Engineering topics

Liang, Yuanzhe

Publications and source records attributed to Liang, Yuanzhe.

3 records

DOE OSTI2023

Circular Plastics Technologies: Depolymerization of Polymers Into Parent Monomers

While most commodity plastics were not designed to easily depolymerize, some common plastics can be broken down into their parent monomers in the presence of heat, pressure, catalysts, and/or solvent. Here, we provide a high-level overview of the depolymerization technologies that have been studied and/or scaled as promising monomer-loop recycling processes for selective plastic waste streams. Namely, commodity plastics that are considered unzippable/depolymerizable include polyethylene terephthalate, polyamides, polymethyl methacrylate, and polystyrene. Monomer-loop recycling technologies are one of several pathways toward a circular economy for plastics.

circularity↗

DOE OSTI2023

Novel method for accurately estimating membrane transport properties and mass transfer coefficients in reverse osmosis

Here, we present a simple and robust method to simultaneously characterize the water and salt permeability (A, B) of reverse osmosis (RO) membranes and mass transfer coefficient (k) in membrane modules. The proposed methodology comprises a set of RO experiments performed at different operating pressures or stages. The measured water and salt fluxes in each stage are simultaneously fitted to the RO transport equations by performing a non-linear regression, using A, B, and k as regression parameters. We first perform a systematic accuracy analysis of the proposed method across the full operational range of RO. The assessment shows that the method accuracy is substantially higher than current methods and increases with number of experimental stages and driving forces. This assessment is used to inform the design of an experimental protocol that minimizes errors in estimated A, B, and k. We then evaluate two commercial RO membranes following the new protocol. For both membranes, A and B parameters decrease by 17% and 15% from the dilute solution to seawater concentrations, whereas the k parameter remains constant. Our study demonstrates that the proposed method, informed by data-driven experimental designs, provides a new approach for accurately characterizing transport phenomenon in membrane processes with feeds of less than 100 g/L total dissolved solids.

36 MATERIALS SCIENCE↗

DOE OSTI2023

Trends and future outlooks in circularity of desalination membrane materials

Reverse osmosis desalination is one of the most important and increasingly popular technologies to augment available water resources. Central to the technology is a thin-film-composite polyamide membrane capable of separating pure water from seawater or brine. Since its conception and initiation, the membrane industry has followed a linear life-cycle scheme. However, increasing production costs of fossil-based materials and more stringent environmental regulations drive the initiatives to adapt to a circular economy of membrane materials. In this perspective, we briefly summarize the pressing issues in the state-of-the-art membrane industry, then discuss the opportunities in future technology innovations with a focus on sustainable membrane manufacturing and recycling, and lastly provided an outlook for future membrane design and fabrication towards a circular economy.

29 ENERGY PLANNING, POLICY, AND ECONOMY↗