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After obtaining the PhD title in 2010 in Materials Science, I continuously conducted my research activity at the Transilvania University of Brasov, addressing multidisciplinary topics: optimizing photocatalytic processes that involve novel solutions, development of photocatalyst based on semiconductors allowed thermodynamic modelling of bandgap position in hybrid systems of two semiconductors, a new approach to multi-component systems dyes by simultaneous analysis of two dyes mixed solutions using first-order derivative absorption spectra of dyes solutions, developed and prototyped a laboratory photoreactor with controlled radiation (UV and/or Vis), heterogeneous photodegradation of industrial wastewater from the textile industry, photodegradation of wastewater - laboratory and scale-up experiments in a solar pilot plant. The habilitation obtained in 2018, contains interdisciplinary expertise in the photocatalytic application in environment, wastewater pollution control, monitoring and modelling, materials synthesis and characterisation, modelling process in the semiconductor. All the above can fit into the fields of environmental engineering and materials engineering.
Project Goal: The main goal of the present proposal is the development of highly extended 3D [email protected] heterojunctions with improved photocatalytic performance for environmentally friendly reactions. High-surface area activated carbons modified with graphene (or graphene derivatives) will be used as 3D platforms to grow a thin TiO2 nanofilm so that the final composite will give rise to an optimal photocatalytic performance based on the Z-scheme heterojunction model. These composites will be designed to take advantage of the excellent photocatalytic performance of TiO2 and graphene, and the superior conversion of light in the confined nanospace of activated carbon materials. The development of a controlled porous network and a well-defined surface chemistry (including a well-dispersed TiO2 nanofilm) will provide a bifunctional system able to adsorb and convert simultaneously or in pulsed-mode i) CO2 into value-added chemicals, and ii) air and water pollutants into harmless compounds.
Current Stage: in progress
Project Goal: During the last three decades it was established that theoretical modelling plays an important role not only in fundamental research, but also has strong impact on engineering disciplines and technical challenges. The main focus of the project is multiscale modelling of transition metal oxyhydrides – an emerging class of materials - combined with experimental verification of the theoretically predicted material properties and evaluate applications in superconductivity, energy saving, and photocatalysis for breakdown of contaminants in water. This is a multidisciplinary project combining expertize of specialists in materials science, environmental technologies, physicists, chemists, and engineers. The consortium consists of experts from education- and basic research-oriented Institutions, an applied research Institution, and SMEs. It will form a platform for enhancing the ongoing collaboration, provide training of young scientists, exchange of infrastructure, new ideas, and competence.
Current Stage: in progress
Nanoparticles have applications in various fields such as manufacturing and materials synthesis, the environment, electronics, energy harvesting, and medicine. Besides many applications of nanoparticles, further research is required for toxic environmental effect investigation. The toxic effect of titanium dioxide nanoparticles on the physiology of the green alga Chlorella vulgaris was studied with a widely used pesticide, imidacloprid (IMD). Chlorella vulgaris was exposed for 120 h in Bold’s basal medium to different toxic compounds, such as (i) a high concentration of TiO2 nanoparticles, 150–2000 mg/L, usually optimised in the photocatalytic degradation of wastewater, (ii) an extremely toxic pesticide for the aquatic environment, imidacloprid, in concentrations ranging from 5 to 40 mg/L, (iii) TiO2 nanoparticles combined with imidacloprid, usually used in a photocatalytic system. The results show that the TiO2 nanoparticles and IMD inhibited Chlorella vulgaris cell growth and decreased the biovolume by approximately 80% when 2 g/L TiO2 was used, meaning that the cells devised a mechanism to cope with a potentially stressful situation; 120 h of Chlorella vulgaris exposure to 40 mg/L of IMD resulted in a 16% decreased cell diameter and a 41% decrease in cell volume relative to the control sample, associated with the toxic effect of pesticides on the cells. Our study confirms the toxicity of nanoparticles through algal growth inhibition with an effective concentration (EC50) value measured after 72 h of 388.14 mg/L for TiO2 and 13 mg/L for IMD in a single-toxic system. The EC50 of TiO2 slowly decreased from 258.42 to 311.11 mg/L when IMD from 5 to 20 mg/L was added to the binary-toxic system. The concentration of TiO2 in the binary-toxic system did not change the EC50 for IMD, and its value was 0.019 g/L. The photodegradation process of imidacloprid (range of 5–40 mg/L) was also investigated in the algal medium incubated with 150–600 mg/L of titanium dioxide.
Cristina Adochite; Luminita Andronic. Toxicity of a Binary Mixture of TiO2 and Imidacloprid Applied to Chlorella vulgaris. International Journal of Environmental Research and Public Health 2021, 18, 7785 .
AMA StyleCristina Adochite, Luminita Andronic. Toxicity of a Binary Mixture of TiO2 and Imidacloprid Applied to Chlorella vulgaris. International Journal of Environmental Research and Public Health. 2021; 18 (15):7785.
Chicago/Turabian StyleCristina Adochite; Luminita Andronic. 2021. "Toxicity of a Binary Mixture of TiO2 and Imidacloprid Applied to Chlorella vulgaris." International Journal of Environmental Research and Public Health 18, no. 15: 7785.
Nanocomposites with polymer matrix offer excellent opportunities to explore new functionalities beyond those of conventional materials. TiO2, as a reinforcement agent in polymeric nanocomposites, is a viable strategy that significantly enhanced their mechanical properties. The size of the filler plays an essential role in determining the mechanical properties of the nanocomposite. A defining feature of polymer nanocomposites is that the small size of the fillers leads to an increase in the interfacial area compared to traditional composites. The interfacial area generates a significant volume fraction of interfacial polymer, with properties different from the bulk polymer even at low loadings of the nanofiller. This review aims to provide specific guidelines on the correlations between the structures of TiO2 nanocomposites with polymeric matrix and their mechanical properties. The correlations will be established and explained based on interfaces realized between the polymer matrix and inorganic filler. The paper focuses on the influence of the composition parameters (type of polymeric matrix, TiO2 filler with surface modified/unmodified, additives) and technological parameters (processing methods, temperature, time, pressure) on the mechanical strength of TiO2 nanocomposites with the polymeric matrix.
Cristina Cazan; Alexandru Enesca; Luminita Andronic. Synergic Effect of TiO2 Filler on the Mechanical Properties of Polymer Nanocomposites. Polymers 2021, 13, 2017 .
AMA StyleCristina Cazan, Alexandru Enesca, Luminita Andronic. Synergic Effect of TiO2 Filler on the Mechanical Properties of Polymer Nanocomposites. Polymers. 2021; 13 (12):2017.
Chicago/Turabian StyleCristina Cazan; Alexandru Enesca; Luminita Andronic. 2021. "Synergic Effect of TiO2 Filler on the Mechanical Properties of Polymer Nanocomposites." Polymers 13, no. 12: 2017.
Finding new technologies and materials that provide real alternatives to the environmental and energy-related issues represents a key point on the future sustainability of the industrial activities and society development. The water contamination represents an important problem considering that the quantity and complexity of organic pollutant (such as dyes, pesticides, pharmaceutical active compounds, etc.) molecules can not be efficiently addressed by the traditional wastewater treatments. The use of fossil fuels presents two major disadvantages: (1) environmental pollution and (2) limited stock, which inevitably causes the energy shortage in various countries. A possible answer to the above issues is represented by the photocatalytic technology based on S-scheme heterostructures characterized by the use of light energy in order to degrade organic pollutants or to split the water molecule into its components. The present mini-review aims to outline the most recent achievements in the production and optimization of S-scheme heterostructures for photocatalytic applications. The paper focuses on the influence of heterostructure components and photocatalytic parameters (photocatalyst dosage, light spectra and intensity, irradiation time) on the pollutant removal efficiency and hydrogen evolution rate. Additionally, based on the systematic evaluation of the reported results, several perspectives regarding the future of S-scheme heterostructures were included.
Alexandru Enesca; Luminita Andronic. Photocatalytic Activity of S-Scheme Heterostructure for Hydrogen Production and Organic Pollutant Removal: A Mini-Review. Nanomaterials 2021, 11, 871 .
AMA StyleAlexandru Enesca, Luminita Andronic. Photocatalytic Activity of S-Scheme Heterostructure for Hydrogen Production and Organic Pollutant Removal: A Mini-Review. Nanomaterials. 2021; 11 (4):871.
Chicago/Turabian StyleAlexandru Enesca; Luminita Andronic. 2021. "Photocatalytic Activity of S-Scheme Heterostructure for Hydrogen Production and Organic Pollutant Removal: A Mini-Review." Nanomaterials 11, no. 4: 871.
In the last years, nanoparticles such as TiO2, ZnO, NiO, CuO and Fe2O3 were mainly used in wastewater applications. In addition to the positive aspects concerning using nanoparticles in the advanced oxidation process of wastewater containing pollutants, the impact of these nanoparticles on the environment must also be investigated. The toxicity of nanoparticles is generally investigated by the nanomaterials’ effect on green algae, especially on Chlorella vulgaris. In this review, several aspects are reviewed: the Chlorella vulgaris culture monitoring and growth parameters, the effect of different nanoparticles on Chlorella vulgaris, the toxicity of photocatalyst nanoparticles, and the mechanism of photocatalyst during oxidative stress on the photosynthetic mechanism of Chlorella vulgaris. The Bold basal medium (BBM) is generally recognized as an excellent standard cultivation medium for Chlorella vulgaris in the known environmental conditions such as temperature in the range 20–30 °C and light intensity of around 150 μE·m2·s−1 under a 16/8 h light/dark cycle. The nanoparticles synthesis methods influence the particle size, morphology, density, surface area to generate growth inhibition and further algal deaths at the nanoparticle-dependent concentration. Moreover, the results revealed that nanoparticles caused a more potent inhibitory effect on microalgal growth and severely disrupted algal cells’ membranes.
Cristina Adochite; Luminita Andronic. Aquatic Toxicity of Photocatalyst Nanoparticles to Green Microalgae Chlorella vulgaris. Water 2020, 13, 77 .
AMA StyleCristina Adochite, Luminita Andronic. Aquatic Toxicity of Photocatalyst Nanoparticles to Green Microalgae Chlorella vulgaris. Water. 2020; 13 (1):77.
Chicago/Turabian StyleCristina Adochite; Luminita Andronic. 2020. "Aquatic Toxicity of Photocatalyst Nanoparticles to Green Microalgae Chlorella vulgaris." Water 13, no. 1: 77.
Applications of TiO2 nanomaterials in photocatalysis, batteries, supercapacitors and solar cells, have seen widespread development in recent decades. Nowadays, black TiO2 have won attention due to enhancing the solar light absorption by the formation of oxygen vacancies and Ti3+ defects, to promote the separation of photo-generated charge carriers leading to the improvement of the photocatalytic performance in H2 production and pollutants degradation. The enhanced photocatalytic activity of black TiO2 is also due to a lattice disorder on the surface and the presence of oxygen vacancies, Ti3+ ions, Ti-OH and Ti-H groups. Enhancing the optical absorption characteristics of TiO2 and change of energy level and band-gap of materials have been successfully demonstrated to improve their photocatalytic activities, especially for black TiO2 nanoparticles, which promote visible light absorption. The current review focuses on the investigation of the chemical reduction synthetic route for black TiO2 nanomaterials, and their proposed association with green applications such as photodegradation of organic pollutants and photocatalytic water splitting. The synthesis methods of black TiO2 involves the changes from Ti4+ to Ti3+ state, into different strategies: (1) The use of highly active hydrogen species such as H2, H2/Ar or H2/N2 gases, and metal hydrides (NaBH4, CaH2), (2) the reduction by active metals such as aluminum, magnesium and zinc, and (3) organic molecules such as imidazole and ascorbic acid.
Luminita Andronic; Alexandru Enesca. Black TiO2 Synthesis by Chemical Reduction Methods for Photocatalysis Applications. Frontiers in Chemistry 2020, 8, 1 .
AMA StyleLuminita Andronic, Alexandru Enesca. Black TiO2 Synthesis by Chemical Reduction Methods for Photocatalysis Applications. Frontiers in Chemistry. 2020; 8 ():1.
Chicago/Turabian StyleLuminita Andronic; Alexandru Enesca. 2020. "Black TiO2 Synthesis by Chemical Reduction Methods for Photocatalysis Applications." Frontiers in Chemistry 8, no. : 1.
Ternary composites of TiO2–CuxS–fly ash were used in simultaneous adsorption and photocatalysis processes for the removal of organic (dye) pollutants. Composites of semiconductor (TiO2, CuxS) nanomaterials hosted within matrices of fly ash, such as film heterostructures, are promising materials for advanced wastewater treatment. The combination of adsorption and photocatalysis processes was investigated in the removal of methylene blue (MB), considered as a standard in photocatalysis. Ternary film heterostructures obtained by doctor blade technique allows overcoming the separation step of particles from treated wastewater. The comparison between the adsorption and photodegradation tests performed with TiO2–CuxS–fly ash showed that in dark conditions, the MB removal was 75% after 360 min, while in the presence of UV radiation, almost total dismissal of MB was achieved in the same treatment period. The degradation rate of MB, when H2O2 is used as an electron acceptor, could reach 90% in adsorption and 99% in simultaneous adsorption/photocatalysis processes. The adsorption isotherm was found to follow the Langmuir and Freundlich models.
Luminita Andronic; Luminita Isac; Cristina Cazan; Alexandru Enesca. Simultaneous Adsorption and Photocatalysis Processes Based on Ternary TiO2–CuxS–Fly Ash Hetero-Structures. Applied Sciences 2020, 10, 8070 .
AMA StyleLuminita Andronic, Luminita Isac, Cristina Cazan, Alexandru Enesca. Simultaneous Adsorption and Photocatalysis Processes Based on Ternary TiO2–CuxS–Fly Ash Hetero-Structures. Applied Sciences. 2020; 10 (22):8070.
Chicago/Turabian StyleLuminita Andronic; Luminita Isac; Cristina Cazan; Alexandru Enesca. 2020. "Simultaneous Adsorption and Photocatalysis Processes Based on Ternary TiO2–CuxS–Fly Ash Hetero-Structures." Applied Sciences 10, no. 22: 8070.
The diversification of pollutants type and concentration in wastewater has underlined the importance of finding new alternatives to traditional treatment methods. Advanced oxidation processes (AOPs), among others, are considered as promising candidate to efficiently remove organic pollutants such as dyes or pharmaceutical active compounds (PhACs). The present minireview resumes several recent achievements on the implementation and optimization of photoactive heterostructures used as photocatalysts for dyes and PhACs removal. The paper is focused on various methods of enhancing the heterostructure photocatalytic properties by optimizing parameters such as synthesis methods, composition, crystallinity, morphology, pollutant concentration and light irradiation.
Alexandru Enesca; Luminita Andronic. The Influence of Photoactive Heterostructures on the Photocatalytic Removal of Dyes and Pharmaceutical Active Compounds: A Mini-Review. Nanomaterials 2020, 10, 1766 .
AMA StyleAlexandru Enesca, Luminita Andronic. The Influence of Photoactive Heterostructures on the Photocatalytic Removal of Dyes and Pharmaceutical Active Compounds: A Mini-Review. Nanomaterials. 2020; 10 (9):1766.
Chicago/Turabian StyleAlexandru Enesca; Luminita Andronic. 2020. "The Influence of Photoactive Heterostructures on the Photocatalytic Removal of Dyes and Pharmaceutical Active Compounds: A Mini-Review." Nanomaterials 10, no. 9: 1766.
The presence of toxic, non-biodegradable and harmful organic pollutants in soils, wastewater, and atmosphere has become an indisputable, and global fact as a significant environmental problem. The heterogeneous photocatalysis, an advanced oxidation process (AOP) using semiconductor materials as catalysts, is a topic of great interest considering the possibility of the pollutants removal from water. The photocatalytic degradation of organic contaminants (i.e., dyes, pesticides, phenolic compounds) present in water using semiconductor materials depends on a number of parameters such as: the bandgap energy, phase composition, crystallinity, morphology and surface area of catalyst, electron-hole recombination rate, intensity of light, and adsorption capacity of the dye on the photocatalyst surface. One of the important constraints related to the catalyst photocatalytic efficiency is the fast recombination of the photogenerated electrons and holes. Therefore, various strategies have been involved in promoting the charge separation, including the development of heterojunction between two semiconductor materials, by tailoring the photocatalysts properties. This mini-review deals with the recent developments on dyes photodegradation using as catalysts various heterojunctions based on copper sulfide nanostructures, such as copper sulfide/metal oxide, copper sulfide/metal sulfide, copper sulfide/graphene, copper sulfide/organic semiconductors etc. The effects of different parameters, such as synthesis parameters, particle size, bandgap energy, surface area, and morphology on the photocatalytic activity of copper sulfide heterojunctions for dyes degradation is also highlighted.
Luminita Isac; Cristina Cazan; Alexandru Enesca; Luminita Andronic. Copper Sulfide Based Heterojunctions as Photocatalysts for Dyes Photodegradation. Frontiers in Chemistry 2019, 7, 694 .
AMA StyleLuminita Isac, Cristina Cazan, Alexandru Enesca, Luminita Andronic. Copper Sulfide Based Heterojunctions as Photocatalysts for Dyes Photodegradation. Frontiers in Chemistry. 2019; 7 ():694.
Chicago/Turabian StyleLuminita Isac; Cristina Cazan; Alexandru Enesca; Luminita Andronic. 2019. "Copper Sulfide Based Heterojunctions as Photocatalysts for Dyes Photodegradation." Frontiers in Chemistry 7, no. : 694.
Photoactive heterostructures containing CuxS/ZnO/TiO2 have been obtained by spray pyrolysis deposition followed by post-deposition thermal treatment. The ZnO middle layer morphology was tailored by using chemical additives during the deposition. The samples have crystalline structure with average crystallite size around 80 Å for metal oxides and 90 Å for CuxS. The roughness varies from 27.5 nm for CuxS/dZnO/TiO2 to 33.6 nm for CuxS/pZnO/TiO2 samples. The wettability properties were tested based on the contact angle measurements. The highest surface energy value (106.4 mN/m) corresponding to CuxS/pZnO/TiO2 with 30 min UV irradiation, with a predominant polar component of 85.3 mN/m. The photocatalytic efficiency under UV–Vis light irradiation was evaluated using methylene blue and phenol as pollutants. The highest photocatalytic values (93.4% for methylene blue and 72.3% for phenol) were obtained for CuxS/pZnO/TiO2 heterostructure with successive 30 min UV irradiation at 2 h intervals. The mineralization efficiency was tested using total organic carbon analysis and the results are slightly lower compared with photocatalytic efficiency.
Luminita Isac; Luminita Andronic; Maria Visa; Alexandru Enesca. Selective photocatalytic degradation of organic pollutants by CuxS/ZnO/TiO2 heterostructures. Ceramics International 2019, 46, 4265 -4273.
AMA StyleLuminita Isac, Luminita Andronic, Maria Visa, Alexandru Enesca. Selective photocatalytic degradation of organic pollutants by CuxS/ZnO/TiO2 heterostructures. Ceramics International. 2019; 46 (4):4265-4273.
Chicago/Turabian StyleLuminita Isac; Luminita Andronic; Maria Visa; Alexandru Enesca. 2019. "Selective photocatalytic degradation of organic pollutants by CuxS/ZnO/TiO2 heterostructures." Ceramics International 46, no. 4: 4265-4273.
Anca Duta; Luminita Andronic; Alexandru Enesca. The influence of low irradiance and electrolytes on the mineralization efficiency of organic pollutants using the Vis-active photocatalytic tandem CuInS2/TiO2/SnO2. Catalysis Today 2018, 300, 18 -27.
AMA StyleAnca Duta, Luminita Andronic, Alexandru Enesca. The influence of low irradiance and electrolytes on the mineralization efficiency of organic pollutants using the Vis-active photocatalytic tandem CuInS2/TiO2/SnO2. Catalysis Today. 2018; 300 ():18-27.
Chicago/Turabian StyleAnca Duta; Luminita Andronic; Alexandru Enesca. 2018. "The influence of low irradiance and electrolytes on the mineralization efficiency of organic pollutants using the Vis-active photocatalytic tandem CuInS2/TiO2/SnO2." Catalysis Today 300, no. : 18-27.
The paper is a comprehensive review on the wastewater treatment processes focused on the energy performance and energy efficiency. Extensive studies reported in literature, including results from our Renewable Energy Systems and Recycling R&D Center, are selected to give a clear view on the advantages and disadvantages of traditional and advanced wastewater treatment processes, from the energy consumption perspective. The challenges in terms of energy saving, process optimization and sustainable materials are presented. The traditional processes used in the wastewater plants have limited efficiency for removing the new organic pollutants and usually require environmental aggressive procedures (e.g. chlorination). Advanced wastewater treatments using common raw materials and renewable energy sources represent a sustainable answer to the problem raised by the resilient organic pollutants. So, the paper outlines that advanced wastewater treatment represents a suitable part of the strategy for planning nearly zero energy communities (nZEC).
Alexandru Enesca; Luminita Andronic; Anca Duta; Ion Visa. Sustainable Wastewater Treatment for Households in Small Communities. Springer Proceedings in Energy 2017, 550 -565.
AMA StyleAlexandru Enesca, Luminita Andronic, Anca Duta, Ion Visa. Sustainable Wastewater Treatment for Households in Small Communities. Springer Proceedings in Energy. 2017; ():550-565.
Chicago/Turabian StyleAlexandru Enesca; Luminita Andronic; Anca Duta; Ion Visa. 2017. "Sustainable Wastewater Treatment for Households in Small Communities." Springer Proceedings in Energy , no. : 550-565.
Maria Visa; Luminita Andronic; Alexandru Enesca. Behavior of the new composites obtained from fly ash and titanium dioxide in removing of the pollutants from wastewater. Applied Surface Science 2016, 388, 359 -369.
AMA StyleMaria Visa, Luminita Andronic, Alexandru Enesca. Behavior of the new composites obtained from fly ash and titanium dioxide in removing of the pollutants from wastewater. Applied Surface Science. 2016; 388 ():359-369.
Chicago/Turabian StyleMaria Visa; Luminita Andronic; Alexandru Enesca. 2016. "Behavior of the new composites obtained from fly ash and titanium dioxide in removing of the pollutants from wastewater." Applied Surface Science 388, no. : 359-369.
Materials with photocatalytic and adsorption properties for advanced wastewater treatment targeting reuse were studied. Making use of TiO2 as a well-known photocatalyst, Cu2S as a Vis-active semiconductor, and fly ash as a good adsorbent, dispersed mixtures/composites were prepared to remove pollutants from wastewater. X-ray diffraction, scanning electron microscopy, energy-dispersive X-Ray spectroscopy, atomic force microscopy, band gap energy, point of zero charge (pHpzc) and BET porosity were used to characterize the substrates. Phenol, imidacloprid and dichloroacetic acid were used as pollutants for photocatalytic activity of the new photocatalysts. Experiments using the new dispersed powders were carried out at laboratory scale in two solar simulators and under natural solar irradiation at the Plataforma Solar de Almería, in a Compound Parabolic Collector (CPC) for a comparative analysis of pollutants removal and mineralization efficiencies, and to identify features that could facilitate photocatalyst separation and reuse. The results show that radiation intensity significantly affects the phenol degradation rate. The composite mixture of TiO2 and fly ash is 2-3 times less active than sol-gel TiO2. Photodegradation kinetic data on the highly active TiO2 are compared for pollutants elimination. Photodegradation of dichloroacetic acid was fast and complete after 90min in the CPC, while after 150min imidacloprid and phenol removal was 90% and 56% respectively.
Luminita Andronic; Luminita Isac; Sara Miralles-Cuevas; Maria Visa; Isabel Oller; Anca Duta; Sixto Malato. Pilot-plant evaluation of TiO2 and TiO2-based hybrid photocatalysts for solar treatment of polluted water. Journal of Hazardous Materials 2016, 320, 469 -478.
AMA StyleLuminita Andronic, Luminita Isac, Sara Miralles-Cuevas, Maria Visa, Isabel Oller, Anca Duta, Sixto Malato. Pilot-plant evaluation of TiO2 and TiO2-based hybrid photocatalysts for solar treatment of polluted water. Journal of Hazardous Materials. 2016; 320 ():469-478.
Chicago/Turabian StyleLuminita Andronic; Luminita Isac; Sara Miralles-Cuevas; Maria Visa; Isabel Oller; Anca Duta; Sixto Malato. 2016. "Pilot-plant evaluation of TiO2 and TiO2-based hybrid photocatalysts for solar treatment of polluted water." Journal of Hazardous Materials 320, no. : 469-478.
This paper reports on the synthesis, characterization and adsorption properties of a novel nano-composite obtained using the hydrothermal method applied to a fly ash-TiO2 slurry and hexadecyltrimethyl-ammonium bromide, as surface controlling agent. The new adsorbent was investigated in terms of crystallinity (XRD), surface properties (AFM, SEM, and porosity and BET surface) and surface chemistry (EDX, FTIR). The nanocomposite's properties were sequentially tested in adsorption and photocatalysis processes applied to multi-pollutant synthetic wastewaters loaded with copper cations and two industrial dyes: the acid dye Bemacid Blau and the reactive dye Bemacid Rot; the nano-composite substrate allowed reaching high removal efficiencies, above 90%, both in adsorption and in photodegradation experiments, in optimised conditions.
Maria Visa; Luminita Andronic; Anca Duta. Fly ash-TiO 2 nanocomposite material for multi-pollutants wastewater treatment. Journal of Environmental Management 2015, 150, 336 -343.
AMA StyleMaria Visa, Luminita Andronic, Anca Duta. Fly ash-TiO 2 nanocomposite material for multi-pollutants wastewater treatment. Journal of Environmental Management. 2015; 150 ():336-343.
Chicago/Turabian StyleMaria Visa; Luminita Andronic; Anca Duta. 2015. "Fly ash-TiO 2 nanocomposite material for multi-pollutants wastewater treatment." Journal of Environmental Management 150, no. : 336-343.
From coal combustion millions of tons of ash are being generated every year and this leads to huge environmental problems. Nowadays the annual ash production is about 600 million tons per year from which 75–80 % is fly ash. One solutions for solving this problem would be wastes reuse (fly ash in this case) as second raw material to obtain new materials, such as zeolites, which can be further used as adsorbents/photocatalysts in wastewater treatment for heavy metals, dyes, etc. removal. Fly ash has a suitable composition (amorphous aluminosilicate glass being the prevalent reactive phase) that could allow zeolites production and has the advantage of low cost. Therefore, alkali processing of fly ash, at increased temperature and pressure can be a viable path (e.g. by hydrothermal treatment). Heavy metals are excessively released into the environment due to high urbanization and industrialization. These pollutants do not degrade into harmless end products as the organic pollutants do. They can affect life forms even at low concentrations because of their increased toxicity. For their removal many techniques are used among which adsorption is one representative choice in terms of efficiency and selectivity. This paper presents a synthesis of the results obtained in developing highly efficient fly-ash based substrates for heavy metals removal in advanced wastewater treatment processes. The influence of the fly ash composition (collected from CHP Plants from Romania) is discussed in correlation with the adsorption efficiency of heavy metals and dyes from one, two or three pollutants systems. Further on the efficiency is correlated with the substrates’ properties and hydrothermal processing conditions; the XRD diffractograms confirm the crystalline structure and shows that the main components of modified fly ash are: different mixed compounds of SiO2 and Al2O3, albite, γ oxide Fe2O3. These crystalline components have uniform microporous structures, shown by SEM that supports ionic or highly polar interactions, due to their negatively charged surface.
Maria Visa; Cristina Cazan; Luminita Andronic. Fly Ash Based Substrates for Advanced Wastewater Treatment. Springer Proceedings in Energy 2014, 539 -569.
AMA StyleMaria Visa, Cristina Cazan, Luminita Andronic. Fly Ash Based Substrates for Advanced Wastewater Treatment. Springer Proceedings in Energy. 2014; ():539-569.
Chicago/Turabian StyleMaria Visa; Cristina Cazan; Luminita Andronic. 2014. "Fly Ash Based Substrates for Advanced Wastewater Treatment." Springer Proceedings in Energy , no. : 539-569.
One main reason that limits their large scale application is the cost of the photocatalytic processes, mainly related to the costs of the UV radiation that activates most of the highly efficient photocatalytic materials and therefore, VIS-active photocatalysts are intensively studied; additionally, in industrial processes, fine powders are to be avoided although they have the advantage of larger specific areas, thus potential larger activity. This paper presents a review of the results obtained in the research group in optimizing photocatalysts used as thin films; doctor blade and spray pyrolysis deposition are comparatively analyzed. In situ doping using templating agents (surfactants) represented a viable path to extend the optoelectronic response towards VIS in wide band gap semiconductors. An additional advantage is morphology control reached when using surfactants. By associating two semiconductor photocatalysts as n-n tandems or n-p diode type materials, VIS-activated thin films can be obtained and the step-wise development of a novel family of VIS-active photocatalysts is presented for composite materials containing two or three components from the group of TiO2, WO3, SnO2, ZnO, CuxS.
Anca Duta; Alexandru Enesca; Luminita Isac; Dana Perniu; Luminita Andronic; Cristina Bogatu. Thin Film Vis-Active Photocatalysts for Up-scaled Wastewater Treatment. Springer Proceedings in Energy 2014, 521 -538.
AMA StyleAnca Duta, Alexandru Enesca, Luminita Isac, Dana Perniu, Luminita Andronic, Cristina Bogatu. Thin Film Vis-Active Photocatalysts for Up-scaled Wastewater Treatment. Springer Proceedings in Energy. 2014; ():521-538.
Chicago/Turabian StyleAnca Duta; Alexandru Enesca; Luminita Isac; Dana Perniu; Luminita Andronic; Cristina Bogatu. 2014. "Thin Film Vis-Active Photocatalysts for Up-scaled Wastewater Treatment." Springer Proceedings in Energy , no. : 521-538.
Tian-Yi Ma; Zhan-Ying Zhang; Jian-Liang Cao; Luminita Andronic; Yong Ma; Lei Liu. Structurally and Elementally Promoted Nanomaterials for Photocatalysis. International Journal of Photoenergy 2014, 2014, 1 -2.
AMA StyleTian-Yi Ma, Zhan-Ying Zhang, Jian-Liang Cao, Luminita Andronic, Yong Ma, Lei Liu. Structurally and Elementally Promoted Nanomaterials for Photocatalysis. International Journal of Photoenergy. 2014; 2014 ():1-2.
Chicago/Turabian StyleTian-Yi Ma; Zhan-Ying Zhang; Jian-Liang Cao; Luminita Andronic; Yong Ma; Lei Liu. 2014. "Structurally and Elementally Promoted Nanomaterials for Photocatalysis." International Journal of Photoenergy 2014, no. : 1-2.
Titanium oxide–active carbon composites (TiO2–AC) with photocatalytic activity were prepared by sol–gel method at low temperature. Titanium isopropoxide and active carbon were used as precursors, ethanol as solvent and HNO3 as catalyst. The composition of the studied composites was accomplished by means of X-ray diffraction, and Fourier Transform-Infrared spectrometry. The rutile crystalline phase was present in all samples. In scanning electron microscopy images the TiO2 aggregates existed either on the surface of the active carbon or heterogeneously dispersed over the whole catalyst matrix. The contact angle and point of zero charge measurements were applied to characterise the surface energy and surface charge. The photocatalytic activities of the TiO2–AC composites were evaluated in the bleaching of methyl orange and methylene blue solution from ternary mixture of methyl orange, methylene blue and Triton X100. The double divisor ratio spectra derivative method (as a multivariable calibration method) was developed to overcome the spectral overlapping, for the simultaneous analysis of ternary mixture.
Luminita Andronic; Alexandru Enesca; Cristina Cazan; Maria Visa. TiO2–active carbon composites for wastewater photocatalysis. Journal of Sol-Gel Science and Technology 2014, 71, 396 -405.
AMA StyleLuminita Andronic, Alexandru Enesca, Cristina Cazan, Maria Visa. TiO2–active carbon composites for wastewater photocatalysis. Journal of Sol-Gel Science and Technology. 2014; 71 (3):396-405.
Chicago/Turabian StyleLuminita Andronic; Alexandru Enesca; Cristina Cazan; Maria Visa. 2014. "TiO2–active carbon composites for wastewater photocatalysis." Journal of Sol-Gel Science and Technology 71, no. 3: 396-405.