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Effect of eggshell- and homo-type Ni/Al2O3 catalysts on the pyrolysis of food waste under CO2 atmosphere

Valizadeh S, Ko CH, Lee J, Lee SH, Yu YJ, Show PL, et al.

J Environ Manage, 2021 Sep 15;294:112959.
PMID: 34116308 DOI: 10.1016/j.jenvman.2021.112959

This study highlights the potential of pyrolysis of food waste (FW) with Ni-based catalysts under CO2 atmosphere as an environmentally benign disposal technique. FW was pyrolyzed with homo-type Ni/Al2O3 (Ni-HO) or eggshell-type Ni/Al2O3 (Ni-EG) catalysts under flowing CO2 (50 mL/min) at temperatures from 500 to 700 °C for 1 h. A higher gas yield (42.05 wt%) and a lower condensable yield (36.28 wt%) were achieved for catalytic pyrolysis with Ni-EG than with Ni-HO (34.94 wt% and 40.06 wt%, respectively). In particular, the maximum volumetric content of H2 (21.48%) and CO (28.43%) and the lowest content of C2-C4 (19.22%) were obtained using the Ni-EG. The formation of cyclic species (e.g., benzene derivatives) in bio-oil was also effectively suppressed (24.87%) when the Ni-EG catalyst and CO2 medium were concurrently utilized for the FW pyrolysis. Accordingly, the simultaneous use of the Ni-EG catalyst and CO2 contributed to altering the carbon distribution of the pyrolytic products from condensable species to value-added gaseous products by facilitating ring-opening reactions and free radical mechanisms. This study should suggest that CO2-assisted catalytic pyrolysis over the Ni-EG catalyst would be an eco-friendly and sustainable strategy for disposal of FW which also provides a clean and high-quality source of energy.
Biohydrogen production from catalytic conversion of food waste via steam and air gasification using eggshell- and homo-type Ni/Al2O3 catalysts

Valizadeh S, Lam SS, Ko CH, Lee SH, Farooq A, Yu YJ, et al.

Bioresour Technol, 2021 Jan;320(Pt B):124313.
PMID: 33197736 DOI: 10.1016/j.biortech.2020.124313

Steam and air gasification with 5 wt% Ni/Al2O3 eggshell (Ni-EG) and homo (Ni-H) catalysts were performed for the first time to produce biohydrogen from food waste. The steam gasification produced comparably higher gas yield than air gasification. In non-catalytic experiments, steam gasification generated a higher volume percent of H2, whereas more CO, CO2, CH4, and C2-C4 were produced in air gasification. Ni-EG demonstrated higher potential to obtain H2-rich gases with a low C2-C4 content compared to that obtained by Ni-H, particularly in steam gasification at 800 °C, which produced gaseous products with 59.48 vol% H2. The long-term activity of both catalysts in steam gasification was evaluated, and Ni-EG exhibited higher stability than Ni-H. The ideal distribution of Ni species on the outer region of γ-Al2O3 pellets in Ni-EG resulted in higher activity, stability, and selectivity than Ni-H in both steam and air gasification.
Fulltext Evidence-based cardiovascular magnetic resonance cost-effectiveness calculator for the detection of significant coronary artery disease

Pandya A, Yu YJ, Ge Y, Nagel E, Kwong RY, Bakar RA, et al.

J Cardiovasc Magn Reson, 2022 01 06;24(1):1.
PMID: 34986851 DOI: 10.1186/s12968-021-00833-1

BACKGROUND: Although prior reports have evaluated the clinical and cost impacts of cardiovascular magnetic resonance (CMR) for low-to-intermediate-risk patients with suspected significant coronary artery disease (CAD), the cost-effectiveness of CMR compared to relevant comparators remains poorly understood. We aimed to summarize the cost-effectiveness literature on CMR for CAD and create a cost-effectiveness calculator, useable worldwide, to approximate the cost-per-quality-adjusted-life-year (QALY) of CMR and relevant comparators with context-specific patient-level and system-level inputs.
METHODS: We searched the Tufts Cost-Effectiveness Analysis Registry and PubMed for cost-per-QALY or cost-per-life-year-saved studies of CMR to detect significant CAD. We also developed a linear regression meta-model (CMR Cost-Effectiveness Calculator) based on a larger CMR cost-effectiveness simulation model that can approximate CMR lifetime discount cost, QALY, and cost effectiveness compared to relevant comparators [such as single-photon emission computed tomography (SPECT), coronary computed tomography angiography (CCTA)] or invasive coronary angiography.
RESULTS: CMR was cost-effective for evaluation of significant CAD (either health-improving and cost saving or having a cost-per-QALY or cost-per-life-year result lower than the cost-effectiveness threshold) versus its relevant comparator in 10 out of 15 studies, with 3 studies reporting uncertain cost effectiveness, and 2 studies showing CCTA was optimal. Our cost-effectiveness calculator showed that CCTA was not cost-effective in the US compared to CMR when the most recent publications on imaging performance were included in the model.
CONCLUSIONS: Based on current world-wide evidence in the literature, CMR usually represents a cost-effective option compared to relevant comparators to assess for significant CAD.

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