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161.
Study of flocculation with PONILIT GT-2 anionic polyelectrolyte applied into a chemical wastewater treatment 总被引:1,自引:0,他引:1
Carmen Zaharia Rodica Diaconescu Mioara Surpăţeanu 《Central European Journal of Chemistry》2007,5(1):239-256
This paper discusses the applications of synthetic PONILIT GT-2 anionic polyelectrolyte in conjuction with ferric sulfate
in a chemical wastewater treatment viz. wastewater from ceramics manufacturing. Synthetic wastewaters with different colloid
concentrations were prepared and the coagulation-flocculation process followed by sedimentation and/or filtration was studied.
Variables associated with the chemical wastewater composition, mixing time, and the coagulant and flocculant dose are considered
in order to appreciate the process efficiency in terms of turbidity, chemical oxygen demand (COD), and color removal. The
degrees are higher for turbidity and color (> 80 %) removal respectively, and, satisfactory for COD (< 50 %). An empirical
model was elaborated by a third order rotatable design 23 type, considering ferric sulfate dose, polyelectrolyte dose, and mixing time as independent variables, while the turbidity
and color removal efficiencies were chosen as optimization criteria. The empirical model was found adequate for the chemical
wastewater treatment. Also, an analysis of the model was performed to find the optimal operating conditions, in order to apply
this process for an efficient chemical wastewater treatment using ferric sulfate as coagulation agent and PONILIT GT-2 anionic
polyelectrolyte as flocculation agent. The optimal values correspond to a ferric ions concentration of 6.093 mg/L, a polyelectrolyte
dose of 0.651 mg/L, and a mixing time of 24.024 minutes for turbidity removal (95.869 %), respectively, and, to a ferric ions
concentration of 6.01 mg/L, a polyelectrolyte dose of 0.69 mg/L, and a mixing time of 26 minutes for color removal (98.741
%).
相似文献
162.
Doré K Neagu-Plesu R Leclerc M Boudreau D Ritcey AM 《Langmuir : the ACS journal of surfaces and colloids》2007,23(1):258-264
The massive amplification of fluorescence signal observed upon hybridization of as few as five DNA molecules into self-assembled structures formed between a cationic polymer and DNA oligonucleotides is investigated. These superlighting polymer-DNA aggregates were studied by fluorescence spectroscopy, static and dynamic light scattering, and zeta potential measurements in order to characterize the aggregation behavior and to understand the processes involved during DNA detection. Multi-angle laser light scattering was also used to obtain the weight-average aggregate mass (AM), the aggregation number (Nagg), the radius of gyration (Rg), and the dissymmetry ratio (z). These results have been used, together with TEM imaging, to propose a suitable physical model for the aggregates. 相似文献
163.
Ocsana Opri Ildiko Lung Maria-Loredana Soran Adina Stegarescu Tatiana Cesco Aliona Ghendov-Mosanu Paula Podea Rodica Sturza 《Molecules (Basel, Switzerland)》2022,27(5)
The purpose of this study was to evaluate the sun protection factor (SPF) of cosmetic emulsions with the addition of hydroalcoholic apple extract. First, the total polyphenolic content, the antioxidant activity and SPF properties of the extracts obtained by sonication and refluxing were evaluated. The two extraction methods were improved using the central composite design. For cosmetic emulsion that contained a different concentration of apple extract (10–40%), a SPF value between 0.51 and 0.90 was obtained. The most efficient apple extract was obtained by reflux using 50% ethanol and a 60 min extraction time. The concentrated extract was incorporated in a cosmetic emulsion whose SPF maximum was 0.90. Accordingly, due to photoprotective properties, the apple extract can be a candidate for use in cosmetic formulations. 相似文献
164.
We introduce two partially ordered sets, PnA and PnB, of the same cardinalities as the type-A and type-B noncrossing partition lattices. The ground sets of PnA and PnB are subsets of the symmetric and the hyperoctahedral groups, consisting of permutations which avoid certain patterns. The order relation is given by (strict) containment of the descent sets. In each case, by means of an explicit order-preserving bijection, we show that the poset of restricted permutations is an extension of the refinement order on noncrossing partitions. Several structural properties of these permutation posets follow, including self-duality and the strong Sperner property. We also discuss posets QnA and QnB similarly associated with noncrossing partitions, defined by means of the excedance sets of suitable pattern-avoiding subsets of the symmetric and hyperoctahedral groups. 相似文献
165.
Aura Argseal Ctlin Maxim Mihaela Badea Larisa Ioni Mariana Carmen Chifiriuc Arpad Mihai Rostas Mihaela Bacalum Mina Rileanu Lavinia L. Ru Ileana C. Farcaanu Emilia Elena Iorgulescu Rodica Olar 《Molecules (Basel, Switzerland)》2022,27(3)
In an attempt to increase the biological activity of the 1,2,4-triazolo[1,5-a]pyrimidine scaffold through complexation with essential metal ions, the complexes trans-[Cu(mptp)2Cl2] (1), [Zn(mptp)Cl2(DMSO)] (2) (mptp: 5-methyl-7-phenyl-1,2,4-triazolo[1,5-a]pyrimidine), [Cu2(dmtp)4Cl4]·2H2O (3) and [Zn(dmtp)2Cl2] (4) (dmtp: 5,7-dimethyl-1,2,4-triazolo[1,5-a]pyrimidine), were synthesized and characterized as new antiproliferative and antimicrobial species. Both complexes (1) and (2) crystallize in the P21/n monoclinic space group, with the tetrahedral surroundings generating a square-planar stereochemistry in the Cu(II) complex and a tetrahedral stereochemistry in the Zn(II) species. The mononuclear units are interconnected in a supramolecular network through π–π interactions between the pyrimidine moiety and the phenyl ring in (1) while supramolecular chains resulting from C-H∙∙∙π interactions were observed in (2). All complexes exhibit an antiproliferative effect against B16 tumor cells and improved antibacterial and antifungal activities compared to the free ligands. Complex (3) displays the best antimicrobial activity against all four tested strains, both in the planktonic and biofilm-embedded states, which can be correlated to its stronger DNA-binding and nuclease-activity traits. 相似文献
166.
Alfred Ngenge Tamfu Ozgur Ceylan Geta Crc Emmanuel Talla Rodica Mihaela Dinica 《Molecules (Basel, Switzerland)》2022,27(15)
Propolis is very popular for its beneficial health properties, such as antimicrobial activity and antioxidant effects. It is one of the most long-serving traditional medicines to mankind due to its interesting chemical diversity and therapeutic properties. The detailed chemical information of propolis samples is very necessary to guarantee its safety and for it to be accepted into health care systems. The phenolic profile of the hydroethanolic extract was determined using HPLC-DAD, and the antioxidant was evaluated using five complementary methods. Triterpenoids were isolated using column chromatography and characterized using 1H NMR and 13C NMR. The effects of the extract and the isolated compounds on quorum sensing mediated processes and biofilm formation in bacteria were evaluated. Protocatechic acid (40.76 ± 0.82 µg/g), 4-hydroxybenzoic acid (24.04 ± 0.21 µg/g), vanillic acid (29.90 ± 1.05 µg/g), quercetin (43.53 ± 1.10 µg/g), and luteolin (4.44 ± 0.48 µg/g) were identified and quantified. The extract showed good antioxidant activity in the DPPH•, ABTS•+, CUPRAC, and metal chelating assays, and this antioxidant effect was confirmed by cyclic voltammetry. 27-Hydroxymangiferonic acid (1), Ambolic acid (2), and Mangiferonic acid (3) were isolated from anti-quorum sensing activity at MIC, and it was indicated that the most active sample was the extract with inhibition diameter zone of 18.0 ± 1.0 mm, while compounds 1, 2, and 3 had inhibition zones of 12.0 ± 0.5 mm, 9.0 ± 1.0 mm, and 12.3 ± 1.0 mm, respectively. The samples inhibited the P. aeruginosa PA01 swarming motility at the three tested concentrations (50, 75, and 100 μg/mL) in a dose-dependent manner. The propolis extract was able to inhibit biofilm formation by S. aureus, E. coli, P. aeruginosa, C. albicans, and C. tropicalis at MIC concentration. Compound 1 proved biofilm inhibition on S. aureus, L. monocytogenes, E. faecalis, E. coli, and C. tropicalis at MIC and MIC/2; compound 2 inhibited the formation of biofilm at MIC on S. aureus, E. faecalis, E. coli, S. typhi, C. albicans, and C. tropicalis; and compound 3 inhibited biofilm formation on E. faecalis, E. coli, C. albicans, and C. tropicalis and further biofilm inhibition on E. coli at MIC/4 and MIC/8. The studied propolis sample showed important amounts of cycloartane-type triterpene acids, and this indicates that there can be significant intra-regional variation probably due to specific flora within the vicinity. The results indicate that propolis and its compounds can reduce virulence factors of pathogenic bacteria. 相似文献
167.
Mirela Călinescu Ticuţa Negreanu-Pîrjol Rodica Georgescu Octavian Călinescu 《Central European Journal of Chemistry》2010,8(3):543-549
Three new copper(II) complex compounds with chlorhexidine diacetate as a ligand have been prepared and characterized by elemental
and thermogravimetrical analyses, molar conductances, magnetic susceptibility measurements, infrared, electronic and EPR spectra.
The complexes correspond to the formulas: [Cu2(CHX)Cl4]·2C2H5OH, [Cu2(CHX)Br4]·2C2H5OH and [Cu2(CHX)(CH3COO)2] (CH3COO)2·2C2H5OH, where CHX = chlorhexidine, their composition and stereochemistry depending on the reaction conditions and the metal salt
used. Chlorhexidine acts as neutral tetradentate NNNN donor, coordinating through the four imine nitrogen atoms. Investigations
on antimicrobial activity in vitro show that all the complexes are active against the tested microorganisms, the complex with chloride being more active against
Gram negative bacteria than chlorhexidine diacetate..
相似文献
168.
Cristina Bogatu Dan Geană Rodica Vîlcu Anca Duţă Wim Poot Theo W. de Loos 《Fluid Phase Equilibria》2010
Vapour–liquid, liquid–liquid and liquid–liquid–vapour equilibria in the binary system consisting of trifluoromethane (refrigerant R23) and 1-phenyloctane were determined in the temperature range T = 250–400 K and at pressures up to 15 MPa. The experiments were carried using a Cailletet apparatus according to the synthetic method. The investigated system exhibits type III phase behaviour according to the classification of van Konynenburg and Scott. Modelling of the equilibrium data was done with the Peng–Robinson (PR) and Soave–Redlich–Kwong (SRK) equations of state coupled with classical van der Waals mixing rules. In order to predict the global phase behaviour of the system, one single set of binary parameters was used. The topology of the phase behaviour was correctly reproduced. 相似文献
169.
Mihaela Badea Rodica Olar Dana Marinescu Valentina Uivarosi Victoria Aldea Teodor Octavian Nicolescu 《Journal of Thermal Analysis and Calorimetry》2010,99(3):823-827
A series of new complexes of the type VO(OH)L·nH2O ((1) L: fisetin, n = 3; (2) L: quercetin, n = 2; (3) L: morin, n = 4) were synthesised and characterised by analytical as well as IR and electronic data. The modification evidenced in IR
spectra was correlated with the presence of flavonoid as bidentate in all complexes. The electronic reflectance spectra showed
the d–d transition characteristic for the square-pyramidal stereochemistry of vanadium (IV) ion. The thermal analysis (TG, DTA) in
synthetic air flow elucidated the composition and also the number and nature of the water molecules. The TG curves show three
well-separated thermal events. The first corresponds to the water loss at lower temperatures, which is followed by flavonoid
derivative decomposition and pyrolysis at higher temperatures. The final product is vanadium (V) oxide. 相似文献
170.
We investigate the existence and multiplicity of positive solutions for a system of Riemann–Liouville fractional differential equations, subject to multipoint boundary conditions that contain fractional derivatives, by using some theorems from the fixed point index theory. 相似文献