Where the
world gathers for metal finishing
Q&As since 1989


-----

On Precipitating Nickel from Wastewater

I have a problem regarding precipitating Nickel from wastewater due to the presence of ammonia. Is there any way I can remove ammonia without having to add too much of hazardous chemicals such as strong bases and the like so that I can precipitate nickel?

Joe Nery
student limnologist - Quezon City, Philippines
September 22, 2008

---

September 25, 2008

Hi, Joe. ammonia is easily boiled off, but this may change a water pollution problem into an air pollution problem :-)

Regards,

Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey

---

Use a sulfur based precipitant, at a pH of something like 8. At that value, enough of the ammonia will be present as NH4+, instead of NH3, which is the active complexant.

Dave Wichern
Consultant - The Bronx, New York

---

First of two simultaneous responses --

Thank you for the answers! :p But actually I was looking for environment-friendly precipitants of Nickel. I have to keep the pH to about 6.5-9 and I should not add potentially hazardous components. It's really hard to precipitate nickel and copper when there's ammonia.

Joe Nery
student limnologist - Quezon City, Philippines
September 26, 2008
October 5, 2008

---

Second of two simultaneous responses --

Joe, you can use a precipitant product at a neutral pH to precipitate out the nickel. There are many precipitants available, but because the ammonia is a very tough complexing agent I would recommend a DTC (dimethyldithio carbamate or a diethyldithio carbamate)Either of these two should work, but the diethyl is much more effective on nickel complexes although significantly more expensive than the regular DTC.

The nickel should precipitate out as a nickel carbamate (or whatever precipitant it is that you use), but the ammonia will still be in solution. You have not done anything to get rid of the ammonia.

Gordon Djani
- Greenville, South Carolina
October 6, 2008