Publications by authors named "Laura Bulgariu"

11 Publications

  • Page 1 of 1

Construction of a novel microbial consortium valued for the effective degradation and detoxification of creosote-treated sawdust along with enhanced methane production.

J Hazard Mater 2021 May 27;418:126091. Epub 2021 May 27.

Biofuels Institute, School of the Environment and Safety Engineering, Jiangsu University, Zhenjiang 212013, China. Electronic address:

Lignocellulosic biomass represents an unlimited and ubiquitous energy source, which can effectively address current global challenges, including climate change, greenhouse gas emissions, and increased energy demand. However, lignocellulose recalcitrance hinders microbial degradation, especially in case of contaminated materials such as creosote (CRO)-treated wood, which necessitates appropriate processing in order to eliminate pollution. This study might be the first to explore a novel bacterial consortium SST-4, for decomposing birchwood sawdust, capable of concurrently degrading lignocellulose and CRO compounds. Afterwards, SST-4 which stands for molecularly identified bacterial strains Acinetobacter calcoaceticus BSW-11, Shewanella putrefaciens BSW-18, Bacillus cereus BSW-23, and Novosphingobium taihuense BSW-25 was evaluated in terms of biological sawdust pre-treatment, resulting in effective lignocellulose degradation and 100% removal of phenol and naphthalene. Subsequently, the maximum biogas production observed was 18.7 L/kg VS, while cumulative methane production was 162.8 L/kg VS, compared to 88.5 without microbial pre-treatment. The cumulative energy production from AD-I and AD-II through biomethanation was calculated as 3177.1 and 5843.6 KJ/kg, respectively. The pretreatment process exhibited a significant increase in the energy yield by 83.9%. Lastly, effective CRO detoxification was achieved with EC values exceeding 90%, showing the potential for an integrated process of effective contaminated wood management and bioenergy production.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.jhazmat.2021.126091DOI Listing
May 2021

Equilibrium and Kinetics Studies of Metal Ions Biosorption on Alginate Extracted from Marine Red Algae Biomass ( sp.).

Polymers (Basel) 2020 Aug 21;12(9). Epub 2020 Aug 21.

Department of Environmental Engineering and Management, "Cristofor Simionescu" Faculty of Chemical Engineering and Environmental Protection, Gheorghe Asachi Technical University of Iași, 700050 Iaşi, Romania.

Biosorption is a viable alternative that can be used to remove heavy metal ions from aqueous effluents, as long as the biosorbent used is cost-effective and efficient. To highlight this aspect in this study, alginate extracted from marine red algae biomass ( sp.) was used as biosorbent for the removal of Cu(II), Co(II) and Zn(II) ions from aqueous media. Biosorption studies were performed in a batch system, and the biosorptive performances of the alginate were examined as function of initial solution pH, biosorbent dosage, contact time, initial metal ions concentration and temperature. The optimal experimental conditions were found: initial solution pH of 4.4, a biosorbent dose of 2.0 g/L and a temperature of 22 °C, when over 88% of Cu(II), 76% of Co(II) and 81% of Zn(II) are removed by biosorption. The modeling of the obtained experimental data show that the Langmuir isotherm model and pseudo-second kinetic model well describe the biosorption processes of studied metal ions. The maximum biosorption capacity (q, mg/g) increases in the order: Cu(II) (64.52 mg/g) > Zn(II) (37.04 mg/g) > Co(II) (18.79 mg/g), while the minimum time required to reach the equilibrium is 60 min. Moreover, the regeneration efficiency of alginate is higher than 97% when a 10 N HNO solution is used as desorption agent for the recovery of Cu(II), Co(II) and Zn(II) ions. All these characteristics demonstrate that the alginate extracted from marine algae has promising applications in the decontamination of industrial effluent containing metal ions.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3390/polym12091888DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7563890PMC
August 2020

Sequential treatment of paper and pulp industrial wastewater: Prediction of water quality parameters by Mamdani Fuzzy Logic model and phytotoxicity assessment.

Chemosphere 2019 Jul 5;227:256-268. Epub 2019 Apr 5.

Department of Earth Sciences, Faculty of Natural Sciences, University of Tabriz, 29 Bahman Boulevard, Tabriz, East Azerbaijan, Iran.

Recycling of industrial wastewater meeting quality standards for agricultural and industrial demands is a viable option. In this study, paper and pulp industrial wastewater were treated with three biological treatments viz. aerobic, anaerobic and sequential (i.e. 20 days of anaerobic followed by 20 days of aerobic cycle), associated with simulation modeling by Mamdani Fuzzy Logic (MFL) model of some selected parameters. Electric air diffuser and minimal salt medium in sealed plastic bottles at control temperature were used for aerobic and anaerobic treatments, respectively. The significant reduction in chemical (COD: 81%) and biological oxygen demand (BOD: 71%), total suspended (TSS: 65%), dissolved solids (TDS: 60%) and turbidity (68%) was recorded during sequential treatment. The treated water was irrigated to determine its phytotoxic effects on seed germination, vigor and seedling growth of mustard (Brassica campestris). Sequential treatment greatly reduced phytotoxicity of wastewater and showed the highest germination percentage (90%) compared to aerobic (60%), anaerobic (70%) treatments and untreated wastewater (30%). Regression analysis also endorsed these findings (R = 0.76-0.95 between seed germination, seedling growth and vigor). MFL technique was adopted to simulate sequential treatment process. The results support higher performance of MFL model to predict TDS, TSS, COD, and BOD based on the physico-chemical water quality parameters of raw wastewater, time of treatment and treatment type variation. Based on these findings, we conclude that the sequential treatment could be a more effective strategy for treatment of pulp and paper industrial wastewater with efficiency to be used for agricultural industry without toxic effects.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.chemosphere.2019.04.022DOI Listing
July 2019

Valorisation possibilities of exhausted biosorbents loaded with metal ions - A review.

J Environ Manage 2018 Oct 23;224:288-297. Epub 2018 Jul 23.

Technical University Gheorghe Asachi of Iasi, Faculty of Chemical Engineering and Environmental Protection "Cristofor Simionescu", Department of Environmental Engineering and Management, 700050, Iaşi, Romania. Electronic address:

Biosorption is considered one of the most promising methods for removal of metal ions from aqueous effluents, due to its low-cost and eco-friendly characteristics. However, the exhausted biosorbents loaded with metal ions, obtained at the end of biosorption processes, are still a problem which should be solved to increase the applicability of biosorption on an industrial scale. In this study are examined three possibilities for the valorisation of exhausted biosorbents loaded with metal ions, namely: (i) regeneration and reuse of biosorbents in multiple biosorption cycles, (ii) the use of exhausted biosorbents as fertilizers for soils poor in essential microelements, and (iii) the pyrolysis of exhausted biosorbents, under well defined conditions. The main advantages and disadvantages of each valorisation possibility are reviewed in order to find the best way to use these cheap materials in accordance with the principles of the circular economy and thereby contributing to the development of sustainable biosorption technology.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.jenvman.2018.07.066DOI Listing
October 2018

Nickel phytoextraction through bacterial inoculation in Raphanus sativus.

Chemosphere 2018 Jan 29;190:234-242. Epub 2017 Sep 29.

Department of Environmental Engineering and Management, Technical University Gheorghe Asachi of Iasi, 700050, Iasi, Romania.

A pot experiment was conducted to evaluate the potential of two plant growth promoting rhizobacteria (PGPR) viz. Bacillus sp. CIK-516 and Stenotrophomonas sp. CIK-517Y for improving the growth and Ni uptake of radish (Raphanus sativus) in the presence of four different levels of Ni contamination (0, 50, 100, 150 mg Ni kg soil). Plant growth, dry biomass, chlorophyll and nitrogen contents were significantly reduced by the exogenous application of Ni, however, bacterial inoculation diluted the negative impacts of Ni stress on radish by improving these parameters. PGPR strain CIK-516 increased root length (9-27%), shoot length (8-27%), root dry biomass (2-32%), shoot dry biomass (9-51%), root girth (6-48%), total chlorophyll (4-38%) and shoot nitrogen contents (11-15%) in Ni contaminated and non-contaminated soils. Positive regulation of chlorophyll and nitrogen contents by the inoculated plants shows plant tolerance mechanism of Ni stress. Bacterial strain (CIK-516) exhibited indole acetic acid and 1-amino-cyclopropane-1-carboxylate deaminase potentials which would have helped radish plant to stabilize in Ni contaminated soil and thereby increased Ni uptake (24-257 in shoot and 58-609 in root mg kg dry biomass) and facilitated accumulation in radish (bioaccumulation factor = 0.6-1.7) depending upon soil Ni contamination. Based on the findings of this study, it might be suggested that inoculation with bacterial strain CIK-516 could be an efficient tool for enhanced Ni phytoextraction in radish.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.chemosphere.2017.09.136DOI Listing
January 2018

Neural networks-based modeling applied to a process of heavy metals removal from wastewaters.

J Environ Sci Health A Tox Hazard Subst Environ Eng 2013 ;48(11):1399-412

"Gheorghe Asachi" Technical University, Department of Chemical Engineering, Iasi, Romania.

This article approaches the problem of environment pollution with heavy metals from disposal of industrial wastewaters, namely removal of these metals by means of biosorbents, particularly with Romanian peat (from Poiana Stampei). The study is carried out by simulation using feed-forward and modular neural networks with one or two hidden layers, pursuing the influence of certain operating parameters (metal nature, sorbent dose, pH, temperature, initial concentration of metal ion, contact time) on the amount of metal ions retained on the unit mass of sorbent. In neural network modeling, a consistent data set was used, including five metals: lead, mercury, cadmium, nickel and cobalt, the quantification of the metal nature being done by its electronegativity. Even if based on successive trials, the method of designing neural models was systematically conducted, recording and comparing the errors obtained with different types of neural networks, having various numbers of hidden layers and neurons, number of training epochs, or using various learning methods. The errors with values under 5% make clear the efficiency of the applied method.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1080/10934529.2013.781896DOI Listing
October 2013

Sorption of Pb(II) onto a mixture of algae waste biomass and anion exchanger resin in a packed-bed column.

Bioresour Technol 2013 Feb 7;129:374-80. Epub 2012 Nov 7.

Al. I. Cuza University of Iasi, Faculty of Geography and Geology, Department of Geology and Geochemistry, Romania.

Sorption of Pb(II) was studied by using a biosorbent mixture of algae waste biomass and Purolite A-100 resin in a packed-bed column. Mixing these two components was done to prevent the clogging of the column and to ensure adequate flow rates. Increasing of solution flow rate and initial Pb(II) concentration make that the breakthrough and saturation points to be attained earlier. The experimental breakthrough curves were modeled using Bohart-Adams, Thomas and Yoon-Nelson models, and the parameters for all these models were calculated. A regeneration efficiency of 98% was achieved using 0.1 mol L(-1) HCl and not significant changes in lead uptake capacity after three biosorption/desorption cycles were noted. The biosorbent mixture was able to remove Pb(II) from synthetic wastewater at pH 5.0 and flow rate of 3.5 mL min(-1), and the obtained effluent has better quality characteristics. The biosorbent mixture it is suitable for a continuous system for large-scale applications.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.biortech.2012.10.142DOI Listing
February 2013

Equilibrium and kinetics studies of heavy metal ions biosorption on green algae waste biomass.

Bioresour Technol 2012 Jan 19;103(1):489-93. Epub 2011 Oct 19.

Al. I. Cuza University of Iasi, Faculty of Geography and Geology, Department of Geology and Geochemistry, Romania.

The biosorption of Pb(II), Cd(II), and Co(II), respectively, from aqueous solution on green algae waste biomass was investigated. The green algae waste biomass was obtained from marine green algae after extraction of oil, and was used as low-cost biosorbent. Batch shaking experiments were performed to examine the effects of initial solution pH, contact time and temperature. The equilibrium biosorption data were analyzed using two isotherm models (Langmuir and Freundlich) and two kinetics models (pseudo-first order and pseudo-second order). The results indicate that Langmuir model provide best correlation of experimental data, and the pseudo-second order kinetic equation could best describe the biosorption kinetics of considered heavy metals.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.biortech.2011.10.016DOI Listing
January 2012

On the retention of uranyl and thorium ions from radioactive solution on peat moss.

J Hazard Mater 2010 Feb 30;174(1-3):782-7. Epub 2009 Sep 30.

Faculty of Chemistry, AlI Cuza University of Iasi, Bd 11 Carol I Boulevard, 700506 Iasi, Romania.

The efficiency of the radioactive uranyl and thorium ions on the peat moss from aqueous solutions has been investigated under different experimental conditions. The sorption and desorption of uranyl and thorium ions on three types (unmodified peat moss, peat moss treated with HNO(3) and peat moss treated with NaOH) of peat moss were studied by the static method. Peat moss was selected as it is available in nature, in any amount, as a cheap and accessible sorbent. Study on desorption of such ions led to the conclusion that the most favourable desorptive reagent for the uranyl ions is Na(2)CO(3) 1M while, for the thorium ions is HCl 1M. The results obtained show that the parameters here under investigation exercise a significant effect on the sorption process of the two ions. Also, the investigations performed recommend the peat moss treated with a base as a potential sorbent for the uranyl and thorium ions from a radioactive aqueous solution.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.jhazmat.2009.09.120DOI Listing
February 2010

Adsorption potential of mercury(II) from aqueous solutions onto Romanian peat moss.

J Environ Sci Health A Tox Hazard Subst Environ Eng 2009 Jun;44(7):700-6

Department of Environmental Engineering and Management, Technical University Gheorghe Asachi of Iasi, Iasi, Romania.

This study was undertaken to evaluate the adsorption potential of Romanian peat moss for the removal of mercury(II) from aqueous solutions. The batch system experiments carried out showed that this natural material was effective in removing mercury(II). The analysis of FT-IR spectra indicated that the mechanism involved in the adsorption can be mainly attributed to the binding of mercury(II) with the carboxylic groups of Romanian peat moss. Adsorption equilibrium approached within 60 min. The adsorption data fitted well the Langmuir isotherm model. The maximum adsorption capacity (qmax) was 98.94 mg g(-1). Pseudo-second-order kinetic model was applicable to the adsorption data. The thermodynamic parameters indicate that the adsorption process was spontaneous as the Gibbs free energy values were found to be negative (between -17.58 and -27.25 kJ mol(-1)) at the temperature range of 6-54 degrees C.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1080/10934520902847836DOI Listing
June 2009

Extraction of metal ions in aqueous polyethylene glycol-inorganic salt two-phase systems in the presence of inorganic extractants: correlation between extraction behaviour and stability constants of extracted species.

J Chromatogr A 2008 Jul 22;1196-1197:117-24. Epub 2008 Mar 22.

Technical University Gh. Asachi of Iaşi, Faculty of Chemical Engineering and Environmental Protection, Department of Environmental Engineering and Management, D. Mangeron 71A, Iaşi, Romania.

The use of aqueous polyethylene glycol-inorganic salt two-phase systems for the extraction of metal ions has a great potential due to their durability, non-toxicity and relative low cost. The aqueous phases can be easily separated by centrifugation, and the operation is possible in a range of experimental conditions. The experimental results have shown that for a given aqueous two-phase system, the extraction behaviour of metal ions in presence of inorganic extractants is mainly dependent on the stability of extracted species. In this paper we review our results obtained at metal ion extraction using inorganic extractants and discuss three major types of extraction behaviours.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.chroma.2008.03.054DOI Listing
July 2008