Hexavalent Chromium

[fuelcatalyst]

Info on Chrome +6.

http://www.cdc.gov/niosh/topics/hexchrom/

http://www.epa.gov/safewater/contami...mium.html#four

http://www.clu-in.org/contaminantfoc..._and_Guidance/

http://www.epa.gov/nrmrl/pubs/625r00005/625r00005.pdf

That will make yer head spin. Each body of water has different standards.

http://www.epa.gov/waterscience/meth...files/1636.pdf

[abe58]

OK: If your water is clear you haven't run it long. The water will turn yellow that is the Crome 6 comeing from the plate.
To be forewarned is to be forearmed. Good Luck.

[fuelcatalyst]

Test kit.

http://www.hach.com/hc/search.produc...%3BL,+50+tests

[fuelcatalyst]

Helpful thread.

http://www.hhoforums.com/showthread....light=fructose

[abe58]

Their is an old saying, "You can drag a horse to water but you can't make him drink" My last warning is, I have had a friend with the EPA test my Electrolyte after running for two months.He advised me if I had poured that water on the ground and it leaked into the water table I could have poisoned every neighbor that drank from that water.That good enough for me.

[fuelcatalyst]

ENVR 100
Cr(VI) reduction using fructose, glucose and sucrose
Program Selection: Division of Environmental Chemistry
Topic Selection: Remediation Technologies for Chromium
Lead Presenter's Email: bbilyeu@xula.edu

Bryan Bilyeu1, Patricia Balderas-Hernández2, Gabriela Roa-Morales2, and Carlos Barrera-DÃ*az2. (1) Department of Physics and Engineering, Xavier University of Louisiana, 1 Drexel Drive, New Orleans, LA 70125, bbilyeu@xula.edu, (2) Facultdad de QuÃ*mica (Chemistry), Universidad Autónoma del Estado de México

Abstract

Plating, mining and leather industries produce large amounts of chromium wastes. However, Cr(III) is a thousand times less toxic than Cr(VI) so there is interest in new economical ways to reduce Cr(VI). Cr(VI) can be chemically reduced at low pH. However, a large excess of acid is required to achieve the Cr(VI) reduction to meet environmental standards. Another disadvantage is the large amount of sludge generated, which requires expensive (up to 50% of operational cost) disposal. In this study, fructose, sucrose and glucose at different concentrations (3.84, 28.57 or 50 mg mL-1) were evaluated as reducing agents with a 5 mg L-1 Cr(VI) solution at pH 2.2 and temperatures 20, 35 and 70 °C. Optimum conditions for Cr(VI) reduction were 70 °C with a sugar concentration of 28.57 mg mL-1. Figure 1 shows that fructose was most effective at 94.28% removal, followed by sucrose at 93% and glucose only 32%.




Researcher Provided Non-Technical Summary

Briefly explain in lay language what you have done, why it is significant and what are its implications (particularly to the general public)
Chromium compounds are used in industrial metal plating and leather tanning, but are very toxic carcinogens. They exist in two principle forms: hexavalent [Cr(VI)] and trivalent [Cr(III)], with the trivalent being a thousand times less toxic than the hexavalent. Although state, federal and international agencies strictly regulate chromium levels in industrial wastewater, it still gets into aquatic environments. Treating large environmental systems like lakes and rivers without causing more damage to the ecosystem is a challenge. We have found some natural sugars, like fructose from honey and sucrose from sugar cane can convert highly toxic hexavalent chromium into the less toxic trivalent form.

How new is this work and how does it differ from that of others who may be doing similar research?
Converting hexavalent chromium to the less toxic trivalent form has been done with strong acids and other aggressive treatments, but our method is quite different in that it is quite environmentally friendly and can be done in an active ecosystem with little disruption.

Bryan Bilyeu
Department of Physics and Engineering
Xavier University of Louisiana
1 Drexel Drive
New Orleans, LA 70125

http://acswebcontent.acs.org/communi...inability.html

(third article from the bottom, chart wouldn't copy and paste)

[fuelcatalyst]

Looks like optimum reduction occurs @ 70 degrees C (158 F)

pH of 2.2!!!!


Question if KOH has a pH North of 12 what is the best way to get a solution of KOH to 2.2. Some sort of acid, would the acid create a Cr(VI) laden salt? Which acid would work the best to get to a pH of 2.2 with the least negative effect?

Question: What is 28.57 mg mL-1 is that 28.57 milligarms per milliliter or Liter what?

Sorry I'm sooooo dense.

BTW Abe I get it: Cr(VI) is not good for a person's corn flakes that is why I'm doing this homework.

[Philldpapill]

OK: If your water is clear you haven't run it long. The water will turn yellow that is the Crome 6 comeing from the plate.
To be forewarned is to be forearmed. Good Luck.

Excuse me? I thought it was iron oxide................

Besides, Cr(VI) is typically a redish/purple color. I don't think the "yellow" in the water is from Cr(VI). If it were, that's an insane amount of it.

Yellow water is NOT an indication of Cr(VI) in your water... It happens with straight iron plates, too. It's harmless. This whole Chromium stuff is just more alarmism. Yes, Cr(VI) is dangerous in sufficient quantities. However, there is NO evidence whatsoever that it's even produced in low voltage electrolysis. The energy levels just aren't high enough to produce it. Nonsense!

[Philldpapill]

OK here is what I have found out so far. titanium does not make a good + plate (anode) unless it is coated first.But does make a good - plate (cathode).Crome 6 comes from the -plates not the + plates.So I'm working on a cell with titanium - plates and SS + plates.Still working on spaceing.Not haveing coated titanium for + plates save money.Haven't work with nickel yet.(Cost to much) Abe

Cr(VI) doesn't come from either plate! PERIOD!

However, to back up why you say that... WHY does it form at the negative plate? What chemical reactions are you citing??? Because the ion is positively charged? I don't mean to be such a butthole, but I don't like seeing people making claims without citing where they got that info from. That's how a LOT of misinformation and rumors start.

[fuelcatalyst]

"The acid and base react during neutralization, forming water and a salt. If the acid and base are both very strong (such as concentrated hydrochloric acid or sodium hydroxide), a violent reaction will occur. That’s why most neutralizers are very weak: to slow the reaction. Even with neutralization products, heat and gas will often evolve. Take proper precautions as recommended by the neutralizer’s manufacturer."


http://www.labmanager.com/stips.asp?ID=56

Likely not gonna be easy to get a pH of 2.2 without a whole lotta dilution ta tame the reaction.

Wonder if fructose works in pH of 12?