use this simple formula:

M1V1 = M2V2 for dilution. --> equation 1

where V is volume, M could be either molarity(M), molality(m), percentage(%) or normality(N)

normality = gram equivalent / liter solution ----> equation 2

gram equivalent = relative molecular mass(RMM) / moles of positive ion.

RMM H2SO4 = 98 g/mol

moles of positive ion in chemical formula = 2

therefore you can calculate the normality of 20% H2SO4 if you know the total volume of the solution.

for instance, H2SO4 solution = 10 liters

normality is therefore N = 98/2/10 = 4.9 N

to make 0.05 N H2SO4, use equation 1

4.9N x 10ltrs = 0.05N x V2 ltrs

V2 ltrs = 980 liters.

that means, you have to add in (980 - 10) liters water.

the solution will then become 0.05N H2SO4

Thanks everyone for your help. The supplier is in China as is the deflouridation project. That is why I am using Activated Alumina. The first village we will be working has 6 mg/L fluoride in their drinking water. I have two options for regeneration. 1 is dissolve the fluoride from the AA using sodium hydroxide, rinse and finish with acid to neutralize the lye. 2 is regenerate with aluminum sulfate. 2 takes longer but may be the way to go. Even with longer contact time it would be safer and easier to train the nationals in this very poor area to get better results and I would only have one chemical to deal with.

You will still need a second chemical, as you will need to neutralise the alum solution after is has been used.

Presumably, an excess of agricultural grade lime could be used for that purpose. The fate of the fluoride needs to be considered. In the long run, it would need to be locked up as calcium fluoride, I imagine.

CAUTION.

Always add the Sulphuric acid to the water and not the other way round. The dilution of sulphuric acid causes an exothermic reaction - gives out heat and can cause the water or sulphuric acid to boil.

Tony

In adding the aluminum sulfate can anyone interpret this for me?

(~29 g Al₂ (SO₄)₃ •18 H₂O per liter)

I am tring to get a percentage to treat the AA. The aluminum sulfate is around 17% dry.

Aluminium sulfate is sold as an hydrated salt. So it has water in the crystal structure. That is the 18 H₂O bit. So you need 29g of the hydrated salt, as sold. Often just known as alum.

Aluminium sulfate is corrosive and forms highly acidic solutions in water. That is why you need to neutralise it once you have finished using it. Soluble aluminium is not a nice thing to release into the environment, even more so if it is charged with fluoride and is highly acidic and corrosive.

You need lime, Calcium carbonate in this case, to neutralise it. Use an excess; it is cheap and simple. And you need to know where the fluorine is going to end up. With excess calcium carbonate, I suspect it will be locked up as calcium fluoride.

I must say, I have some concern that someone who needs to ask these questions is offering a service in the area :( Sounds like a recipe for disaster to be honest. I am thinking of the arsenic bores in Bangladesh!!

But at least you are asking questions :-)

Morrie,

I have been doing dafe drinking water development for a while now. The reason I have to ask these questions is to learn how to deal with the problem that is there already. As far as I know no one else has stepped up to do so. The alum is what helps lock the fluoride into the activated alumina. The AA will work by itself but not as effectively.

The boreholes are already there, have been for years. I am familiar with the arsenic producing wells in Bangladesh and Northern India. Years ago an NGO went in and bored the wells not thinking about the arsenic. Now others are dealing with the problem. As I said in the opening statment I am not a chemist but I do know how to get things done. That is why I try to surround myself with people who are smarter than I in areas where I am miserably lacking. I could say, oh well, I am not qualified and sit on my hands hoping someone else will do it. Yes it could be a disaster but in reality it already is affecting many thousands of people.

Alum can't be all that bad if used correctly can it. If it was nobody would even put it in pickles. :-)

Hi Rusty

The alum is what helps lock the fluoride into the activated alumina. The AA will work by itself but not as effectively.

Interesting, I did a bit of a search and could not find any explanation of how the alum worked. I was assuming that it solublized the fluorine by some means that I cannot imagine.

I find it hard to imagine that AA can last more than a few cycles if the fluoride is being locking in there. Where are the new adsorption sites being generated?

I do notice that the among the literature available on the web is a Company from your home town who have published research on this very area, but they don't mention aluminium sulfate as a regenerant.

Alum is not a good word. About the same as lime. Too many different meanings. Personally, I would not pickle anything with aluminium sulfate, nor would I run it off into the environment when simple lime neutralization would prevent any problems. It doesn't pay to be blaze about chemicals by using inappropriate analogies.

I am sure you have good intentions. But I fear you are not in a position to understand the consequences of your actions. I don't want to offside you here, just point out my concerns, which you are free to take onboard or reject.

About the Lime, I would say that is a good response to containing the dispersed fluoride allowing for safe containment and discard of the fluoride. As for the Aluminum sulfate it will help in absorption by the AA. once the AA is near saturation and no longer effective to absorb the fluoride from 6 mg/L to less than 1 mg/L it would be time to regenerate the AA. If you want to learn more do another hundred hours research as I have and dont be an Ass when someone is being genuine in their efforts. I have worked on three continents with sucess serving the rural poor and this will be the forth and yes with sucess.