Novel spray paints for self-decontaminating latrine coatings (University of Texas - Pan American, USA)

  • MaoatUTPA
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Novel spray paints for self-decontaminating latrine coatings (University of Texas - Pan American, USA)

Dear all,
My turn to introduce to you my grant from the Gates Foundation. This is very much about chemistry and fundamental research, so here goes:

Title of grant: Novel spray paints for self-decontaminating latrine coatings
Subtitle: Heterogeneous Nanomaterials with high decontaminating efficiency, high contaminant adsorption and broad solar spectrum utilization
Name of lead organization: University of Texas - Pan American
Primary contact at lead organization: Yuanbing Mao
Grantee location: Edinburg, Texas, USA
Developing country where the research is being or will be tested: China; India; and/or US

Short description of the project:
The proposed spray paints consist of heterogeneous nanomaterials with three nanocomponents. Each component is tailored to address a different demand (e.g. high decontaminating efficiency, high contaminant adsorption, and broad solar spectrum utilization), so the resulting paints will exhibit synergic properties by integrating the individual nanocomponents, realizing full potential of latrine coatings in terms of self-decontaminating performance (e.g. durable, affordable, able to be mass produced, easy to clean, and smooth). More specifically, one nanocomponent can absorb visible and infrared lights, another nanocomponent possesses strong adsorption capability to contaminants, bacteria and fungi, and a nanosized ultraviolet photocatalyst serves as the base component. With appropriate chemical modifications, the proposed three-component nanomaterials can be readily incorporated into commercial spray paints as self-decontaminating latrine coatings with enhance cleanliness.





Goal(s): The goal of this project is to develop spray paints that will exhibit synergic properties by integrating the individual nanocomponents, realizing full potential of latrine coatings in terms of self-decontaminating performance.

Objectives: The main objective of this project is to make more efficient use of sunlight by the resulting coatings in practical sanitary applications. It also aims to select stable nanocomponents to make the coatings resilient to aggressive environment. Moreover, the spray paints are attractive and flexible by possessing various colors like existing paints and being fitted into various pan/squatting platforms for affordable applications.

Start and end date: 27 September 2011 to 31 October 2013, final report due 15 January 2014

Grant type: GCE R7
Funding for this research currently ongoing (yes/no): Yes
Research or implementation partners: N/A
Links, further readings – results to date: N/A.

Key components:
  • Synthesis and characterization of compositionally and morphologically controlled three-component nanomaterials.
  • Incorporation of the nanomaterials into commercial spray paints (such as Krylon and Dupli-Color) for sanitory applications.
  • Evaluation of self-decontaminating activities of the spray paints.

What we demonstrated in the presentation (see attached below) is that the developed nanocomposite photocatalyst possesses strong adsorption capability to contaminants. So far we used a toxic dye molecule, i.e. methylene blue, as an example. And our next targets will be bacteria and fungi. It is important to bring contaminants close to photocatalysts' surfaces to improve self-cleaning effectiveness.

Recently we developed a very facile and low-cost procedure to coat the common photocatalyst TiO2 with adsorbant carbon. The products show much faster photodegradation performance. I am trying to file a patent, so not much details were given on the preparation procedure in the presentation. 

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I have not done any calculation on the costs yet, but am very confident it is facile and cost-effective. We can easily use autoclaves to make the mentioned nanocomposite photocatalysts.

Current state of afffairs:
So far we successfully demonstrated the facile combination of photocatalyst and adsorbent to enhance the adsorption capability to contaminants, and hence improve self-cleaning effectiveness. At the meantime, we also have certain success on the enhancement of absorbed solar portion to improve self-decontamining efficiency. Of course, the selected ultraviolet photocatalysts possess oxidation potential high enought to destroy contanimants, i.e. strong self-decontamining strength. The next step is to keep improving the solar absorption efficiency and to combine the enhanced adsorption efficiency to contaminants with improved solar absorption capability, so to make the final desirable nanostructured photocatalysts. 

Biggest success so far:
As mentioned in the previous point, it is the facile combination of photocatalyst and adsorbent to enhance the adsorption capability to contaminants, and hence improve self-cleaning effectiveness. Previously there were some similar reported studies, but none of them are as facile, cost-effective and efficient as ours. 

Main challenges/frustration:
It is necessary to keep improve the solar absorption efficiency, to make the proposed desirable photocatalysts with broad solar spectrum utilization and high self-decontaminating strength for toilet seat coatings.  

To better understand the adsorption concept, we can use a metaphor here. Someone tries to catch fish in a lake. If he/she just uses bare hands, it is difficult. With the help of a hook and bait, he/she impales fish first. Then fish can be caught much easier. So for our adsorption studies which demonstrated fast photodegradation performance, the photocatalyst is the fish person, the carbon coating is the hook and bait, toxic dye/bacteria/fungi is the fish, and the fast photodegradation performance is similar to faster/easier fish catching.

I am happy to answer any questions about my grant that you may have.

Regards,
Yuanbing

++++++++++++++
Yuanbing Mao, Ph.D.
Assistant Professor

Department of Chemistry
University of Texas - Pan American
1201 West University Drive
Edinburg, TX 78539-2999
USA

Web: portal.utpa.edu/utpa_main/daa_home/cose_...dstaff/chemistry_mao
Blog: maolab.blogspot.com

     
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  • cecile
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  • I am a free lance environmental consultant. I undertake socio-economic studies and research in sanitation projects and translations. I am a former business developer for Ecodomeo (vermicomposting UD toilets manufacturer).
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Re: Novel spray paints for self-decontaminating latrine coatings (University of Texas - Pan American, USA)

Hi Yuanbing,

Your reseach is very innovative and new to my field of knowledge so sorry in advance if my question is weird.
In order to know the efficiency of this paint in decontaminating, do you contaminate first ? And if so, which pathogens did you inoculate ?
For example could there an application for toilets in emergencies and for cholera outbreak ? For flues ? intestinal bacteria ?
I would see an intesting application on door handles for example.
thank you !
Cecile

Cécile Laborderie
MAKATI Environnement
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  • JKMakowka
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  • Just call me Kris :)
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Re: Novel spray paints for self-decontaminating latrine coatings (University of Texas - Pan American, USA)

Yes, door-handles, anal-washing shower handles and toilet flush buttons seem to be almost the only interesting application of this.

What I mean is that toilet surfaces rarely actually have a problem with hygiene, e.g. there is little reason why one should disinfect them (there are more bacteria in your keyboard then can be found on a typical toilet seat).
Now if it was actually cleaning them, in the sense of removing stains I would agree that it makes sense, but I doubt it will have much effect on that.

The main problem in sanitation is to disinfect the fecal matter to allow for safe agricultural reuse, and that problem can't be addressed by your proposed method I guess.

P.S.: Most VIP latrines are intentionally build as dark as possible inside (to not attract flies into the inside), so photoactivating would not work on the toilet seat there anyways.

Microbiologist & emergency WASH specialist
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  • MaoatUTPA
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Re: Novel spray paints for self-decontaminating latrine coatings (University of Texas - Pan American, USA)

Hi Cecile,

Thanks for your kind comments and questions. Yes, you are right. To test the efficiency of our samples, we contaminate first, and so far by using E. coli.

Great points: I also really like to see the applications for toilets in emergencies, countertops, door handles (especially in public areas such as hospitals), and even carpets (of course before incorporating our functional components into paint).

At this moment, their applications for cholera outbreak, flues, or intestinal bacteria needs some more brainstorming.

Thank you!
Yuanbing
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  • MaoatUTPA
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Re: Novel spray paints for self-decontaminating latrine coatings (University of Texas - Pan American, USA)

Hi Julius,
Many thanks for your comments.
Yuanbing
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