Publications by authors named "Andrei Sarbu"

9 Publications

  • Page 1 of 1

Mitigating Antibiotic Resistance Genes in Wastewater by Sequential Treatment with Novel Nanomaterials.

Polymers (Basel) 2021 May 15;13(10). Epub 2021 May 15.

Advanced Polymer Materials and Polymer Recycling Group, National Institute for Research & Development in Chemistry and Petrochemistry ICECHIM, Splaiul Independentei 202, 060021 Bucharest, Romania.

Wastewater (WW) has been widely recognized as the major sink of a variety of emerging pathogens (EPs), antibiotic-resistant bacteria (ARB) and antibiotic resistance genes (ARGs), which may disseminate and impact wider environments. Improving and maximizing WW treatment efficiency to remove these microbial hazards is fundamentally imperative. Despite a variety of physical, biological and chemical treatment technologies, the efficiency of ARG removal is still far from satisfactory. Within our recently accomplished M-ERA.NET project, novel functionalized nanomaterials, i.e., molecularly imprinted polymer (MIP) films and quaternary ammonium salt (QAS) modified kaolin microparticles, were developed and demonstrated to have significant EP removal effectiveness on both Gram-positive bacteria (GPB) and Gram-negative bacteria (GNB) from WW. As a continuation of this project, we took the further step of exploring their ARG mitigation potential. Strikingly, by applying MIP and QAS functionalized kaolin microparticles in tandem, the ARGs prevalent in wastewater treatment plants (WWTPs), e.g., CTXM, B and S, can be drastically reduced by 2.7, 3.9 and 4.9 log (copies/100 mL), respectively, whereas 1, O and A can be eliminated below their detection limits. In terms of class I integron-integrase I (1), a mobile genetic element (MGE) for horizontal gene transfer (HGT), 4.3 log (copies/100 mL) reduction was achieved. Overall, the novel nanomaterials exhibit outstanding performance on attenuating ARGs in WW, being superior to their control references. This finding provides additional merit to the application of developed nanomaterials for WW purification towards ARG elimination, in addition to the proven bactericidal effect.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3390/polym13101593DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8157218PMC
May 2021

Poly(β-cyclodextrin)-Activated Carbon Gel Composites for Removal of Pesticides from Water.

Molecules 2021 Mar 6;26(5). Epub 2021 Mar 6.

Coimbra Chemistry Centre, Department of Chemistry, University of Coimbra, 3004-535 Coimbra, Portugal.

Pesticides are widely used in agriculture to increase and protect crop production. A substantial percentage of the active substances applied is retained in the soil or flows into water courses, constituting a very relevant environmental problem. There are several methods for the removal of pesticides from soils and water; however, their efficiency is still a challenge. An alternative to current methods relies on the use of effective adsorbents in removing pesticides which are, simultaneously, capable of releasing pesticides into the soil when needed. This reduces costs related to their application and waste treatments and, thus, overall environmental costs. In this paper, we describe the synthesis and preparation of activated carbon-containing poly(β-cyclodextrin) composites. The composites were characterized by different techniques and their ability to absorb pesticides was assessed by using two active substances: cymoxanil and imidacloprid. Composites with 5 and 10 wt% of activated carbon showed very good stability, high removal efficiencies (>75%) and pesticide sorption capacity up to ca. 50 mg g. The effect of additives (NaCl and urea) was also evaluated. The composites were able to release around 30% of the initial sorbed amount of pesticide without losing the capacity to keep the maximum removal efficiency in sorption/desorption cycles.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3390/molecules26051426DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7962014PMC
March 2021

Synthesis of titanium nitride via hybrid nanocomposites based on mesoporous TiO/acrylonitrile.

Sci Rep 2021 Mar 3;11(1):5055. Epub 2021 Mar 3.

Faculty of Physics, University of Bucharest, 077125, Măgurele, Romania.

In the present study, the synthesis of titanium nitride (TiN) by carbothermal reduction nitridation (CRN) reaction using nanocomposites made of mesoporous TiO/acrylonitrile with different content of inorganic phase were explored. The choice of hybrid nanocomposite as precursor for the synthesis of TiN was made due to the possibility of having an intimate interface between the organic and inorganic phases in the mixture that can favours CRN reaction. Subsequently, the hybrid composites have been subjected to four-step thermal treatments at 290 °C, 550 °C, 1000 °C and 1400 °C under nitrogen atmosphere. The XRD results after thermal treatment at 1000 °C under nitrogen flow show the coexistence of two crystalline phases of TiO, i.e. anatase and rutile, as well as TiN phase, together with the detection of amorphous carbon that proved the initiation of CRN reaction. Furthermore, the observations based on XRD patterns of samples thermally treated at 1400 °C in nitrogen atmosphere were in agreement with SEM analysis, that shows the formation of TiN by CRN reaction via hybrid nanocomposites mesoporous TiO/acrylonitrile.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1038/s41598-021-84484-3DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7930120PMC
March 2021

Molecularly imprinted films and quaternary ammonium-functionalized microparticles working in tandem against pathogenic bacteria in wastewaters.

J Hazard Mater 2020 11 27;399:123026. Epub 2020 May 27.

National Institute for Research & Development in Chemistry and Petrochemistry ICECHIM, Advanced Polymer Materials and Polymer Recycling Group, Splaiul Independentei 202, 060021, Bucharest, Romania. Electronic address:

Despite major efforts to combat pollution, the presence of pathogenic bacteria is still detected in surface water, soil and even crops due to poor purification of domestic and industrial wastewaters. Therefore, we have designed molecularly imprinted polymer films and quaternary ammonium-functionalized- kaolin microparticles to target specifically Gram-negative bacteria (GNB) and Gram-positive bacteria (GPB) in wastewaters and ensure a higher purification rate by working in tandem. According to the bacteriological indicators, a reduction by 90 % was registered for GNB (total coliforms and Escherichia coli O157) and by 77 % for GPB (Clostridium perfringens) in wastewaters. The reduction rates were confirmed when using pathogen genetic markers to quantify particular types of GNB and GPB, like Salmonella typhimurium (reduction up to 100 %),Campylobacter jejuni (reduction up to 70 %), Enterococcus faecalis (reduction up to 81 %), Clostridium perfringens (reduction up to 97 %) and Shiga toxin-producing Escherichia coli (reduction up to 64 %). In order to understand the bactericidal activity of prepared films and microparticles, we have performed several key analyses such as Cryo-TEM, to highlight the auto-assembly mechanism of components during the films formation, and Si/ C CP/MAS NMR, to reveal the way quaternary ammonium groups are grafted on the surface of kaolin microparticles.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.jhazmat.2020.123026DOI Listing
November 2020

Composite Nanogels Based on Zeolite-Poly(ethylene glycol) Diacrylate for Controlled Drug Delivery.

Nanomaterials (Basel) 2020 Jan 22;10(2). Epub 2020 Jan 22.

Advanced Polymer Materials and Polymer Recycling Group, National Institute for Research and Development in Chemistry and Petrochemistry-ICECHIM, 202 Spl. Independentei, 6th District, P.O. Box 35/174, 060021 Bucharest, Romania.

This study presents the design of novel composites nanogels, based on poly(ethylene glycol) diacrylate and natural zeolite particles, that are able to act as materials with controlled drug delivery properties. Natural zeolite‒nanogels composite, with varying zeolite contents, were obtained by an inverse mini-emulsion technique and loaded with 5-fluorouracil, a widely used chemotherapeutic drug. Herein, the possibility of adjusting final properties by means of modifying the preparation conditions was investigated. The prepared composite nanogels are characterized by dynamic light scattering (DLS), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), and thermogravimetric analysis (TGA). In light of this tunable drug-loading capability, swelling behaviour, and cytotoxicity, these composite nanogels could be highly attractive as drug reservoirs.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3390/nano10020195DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7075022PMC
January 2020

Straightforward Preparation of Naphtodianthrone-Rich Ethanolic Extracts from Wild St. John's Wort.

J Diet Suppl 2020 31;17(1):88-96. Epub 2018 Oct 31.

National Institute for Research & Development in Chemistry and Petrochemistry ICECHIM, Advanced Polymer Materials and Polymer Recycling Group, Bucharest, Romania.

Separation of naphtodianthrones (NTs) from Hypericum perforatum L. (aerial part of St. John's Wort) is still topical due to some hard-to-beat medicinal attributes of these bioactive compounds. Unfortunately, their low bioavailability (0.06%-0.4%) complicates the extraction process. Therefore, developing straightforward and lower-cost methodologies for NT separation is still a priority. In support of this purpose, for preparing NT formulations from flowers and leaves of wild St. John's Wort (hyperici herba), a cutoff preparative methodology is described herein. Combining Soxhlet extraction and reflux extraction, some concentrated and rather pure NT ethanolic-based formulations without chlorophyl and grease were obtained.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1080/19390211.2018.1484404DOI Listing
September 2020

Detection of Bisphenol A in aqueous medium by screen printed carbon electrodes incorporating electrochemical molecularly imprinted polymers.

Biosens Bioelectron 2018 Jul 21;112:156-161. Epub 2018 Apr 21.

Laboratoire MAPIEM, EA 4323, Université de Toulon, 83041 Toulon Cedex 9, France. Electronic address:

Electrochemical molecularly imprinted polymers (e-MIPs) were for the first time introduced in screen-printed carbon electrodes (SPCE) as the sensing element for the detection of an organic pollutant. To play this sensing role, a redox tracer was incorporated inside the binding cavities of a cross-linked MIP, as a functional monomer during the synthesis step. Ferrocenylmethyl methacrylate was used for this purpose. It was associated with 4-vinylpyridine as a co-functional monomer and ethylene glycol dimethacrylate as cross-linker for the recognition of the endocrine disruptor, Bisphenol A (BPA), as a target. Microbeads of e-MIP and e-NIP (corresponding non-imprinted polymer) were obtained via precipitation polymerization in acetonitrile. The presence of ferrocene inside the polymers was assessed via FTIR and elemental analysis and the polymers microstructure was characterized by SEM and nitrogen adsorption/desorption experiments. Binding isotherms and batch selectivity experiments evidenced the presence of binding cavities inside the e-MIP and its high affinity for BPA compared to carbamazepine and ketoprofen. e-MIP (and e-NIP) microbeads were then incorporated in a graphite-hydroxyethylcellulose composite paste to prepare SPCE. Electrochemical properties of e-MIP-SPCE revealed a high sensitivity in the presence of BPA in aqueous medium compared to e-NIP-SPCE with a limit of detection (LOD) of 0.06 nM. Selectivity towards carbamazepine and ketoprofen was also observed with the e-MIP-SPCE.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.bios.2018.04.022DOI Listing
July 2018

Efficient removal of Indigo Carmine dye by a separation process.

Water Sci Technol 2016 Nov;74(10):2462-2473

Polymer Department, National Research and Development Institute for Chemistry and Petrochemistry-ICECHIM, Splaiul Independentei, no. 202, P.O. 060021, Bucharest, Romania.

This study is aimed at developing an innovative approach for Indigo Carmine dye removal from synthetic solutions by electrodialysis, carried out using ion exchange membranes. The batch electrodialysis system was operated at various current intensities: 0.05, 0.1 and 0.15 A. The pH and conductivity of solutions were measured before and after using electrodialysis process. The colour removal efficiency (CR %) was determined by spectrographic analysis and the energy consumption (EC) was calculated. The obtained results show that the pH of treated solution increases due to the increase in solution conductivity. Moreover, the values of CR % and EC increase when increasing current intensity. The optimal value was obtained at 0.15 A (CR > 97%). The membranes were characterized by Fourier transform infrared spectroscopy, thermogravimetric analysis and scanning electron microscopy.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.2166/wst.2016.388DOI Listing
November 2016

An innovative approach to prepare hypericin molecularly imprinted pearls using a "phyto-template".

Talanta 2016 23;148:37-45. Epub 2015 Oct 23.

National Research and Development Institute for Chemistry and Petrochemistry INCDCP-ICECHIM, Advanced Polymer Materials and Polymer Recycling, 202 Splaiul Independentei, 060021 Bucharest, Romania. Electronic address:

In this paper, an innovative method that uses hypericin "phyto-template" molecules is being applied herein for the first time to produce molecularly imprinted polymer (MIP) pearls able to selectively retain hypericin from Hypericum Perforatum L primary extracts. For this purpose, the wet phase inversion method was preferred for preparing the hypericin-MIP pearls for several reasons referring to economical benefits but also due to the fact that hypericin "phyto-template" molecules can be generated along with the phase inversion of the copolymer. Practically, the precursor poly(acrylonitrile-co-methacrylic acid) solution was mixed with a purified and concentrated naphtodianthrone phyto-extract (consisting only of hypericin and pseudo-hypericin). In the subsequent phase inversion step hypericin was trapped in the copolymer droplets, as a result to its poor solubility in the inversion water bath, and further served as "phyto-template" in the imprinting step. This in situ repartition of hypericin and pseudo-hypericin was sustained by HPLC-DAD chromatograms which recorded only the presence of hypericin during the extraction stage of imprinted pearls. Batch rebinding measurements, all together, validated the efficiency of this innovative imprinting procedure. The hypericin rebinding of imprinted pearls was quantitative (up to 318 µg/L) and approximately 5 times more specific relative to the blank pearls. Competitive re-binding revealed a more selective behaviour of imprinted pearls for hypericin when the up-take was measured against pseudohypericin (selectivity coefficient above 4.50).
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.talanta.2015.10.061DOI Listing
September 2016
-->