# Residual catalyst leaching from PETE

I am trying to look for healthy options for 5 gallon water jugs. The problem is all the plastic 5 gallon water jugs on the market are either made of #1 PETE (BPA free) or #7 (which contains BPA). It seems #1 PETE is healthier option but it turns out #1 PETE is known to leach a bit of antimony oxide ($\ce{Sb2O3}$ catalyst, used in its synthesis) into water.

So my question is if I bathe the jug in water, so that the antimony oxide can leach into the water and wash the jug one more time, can all the antimony be removed that way?

• @Mithoron Actually, $\ce{Sb2O3}$ is used in PET production as a catalyst, and it's a relevant question IMO. – andselisk Jan 12 '18 at 1:11
• You should just make a link to source and be careful with capitalisation & punctuation. I didn't know about this Sb2O3 issue, and found it hard to believe. It doesn't seem to be particularly sever, but if it's supposed to be water to drink then metal would be better then plastic. – Mithoron Jan 12 '18 at 15:35

Let's ignore the safety aspect here, and focus on the 'if i bathe the jug in water so that all the antimony can leach into the water and wash the jug one more time, can all the antimony be removed that way'. In short, no.

There have been a number of studies on antimony in PET bottles. They look at various factors that influence the rate of leaching of Sb from PET bottles. These factors include temperature, UV, colour of bottle, pH, bottle volume and time. There is evidence that leaching is still occurring well beyond 6 months. One study suggests that leaching levels out after about 800 days. Another study calculates that the total levels of Sb in the plastic are very unlikely to be completely leached out.

Factors that have significant influence of amount of Sb leached include:

• time stored (major influence)
• temperature (higher temps have major influence)
• volume of bottle (smaller volume bottles have higher SA/vol ratio and increase leaching)
• type/origin of PET (significant differences between the colour of bottles used in one study)

I'm not aware of a study that attempts to find the conditions whereby Sb no longer leaches into the water, but effectively you would need to bathe the the bottle at high temperature for several days at a time, repeatedly, over months. That's just not going to happen.

Some useful references for you include:

• Thank you, this answer is exactly what i am looking for. It seems like the rate of leaching is not as fast as i thought. Based on your information, if i use this type of plastic to store water for a weekat a time at 23 degree C, it should not have much of an impact on my health then. But dam i wish there was s safer alternative – allen thompson Jan 12 '18 at 5:09
• Greater concern comes from the storage of water at higher temperatures during transport and warehouse storage before it gets to the consumer. Feel free to accept the answer in order to close the question if has addressed your questions. – long Jan 12 '18 at 22:09