Mircea Gabriel Macavei

@upb.ro

National University of Science and Technology Politehnica of Bucharest

Mircea Gabriel Macavei


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https://researchid.co/mircea.macavei
Researcher in thermochemical conversion and waste valorization, with expertise in conventional and microwave-assisted pyrolysis, gasification, reaction kinetics, catalyst and susceptor development, and process modeling. Current work focuses on the conversion of polymeric and animal-derived wastes through integrated experimental and modeling approaches, with emphasis on process optimization, mass–energy assessment, and the development of sustainable waste-to-resource pathways.

RESEARCH, TEACHING, or OTHER INTERESTS

Renewable Energy, Sustainability and the Environment, Environmental Engineering, Waste Management and Disposal
7

Scopus Publications

63

Scholar Citations

4

Scholar h-index

3

Scholar i10-index

Scopus Publications

  • Bio-based compounds from synergistic processing of bone waste via advanced ultrasound assisted-enzymatic pretreatment and fast pyrolysis
    Gabriela Ionescu, Mircea Gabriel Macavei, Mariana Pătrașcu, Agata Mlonka-Mędrala, Gabriela Petcu, Szymon Sobek, Aneta Magdziarz, Cosmin Mărculescu
    Bioresource Technology, 2026
    • CBW pretreatment and fast pyrolysis conditions enhanced the gas energy potential. • Enzymatically pretreatment enhances biochar properties to be utilized as functional material. • Production of high concentrations of pyrrole and pyrrolo[1,2-a] pyrazine-1,4-dione,hexahydro. • New synergistic process that boosts products’ potential functionalities. This study investigates the synergistic processing of chicken bone waste through a novel combination of advanced ultrasound-assisted enzymatic pretreatment and fast pyrolysis conditions (500–900 °C, ∼100 °C/min). The higher process temperature inhibits CO 2 , and promotes ≥ C 2 , CH 4 , CO and H 2 . The pyrolysis gas energetic potential reaches a maximum of 33 MJ/Nm 3 , thus can serve as biofuel. The bio-oil derived from the pyrolysis of feedstock, whether pretreated by classical or enzymatic methods, yields rich in N -heterocycles. At ≥ 700 °C, bio-oil contains more heterocyclic compounds and hydrocarbons. Pyrolysis of enzymatically pretreated feedstock results in higher concentrations of pyrrole and pyrrolo[1,2- a ]pyrazine-1,4-dione, hexahydro, which are valuable for the synthesis of organonitrogen compounds relevant to the agriculture, pharmaceutical and advanced materials industries. The H/C < 0.7 and O/C < 0.28 ratios, together with the phosphorus content, indicated a stable high-quality biochar. The increase of process temperature decreases biochar yield, doubles ash content, promotes density and improves thermal stability. The total heat absorbed increases from 22 kJ (500 °C) to 39 kJ (900 °C), indicating a moderate energy demand for pyrolysis. This synergistic processing promotes sustainable poultry waste management and facilitates the circular utilisation of bio-based, compound-oriented products, for their potential use as renewable gases, green chemicals and functional biochar.
  • Bio-based material as microwave susceptor and catalyst support for plastic waste microwave-assisted pyrolysis
    Mircea Gabriel Macavei, Mariana Pătrașcu, Gabriela Ionescu, Virginia-Cora Gheorghe, Gabriela Petcu, Adrian Volceanov, Aneta Magdziarz, Cosmin Mărculescu
    Clean Technologies and Environmental Policy, 2025
    Worldwide, the waste generated by the food industry sector is expected to increase due to demographic extension and consumer-driven society effect. One type of this waste is represented by animal bone. This study explores the valorization of biochar obtained from chicken bone waste (CBW) pyrolysis at 500–700 °C. The biochar obtained at 700 °C showed better characteristics, such as higher porosity, specific surface area and dielectric proprieties. Further on, the biochar was activated through microwave (MW) treatment to improve its structure and morphology. The activated biochar was investigated as microwave susceptor material and catalyst support for microwave-assisted pyrolysis of low-density polyethylene (LDPE) packaging waste. Compared to common microwave susceptors, the activated biochar proved good microwave absorption capabilities, reaching temperatures of 450 °C. Additionally, the biochar was used as catalyst support, doped with silicon, titanium, and zinc oxides with applications in plastic pyrolysis. As catalyst in microwave-assisted pyrolysis (MAP) of LDPE, it enhanced the gas yield of the process, obtaining a pyro-gas composition rich in hydrogen (43%). These findings prove the dual functionality of the CBW-derived biochar, providing a new sustainable solution for converting chicken bone and plastic waste into value-added products. Graphical abstract
  • Heat and flow dynamics in biomass reactors under pyrolysis conditions: Computational insights
    Mihai Rares Sandu, Dorin Boldor, Mircea Gabriel Macavei, Aneta Magdziarz, Cosmin Marculescu
    Renewable Energy, 2025
    This study investigates the heat transfer and fluid flow phenomena in a tubular reactor designed for biomass pyrolysis, using both experimental and numerical methods. A comprehensive 3D Computational Fluid Dynamics (CFD) model was developed in COMSOL Multiphysics, incorporating the reactor geometry, operating parameters, and biomass properties to simulate thermal behavior. Experiments were conducted with chicken wing bones as feedstock, with temperatures monitored at three points along the reactor to validate the model. The simulations replicated experimental conditions, including nitrogen flow at 0.5 l/min and reactor wall temperature set at 550 °C. The model accurately predicted temperature distributions and heat transfer within the reactor, with deviations below 5 % at steady-state. Results showed that thermal equilibrium was achieved at 960 s in the empty reactor and 1200 s in the reactor with biomass loaded at the center, with uniform temperatures of approximately 520–550 °C along the reactor. Axial and radial temperature uniformity was observed, though localized heat accumulation occurred in the reactor's middle section during early heating phases. This research advances the predictive modeling of biomass pyrolysis by providing a validated tool for optimizing reactor design. These findings contribute to sustainable bioenergy technologies by improving reactor efficiency and enabling the effective utilization of organic feedstocks for bio-based products.
  • KINETIC INVESTIGATION OF LOW-DENSITY POLYETHYLENE PYROLYSIS: EFFECTS OF HEATING RATE
    UPB Scientific Bulletin Series C Electrical Engineering and Computer Science, 2025
  • ENERGY RECOVERY FROM BONE WASTE GASIFICATION
    Energy Environment Efficiency Resources Globalization, 2025
  • New integrated processing of chicken bone waste using an enzymatic pretreatment and slow pyrolysis to produce green chemicals
    Gabriela Ionescu, Mircea Macavei, Mariana Pătrascu, Adrian Volceanov, Roxana Pătrascu, Sebastian Werle, Agata Mlonka-Mędrala, Alina Elena Coman, Aneta Magdziarz, Cosmin Mărculescu
    Energy Conversion and Management, 2025
    • Combined biological and slow pyrolysis conversion of bone waste into green chemicals. • New enzymatic mix of protease, lipase and amylase pretreatment for chicken bone waste. • Novel integrated processing enhances potential functionalities of pyrolysis products. • Producing alkanes, fatty acids, ketone, aldehydes, furan deriv., phenolic compounds. The growing global demand for meat consumption, especially for poultry, has led to an increase in bone waste production that necessitates sustainable waste management strategies. This study proposes a new processing method for Chicken Bone Waste (CBW) and evaluates the reactant’s potential usage. The novel approach to this issue consists of the integration of an enzymatic pretreatment to CBW before being subjected to the pyrolysis process. First, the CBW were classically processed (CBW classic) and then underwent a novel enzymatic pretreatment that consisted of a mixture of protease, lipase, and amylase (CBW enzymes). The pretreated CBW were slowly pyrolyzed (10 °C/min) at temperatures between 500–900 °C. The increase in temperature led to a decrease in biochar yield of 45 ± 3 wt%. In addition, the biochar thermal stability increased with the augmentation of process temperature. The pyro-gas primary consists of CO 2 and ≥ C 2 , CO, CH 4, and H 2 . Higher process temperatures enhanced the production of ≥ C 2 and H 2 . The maximum oil yields were 45.3 wt% (600 °C, CBW classic) and 38.5 wt% (500 °C, CBW enzymes). The bio-oil obtained from CBW enzymes at 600 °C exhibits higher yielding valuable compounds. Chemicals identified in the main groups can be used as scaffolds for plant protection products, waxes and polishes, fireproofing, textiles, rubber, jet fuel, biodiesel, etc. The study concludes that the novel integrated processing enhances the potential functionalities of pyrolysis products by producing green, renewable chemicals and resources.
  • Thermochemical Conversion of Animal-Derived Waste: A Mini-Review with a Focus on Chicken Bone Waste
    Mircea Gabriel Macavei, Virginia-Cora Gheorghe, Gabriela Ionescu, Adrian Volceanov, Roxana Pătrașcu, Cosmin Mărculescu, Aneta Magdziarz
    Processes, 2024
    Food waste, particularly animal-derived waste, presents a significant challenge globally, prompting the need for sustainable management strategies. In 2022, the amount of food waste per capita reached 131 kg/capita in the EU (European Union), which is why the search for environmentally friendly ways to manage food waste through thermochemical conversion processes has gained momentum in recent years. Animal-derived waste is a good source of organic matter (proteins, lipids, and polysaccharides) and mineral compounds (calcium phosphate, mostly hydroxyapatite). This composition makes animal-derived waste valuable for the extraction of chemical compounds, such as hydroxyapatite (HAp), which constitutes up to 70 wt% of animal bones; keratin; collagen; and hyaluronic acid (HA), to produce pharmaceutical, medical, or industrial by-products. The thermochemical conversion of chicken bones through pyrolysis and gasification creates a new opportunity to valorize this type of waste by reintroducing valuable by-products into the economy and thus achieving sustainable waste management objectives. The results of this study showcase the multiple applications of the pyrolysis of chicken bone waste products (as adsorbents in aqueous mediums, catalysts, fertilizers, and biomedical applications) and the necessity of a better exploration of the gasification process of chicken bone waste. Therefore, this study explores the properties of animal-derived waste and discusses the pyrolysis and gasification of chicken bone waste, the influence of process conditions on product yields, and the catalytic enhancement of these thermochemical processes.

RECENT SCHOLAR PUBLICATIONS

  • Bio-based compounds from synergistic processing of bone waste via advanced ultrasound assisted-enzymatic pretreatment and fast pyrolysis
    G Ionescu, MG Macavei, M Pătraşcu, A Mlonka-Mędrala, G Petcu, ...
    Bioresource Technology, 134860 , 2026
    2026
  • Energy recovery from bone waste gasification
    MG Macavei, R Pătrașcu, G Ionescu, C Mărculescu
    EMERG: Energy. Environment. Efficiency. Resources. Globalization 11 (4) , 2025
    2025
  • Kinetic investigation of low-density polyethylene pyrolysis: effects of heating rate
    MG Macavei, G Ionescu, C Mărculescu
    UPB Scientific Bulletin, Series C: Electrical Engineering 87 (3), 509-523 , 2025
    2025
  • Bio-based material as microwave susceptor and catalyst support for plastic waste microwave-assisted pyrolysis
    MG Macavei, M Pătrașcu, G Ionescu, VC Gheorghe, G Petcu, ...
    Clean Technologies and Environmental Policy, 1-15 , 2025
    2025
    Citations: 13
  • Heat and flow dynamics in biomass reactors under pyrolysis conditions: Computational insights
    MR Sandu, D Boldor, MG Macavei, A Magdziarz, C Marculescu
    Renewable Energy 244, 122691 , 2025
    2025
    Citations: 7
  • Energy recovery and economic viability of animal-derived waste air gasification for syngas production
    MG Macavei, R Pătrașcu, C Mărculescu
    International Conference of Management and Industrial Engineering 12, 538-545 , 2025
    2025
  • New integrated processing of chicken bone waste using an enzymatic pretreatment and slow pyrolysis to produce green chemicals
    G Ionescu, M Macavei, M Pătrascu, A Volceanov, R Pătrascu, S Werle, ...
    Energy Conversion and Management 323, 119281 , 2025
    2025
    Citations: 18
  • Thermochemical conversion of animal-derived waste: A mini-review with a focus on chicken bone waste
    MG Macavei, VC Gheorghe, G Ionescu, A Volceanov, R Pătrașcu, ...
    Processes 12 (2), 358 , 2024
    2024
    Citations: 25

MOST CITED SCHOLAR PUBLICATIONS

  • Thermochemical conversion of animal-derived waste: A mini-review with a focus on chicken bone waste
    MG Macavei, VC Gheorghe, G Ionescu, A Volceanov, R Pătrașcu, ...
    Processes 12 (2), 358 , 2024
    2024
    Citations: 25
  • New integrated processing of chicken bone waste using an enzymatic pretreatment and slow pyrolysis to produce green chemicals
    G Ionescu, M Macavei, M Pătrascu, A Volceanov, R Pătrascu, S Werle, ...
    Energy Conversion and Management 323, 119281 , 2025
    2025
    Citations: 18
  • Bio-based material as microwave susceptor and catalyst support for plastic waste microwave-assisted pyrolysis
    MG Macavei, M Pătrașcu, G Ionescu, VC Gheorghe, G Petcu, ...
    Clean Technologies and Environmental Policy, 1-15 , 2025
    2025
    Citations: 13
  • Heat and flow dynamics in biomass reactors under pyrolysis conditions: Computational insights
    MR Sandu, D Boldor, MG Macavei, A Magdziarz, C Marculescu
    Renewable Energy 244, 122691 , 2025
    2025
    Citations: 7
  • Bio-based compounds from synergistic processing of bone waste via advanced ultrasound assisted-enzymatic pretreatment and fast pyrolysis
    G Ionescu, MG Macavei, M Pătraşcu, A Mlonka-Mędrala, G Petcu, ...
    Bioresource Technology, 134860 , 2026
    2026
  • Energy recovery from bone waste gasification
    MG Macavei, R Pătrașcu, G Ionescu, C Mărculescu
    EMERG: Energy. Environment. Efficiency. Resources. Globalization 11 (4) , 2025
    2025
  • Kinetic investigation of low-density polyethylene pyrolysis: effects of heating rate
    MG Macavei, G Ionescu, C Mărculescu
    UPB Scientific Bulletin, Series C: Electrical Engineering 87 (3), 509-523 , 2025
    2025
  • Energy recovery and economic viability of animal-derived waste air gasification for syngas production
    MG Macavei, R Pătrașcu, C Mărculescu
    International Conference of Management and Industrial Engineering 12, 538-545 , 2025
    2025