Tohoku University · Engineering
Professor Zhengyang Zhang's research lab specializes in sustainable materials management, with a focus on circular economy systems, material flow analysis, and resource recovery. The lab investigates the environmental and socioeconomic impacts of global supply chain disruptions—particularly in food and fertilizer—while advancing innovative recycling and reuse strategies for critical materials like aluminum and steel in automotive applications. It also explores emerging technologies such as photocatalytic hydrogen production and the traceability of agricultural plastic pollution to support sustainable development. The lab integrates dynamic modeling tools like the MaTrace model to quantify material dissipation and evaluate the effectiveness of remanufacturing and recycling in closing material loops.
Figures are computed from collected data and may differ slightly.
Disruptions of key food and fertilizer exports from Russia and Ukraine have exposed many countries to challenges accessing some commodities since these countries' war began. We evaluated the short-term, external, and direct impacts of disruptions of six food commodities and three types of fertilizer supplies from Russia and Ukraine on food access for all trading partners of the two countries by applying a set of trade and socioeconomic indicators. We found that the external food supplies of 279
Electrification and vehicle weight reduction (lightweighting) trends are driving demand for wrought aluminum alloys. Given that aluminum scrap is currently downgraded as it is recycled into cast aluminum alloys, an imbalance in aluminum cycles is predicted to occur. We identified secondary aluminum flows by distinguishing alloy type in China with material flow analysis. Considering the adoption of advanced recovery techniques and the trends towards greater use of electric vehicles and vehicle li
Remanufacturing gives a full new service life for every usage cycle of a product. Since remanufacturing avoids material dissipation, it is conceivably superior to material recycling. However, quantifying the effectiveness of remanufacturing is difficult due to the fundamental lack of indicators and supporting tools designed for the task. In this study, the volume of avoided material dissipation was adopted as an evaluation indicator to measure the effect of product service life extension. The ci
We report an azide-functionalized cobaloxime proton-reduction catalyst covalently tethered into the Wurster-type covalent organic frameworks (COFs). The cobaloxime-modified COF photocatalysts exhibit enhanced photocatalytic activity for hydrogen evolution reaction (HER) in alcohol-containing solution with no presence of a typical sacrificial agent. The best performing cobaloxime-modified COF hybrid catalyzes hydrogen production with an average HER rate up to 38 μmol h<sup>-1</sup> in ethanol/pho
Plastic pollution from agricultural production poses discernible risks to food security and safety. This work endeavors to address the gap of quantification and traceability of agricultural plastic pollution by estimating plastic loss associated with diverse farm activities and explore potential mitigation strategies. Results revealed that annual agricultural plastic pollution in China amounted to 570 kt. The main sources of the pollution were identified as the use of mulching film in agricultur
According to the concept of a circular economy, further promotion of reuse and recycling might aid in closing the loop. However, material recycling may cause various types of material losses due to thermodynamic limitations and product complexity. In this study, we focused on automobile engines and their reuse, with the aim of quantifying the amount of dissipated steel alloy and its constituent elements (nickel and chromium) from the engine recycling process. We also elaborated upon their dissip
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