Maria Râpă

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• Ass.Prof. Dr. Eng. Habil.
• Ass. Prof. Dr. Eng. Habil. at Universitatea Națională de Știință și Tehnologie Politehnica București

Heavy metals represent a class of pollutants detected at concentrations lower than 10 ppm in different matrices that are intensively monitored due to having a major impact on human health. Industrial activities including mining, agriculture, and transport, determine their presence in different environments. Corrosion phenomena of various installati...

The assessment of plastic pollution due to microplastics (MPs) and nanoparticles (NPs) was performed for the first time on water samples from four natural sites located near the beaches of Krk Island, Croatia, namely Melska, Črnika, rt Šilo, and Zala. MP and NP occurrence was investigated for the water samples collected during December 2022 and Jun...

This paper focuses on identifying the human health risks as a result of the presence of polycyclic aromatic hydrocarbons (PAHs) in groundwater due to the Bucharest landfill leakages. The main subjects were neighboring areas as the main receptors. The functional landfill located near the capital of Romania was selected as a case study. Fluorene (Pf)...

The increasing demand for sustainable energy solutions has prompted a significant interest in non-conventional energy sources, leading to the development of innovative materials that can enhance energy conversion and storage efficiency. This review paper explores the pivotal role of zirconium dioxide (ZrO2) in industrial applications related to non...

Acute and chronic wounds present a significant healthcare challenge, requiring innovative solutions for effective treatment. The exploitation of natural by-products with advanced cell regeneration potential and plant-based materials, which possess bioactive properties, is an innovative topic in wound management. This study investigates the potentia...

Microplastics (MPs) and nanoplastics (NPs) both represent significant concerns in environmental sciences. This paper aims to develop a convenient and efficient methodology for the detection and measurement of MPs and nanoparticles from surface seawater and to apply it to the water samples collected from the UNESCO site of Venice and its lagoon, mor...

This review summarizes recent data related to the management of marine plastic litter to promote sustainable development. It discusses the distribution and identification of marine plastic litter, assesses the potential socio-economic and environmental impacts of these pollutants, and explores their recovery strategies, from a circular economy pers...

Gelatin nanofibers are known as wound-healing biomaterials due to their high biocompatible, biodegradable, and non-antigenic properties compared to synthetic-polymer-fabricated nanofibers. The influence of gamma radiation doses on the structure of gelatin nanofiber dressings compared to gelatin of their origin is little known, although it is very i...

Essential oils are valuable alternatives to synthetic antibiotics that have the potential to avoid the pathogen resistance side effects generated by leather. Helichrysum italicum and Lavandula latifolia essential oils combined with fish scale gelatin were electrospun using a coaxial technique to design new bioactive materials for skin wound dressin...

Water pollution stands as a pressing global environmental concern, elevating the significance of innovative, dependable, and sustainable solutions. This study represents an extensive review of the use of photocatalytic zinc oxide nanoparticles (ZnO NPs) for the removal of emerging pollutants from water and wastewater. The study examines ZnO NPs’ di...

This study investigates the detection of microplastic in the Adriatic Sea, considering various plastic waste-generating activities from neighboring countries as a source of pollution. Seven water samples were collected from three locations around the Venice Lagoon in Italy and four around the island of Krk in Croatia. Microplastics, categorised as...

The aim of this study was to design a dual-layer wound dressing as a new fibrous biomaterial based on the valorization of animal-derived proteins. The first layer was fabricated by the deposition of poly(ethylene oxide) (PEO) loaded with keratin hydrolysate (KH) via a mono-electrospinning process onto a poly(lactic acid) (PLA) film, which was used...

Magnetite nanoparticles have attracted interest of researchers from different science fields such as medicine, biology, physics, or chemistry due to their multifunctional properties including biocompatibility, superparamagnetism and low toxicity. Several methods have been developed to synthesize magnetic nanoparticles with controlled size, shape, a...

Wound healing is a complex mechanism that involves different types of cells to restore damaged skin layers. Therefore, different types of medical bandages are used. Keratin and Matricaria chamomilla extract based electrospun medical dressings may improve wound healing process due to promotion of different types of cells that take act in skin regene...

Anthropogenic microplastics (MPs) and nanoplastics (NPs) are ubiquitous pollutants found in aquatic, food, soil and air environments. Recently, drinking water for human consumption has been considered a significant pathway for ingestion of such plastic pollutants. Most of the analytical methods developed for detection and identification of MPs have...

Citation: Doukeh, R.; Râpȃ, M.; Matei, E.; Prodan, D.; Győrgy, R.; Trifoi, A.; Banu, I. An Evaluation of Glycerol Acetalization with Benzaldehyde over a Ferromagnetic Heteropolyacid Catalyst. Catalysts 2023, 13, 782. https://doi. Abstract: Tungstophosphoric acid (H 3 PW 12 O 40) supported on silica-coated magnetite nanoparticles has been prepared a...

Hydrolysed collagen obtained from bovine leather by-products were loaded with ginger essential oil and processed by the electrospinning technique for obtaining bioactive nanofibers. Particle size measurements of hydrolysed collagen, GC-MS analysis of ginger essential oil (EO), and structural and SEM examinations of collagen nanofibers loaded with g...

Ultra-high-molecular-weight polyethylene (UHMWPE) matrices containing low-density polyethylene (LDPE), hydroxyapatite (HAp) as filler, and rosemary extract (RM) as stabilizer were investigated for their qualification for long-term applications. The significant contributions of the blend components were analyzed, and variations in mechanical propert...

The aim of this study was to obtain biocomposites consisting of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV), bacterial cellulose (BC) and α-tocopherol by a melt processing technique for potential use in biomedical applications. The melt processing and roughness of biocomposites were evaluated and compared to sample without BC. The degradati...

The preservation of food represents one of the greatest challenges in the food industry. Active packaging materials are obtained through the incorporation of antimicrobial and/or antioxidant compounds in order to improve their functionality. Further, these materials are used for food packaging applications for shelf-life extension and fulfilling co...

Ferrous waste by-products from the metallurgical industry have a high potential for valorization in the context of the circular economy, and can be converted to value-added products used in environmental remediation. This research reviews the latest data available in the literature with a focus on: (i) sources from which these types of iron-based w...

This research emphasizes the performance of some eco-friendly carbon materials as hydrochars (HC) obtained by the hydrothermal carbonization (HTC) process applied to walnut shell (WS) biowaste. These materials display promising properties that can be used for environmental applications such as emerging pharmaceutical pollutant retention from water...

Bioactive collagen–chitosan–lemongrass (COL–CS–LG) membranes were prepared by casting method and analyzed for potential biomedical applications. For COL–CS–LG membranes, LG essential oil release, antioxidant properties, in vitro cytotoxicity and antimicrobial assessments were conducted, as well as free radical determination after gamma irradiation...

Bio-based plasticizers derived from renewable resources represent a sustainable replacement for petrochemical-based plasticizers. Vegetable oils are widely available, non-toxic and biodegradable, resistant to evaporation, mostly colorless and stable to light and heat, and are a suitable alternative for phthalate plasticizers. Plasticized poly(lacti...

Innovative composites based on polypropylene waste impurified cu HDPE (PPW) combined with two thermoplastic block-copolymers, namely styrene-butadiene-styrene (SBSBC) and styrene-isoprene-styrene (SISBC) block-copolymers, and up to 10 wt% nano-clay, were obtained by melt blending. SBSBC and SISBC with almost the same content of polystyrene (30 wt%)...

The extending material durability of poly(lactic acid) (PLA)/styrene-isoprene-styrene copolymer (SIS) blend with 30% of SIS by the presence of acrylic acid (AA) and two stabilizers, caffeic acid or vanillic acid, is evaluated by γ-irradiation at technological doses (25 or 50 kGy) applied for sterilization or for the manufacturing of several commodi...

In today’s world, due to population increase, there are many alarming and potential catastrophic problems like climate change, environmental pollution and an enormous mass of wastes constantly produced by humankind to find innovative solutions for the management, recycling, and valorization of biowaste from agricultural production, food processing,...

The aim of this review is to bring together the main natural polymer applications for environmental remediation, as a class of nexus materials with advanced properties that offer the opportunity of integration in single or simultaneous decontamination processes. By identifying the main natural polymers derived from agro-industrial sources or monome...

The irradiation of polymeric materials with ionizing radiation (γ-rays, X-rays, accelerated electrons, ion beams, etc.) may lead to disproportion, hydrogen abstraction, arrangements, degradation, and/or the formation of new bonds. The purpose of this paper is to evaluate the effect of gamma irradiation on some new poly(lactic acid) (PLA)-based blen...

This article presents current possibilities of using polyester-based materials in hard and soft tissue engineering, wound dressings, surgical implants, vascular reconstructive surgery, ophthalmology, and other medical applications. The review summarizes the recent literature on the key features of processing methods and potential suitable combinati...

This paper presents a comprehensive literature review surveying the most important polymer materials used for electrospinning processes and applied as membranes for the removal of emerging pollutants. Two types of processes integrate these membrane types: separation processes, where electrospun polymers act as a support for thin film composites (TF...

Among the promising sustainable materials of modern times, biopolymeric nanocomposites have received an increased interest for orthopedic applications due to their excellent mechanical, biocompatibility, bioactivity properties, and special architecture for the cells proliferation, differentiation, and migration in bone tissue regeneration. The aim...

Polyvinylchloride (PVC) is a thermoplastic polymer widely used in large applications due to the excellent balance between cost and properties. Due to the environmental and human health concerns of consumption of petrochemical-based plasticizers, the use of bio-based plasticizers has been increasing. The new blends of PVC made with green plasticizer...

Despite the fact that PVC is one of the most useful materials available to the plastic market, with properties as strong, durable, versatile and lightweight, low cost and chemical resistance, its inadequate disposal has contributed to strong noneconomic issues based on the negative effects of chlorine. The use of biodegradable polymers and their mi...

Massive amounts of industrial and agricultural water around the world are polluted by various types of contaminants that harm the environment and affect human health. Alginic acid is a very versatile green polymer used for heavy metal adsorption due to its availability, biocompatibility, low cost, and non-toxic characteristics. The aim of this pape...

In this study, lemon balm (Melissa officinalis L.) and dill (Anethum graveolens L.) essential oils (EOs) were encapsulated into collagen hydrolysates extracted from bovine tendons and rabbit skins, both mixed with chitosan (CS) by using the coaxial electrospinning technique for potential wound dressing applications. The morphology and chemical comp...

One approach to develop innovative antimicrobial wound dressing materials is to use natural polymers loaded with antimicrobial agents. The valorisation of animal proteins as biomaterials with antimicrobial properties is a new concern for development of wound healing. Plant esssential oils (EO) also indicate a potential approach for new wound dressi...

The present work reported the preparation of biocomposites based on poly(3-hydroxybutyrate) (PHB), plasticizer, and bacterial cellulose (BC) by melt processing and their testing by means of thermal properties (DSC), water absorption, and in vitro degradation. The surface of the biocomposites was analyzed via atomic force microscopy (AFM). In vitro...

The aim of this paper was to select keratin hydrolysate with bioactive properties by using the enzymatic hydrolysis of wool. Different proteolytic enzymes such as Protamex, Esperase, and Valkerase were used to break keratin molecules in light of bioactive additive preparation. The enzymatic keratin hydrolysates were assessed in terms of the physico...

The paper addresses environmental protection by valorizing an important agri-food waste category, namely fruit and vegetables with focusing on the main characteristics regarding consumption, waste quantities, and ways for valorizing these materials. Thus, vast research was undertaken in order to emphasize the main commodities and their potential ap...

Biopolymers are polymers obtained from biological origins and used for industrial applications in food packaging. A biopolymer should be non-toxic, non-carcinogenic, biodegradable and also adequately available for their widespread applications. The aim of this study was to obtain packaging materials for food, as films prepared in the laboratory, ba...

Due to its valuable compounds, food waste has been gaining attention in different applications, such as life quality and environment. Combined with circular economy requirements, a valorization method for waste, especially banana waste, was to convert them into adsorbents with advanced properties. The banana waste, after thermal treatment, was used...

The electrospun nanosystems containing poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) and 1 wt% Fe doped ZnO nanoparticles (NPs) (with the content of dopant in the range of 0–1 wt% Fe) deposited onto polylactic acid (PLA) film were prepared for food packaging application. They were investigated by scanning electron microscopy (SEM), energy dis...

Due to the environmental concerns related to the use of nondegradable polymers, the market for bioplastic-based materials is increasing. Currently, bioplastic materials are used in bags, medical devices, food packaging, automotive, and electronics areas. Not all bioplastics are biodegradable, but they are derived from renewable resources and permit...

Several recipes based on PLA, bio-plasticizers, and active agents such as vitamin E and cold-pressed rosehip seed oil encapsulated into chitosan by the emulsion method named here as chitosan modified (CS-M) were elaborated by melt compounding for food packaging applications. Resulted biocomposites have been investigated from the point of view of ph...

The need to recycle and develop nanomaterials from waste, and use them in environmental applications has become increasingly imperative in recent decades. A new method to convert the mill scale, a waste of the steel industry that contains large quantity of iron and low impurities into a nanoadsorbent that has the necessary properties to be used for...

The present paper reported the obtaining of an environmental friendly adsorbent based on sodium alginate, chitosan and glass bubbles. CaCl2 was used as crosslinking agent for sodium alginate favoring the interactions by physical bonds between the negative groups (-COO) of biopolymer and the Ca ions. The experimental study to determine the Cu(II) up...

In this study, sodium alginate film (Alg) was coated with electrospun collagen glue (Col) extracted from rabbit skin waste, loaded with different commercial antimicrobial agents (chitosan, AG425K and ZnONPs) and investigated in terms of morphological, structural and biological properties. The coated nanostructures were characterized using scanning...

The aim of this paper is to obtain two types of bio-based membranes by electrospinning process: one based on polylactic acid (PLA), and PLA/polyhydroxybutyrate (PHB), and the second by coating the PLA/PHB membrane with chitosan (CS) and CS/activated coal (AC), respectively for removal of micropollutants from aqueous water. The designed bio-based el...

There are different types of emerging pollutants from organic to inorganic substances, also including nanoparticles an microplastics. Often, the use of photocatalytic methods applied for organic contaminants generate low molecular organic compounds less toxic for the environment. The most common and efficient nanomaterial used for photodegradation...

Keratin is a fibrous protein abundant in nature, being the component of wool, hair, hooves, horns, feathers, and claws. Keratin is one of the most valuable natural biopolymers due to its chemical versatility and biological performance. At the molecular level, keratin is distinguished from other biopolymers by its high concentration of cysteine-cont...

Lemon balm (Melissa officinalis L.) belongs to the Lamiaceae family. Essential oil extracted from the aerial parts of lemon balm has been investigated for the protection of fruits during storage, as insecticidal, as well as in medicine, due to its bioactive properties. In this paper, the composition and identification of components from Melissa off...

This paper assessed the collagen glue (Col) from rabbit skin for use as a raw material in combination with different water-based dispersants of antimicrobial agents such as ZnO NPs, TiO2 NPs doped with nitrogen and Ag NPs (TiO2-N-Ag NPs), and chitosan (CS) for the production of biocompatible and antimicrobial nanofibers. The electrospun nanofibers...

The study aim was the synthesis and characterization by thermal and structural properties of nanofibers, obtained by electrospinning using styrene butadiene blockcopolymers (SBS) and styreneisoprene blockcopolymers (SIS), as well as their composites with isofural. In the first step, styrenebutadiene blockcopolymers (SBS) and styrene isoprene blockc...

Nanocomposite materials based on poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBHV) and modified mineral clay layered double hydroxides (LDH-SDS) were explored as novel nanostructured materials for potential tissue engineering applications. The mineral clay inorganic phase was modified with an anionic long-chain structure of carbon atoms, such as...

Keratin hydrolysates were obtained from sheep wool by alkaline hydrolysis at different concentrations of KOH (3%, 5% and 8%) and temperatures (75°C, 85°C, 95°C and 99°C) of the reaction medium. The protein content of the keratin extracts was between 65.54% and 87.10%. Particle measurements showed a decrease in particle size with the increase of con...

This paper is focused on obtained two catalysts such as TiO 2 nanoparticles and Fe 3 O 4 /SiO 2 /TiO 2 nanocomposite for adsorption and photocatalytic degradation of methylene blue (MB) dyes from aqueous solution. The morphology, structure and chemical proprieties of synthesized materials were investigated by X-ray diffraction (XRD) analysis, scann...

Concentrated collagen hydrolysate (HC10CC), rabbit collagen glue (RCG), and keratin hydrolysate (KH) were investigated in terms of their extraction from mammalian by-products and processing by electrospinning. The electrospun nanofibers were characterized by scanning electron microscopy coupled with the energy dispersive X-ray spectroscopy (SEM/EDS...

Trichophyton interdigitale is a common fungus causing onychomycosis of the nail in humans. Plants are a rich source of bioactive compounds with antifungal properties used in various compositions in pharmaceuticals, cosmetics or various industrial products. In the present paper, the antifungal activity of two kinds of leathers was tested: ecological...

This study presents a detailed analysis of thermal and radiation resistances of low density polyethylene (LDPE)/ultra-high molecular weight polyethylene (UHMWPE) blends containing hydroxyapatite as functional filler and rosemary acting as antioxidant against oxidative degradation. Three main procedures, chemiluminescence (CL), Fourier transform inf...

In this study we evaluated the degradation behaviour of some polymeric bionanocomposites based on polylactic acid (PLA), hydrolysed collagen (HC) and silver nanoparticles (AgNPs) obtained by melt processing, by exposure at soil action for 30 days and 60 days. The quantification of the bionanocomposites� degradability was investigated by the weight...

This research aimed to obtain biocompatible and antimicrobial nanofibres based on concentrated collagen hydrolysate loaded with thyme or oregano essential oils as a natural alternative to synthesis products. The essential oils were successfully incorporated using electrospinning process into collagen resulting nanofibres with diameter from 471 nm t...

Bionanocomposites including poly(lactic acid) (PLA), collagen, and silver nanoparticles (AgNPs) were prepared as biocompatible and stable films. Thermal properties of the PLA-based bionanocomposites indicated an increase in the crystallinity of PLA plasticized due to a small quantity of AgNPs. The results on the stability study indicate the promisi...

Bone regeneration is a claim challenge in addressing bone defects with large tissue deficits, that involves bone grafts to support the activity. In vitro biocompatibility of the bacterial cellulose-modified polyhydroxyalkanoates (PHB/BC) scaffolds and its osteogenic potential in critical-size mouse calvaria defects had been investigated. Bone promo...

The samples consisting of poly (lactic acid) (PLA) and styrene-isoprene-styrene triblock polymers (SIS) were investigated for the evaluation of their stability qualification. The accelerated degradation was achieved by γ-exposure when structural modifications were watched. Three SIS loadings (10, 20 and 30 wt%) were blended in PLA matrix. The conce...

The study aim was the synthesis and characterization by thermal and structural properties of nanofibers, obtained by electrospinning using styrene-butadiene block-copolymers (SBS) and styrene-isoprene block-copolymers (SIS), as well as their composites with isofural [1]. In the first step, styrene-butadiene block-copolymers (SBS) and styrene-isopre...

The recycled polypropylene (rPP) materials that meet technical requirements such as reducing the dimensions and improving the tensile, elongation, impact strength, thermal stability, as well as melt processing, are required for the manufacturing industry. In this paper, we studied the mechanical and thermal properties of post-consumer rPP by adding...

New photocatalytic membranes based on polylactic acid (PLA)/TiO2 hybrid nanofibers deposited on fiberglass supports were prepared and tested for the removal of ampicillin from aqueous solutions. The electrospinning technique was used to obtain hybrid nanofibers that were deposited on three types of fiberglass with different structures, resulting in...

The purpose of this research is to obtain antifungal and antibacterial treatments based on natural compounds of essential oils of geranium, pine, and rosemary for cotton and leather linings to make leather, fur articles, and footwear. The main characteristic absorption bands for the functional groups of geranium, pine and rosemary essential oils we...

The effects of two nano– and micro– size classes of hydroxyapatite particles ((Ca10(PO4)6(OH)2), HAp) on the controlled stability behavior of poly(lactic acid) are investigated by chemiluminescence, thermal analysis, water uptake and contact angle measurements. The accelerated degradation was achieved by γ-irradiation, when the two constitutive pha...

The study aimed to synthesize nanofibers based on styrene-ethylene-butylene-styrene block-copolymers (SEBS) [1] and its composite derivatives, through the electrospinning (Figure 1) process [2]. Styrene-ethylene-butylene-styrene (SEBS) 1652 manufactured by Kraton was used as the basic polymer. This is a translucent thermoplastic elastomer, with a l...

In the field of water depollution, considerable attention in past years was given to bio-based and [...]

Graphene and its derivatives have attracted considerable attention in recent years as potentialmaterials for various applications because of their unique physical-chemical properties [...]