Has a UC Berkeley chemistry lab discovered the holy grail of plastic recycling?

[NNadir]

8. I accessed the full paper. It's obviously a good paper, but they worked with isolated known materials, not mixed...

...waste.

A picture from the text:



The caption:

Fig. 3. Experiments on the tandem catalytic cracking and isomerizing ethenolysis of polyolefins (CIE).
(A) Yields of CIE on various examples of commercial and waste polypropylene: PP (1.00 g, 23.8 mmol of monomer units), WO3/SiO2 (400.0 mg, 0.1075 mmol W), and Na/γ-Al2O3 (400.0 mg, 1.740 mmol Na) heated to 320°C under 15.0 bar of ethylene (175 mmol) for 90 min. (B) Yields of CIE on various examples of commercial and waste polyethylene: PE (1.00 g, 35.7 mmol of monomer units), WO3/SiO2 (400.0 mg, 0.1075 mmol W), and Na/γ-Al2O3 (400.0 mg, 1.740 mmol Na) heated to 320°C under 15.0 bar of ethylene (175 mmol) for 90 min. (C) Photographs of sources of waste subjected to CIE: waste HDPE (left), waste PP (middle), waste LDPE from a bread bag (right).

(CIE = catalytic cracking and isomerizing ethenolysis)

To my mind, separations are still required; relying on consumers to understand the chemical nature of polymers clearly isn't working.

While I credit the paper as being innovative, and perhaps useful in some settings, to my mind the most likely to succeed approach to this very serious problem would be high temperature (supercritical or at the edge of supercriticality) steam reforming, which oxidizes everything to CO + H₂, "syn gas," hydrogenation of the syn gas to methanol, followed, as necessary by demand, the MTO (methanol to Olefins) reaction. This would only be sustainable in the case nuclear energy were the source of the supercritical water, or sub-supercritical steam.

As to whether I believe a "holy grail" has been obtained, my answer is a firm "no."