2024, Volume 70(74), Issue 1 (March)

Contents

pages 1- 8   Download

Preserving The Mechanical Properties of Metakaolin-Based Geopolymer Composite Exposed to Thermal Stress by Using Refractory Filler Wastes

LUCIAN PĂUNESCU, Daily Sourcing & Research SRL Bucharest, Romania, lucianpaunescu16@gmail.com
ADRIAN IOANA, National University of Science and Technology POLITEHNICA Bucharest, Faculty of Science and Materials Engineering, Romania
ENIKÖ VOLCEANOV, National University of Science and Technology POLITEHNICA Bucharest, Faculty of Science and Materials Engineering, Romania, Metallurgical Research Institute SA Bucharest, Romania

pages 9 - 22   Download
DOI: 10.5281/zenodo.11144762
Abstract
Metakaolin-based geopolymer composite with addition of refractory filler wastes (super-aluminous concrete and silica fire brick) recycled from heating oven demolition was designed and tested under thermal stress conditions at temperatures up to 900°C. The method of alkaline activating patented by Davidovits was applied. The originality of the work consists in choosing the super-aluminous concrete waste from the demolition as the main raw material of the process, increasing the heat treatment temperature to 90°C, and adopting the storage for a much longer period (28 days). Tests to thermal stress by exposure to 600 and 750°C showed the favourable influence of the addition of refractory fillers on preserving the mechanical stability of the geopolymer composite. The loss of compression and flexural resistance after exposure to 900°C compared to the reference sample is acceptable for using this technique in the case when the stability at high temperature is required.
Keywords: geopolymer composite, refractory filler waste, metakaolin, thermal stress, mechanical strength.

Quantitative Spectrophotometric Determination of Au(III) Ions in Aqueous Solution with Basic Violet 10 Dye

BIANCA-MARIA HĂISAN, “Gheorghe Asachi” Technical University of Iaşi, “Cristofor Simionescu” Faculty of Chemical Engineering and Environmental Protection, Iaşi, Romania
ALEXANDRA-GEORGIANA APOSTICĂ, “Gheorghe Asachi” Technical University of Iaşi, “Cristofor Simionescu” Faculty of Chemical Engineering and Environmental Protection, Iaşi, Romania
LAURA BULGARIU, “Gheorghe Asachi” Technical University of Iaşi, “Cristofor Simionescu” Faculty of Chemical Engineering and Environmental Protection, Iaşi, Romania, lbulg@ch.tuiasi.ro

pages 23 - 34   Download
DOI: 10.5281/zenodo.11145069
Abstract
Spectrophotometric determination of Au(III) ions with Basic Violet 10 dye is a rapid, sensitive and accurate method that can be used in quantitative analysis. The colour reaction occurs immediately in acidic aqueous solution (pH = 0, HCl solution), and this represents an important advantage from a practical point of view. The qualitative parameters of coloured Au(III)-complex (maximum wavelength (500 nm), width of the spectral band (120 nm) and molar absorption coefficient (2.55·104 L·mol-1·cm-1)) suggest the possibility of using this reaction in quantitative analysis. Lambert-Beer’s law was obeyed in the Au(III) concentration range of 0.4 – 2.0 mg·L-1, while the detection limit and limit of quantification were found to be 0.067 mg·L-1 and 0.22 mg·L-1. This colour reaction is quite selective for Au(III) ions in the presence of some interfering ions (Cu(II), Zn(II), Na(I)), while other metal ions (such as Ca(II), Mg(II), Co(II)) interfere to a great extend. The measurements performed using tap water as a background, showed that there are significant differences between the concentration of Au(III) ions, added and calculated from the calibration curve, which limits the applicability of this method in the analysis of real samples.
Keywords: Spectrophotometric method; Au(III) ions; Basic Violet 10; quantitative analysis.

Visible-Light Photocatalytic Degradation of Tartrazine Using ZnO Nanoparticles: Preliminary Phytotoxicity Investigations on Treated Solutions

MARIA PAIU, “Gheorghe Asachi” Technical University of Iași, “Cristofor Simionescu” Faculty of Chemical Engineering and Environmental Protection, Iași, Romania
LIDIA FAVIER, Univ Rennes, Ecole Nationale Supérieure de Chimie de Rennes, CNRS, ISCR – UMR6226, Rennes, France DOINA LUTIC, “Alexandru Ioan Cuza” University from Iași, Faculty of Chemistry, Iași, Romania
RALUCA-MARIA HLIHOR, “Ion Ionescu de la Brad” Iași University of Life Sciences, Faculty of Horticulture, Department of Horticultural Technologies, Iași, Romania
MARIA GAVRILESCU, “Gheorghe Asachi” Technical University of Iași, “Cristofor Simionescu” Faculty of Chemical Engineering and Environmental Protection, Iași, Romania, Academy of Romanian Scientists, Bucharest, Romania, mgav@tuiasi.ro

pages 35 - 46   Download
DOI: 10.5281/zenodo.11145259
Abstract
Effluents containing synthetic dyes are often discharged untreated, contributing to widespread contamination and disrupting aquatic ecosystems. Advanced oxidation processes (AOPs), particularly photocatalysis, offer promising alternative solutions to address this issue. This study investigates the photocatalytic degradation of tartrazine (TZ) using elaborated zinc oxide. The toxicity of the transformation products generated during this process was also examined. Preliminary phytotoxicity tests using Lepidium sativum L. seeds revealed significant growth of vegetative organs in untreated solutions. Similar values to the control sample were observed in photocatalytically treated solutions, possibly due to the conversion of toxic intermediates into less harmful by-products. The successful elimination of TZ under visible-light irradiation conditions confirms the potential of ZnO-based photocatalysis as a viable solution for mitigating water pollution caused by food dye contaminants.
Keywords: degradation, food dyes, Lepidium sativum, photocatalysis, phytotoxicity.

Squalene – Background and Perspectives in Cosmeceuticals Formulas

CLAUDIA MAXIM, “Gheorghe Asachi” Technical University of Iași, “Cristofor Simionescu” Faculty of Chemical Engineering and Environmental Protection, Iași, Romania
DELIA TURCOV, “Gheorghe Asachi” Technical University of Iași, “Cristofor Simionescu” Faculty of Chemical Engineering and Environmental Protection, Iași, Romania, ”Grigore T. Popa” University of Medicine and Pharmacy Iași, Faculty of Medical Bioengineering, Iași, Romania
ANDREEA GABRIELA BULGARIU, “Gheorghe Asachi” Technical University of Iași, “Cristofor Simionescu” Faculty of Chemical Engineering and Environmental Protection, Iași, Romania
DANIELA ȘUTEU, “Gheorghe Asachi” Technical University of Iași, “Cristofor Simionescu” Faculty of Chemical Engineering and Environmental Protection, Iași, Romania, danasuteu67@yahoo.com

pages 47 - 57   Download
DOI: 10.5281/zenodo.11145431
Abstract
The barrier function of the skin layers is particularly important for skin health. Risk factors that compromise the integrity of this function act continuously, so that the daily skin ritual must ensure, among other things, the restoration of the basic elements necessary for this purpose. One of the modern assets included with this purpose in dermatocosmetic formulas is squalene. Its role is multiple: restores lipid balance on the skin surface, prevents transepidermal water loss, protects against oxidative damage. It can also act as a carrier for other active substances in the deep layers of the skin. As much is already known about squalene, so many aspects are still being researched on its optimal obtaining and use. This article summarizes the current information about this undeniably valuable and necessary ingredient in modern dermatocosmetic formulas.
Keywords: dermatocosmetic, skin lipid, squalene, plant resource.

Detection of High CH4 Concentrations at Natural Gas End-Use Distribution Network in Urban Areas

MUSTAFA HMOUDAH, Faculty of Environmental Science and Engineering, University of Babeş-Bolyai, Cluj-Napoca, Romania, mustafa.hmoudah@gmail.com
CRISTIAN POP, Faculty of Environmental Science and Engineering, University of Babeş-Bolyai, Cluj-Napoca, Romania
CĂLIN BACIU, Faculty of Environmental Science and Engineering, University of Babeş-Bolyai, Cluj-Napoca, Romania

pages 59 - 68   Download
DOI: 10.5281/zenodo.11145577
Abstract
Since the industrial revolution, CH4 emissions have increased by 150%. Urban Areas are responsible for approximately 60% of these emissions, mainly coming from anthropogenic activities. Besides, urbanization caused changes in land use and reduced CH4 sinks. The sources of CH4 emissions in Urban Areas still have a high degree of uncertainty. Recent studies have stated that leaks from natural gas distribution networks are significant sources of CH4 in the atmosphere, and they also represent a potential loss of energy resources. However, emissions from end-use natural gas networks are poorly explored in the literature. The main contributors in the Romanian CH4 budget are the agriculture and energy sectors. Over the period 1989–2000, methane emissions rate decreased by 34% due to sectoral changes in agriculture and fossil fuels. Nevertheless, the Romanian national inventory doesn’t report CH4 emissions from urban areas. This study investigates CH4 concentration from the end-use natural gas distribution networks in Cluj-Napoca, the second-largest city in Romania in terms of population. These points can be identified as part of the natural gas distribution networks that serve natural gas to end users for gas consumption. The detected points were pipeline junctions and natural gas meters. The estimation of CH4 concentration in the atmosphere was carried out based on a laser CH4 sensor Tunable Diode Laser Absorption Spectroscopy (TDLAS) with high measuring accuracy of 0.1 ppmv. This CH4 concentration detection was performed from December 2022 to January 2023 at 74 natural gas end-use points. The determination of whether to represent leaks or not was quite after estimating the background level in the city and comparing the obtained concentrations with this background. This study has revealed that 76% of the detected end-use natural gas distribution points have gas leaks and represent continuous contributors to CH4 annual budget. However, this contribution to the annual budget should be estimated. Moreover, the results of this study indicate the presence of high leaks from natural gas end-use points in urban areas. They suggest in-depth investigation and allocation of all natural gas leaks at the end-use points, in order to take certain reduction measures regarding CH4 mitigation.
Keywords: greenhouse gas, methane, atmosphere, urban areas, natural gas end-use networks, gas leaks.

Strength and Porous Building Material Prepared from Recycled Residual Glass Through Microwave Radiation

LUCIAN PĂUNESCU, Daily Sourcing & Research SRL Bucharest, Romania, lucianpaunescu16@gmail.com
SORIN MIRCEA AXINTE, Daily Sourcing & Research SRL Bucharest, Romania, National University of Science and Technology POLITEHNICA Bucharest, Faculty of Applied Chemistry and Materials Science, Bucharest, Romania

pages 69 - 80   Download
DOI: 10.5281/zenodo.11145677
Abstract
New method of producing strength and porous cellular glass with load-bearing properties from recycled flat glass using simultaneously two expanding agents: glycerol (liquid) and eggshell (solid) recycled as a by-product from the food industry was designed and tested by microwave heating. Eggshell was used as a substitute for the usual calcium carbonate and the microwave heating was made by the original method of predominantly direct and partially indirect heating leading to energy saving. Results showed that cellular glass with low bulk density (0.16-0.19 g·cm-3) and high compression strength (up to 7.6 MPa) were obtained.
Keywords: cellular glass, flat glass waste, microwave heating, glycerol, eggshell.

Exploring Hesperidin's Therapeutic Potential in Cancer Therapy: A Review

MĂLINA MARIA CERNĂTESCU, “Grigore T. Popa” University of Medicine and Pharmacy Iași, Faculty of Medicine, Iași, Romania, malinacernatescu1@gmail.com
CLAUDIA COBZARU, “Gheorghe Asachi” Technical University of Iași, “Cristofor Simionescu” Faculty of Chemical Engineering and Environmental Protection, Iași, Romania
CORINA CERNĂTESCU, “Gheorghe Asachi” Technical University of Iași, “Cristofor Simionescu” Faculty of Chemical Engineering and Environmental Protection, Iași, Romania

pages 81 - 88   Download
DOI: 10.5281/zenodo.11145798
Abstract
Hesperidin, a flavonoid abundant in citrus fruits, has gathered attention for its promising anti-cancer properties. This review explores the complex mechanisms through which hesperidin influences oncogenesis and tumour progression. Studies reveal hesperidin's ability to target key pathways involved in cancer development, including hypoxia-induced HIF-1α activation, oxidative stress-mediated signalling, and epithelial-mesenchymal transition (EMT). In vitro and in vivo experiments showed hesperidin's capacity to inhibit angiogenesis, to suppress cell proliferation, and to induce apoptosis in various cancer models. Furthermore, hesperidin has been demonstrated to exhibit synergistic effects with conventional chemotherapy, thereby enhancing its anti-cancer efficacy, while simultaneously reducing its associated risks. Aside from the promising preclinical findings, further clinical studies are needed in order to elucidate hesperidin's therapeutic potential and to optimize its use in cancer treatment strategies. Understanding the complex interaction between hesperidin and cancer-related pathways could accelerate the development of novel therapeutic approaches, with the goal of preventing cancer progression and improving patient outcomes.
Keywords: Hesperidin, Cancer therapy, Hypoxia, Oxidative stress, Epithelial-mesenchymal transition.

The Photocatalytic Degradation of Ceftriaxone in Wastewater Using Hybrid ZnS-ZnO Photocatalyst

GABRIELA ANTOANETA APOSTOLESCU, “Gheorghe Asachi” Technical University of Iași, Romania, “Cristofor Simionescu” Faculty of Chemical Engineering and Environmental Protection, Iași, Romania
MIHAELA AURELIA VIZITIU, “Gheorghe Asachi” Technical University of Iași, Romania, “Cristofor Simionescu” Faculty of Chemical Engineering and Environmental Protection, Iași, Romania
ISABELA CONSTANȚA LUCHIAN, “Gheorghe Asachi” Technical University of Iași, Romania, “Cristofor Simionescu” Faculty of Chemical Engineering and Environmental Protection, Iași, Romania
VALERIA DUBĂSARI, “Gheorghe Asachi” Technical University of Iași, Romania, “Cristofor Simionescu” Faculty of Chemical Engineering and Environmental Protection, Iași, Romania
IOANA IZABELA ZAHARIA, “Gheorghe Asachi” Technical University of Iași, Romania, “Cristofor Simionescu” Faculty of Chemical Engineering and Environmental Protection, Iași, Romania
ȘTEFANIA ALESANDRA BOBEȘ, “Grigore Alexandrescu” Emergency Children’s Hospital, Bucharest, Romania
CĂTĂLIN DUMITREL BALAN, “Gheorghe Asachi” Technical University of Iași, Romania, “Cristofor Simionescu” Faculty of Chemical Engineering and Environmental Protection, Iași, Romania
RAMONA ELENA TĂTARU-FĂRMUȘ, “Gheorghe Asachi” Technical University of Iași, Romania, “Cristofor Simionescu” Faculty of Chemical Engineering and Environmental Protection, Iași, Romania
NICOLAE APOSTOLESCU, “Gheorghe Asachi” Technical University of Iași, Romania, “Cristofor Simionescu” Faculty of Chemical Engineering and Environmental Protection, Iași, Romania, nicolae.apostolescu@academic.tuiasi.ro

pages 89 - 100   Download
DOI: 10.5281/zenodo.11145904
Abstract
The elimination of organic pollutants from water poses a considerable challenge in environmental remediation in this study, the potential of ZnS-ZnO semiconductors as efficient photocatalysts for degrading aqueous solutions of ceftriaxone (CEF) was investigated in a mini-UV reactor. The ZnS-ZnO heterostructures were synthesized via the hydrothermal method and characterized using analytical techniques (SEM, FTIR), demonstrating considerable photocatalytic activity (UV-Vis monitoring), with degradation of CEF occurring within a relatively short period of time.
Keywords: ceftriaxone, degradation, photocatalysis, ZnS - ZnO.

Synthesis and Characterization of Azobenzene Alkylated Mesogen with Fluorine Substituent

IULIAN BERLADEAN, “Gheorghe Asachi” Technical University of Iași, “Cristofor Simionescu” Faculty of Chemical Engineering and Environmental Protection, Iași, Romania
AUREL SIMION, “Gheorghe Asachi” Technical University of Iași, “Cristofor Simionescu” Faculty of Chemical Engineering and Environmental Protection, Iași, Romania
IRINA CÂRLESCU, “Gheorghe Asachi” Technical University of Iași, “Cristofor Simionescu” Faculty of Chemical Engineering and Environmental Protection, Iași, Romania, icarlescu@ch.tuiasi.ro
NICOLAE HURDUC, “Gheorghe Asachi” Technical University of Iași, “Cristofor Simionescu” Faculty of Chemical Engineering and Environmental Protection, Iași, Romania

pages 101 - 105   Download
DOI: 10.5281/zenodo.11146121
Abstract
The paper presents synthesis and characterization of azobenzene compound that contains 10 carbon atoms as flexible terminal chain and one fluorine atom as lateral polar substituent. The synthesis was achieved by diazotization of 4-amino benzoic acid and coupling of diazonium salt to 2-fluorophenole, followed by alkylation with a bromoalkyl compound. The synthetized compounds were purified and their structures were confirmed by 1H-NMR and 13C-NMR studies.
Keywords: diazotization, coupling, fluorine, alkylation.