Claudia Maria Simonescu

Polytechnic University of Bucharest | UPB · Department of Analytical Chemistry and Environmental Engineering

The aim of the research was to prepare silica adsorbents using an environmentally friendly pathway, a template synthesis with saponin biosurfactant as a structure-directing agent. The adsorbents prepared in this way exhibit improved adsorption properties while maintaining environmental innocuousness. For the preparation of porous silica, the biosur...

The development of new composite membranes is required to separate chemical species from aggressive environments without using corrective reagents. One such case is represented by the high hydrochloric acid mixture (very low pH and pCl) that contains mixed metal ions, or that of copper, cadmium, zinc and lead ions in a binary mixture (Cu–Zn and Cd–...

In this study, three novel magnetic nanocomposites based on carboxyl-functionalized SBA-15 silica and magnetite nanoparticles were prepared through an effective and simple procedure and applied for methylene blue (MB) and malachite green G (MG) adsorption from single and binary solutions. Structure, composition, morphology, magnetic, and textural p...

A sensitive method using liquid chromatography with diode array detector for the simultaneous determination of Congo Red (CR) and Methyl Orange (MO) synthetics dyes was developed and applied to synthetic water solutions. Chromatographic separation was achieved using an Acclaim Surfactant Plus chromatographic column (150 x 3.0 mm, 3 µm) in gradient...

A research study was conducted to establish the effect of the presence of sodium bis-2-ethyl-hexyl-sulfosuccinate (DOSS) surfactant on the size, shape, and magnetic properties of cobalt ferrite nanoparticles, and also on their ability to remove anionic dyes from synthetic aqueous solutions. The effect of the molar ratio cobalt ferrite to surfactant...

(1) Background: A comparative research study to remove Congo Red (CR) and Methyl Orange (MO) from single and binary solutions by adsorption onto cobalt ferrite (CoFe2O4) and cobalt ferrite–chitosan composite (CoFe2O4-Chit) prepared by a simple coprecipitation method has been performed. (2) Methods: Structural, textural, morphology, and magnetic pro...

Surface water contamination by synthetic dyes generates human and wildlife adverse health effects and causes photosynthesis activity decrease due to intense sunlight absorption of these pollutants. 50% of total discharged industrial effluents contain azo dyes. Congo Red is a benzidine based anionic azo dye that is usually employed in the rubber, pa...

The aim of this research paper is to present a simple and efficient method to prepare zeolite materials from thermal power plant fly ash which is one of the most important waste resulted from power plants. The method of preparation of zeolite materials consists of alkaline activation followed by calcination at different temperatures. The zeolite ma...

Calcium alginate (CaAlg) beads were prepared using ultrasound for use in the removal of lead from natural and wastewaters by ion exchange. Ultrasound was applied in a batch mode with an ultrasonic bath or in a flow mode using an ultrasonic clamp-on device. For comparison purposes the synthesis was performed in batch mode in the absence of the ultra...

Nowadays, the concerns regarding cadmium pollution increased steadily, due to its serious damages to the environment and human health. Consequently, stringent limits have been set for this heavy metal ion both in industrial and drinking water. Numerous traditional and unconventional methods were applied to reach these limits. In this paper, two pho...

Mining activities have a high negative impact on the environment and on human health. Environmental impacts can result in contamination of surface water, groundwater, soil and air. Large volumes of wastewater produced by mining activities have to be remediated before being discharged into the environment. Due to the complex composition of wastewate...

The experimental study aimed to establish the potential applications of the nano- and micrometric powders of hydroxyapatite in the removal processes of Cu(II) ions from synthetic aqueous solutions. For this purpose, hydroxyapatite (HAP) was used in the form of: 1) nanometric powder (labeled nano-HAP), and 2) calcium alginate hydroxyapatite composit...

In the present paper, the adsorptive Pb(II) removal from synthetic aqueous solutions using a 2 cm diameter hydroxyapatite column has been studied through column adsorption experiments by varying column depths (1, 2, 3, 4 cm) and flow rate (10, 15, 22.5 mL/min). Different types of synthetic hydroxiapatites have been involved in experiments. Column d...

A series of three chitosan-based magnetic composites was prepared through a simple coprecipitation method. It was investigated the influence of mass ratio between chitosan and magnetite on the physical and chemical properties of the composites in order to establish the optimum conditions for obtaining a composite with good adsorption capacity for P...

A kinetic study has been carried out with two hydroxyapatite nanopowders to establish the mechanism involved in heavy metals removal from aqueous synthetic solutions. The samples of nanohydroxyapatite have been previously characterized. The first sample represents a pure hydroxyapatite (HAP) nanopowder named HAP-1, and the second sample (HAP-2) con...

Two types of nanohydroxyapatite samples have been obtained by wet chemical precipitation synthesis, involving calcium nitrate tetrahydrate and diammonium hydrogen phosphate as precursors in different conditions. Powders obtained were characterized by X-ray diffraction (XRD) and FTIR spectroscopy. The equilibrium isotherm models related with lead an...

Three Schiff base-functionalized mesoporous silicas: MCM-41@salen, HMS-C12@salen and HMS-C16@salen have been synthesized by a post-synthetic grafting strategy and their sorption capacities toward Pb(II) from synthetic aqueous solutions have been assessed. FTIR spectra, TG/DSC analyses, X-ray powder diffraction, X-ray photoelectron spectroscopy (XPS...

Fe3O4, Fe3O4@SiO2, and Fe3O4@SiO2@ICPTES-cysteine MNPs have been prepared by the deposition of silica onto magnetite nanoparticles via controlled hydrolysis of TEOS. The new formed silica surface has been functionalized by grafting 3-(triethoxysilyl) propyl isocyanate (ICPTES) and, subsequently, by condensation of isocyanate moiety with cysteine. T...

The application of biopolymer-based sorbents in solving some environmental problems such as the removal and recovery of heavy metals from natural polluted water and wastewater has received lately a lot of attention due to their unique characteristics. The fundamental properties that recommend the usage of biopolymers-based sorbents for environmenta...

The purpose of this research paper is to use chitosan/hydroxyapatite composites to remove lead, copper, zinc and nickel from multi-metal aqueous systems. The comparative studies were performed in a batch system. The effects of the removal process parameters such as, pH, contact time, initial metal ions concentration, and type of chitosan/hydroxyapa...

Three novel magnetic adsorbents were synthesized through the immobilization of di-, tri-, and tetraamine onto the surface of silica coated magnetite nanoparticles. The adsorbents were characterized by XRD patterns, FTIR spectroscopy, elemental and thermogravimetric analysis, magnetic measurements, SEM/TEM, EDX spectroscopy, and N2 adsorption/desorp...

This research study deals with lead and nickel simultaneous removal from aqueous solutions by the use of chitosan coated cobalt ferrite as adsorbent. Batch removal tests were performed in order to establish the main parameters that influence the sorption capacity, removal efficiency and the selectivity of this adsorbent. The values of sorption capa...

The aim of this work was to use glutaraldehyde-crosslinked chitosan (Chit-GLA) beads to remove lead(II), nickel(II), zinc(II) and copper(II) from polycationic aqueous solutions. The batch experiments were carried on to test the influence of different parameters such as: pH, contact time, and initial ion concentration on adsorption of metal ions ont...

This research study deals with lead(II)/Pb2 + removal from aqueous solutions by calcium alginate (CA) and chitosan coated calcium alginate (CCCA) as adsorbents, in batch experiments. A simple synthesis method was used to prepare both adsorbent materials. CA and CCCA were characterized using infrared spectroscopy (FT-IR), scanning electron microscop...

In the present work, nano-hydroxyapatite (nano-HAP) prepared in microwave field was applied to remove lead(II), nickel(II), zinc(II) and copper(II) from polycationic aqueous solutions. Optimum adsorption conditions were evaluated using batch experiments. Effect of various physicochemical parameters such as: pH, contact time, and initial ion concent...

This study aimed to investigate the effect of preparation conditions on different hydroxyapatite nanopowders (n-HAP) obtained on the laboratory scale, by the solution-precipitation and sol-gel method, and correlate the main characteristics like crystallinity and specific surface area with the ion Pb2+ immobilization capacity. It is tested the incre...

Nano-hydoxyapatite was prepared using a rapid microwave method as an effective sorbent for lead(II) and copper(II) removal from aqueous solutions. The surface of the produced nano-hydoxyapatite has a porous structure and the specific surface area according to the BET model in value of 88.75 mg/g. Batch experiments revealed that removal ration incre...

A comparative study regarding air pollution with PM 2.5 and PM 10 in Tg-Jiu in 2014 was performed taking into account that Tg-Jiu is one of the most recognized polluted city in Romania. The major sources of PM 2.5 and PM 10 in Tg-Jiu are motor vehicles, coal combustion, secondary aerosols and industrial sources mainly mining activities. Standardize...

In this study, chitosan/hydroxyapatite composite particles were prepared using as raw materials nano- and microparticles of hydroxyapatite obtained by different synthesis methods. The chitosan/hydroxyapatite composites were characterized using infrared spectroscopy (FT-IR), X-ray diffraction, and scanning electron microscopy (SEM). Evidence of hydr...

This work reports the results obtained in the process of lead removal from synthetic aqueous solutions by different types of chitosan/hydroxyapatite (CHIT-HAP) composites. Batch experiments were performed to test sorption capacity of chitosan/hydroxyapatite composites. The solution’s pH, contact time and concentration of lead ions in the initial so...

The study aims to assess groundwater quality considering its importance for the development of human communities. The water samples used in the study were collected from wells located in two areas of the Gorj County affected by industrial activities, namely: Ticleni area affected by oil extraction and Turceni area situated under the influence of th...

The present paper deals with sot-gel preparation of hydroxyapatite powders for bio uses by performing several techniques of gelation and thermal treatments of dried gels. The hydroxyapatite formation and decomposition are checked by X-ray diffraction which showed that the tri-calcium phosphate apparition takes place as the result of thermal treatme...

The aim of this research study was to investigate the effectiveness of chitosan beads chemically by crosslinking with glutaraldehyde in zinc removal from aqueous solutions. The effect of the followings parameters such as: glutaraldehyde concentration used in obtaining copolymers, zinc level in initial solution, time, and pH value was investigated....

This paper presents a research study related to assessment of the quality status of Motru and Motru Sec rivers from measured values for physico-chemical parameters such as temperature, pH, suspended solids, nitrate, total phosphorus, dissolved oxygen and biochemical oxygen into three monitoring sections in 2012-2014. By analyzing the results obtain...

Abstract Mesoporous CoFe2O4 nanoparticles were synthesized through a simple precipitation method using cetyltrimethylammonium bromide (CTAB) as surfactant. Variation of surfactant concentration have been investigated to synthesize CoFe2O4 nanoparticles with superior textural properties. The samples were characterized by FTIR, TG/DSC, XRD, SEM, N2 a...

This study deals with the preparation and characterization of chitosan-glutardialdehyde (Chit-GLA) copolymers at different glutardialdehyde concentration. The sorption properties of Chit-GLA copolymers were evaluated comparatively in copper ions removal process from aqueous solutions. For this purpose, the experiments were carried out in a batch re...

Two types of (Ca10(PO4)6(OH)2) hydroxyapatite (HAP) powders with high purity were obtained using two different synthesis methods – a wet chemical synthesis method such as precipitation from aqueous solution and a dry chemical method such as solid-state sintering. Both types of powders were characterized by X-ray diffraction, FT-IR analysis, scannin...

Microwave processing was used to obtain porous hydroxyapatite (HAp) granules. Ca(NO3)2·4H2O and (NH4)2HPO4 were used as raw materials. The resulted suspensions from the synthesis in the microwave field have been dehydrated at 120°C, and thermally treated at 300°C to eliminate the ammonium nitrate obtained. Synthesized powder was characterized by X-...

The measurements of the hourly ground-level ozone (O3) concentration of two monitoring stations from Târgu Jiu and Rovinari area was analysed because elevated O3 concentrations have a negative impact to humans, vegetation, animals and materials. The temporal distribution pattern of ozone in relation to solar radiation intensity was observed. The me...

Nitrogen oxides emitted primarily from the burning of solid, liquid and gases in various industrial plants, residential heating, commercial and from road traffic have many negative effects to the environment and human health. Nitrogen oxides contribute to the aquatic ecosystems eutrophication and to the acidification of environmental components suc...

This paper presents the assessment of air quality in the influence area of Turceni power plant from Goij County during 2012-2013 regarding PM10 and heavy metals contents. The network of air quality monitoring station in the Turceni area includes one automatic air quality monitoring industrial station (code GJ - 3) located in the northwest to plant....

The aim of this research is the preparation of chitosan/Ag/ZnO (CS/Ag/ZnO) system via chemical precipitation method followed by thermal treatment at 125°C for 8 hours. The CS/Ag/ZnO system obtained was characterized by UV-VIS absorption spectroscopy (UV-Vis), X-ray diffraction (XRD), atomic force microscopy (AFM) and photocatalytic characterization...

This paper presents a comparative study regarding the use of chitosan and cross-linked with glutaraldehyde (GLA) chitosan microparticles in the retention of Pb(II) ions from aqueous solutions with low Pb(II) levels. Initial Pb(II) ion concentration, contact time, and pH are parameters considered. Sorption capacity value reaches 43.78 mg Pb(II)·g-1...

This paper presents the physical and chemical changes in chitosan flakes, having as purpose the improving of mechanical strength, and the enhancing of the resistance of chitosan against acid, alkali and other chemicals. These changes led to obtaining chitosan and cross-linked with glutaraldehyde (GLA) chitosan microparticles, by means of a simple a...

In this study, the removal of Cu(II) and Ni (II) ions from aqueous solution using chitosan and chemical modified chitosan in a batch adsorption system was studied. Our results led to the conclusion that chemical modification of chitosan decreased the adsorption capacity for Cu(II) and Ni(II) ions, but increased it’s resistance in acidic medium.

This paper presents the current state of PM10 air pollution in the area of influence of Rovinari thermal power plant in Gorj county. In the Rovinari area the air quality monitoring network includes an automatic station on the Southeast part of Rovinari town. PM10 concentration was monitored by this automatic station (code GJ- 2). The reference meth...

This paper presents experimental studies regarding the determination of heavy metals content in soils from Târgu-Jiu. The soil samples were collected from four distinct points, and on two depth profiles: 0-10 cm, and 10-20 cm. Extraction using solution of H2SO4 98%, and H2O2 50% was performed with a Hach Digesdahl Mineralizer. Determination of Cd,...

Natural or synthetic hydroxyapatite [Ca10(PO4)6(OH)2] has a high exchange capacity for divalent heavy metal ions and is used to treat wastewater containing such ions. The reaction mechanism of hydroxyapatite with lead salts is carried out by dissolution followed by precipitation pyromorphite. As-synthesized HAp granules were analyzed by X-ray diffr...

The mining industry has various influences on the environment expressed in all production and preparation phases. Carboniferous waste accumulated in waste dumps have ecological and social impact. Thus promoting the valorisation directions exceeds the local interests and becomes a national problem. The paper presents studies regarding the recovery o...

This paper presents a comparative study on air pollution by PM10 (particles with aerodynamic diameter less than 10 μm) in area Târgu Jiu – Rovinari – Turceni from Gorj County. The main antrophogenic sources of particulate matter in this area are thermal power stations (in Gorj County are located two large power plants from Rovinari and Turceni), in...

Abstract. The paper presents the assessment of the impact of surface mining exploitation on the environment. There was experimentally determined the impact produced by the surface mining exploitation on the air and the pollution with SO2, NO2, NH3, suspension powders and sedimentary powder in the period 2008–2009. Also, there was experimentally det...

The basic objectives of the present research were to study the sorption mechanism of zinc(II) ions onto chitosan and contribute to understanding and modelling the equilibrium of the sorption processes. The sorption capacity of zinc(II) was examined by varying experimental conditions such as zinc concentration in initial solutions, contact time, pH,...

At present, heavy metals pollution is becoming a more and more serious problem for the environment and public health. Removal of heavy metals and metalloids from aqueous solutions is generally achieved through several processes such as chemical precipitation/neutralization, solvent extraction, ion exchange, membrane separation, reverse osmosis, or...

The solid and liquid waste with heavy metal content that are discharged direct or indirect in environment determine negative effects for organisms, and environment. The main heavy metals found in wastewaters and solid wastes are cadmium, chromium, lead, nickel, zinc, copper, mercury, and arsenic. From these heavy metals, copper in high concentratio...

In recent years glass industry was affected by the tendency to avoid use of potentially hazardous or polluting substances. This trend was found especially on the more developed country markets, but also for Romanian glass manufacturers. The paper presents obtaining of some red colored glasses containing copper which replace cadmium-based red glasse...

Heavy metals accumulated in the air are largely due to human activities. This paper presents a comparative study on air pollution by heavy metals in the Tg-Jiu - Rovinari - Turceni area from Gorj County. Experimental determination of heavy metals was performed according to SR EN 14902-2007 standard. The results obtained show that values of heavy me...

The paper presents an issue of topical interest which is the recovery of some industrial wastes in obtaining of some useful products. Recovery of processed wastes resulted from the fabrication process of E fiber glass can be also made for the obtaining of some vitreous glazes for the household faience. To obtain vitreous glazes were used, in additi...

Compared with conventional methods used in heavy metals removal from wastewater from electroplating and leather industry, biosorption is an efficient alternative to decrease the concentration of heavy metals from solutions of ppm to ppb concentrations using low cost materials. This process is much faster than other processes used to remove heavy me...

Heavy metals are the most important water pollutants as they cause serious environmental and health problems. The main processes used for heavy metals removal from aqueous solutions are: chemical precipitation, solvent extraction, ion-exchange, reverse osmosis or adsorption. All these processes have advantages and disadvantages. Adsorption can be a...

In this study, copper sulfide CuS (covellite) was obtained, starting from the Cu(CH3COO)2.H2O and thiourea ((NH2CSNH2) system, and working in presence or absence of sodium-bis(2-ethylhexyl) sulfosuccinate (Na-AOT). Samples obtained from Cu(CH3COO)2.H2O:NH2CSNH2:Na-AOT system were deposited as thin films on the glass substrates. CuS samples obtained...

The present work aims to use chitosan in Fe(III) removal from aqueous solutions and evaluates their sorption capacity. Experiments were carried out as function of contact time, agitation rate, pH and the concentration Fe(III) ions in initial solution. The Langmuir and Freundlich adsorption models were applied to describe the isotherms and isotherm...

In this paper we present the preparation and the investigation of the liquid crystal properties of a series of dinuclear carboxylato bridge Pd(II) complexes bearing six alkoxy peripheral chains in the molecule. Their structures were assigned based on elemental analysis, IR and 1H NMR spectroscopy whereas the thermal behaviour was investigated by po...

The paper presents the valorization of galvanic wastes with nickel content. This process consists in waste incorporation in a borosilicate glass, and the obtaining of some glasses which maybe used in industry.There were prepared glasses using both wastes and natural material as raw materials. The dissolving of the samples was carried out in electri...

In the Gorj County there are two high-power energetic complexes, Turceni Power Station and Rovinari Power Station, both using as fuel the lignite extracted from the coal basin of Oltenia. The burning of the coal in air suspension in order to produce electric energy results in slag and ash, eliminated by storage, so that warehouses were set up to st...

In Romania, and especially in the Gorj county, a large part of the industrial activities is related to the mining industry. The paper presents the study of the air pollution by the industrial activities taking place in the mining exploitation. There were determined: SO2', NO2', NH3 from air and the air-borne pollutions, the fraction PM 10 according...

This paper presents the obtaining of copper sulfide CuS (covelite) from Cu(CH3COO)2·H2O and thioacetamide (TAA) system. The reaction was conducted in presence or absence of sodium-bis(2-ethylhexyl) sulfosuccinate (Na-AOT). The effects of various reaction parameters on the size and on the shape of nanoparticles have been examined. CuS obtained was c...