Chemical water treatment: Acid base reaction

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SUMMARY

The discussion centers on the challenges of neutralizing hydrochloric acid (HCl) in wastewater treatment using nanotechnology. The proposed solution involves adding sodium hydroxide (NaOH) to neutralize HCl, but concerns arise regarding the formation of toxic salts, particularly potassium chloride and magnesium chloride. The discussion emphasizes the need for precise sensors to measure HCl concentration and automate the addition of NaOH to achieve a neutral pH of 7. The feasibility of this approach is questioned due to the variability in HCl concentration based on numerous factors, including individual health conditions.

PREREQUISITES
  • Understanding of acid-base reactions, specifically HCl and NaOH interactions.
  • Familiarity with wastewater treatment processes and nanotechnology applications.
  • Knowledge of sensor technology for measuring pH and chemical concentrations.
  • Basic principles of chemical engineering related to reaction kinetics and equilibrium.
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  • Research advanced pH sensor technologies for real-time monitoring in wastewater treatment.
  • Explore chemical reaction pathways for neutralizing strong acids in aqueous solutions.
  • Investigate the implications of salt formation in wastewater treatment and potential toxicity.
  • Study automated control systems for chemical dosing in industrial applications.
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Environmental engineers, wastewater treatment professionals, and researchers in chemical engineering focusing on acid-base reactions and nanotechnology applications in water treatment.

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I was thinking of a hypothetical waste system that uses nanotechnology to its advantage.

At the individual level, waste just passes through into pipes when flushed like it normally does.

But once it reaches the water treatment plant there is an initial filter to catch solid waste(in other words poop) and divert it to a different part of the system where it gets dried and eventually ground into a biosolid that can be used as fertilizer.

Meanwhile all the urine, vomitus, blood, and any diarrhea that didn't get caught by the initial filter is passed through a series of filters to catch smaller and smaller waste products from cells all the way to molecules like urea being blocked with a nanofilter. Only a few compounds besides water are left. Yes there are still small ions like potassium and this might actually pose a problem.

But the real threat is that HCl is still in the water. Pepsin and other enzymes have been blocked by the nanofilters but HCl is still small enough to pass through all of the filters. A nanofilter that can block HCl is so impractical that it would most likely block the water itself until either the water treatment system or the microfilters and nanofilters burst from pressure and you end up with a critical failure either way.

So there has to be a chemical reaction that either deactivates the HCl and thus renders it harmless or a reaction that leaves no trace of HCl .

I was thinking that to render the water safe, NaOH should be added to increase the amount of saltwater and totally get rid of the HCl. But then I realized that with potassium and other ions besides sodium and chloride still in the water this could make the water toxic due to toxic salts forming.

Potassium chloride is the least harmful of all the salts that could form besides sodium chloride. Other than the bitter taste, there is basically nothing wrong with using potassium chloride. Similar for calcium chloride. Magnesium chloride though could cause diarrhea due to the magnesium(I know at least part of that diarrhea is from magnesium because the magnesium supplement I take helps to prevent constipation). I am not as worried about hydroxides because those would react with hydrogen ions to produce water.

But those salts are not the only problem. The other problem is how much NaOH to add.

I mean to get HCl down to 0 every time, there would have to be sensors to not only know the volume of water but also the concentration of HCl and a relatively complicated math problem like this:[HCl]∗x=a mol HCl=a mol NaOH=[NaOH]∗yWhat is complicated about it? Well for one how would you sense the exact concentration of a strong acid or base without damaging the sensory equipment? And unless you regularly go to the water treatment plant with this nanotechnology, you won't know what the concentration of NaOH is. And the concentration of HCl will most likely vary day to day depending on factors such as these:

  • How often any given person vomits
  • Hydration level before vomiting
  • Amount of bile in the vomit
  • Dilution of stomach acid
  • Amount of blood in the vomit if any
  • Prevalence of vomiting from any cause
  • Total Volume of vomit
So basically my question is how can I have the part of the system after the filters be constantly sensing the exact concentration of HCl , doing the math, and adding the amount of NaOH that will get the concentration of HCl down to exactly 0?
 
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You could put an electronic pH meter at the end of your process and test for ph7, considered to be exactly neutral.
If the meter reads a pH lower than 7 then not all of the acid is being neutralized so you need to add more of the base substance upstream
That adjustment could be made fully automated.
While there would a small amount of lag between making an adjustment and the pH returning to neutral, I don't think it would be enough lag to worry about.
 
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I also think this is personal theory. Bacteria and oxygen do what you are talking about at essentially no cost compared to your proposal.

FYI- we really do not support personal theory.
 
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