Hello,

If a proper geopolymer mixture is designed and built, then it will have no adverse effect on the environment. In fact, geopolymers are used to encapsulate hazardous waste and heavy metals. therefore, no issues will arise.

However, if the system is not designed properly, it will not have a chemically stable structure (Na/Al=1) and therefore, heavy leaching could take place. In this case salty substances could be released into surrounding environment.

here is a link of my article...hope its helpful for your research

Article Quarry Waste as Precursors in Geopolymers for Civil Engineer...

It's very difficult to answer to this question unsless the experiment has not been done

Production of Sodium Hydroxide via electrolysis with a Mercury electrode has been an environmental disaster. See for example

https://www.victoriaadvocate.com/counties/calhoun/decades-later-mercury-still-poisons-parts-of-lavaca-bay/article_639df238-3dd4-11e8-9284-27c91c0998bd.html

All industrial processes will have some effects. Have not quantified. However Environmental effects are much less than those by production of OPC clinker based cements.

Sodium silicate is also known as the stable compound in soil, so it has no environmental impacts. Although sodium hydroxide might lead to react with CO2 in soil, it will not have a significant impact on the environment.

read : emission, fate and effects of soluble silicate (water glass )in the aquatic environment . by : Henno p .van Dokkum .

environmental science and technology . 2003 .

Effect of sodium silicate to sodium hydroxide ratios on durability of geopolymer mortars containing natural and artificial pozzolans, it has no harmful effects to environment because these are under the category of natural and artificial pozzolans.

As an alternative to sodium hydroxide, sodium carbonate can be used in the geopolymer mix design. Some processes such as Bayer Process already uses considerable amount of sodium hydroxide. If the waste containing sodium hydroxide residue can be used as a raw material for geopolymers, required amount of sodium hydroxide is already there. If correct amounts of sodium hydroxide and sodium silicate are used in the geopolymer mix design, the geopolymer produced will not have additional sodium hydroxide for it to leach out.

In the geopolymer all components are chemically bound and, accordingly, the sodium hydroxide and sodium silicate are encapsulated (there is not pollution exept cases, when it is not mixed yet).

I have quantified the environmental impacts in some mixtures. The quantification of the impact of course depends on the concentration and the amount of the activator you use. It also depends on what part of the environment you want to know the impact on (global warming, ecotoxicity, everything combined?). If you take into account several impact categories, roughly, if you count the impact per ton of the active content of a sodium silicate activator, it is about the same as the impact per ton of Portland cement. However, you use less sodium silicate in geopolymers than Portland cement in cement, so the impact for a geopolymer concrete should be lower. However, if you make it from metakaolin, also the impact of digging up clay and calcining it should be taken into account.

My calculations are presented in this paper:

Article Mix-design Parameters and Real-life Considerations in the Pu...

Excess amount of alkaline solutions usually appear as efflorescence. efflorescence appears with interaction of carbon dioxide and resulting compounds are soluble into water. Therefore, efflorescences geopolymers will increase alkalinity of water, consequently influence of alkalinity on the environment should be discussed in this case. Increase in alkalinity of geopolymers is stronger than that of OPC based concrete which has low solubility. By my opinion geopolymers alkalinity has more adverse effect on environment.

I agree with the above-esteemed researchers that this topic needs exclusive investigations and I am sure, many would have been already investigating the exact pollution levels affecting our environment.

However, in terms of finding the carbon emissions, I suggest you go through this article below:

Alsalman, Ali, Lateef N. Assi, Rahman S. Kareem, Kealy Carter, and Paul Ziehl. "Energy and CO2 emission assessments of alkali-activated concrete and Ordinary Portland Cement concrete: A comparative analysis of different grades of concrete." Cleaner Environmental Systems 3 (2021): 100047.