Dextrose for Hex-chrome Reduction

I have heard that dextrose can be used to reduce hex-chrome to tri-chrome in alkaline waters.

Has anyone tried this?

How does this work exactly and how efficient is it?

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• Alkaline
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5 Answers

1. https://www.slideshare.net/mobile/ArvindGupta9/methods-for-removal-of-chromium

   The above link is useful.

   Enhanced chromium reductase activity is the key in bioremediation.

2. Yes you hered right,Both the strains of Y. lipolytica were cultivated on YEPD medium (yeast extract, 3.0; peptone, 10.0; dextrose, 10.0 g l−1 of distilled water) for 48 h on a shaker at optimum temperatures. The cells were harvested by centrifugation at 6000 × g for 10 min at 4 ◦C and washed thrice with distilled water. Washed cells were suspended in distilled water in a proportion of 1:2 (w/v) and this ‘standard yeast suspension’ was used for subsequent biosorption studies. For all experiments, the source of Cr (VI) was provided as K2Cr2O7 in distilled water. Dry weight of the biomass was determined for each set and this was used during further calculations.

    

   https://www.google.co.in/url?sa=t&rct=j&q=&esrc=s&source=web&cd=4&cad=rja&uact=8&ved=0ahUKEwjzjqbUxKHUAhUMLY8KHaVuCXsQFghDMAM&url=https%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fpmc%2Farticles%2FPMC3131624%2F&usg=AFQjCNFLbpjdlK9263zc5D0khn0kmCmKwA

    

   https://www.google.co.in/url?sa=t&rct=j&q=&esrc=s&source=web&cd=5&cad=rja&uact=8&ved=0ahUKEwjS3KHSw6HUAhVEgI8KHS1lDdIQFghJMAQ&url=https%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fpmc%2Farticles%2FPMC3658643%2F&usg=AFQjCNFewVVW4fuOMIbhxO9QoSOECn6q9A

    

3. By the  way I forgot to mention that Chrome VI is not a cancer risk anywhere near drinking water exposure levels. Canada has recently updated the technical rationale for its drinking water guideline with all of the new and very substantial toxicology data base, and kept its original value of 50 ppb; the US standard is 100 ppb. It concluded, as has been  recognized for at least 70 years, that ingested Cr VI is a threshold carcinogen, meaning that there is a safe level without risk. Humans have a much greater innate CrVI to CrIII reduction capacity than the test mouse that had the cancers in the very high dose test studies that triggered the activity. California's 10 ppb standard has been rescinded in the last few weeks by the court because they did not provide the appropriate impact analysis that is required in their statute.

   2 Comments

   1. For an industrial waste it is probably simpler and cheaper to use the standard inorganic reducing agents like sulfur dioxide, bisulfite or ferrous that are reactive over a wider range of conditions.

   2. Thank you for the information. I am working on industrial waste streams. We do not have to be anywhere as low as drinking water limits. We are exploring alternative ways to reduce hex chrome and this came up.

4. Dextrose is an aldo sugar so it has some reducing capacity, but it is probably slow and you would not want to add more TOC to the drinking water, if that is what you are treating. . Better to use traditional reducing chemicals like ferrous salts  or bisulfite.

5. We used a biochemical reactor (BCR) to reduce hex chrome to tri-chrome and precipitate it as Cr(OH)3.  See the abstract attached; we didn't submit a manuscript for this paper.  The BCR was not "powered" by detrose per se but the organic substrate we used probably produced similar compounds to create a reducing environment.  To learn more about BCRs, see http://itrcweb.org/bcr-1/.