Design of Experiment (DoE): Light Energy + Molecular Dynamics For Transformation Of Plastic Into Water

Author: Sarah Ikerd, Studio Shangri-La, sarah.ikerd@studio-shangri-la.com

Visualizations by Meta AI Llama 3

On ResearchGate

The next step in creating photocatalytic circular waste receptacles that can transform plastic into water, as in the beautifully illustrated accompanying visualizations by Meta AI, is to specifically hone that process. The first focus will be on the common PET, although plastic bottles can also include HDPE in the form of caps, and also polypropylene for labels.

Several online sources project plastics like PET taking around 450 years to decompose. (1) Fundamentally, it’s a few plentiful and well known elements, polymerized: Carbon, Hydrogen and Oxygen.

In this particular approach to breakdown or transformation, the individual elements and terminal ends of the larger polymer would be targeted, rather than the whole structure of the polymer or macromolecule.

Now it’s important to collect data relevant to this task — that is, of guiding or signaling electrons to different positions with light energy. There could very well be a light equivalent of cymatics, or use of that phenomenon, a vibrational re-arranging. That remains to be seen fully in physical testing. In the meantime, the goal is to achieving as much “Design of Experiment” as possible.

First, let’s looks at ionization levels (energies), what it would take to move the outermost valence electrons – which have more interaction and freedom – of Carbon, Hydrogen, and Oxygen (2):

· Hydrogen (H) = 13.598 eV (electronvolts)
· Carbon (C): 11.26 eV
· Oxygen (O): 13.618 eV

The goal is to tap into the synergy of molecules non-destructively in the spirit of ‘cooperative inquiry,’ seeking to understand and work with, rather than control or dominate.

Current analysis indicates that by targeting the terminal ends of the polymer with the first ionization levels, that this may be enough to mobilize some desired byproducts. Next let’s take a look a the types of lights to employ by eV to nanometer conversion. (2)

Hydrogen = 91.178 nanometers — UVX 91-200 nm sits on the border between UV and X-ray

Carbon = 110.110 nm

Oxygen = 91.044 nm

These are all extreme ultraviolet and so more difficult to create and handle, and thus less safe. So, it may be very useful to multiple for harmonics of these nanometer ionization levels. That brings another level of meaning to seeking harmonious balance, and also means it makes good sense proceeding with ultraviolet at 200-400 nm.

Let’s look at the harmonic series or multiples of those ionization levels in equivalent nanometers or light energy:

Hydrogen = 91.178 nm

Here are the first 9 multiples of the fundamental wavelength 91.178 nm:

1. Fundamental: 91.178 nm (extreme uv)
2. 2nd multiple: 182.356 nm
3. 3rd multiple: 273.534 nm
4. 4th multiple: 364.712 nm
5. 5th multiple: 455.890 nm (violet light)
6. 6th multiple: 547.068 nm (green-blue light)
7. 7th multiple: 638.246 nm (orange-red light)
8. 8th multiple: 729.424 nm (red light)
9. 9th multiple: 820.602 nm (red light)
10. 10th multiple: 911.780 nm (red light)
11. 11th multiple: 1002.958 nm (near-infrared, but still visible)
12. 12th multiple: 1094.136 nm (near-infrared, still visible – deep red glow, almost imperceptible)
13. 13th multiple: 1185.314 nm (near-infrared, slightly less visible – warm grayish light)
14. 14th multiple: 1276.492 nm (near-infrared, less visible – cool grayish, almost indistinguishable from darkness)

Next is Carbon and here are the 14 multiples:

1st Fundamental: 110.110 nm (XUV)

2nd multiple: 220.220 nm (UV)

3rd multiple: 330.330 nm (UV)

4th multiple: 440.440 nm (violet)

5th multiple: 550.550 nm (green)

6th multiple: 660.660 nm (red)

7th multiple: 770.770 nm (IR)

8th multiple: 880.880 nm (IR)

9th multiple: 991.000 nm (IR)

10th multiple: 1102.120 nm (IR)

11th multiple: 1213.240 nm (IR)

12th multiple: 1324.360 nm (IR)

13th multiple: 1435.480 nm (IR)

14th multiple: 1546.600 nm (IR)

Notice that this harmonic series for the first ionization level of Carbon is a mathematically intriguing repeating or cyclic decimal! And going the other direction of relaxing valence electrons, there is more repetition at the 1/2 and 1/5 harmonics.

Finally, on this topic anyway, here are the 14 multiples of Oxygen’s 91.044 nm wavelength, listed with their corresponding colors:

1. 91.044 nm (fundamental) – ultraviolet
2. 182.088 nm (2 x 91.044 nm) – ultraviolet
3. 273.132 nm (3 x 91.044 nm) – ultraviolet
4. 364.176 nm (4 x 91.044 nm) – ultraviolet
5. 455.220 nm (5 x 91.044 nm) – violet
6. 546.264 nm (6 x 91.044 nm) – green
7. 637.308 nm (7 x 91.044 nm) – yellow
8. 728.352 nm (8 x 91.044 nm) – yellow-orange
9. 819.396 nm (9 x 91.044 nm) – orange
10. 910.440 nm (10 x 91.044 nm) – orange-red
11. 1001.484 nm (11 x 91.044 nm) – red
12. 1092.528 nm (12 x 91.044 nm) – red
13. 1183.572 nm (13 x 91.044 nm) – near-infrared
14. 1274.616 nm (14 x 91.044 nm) – near-infrared

These multiples are in the ultraviolet (UV) visible and near infrared spectrum, making them much more practical and safe for use in a device / waste receptacle. The UV wavelengths have been of particular recent research interest for photocatalysis, but with other catalysts. (3)

The next group of data to collect is bond angles, or molecular geometry:

In PET plastic the overall geometry is “trigonal planar” and so the favored angle is 120 degrees (4) and also linear, 180 degrees.

The favored bond angles in water are ~109 degrees and 104.5 degrees. Interestingly, the V shape or bent formation of a water molecule is shared in common with methylene, which is contained within PET. (5)

And given the aforementioned angles, a plausible theoretical container shape would be a hexagonal prism, given the 120 degree angle between sides. As you can see from the visualizations though, there are many possibilities to explore.

Going forward with “Design of Experiment” and using photocatalysis, it’ll also be important to consider optimizing factors such as:

· Light source
· Light intensity
· Possible additional catalyst & concentration
· Reaction time
· Temperature
· Possible solvent

Overall, the photocatalysis process described here represents a safe and efficient possible approach for circular waste receptacles of different favorable shapes and sizes, being the process uses light in a safe range of the spectrum in order to activate the molecular transformation, modifying the PET polymer chains. This method has several advantages: Mild reaction conditions, high selectivity, low energy requirements, and being environmentally friendly. The approach described here also represents a novel intersectionality of sciences in order to achieve a high impact result for planetary cleanup and sustainability.

1. “In Images: Plastic is Forever” | United Nations | June 2021 | https://www.un.org/en/exhibits/exhibit/in-images-plastic-forever

2. Electron-volts to volts calculator | RapidTables | https://www.rapidtables.com/calc/electric/ev-to-volt-calculator.html

3. “Effect of wavelengths on photocatalytic oxidation mechanism of sulfadiazine and sulfamethoxazole in the presence of TiO₂” | Journal of Environmental Chemical Engineering | Volume 9, Issue 5, October 2021, 106243 | Danping Li, Ning Zhang, Rongfang Yuan, Huilun Chen, Fei Wang, Beihai Zhou | https://www.sciencedirect.com/science/article/abs/pii/S2213343721012203

4. “5.2: Molecular Shape” | Oregon Institute Of Technology | https://chem.libretexts.org/Courses/Oregon_Institute_of_Technology/OIT%3A_CHE_202_-_General_Chemistry_II/Unit_5%3A_The_Strength_and_Shape_of_Covalent_Bonds/5.2%3A_Molecular_Shape

5. “10.2: VSEPR Theory – The Five Basic Shapes” | LibreTexts Chemistry | https://chem.libretexts.org/Bookshelves/General_Chemistry/Map%3A_A_Molecular_Approach_(Tro)/10%3A_Chemical_Bonding_II-_Valance_Bond_Theory_and_Molecular_Orbital_Theory/10.02%3A_VSEPR_Theory_-_The_Five_Basic_Shapes