Sorin Ștefan Biriș

Prof. Dr. Sorin Ștefan Biriș

University Politehnica of Bucharest, Bucharest, Bucureşti, Romania
orcid

Research Focus & Metrics

Academic Career Length

8Years (2019-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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5 September 2022 in Sustainability
Verified
Journal Article
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Nicoleta UngureanuNicoleta Ungureanu
Nicoleta Ungureanu
Valentin Nicolae VLADUTValentin Nicolae VLADUT
Valentin Nicolae VLADUT
Sorin Ștefan BirișSorin Ștefan Biriș
Sorin Ștefan Biriș
Sugarcane is a lignocellulosic crop and the juice extracted from its stalks provides the raw material for 86% of sugar production. Globally, sugarcane processing to obtain sugar and/or ethanol generates more than 279 million tons of solid and liquid waste annually, as well as by-products; namely, straws, bagasse, press mud, wastewater, ash from bagasse incineration, vinasse from ethanol distillation, and molasses. If not properly managed, this waste will pose risks to both environmental factors and human health. Lately, valorization of waste has gained momentum, having an important contribution to the fulfillment of policies and objectives related to sustainable development and circular bioeconomy. Various technologies are well-established and implemented for the valorization of waste and by-products from sugarcane processing, while other innovative technologies are still in the research and development stage, with encouraging prospects. We propose a sustainable sugarcane processing flow and present an analysis of the physico-chemical characteristics of generated wastes and by-products. We emphasize the available possibilities of valorizing each waste and by-product, considering that they are important biomass resources for obtaining biofuels and a wide range of other products with added value, which will contribute to the sustainability of the environment, agriculture, and human health worldwide.

29 August 2025 in Sustainability
Verified
Journal Article
Open access
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Nicoleta UngureanuNicoleta Ungureanu
Nicoleta Ungureanu
Valentin Nicolae VLADUTValentin Nicolae VLADUT
Valentin Nicolae VLADUT
Sorin Ștefan BirișSorin Ștefan Biriș
Sorin Ștefan Biriș
NGNeluș Evelin Gheorghiță
Neluș Evelin Gheorghiță
MIMariana Ionescu
Mariana Ionescu
The increasing demand for renewable energy has intensified research on lignocellulosic biomass pyrolysis as a versatile route for sustainable energy and resource recovery. This study provides a comparative overview of main pyrolysis regimes (slow, intermediate, fast, and flash), emphasizing operational parameters, typical product yields, and technological readiness levels (TRLs). Reactor configurations, including fixed-bed, fluidized-bed, rotary kiln, auger, and microwave-assisted systems, are analyzed in terms of design, advantages, limitations, and TRL status. Key process parameters, such as temperature, heating rate, vapor residence time, reaction atmosphere, and catalyst type, critically influence the yields and properties of biochar, bio-oil, and syngas. Increased temperatures and fast heating rates favor liquid and gas production, whereas lower temperatures and longer residence times enhance biochar yield and carbon content. CO2 and H2O atmospheres modify product distribution, with CO2 increasing gas formation and biochar surface area and steam enhancing bio-oil yield at the expense of solid carbon. Catalytic pyrolysis improves selectivity toward target products, though trade-offs exist between char and oil yields depending on feedstock and catalyst choice. These insights underscore the interdependent effects of process parameters and reactor design, highlighting opportunities for optimizing pyrolysis pathways for energy recovery, material valorization, and sustainable bioeconomy applications.

23 July 2025 in Sustainability
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Journal Article
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Nicoleta UngureanuNicoleta Ungureanu
Nicoleta Ungureanu
Valentin Nicolae VLADUTValentin Nicolae VLADUT
Valentin Nicolae VLADUT
Sorin Ștefan BirișSorin Ștefan Biriș
Sorin Ștefan Biriș
MIMariana Ionescu
Mariana Ionescu
NGNeluș Evelin Gheorghiță
Neluș Evelin Gheorghiță
Gasification of municipal solid waste and other biogenic residues (e.g., biomass and biowaste) is increasingly recognized as a promising thermochemical pathway for converting non-recyclable fractions into valuable energy carriers, with applications in electricity generation, district heating, hydrogen production, and synthetic fuels. This paper provides a comprehensive analysis of major gasification technologies, including fixed bed, fluidized bed, entrained flow, plasma, supercritical water, microwave-assisted, high-temperature steam, and rotary kiln systems. Key aspects such as feedstock compatibility, operating parameters, technology readiness level, and integration within circular economy frameworks are critically evaluated. A comparative assessment of incineration and pyrolysis highlights the environmental and energetic advantages of gasification. The valorization pathways for main product (syngas) and by-products (syngas, ash, tar, and biochar) are also explored, emphasizing their reuse in environmental, agricultural, and industrial applications. Despite progress, large-scale adoption in Europe is constrained by economic, legislative, and technical barriers. Future research should prioritize scaling emerging systems, optimizing by-product recovery, and improving integration with carbon capture and circular energy infrastructures. Supported by recent European policy frameworks, gasification is positioned to play a key role in sustainable waste-to-energy strategies, biomass valorization, and the transition to a low-emission economy.

3 June 2023 in Agriculture
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Journal Article
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NNNeiko V. Nikolov
Neiko V. Nikolov
AAAtanas Atanasov
Atanas Atanasov
Boris Ivanov EvstatievBoris Ivanov Evstatiev
Boris Ivanov Evstatiev
Valentin Nicolae VLADUTValentin Nicolae VLADUT
Valentin Nicolae VLADUT
Sorin Ștefan BirișSorin Ștefan Biriș
Sorin Ștefan Biriș
The reduction of the population and labour force in rural areas, adverse climate changes, soil pollution and degradation, and reduced soil fertility necessitate new and intensive approaches to and methods of vegetable production. In this study, a new high-tech, small-scale hydroponic system based on the Internet of Things (IoT) for growing leafy vegetables was designed. For the assembly of the high-tech small-scale hydroponic system, low-cost materials and sensors are used, allowing remote monitoring and process automation during the cultivation of leafy vegetables and seedlings. Experimental investigations of the installation were conducted, with lettuce as the grown crop. The environmental and technological parameters of the system were monitored and analysed in order to assess the suitability of the system. The obtained results confirm that the small-scale hydroponic system maintained the set parameters of air temperature, air humidity and pH of the nutrient solution within the optimal limits for growing lettuce. Other parameters, such as temperature and electrical conductivity of the nutrient solution, had small deviations from the required optimal limits. In the initially set experiment, 75% germination of the lettuce seeds was achieved. The main advantages of the proposed hydroponic system are the simplicity of its management and easy installation. Furthermore, it offers the possibility for remote monitoring and control without any high requirements towards the experience of the user with such facilities. The designed and implemented small hydroponic system can help small and medium-sized vegetable growers achieve indoor sustainable farming of leafy vegetables year-round.

22 September 2022 in Agriculture
Verified
Journal Article
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Valentin Nicolae VLADUTValentin Nicolae VLADUT
Valentin Nicolae VLADUT
Sorin Ștefan BirișSorin Ștefan Biriș
Sorin Ștefan Biriș
PCPetru Cârdei
Petru Cârdei
IGIuliana Gageanu
Iuliana Gageanu
DCDan Cujbescu
Dan Cujbescu
GTGabriel-Ciprian Teliban
Gabriel-Ciprian Teliban
The paper presents a mathematical model that characterizes the process of threshing and separation from the threshing machine with an axial flow of a thresher, taking into account the following input parameters: material flow, rotor speed, distance between rotor and counter rotor, mean density of processed material, feed speed, length of thresher and separating surface. Output parameters, such as the distribution function of separated seeds, distribution density function of separated seeds and distribution function of free seeds in the threshing space, as well as the distribution function of unthreshed seeds, together with the value of evacuation losses, were used to control the modeling process.

25 May 2021 in Materials
Verified
Journal Article
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OSOana Stoian
Oana Stoian
Cristina CovaliuCristina Covaliu
Cristina Covaliu
Gigel ParaschivGigel Paraschiv
Gigel Paraschiv
G(Gina-Alina Catrina (Traistaru)
Gina-Alina Catrina (Traistaru)
Mihai Nita-LazarMihai Nita-Lazar
Mihai Nita-Lazar
PTPaula Tudor
Paula Tudor
The aim of this article is to present a nonconventional method for the efficient removal of lead ions from industrial wastewater. For this purpose, magnetite nanomaterial was used, which was very easily separated from the wastewater at the end of the treatment due to its magnetic properties. Currently, nanotechnology is an efficient and inexpensive manner that is being researched for wastewater treatment. Additionally, iron oxide nanoparticles are widely used to remove heavy metal ions from water due to their special properties. The experimental results detailed in this article show the influence of pH and contact time on the process of adsorption of lead ions from wastewater. The magnetite nanomaterial had its maximum efficiency of speed when the wastewater had pH 6. At a lower pH, the highest treatment efficiency was over 85%, and the required contact time has doubled. When the pH increases above 6, the precipitation process occurs. Langmuir and Freundlich models were used to describe the adsorption process.