Cloth baby diapers made with polyester fabric and polyester microfiber Terry cloth can wind up with a very strong ammonia build-up after many washings; strong enough to burn baby‘s bum. I am curious to know a safe, economical, effective ammonia removal method. I prefer to know and understand the chemistry behind it, rather than just a brand of detergent (For example, I know that Rockin‘ Green sells a good detergent for ammonia removal, but I‘d like to understand why.) Also, would the addition of 1/2 cup of white vinegar to the final rinse cycle (where the water is hard) prevent the build-up in the first place? Thanks!
No, if you constantly add vinegar to the wash, you will get vinegar stink instead. You need to strip your diapers every once in a while, and the easiest way is with bleach and a little (little, little!!) bit of regular old blue Dawn. I don't know the chemical reasons behind it, but it works wonders. You wash with those, and then you rinse a couple of times until the bubbles are gone. All diapers need to be stripped eventually, but if you are having to strip very often, then your washing routine is not right. You are probably using too much detergent, and perhaps not the right brand for your water/your machine. Hard water vs. soft is different, HE machine vs. regular is different. And something super-cheap that you can add to your wash or soak in is old-fashioned Borax.
I would not be surprised to find some detergents with aluminum sulfate this is alum, the stuff used to make pickles crispy the aluminum ions from the alum react with water to form AlOH)2+ which leaves behind H+ which would neutralize the ammonia the white vinegar idea might work but could leave behind acetate ions which could be irritating if you feel like experimenting you might try vinegar in the rinse cycle then reset the control to do a second rinse to remove residue
the ingredients for that brand of soap are simply baking soda, hydrogen peroxide, sulfate, chelaters (for dealing with hard water), and surfactants (soap). i can't say I'm positive how this combination removes ammonia, but the peroxide seems like a likely candidate as it could oxidize the ammonia into less harmful nitrates. this probably wouldnt be a good thing to add directly to your laundry as it could bleach your clothes if it wasn't in the proper concentrations. vinegar might work, on the basis that it could protonate the ammonia to try to make it more water soluble and less polyester soluble. if you're really getting that much ammonia build up, you should be able to smell it in the clothes, so you can try some vinegar and see if it removes the smell. as I understand it, straight ammonia is not the problem, but rather leftover urea (from urine) that is difficult to get rid of directly but slowly releases ammonia as it breaks down. if thats the case, you can still try vinegar, but you'll also want to use hot water to try to facilitate the solubilty. i would also suggest that rather than adding vinegar to the final rinse to instead do a hot pre-rinse with vinegar, as the detergent you use (such as the rockin green) is likely to have bases in it like sodium bicarb that will make the vinegar ineffective. i have to admit alot of this is simple speculation as I neither have children nor am terribly familiar with the chemistry of baby butts ;)