The next projected steps in the photocatalysis project for a circular ‘trashcan of the future’ are to get a more specific and efficient by understanding from the macro to the nano levels what is occurring and optimizing for the desired results of producing useful byproducts, most importantly water. That means developing a consist formula or process for conversion, knowing exactly how to conduct electrons into their new positions. With water, that is also well rehearsed in their atomic repertoire. The vision is waste receptacles of various kinds producing byproducts that people want and need. Imagine a public trash can that also doubles as a water fountain and purifier. Discussed here is the goal of drawing on different disciplines and weaving together known information to achieve the design build.
Microscopy:
Different types of microscopy will be valuable for the materials characterization of different plastics – especially ‘forever’ plastics, as well as data analysis and visualization for the purpose of effectively communicating the findings to others. Different plastic samples from PET to Polypropylene can be exposed to different types or bandwidths of light, and observed on the atomic level for response. There’s several types of microscopy that can contribute to gathering important information, from Electron to Fluorescence to the Laser Scanning Microscope. It’s important to quantify, use and observe the energy levels required for particular atomic electron transitions, or quantum leaps or jumps. And electrical current or field facilitates the movements. (1)
The energy to shift levels, positive or negative, could be for either photoexcitation or relaxation. Collecting these ionization energy levels, in addition to bond angles, represents known information that will be put to new and novel use in the device, but certainly not limited to the device.
The output of all relevant data and observations will be the ultimate light combination or sequence to install in order to achieve plastic to water conversion. Or perhaps even plastic to light. Other concurrent and numerous academic and industrial findings in photonics are tremendously encouraging for the success of this project, such as a recent demonstration at MIT of photomolecular evaporation without heat. (2)
It’s possible the designs and light interactions of the microscopes themselves with the plastic samples will also inspire the interior design of the receptacle – with type of light, use of filters, mirrors and more. Another goal is still to keep things as streamlined as possible, for ease of reproduction and adaptability to other installations.
Materials Science:
The above microscopy viewpoint is further inspired by touring the MIT Nano facility, which is open to external users, and materials testing. Regarding materials, it’s important that the construction of the container be conducive to light reflectivity, possibly amplification and enhancing the photochemical process. Some highly reflective materials include aluminum, steel and silver, and those could be used for the interior. The exterior could also be aluminum, or other safe material that blocks or absorbs radiation. Thus far galvanized steel has been testing and the combination of steel and UV was enough to produce a little bit of water from PET.
In more experimental territory, perhaps the combination of aluminum and graphene aka “doped graphene” may be appropriate given other research indicating its usefulness in “the catalytic decomposition of undesirable materials” (3) and for oxygen reduction reaction, and photochemical water splitting. (4) Another strong possibility could be anodized steel, and anodized with zinc oxide, which is a known as an effective photocatalyst. A combination of the above-mentioned materials could enhance the overall function of the ‘trash can of the future.’ All parts of the design will be geared towards successful interaction with the photochemical task, with manufacturing feasibility and sustainability at the forefront.
As for the specific light components, ultraviolet purple, green and blue are looking promising, with results from just UV lights. And then, cold or cool lasers are another possibility. (2) Still though, safety for public use in a variety of circumstances is the priority.
Functional Design:
The aesthetic design and architecture or topography can also contribute to the photochemical process. The most important design goal is to facilitate or enhance the process. By scaling the micro to the macro, the appearance of the receptacles could be intriguing and beautiful, adding to public spaces in their physical presence, as well as extremely useful.
Prism structures, for example, are known for many light-related advantages, including special correlation of dihedral angles of the surfaces (between prism faces) and bond angles between the molecules. This would look like a sculptural container.
The Wedge Prism is a compelling example, or a Hexagonal Prism to complement the ionization of the benzene ring in PET. Or, consider a trapezoidal dumpster or equally intriguing yet also geometrically advanced shape, that you just deposit your trash into, and then the receptacle basically converts into something useful like water, or possibly pure light. This amazing feat is looking more feasible by the day. And more like an art installation too.
Conclusion:
To solve the puzzle of creating a high functioning, photocatalytic and circular waste receptacle, it’s necessary to work simultaneously at different levels along the spectrum of relevant sciences, from considering the movement of atoms and molecules, to the smart engineering of the macrostructure.
How much and in what way does one have to move the molecules of PET to get water byproduct? Going forward, accessing more advanced equipment, and assembling information such as the energy levels of different orbitals, will eventually answer this. Thus far AI and ML have not been utilized, but their potential could help speed up calculations and optimization. Thus far, the human ability to think both inside and outside of systems is proving useful, as well as the ability to cross reference or be ‘cross-functional.’ It is helping to stay curious, with awe and reverence for the forces of nature. The next article post will be about molecular geometry, angles and energy levels.
It’s reasonable to expect that when applying advanced tools to specific goal directed tasks that ask a different set of questions; that when looking at the intelligence of nature from a different perspective or dimension, and setting up favorable conditions — there may very well be new and different results, new and evolving behaviors in response. The present future is bright.
1. “Electrical Current” | Iowa State University | Center For Nondestructive Evaluation | https://www.nde-ed.org/Physics/Electricity/voltage.xhtml
2. “How light can vaporize water without the need for heat” | David L. Chandler | MIT News | April 23, 2024 | https://news.mit.edu/2024/how-light-can-vaporize-water-without-heat-0423
3. Direct synthesis of large-area Al-doped graphene by chemical vapor deposition: Advancing the substitutionally doped graphene family | Nano Research, Volume 15, Issue 2, p.1310-1318Pub Date: February 2022 | Ullah, Sami | Liu, Yu | Hasan, Maria ; Zeng, Wenwen ; Shi, Qitao ; Yang, Xiaoqin ; Fu, Lei ; Ta, Huy Q. ; Lian, Xueyu ; Sun, Jingyu ; Yang, Ruizhi ; Liu, Lijun ; Rümmeli, Mark H. | https://ui.adsabs.harvard.edu/abs/2022NaRes..15.1310U/abstract
4. “Amplification of intense light fields by nearly free electrons” | 2018 | Nat Phys. | Mary Matthews,1 Felipe Morales,2 Alexander Patas,3Albrecht Lindinger,3 Julien Gateau,1 Nicolas Berti,1Sylvain Hermelin,1 Jerome Kasparian,1 Maria Richter,4Timm Bredtmann,2 Olga Smirnova,2 Jean-Pierre Wolf,1 and Misha Ivanov2 | | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6071854/
5. “Introduction To Optical Prisms” | Edmund Optics | https://www.edmundoptics.com/knowledge-center/application-notes/optics/introduction-to-optical-prisms/