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1.
Molecules ; 29(9)2024 May 04.
Artículo en Inglés | MEDLINE | ID: mdl-38731626

RESUMEN

The current study comprehensively investigates the adsorption behavior of chromium (Cr(III)) in wastewater using Algerian kaolinite clay. The structural and textural properties of the kaolinite clay are extensively characterized through a range of analytical methods, including XRD, FTIR, SEM-EDS, XPS, laser granulometry, N2 adsorption isotherm, and TGA-DTA. The point of zero charge and zeta potential are also assessed. Chromium adsorption reached equilibrium within five minutes, achieving a maximum removal rate of 99% at pH 5. Adsorption equilibrium is modeled using the Langmuir, Freundlich, Temkin, Elovich, and Dubinin-Radushkevitch equations, with the Langmuir isotherm accurately describing the adsorption process and yielding a maximum adsorption capacity of 8.422 mg/g for Cr(III). Thermodynamic parameters suggest the spontaneous and endothermic nature of Cr(III) sorption, with an activation energy of 26.665 kJ/mol, indicating the importance of diffusion in the sorption process. Furthermore, advanced DFT computations, including COSMO-RS, molecular orbitals, IGM, RDG, and QTAIM analyses, are conducted to elucidate the nature of adsorption, revealing strong binding interactions between Cr(III) ions and the kaolinite surface. The integration of theoretical and experimental data not only enhances the understanding of Cr(III) removal using kaolinite but also demonstrates the effectiveness of this clay adsorbent for wastewater treatment. Furthermore, this study highlights the synergistic application of empirical research and computational modeling in elucidating complex adsorption processes.

2.
ACS Omega ; 9(8): 9076-9089, 2024 Feb 27.
Artículo en Inglés | MEDLINE | ID: mdl-38434904

RESUMEN

A theoretical investigation was conducted using DFT/PW91/TZP/DMSO calculations on a complete set of exhaustive lists of 18 compounds resulting from the complexation of trans-2,4,3',5'-tetrahydroxystilbene (T-OXY) and cis-2,4,1',3'-tetrahydroxystilbene (C-OXY) with copper metal cations (Cu+ and Cu2+). The ligand-binding sites are the critical points of Quantum Theory of Atoms in Molecules (QTAIM) analysis on neutral and deprotonated ligands. Various mechanisms, including hydrogen atom transfer (HAT), sequential proton loss electron transfer (SPLET), single electron transfer followed by proton transfer (SET-PT), and bond dissociation energy (BDE(E0)) calculations, were employed to quantify the antioxidant activity. The BDE(E0) mechanism emerged as the most suitable approach for such analyses to evaluate the departure of hydrogen atoms since the results show the HAT mechanism is the most likely occurring. Particularly intriguing were the anionic Cu+ complexes with ligands adopting trans configurations and deprotonated conformations, displaying superior antioxidant activity compared to their counterparts. Remarkably, a single ligand within the Cu+ complex exhibited exceptional antioxidant prowess, yielding a BDE(E0) value of 91.47 kcal/mol. Furthermore, a complex involving two deprotonated ligands demonstrated antioxidant activity of 31.12 kcal/mol, signifying its potential as a potent antiradical agent, surpassing T-OXY by a factor of 3.91 and even surpassing the antioxidant efficiency of Vitamin C.

3.
Heliyon ; 10(5): e26285, 2024 Mar 15.
Artículo en Inglés | MEDLINE | ID: mdl-38449640

RESUMEN

The work deals with the removal of two dyes, namely methylene blue (MB) and methyl orange (MO), from polluted water by adsorption onto CuO nanoparticles synthesized with a green synthesis procedure, starting from plant resources. Adsorption isotherms are determined at different temperatures aiming at investigating the adsorption mechanisms of the two dyes. The experimental results indicate that, for both MB and MO, the adsorption capacity increases with increasing temperature, with slight differences in the case of MO. Comparatively, the CuO nanoparticles show a higher MB adsorption capacity with respect to MO. A modelling analysis is carried out with a multilayer model derived from statistical physics, selected among a group of models, each hypothesizing a different number of adsorbed molecules layers. The analysis of model parameters allows determining that the adsorbate molecules exhibit a non-parallel orientation on the surface of biosynthesized CuO nanoparticles and each functional group of the adsorbent binds multiple molecules, simultaneously.The model also allows determining the number of dye molecule layers formed on adsorbent surface, in all the cases resulting higher than three, also confirming the effect of temperature on the maximum adsorption capacity.Specifically, the total number of dye layers formed on biosynthesized CuO nanoparticles surface exhibited a range of 4.17-4.55 for MB dye and of 3.01-3.51 for MO dye.Finally, the adsorption energies reveal that adsorption likely involves physical forces (all resulting all below 22 kJ/mol), i.e. hydrogen bonding and van der Waals forces. The adsorption energies for the interactions between dye molecules are lower than those calculated for the interactions between the dye molecules and the adsorbent surface.

4.
Int J Mol Sci ; 25(2)2024 Jan 14.
Artículo en Inglés | MEDLINE | ID: mdl-38256105

RESUMEN

This study investigates the efficacy of adsorbents from locally sourced olive waste-encompassing olive skins, leaves, and pits, recovered from the initial centrifugation of olives (OWP)-and a composite with sodium alginate (OWPSA) for the removal of Cu2+ ions from synthetic wastewater. Experimental analyses conducted at room temperature, with an initial Cu2+ concentration of 50 mg/L and a solid/liquid ratio of 1 g/L, showed that the removal efficiencies were approximately 79.54% and 94.54% for OWP and OWPSA, respectively, highlighting the positive impact of alginate on adsorption capacity. Utilizing statistical physics isotherm models, particularly the single-layer model coupled to real gas (SLMRG), allowed us to robustly fit the experimental data, providing insights into the adsorption mechanisms. Thermodynamic parameters affirmed the spontaneity and endothermic nature of the processes. Adsorption kinetics were interpreted effectively using the pseudo-second-order (PSO) model. Molecular modeling investigations, including the conductor-like screening model for real solvents (COSMO-RS), density functional theory (DFT), and atom-in-molecule (AIM) analysis, unveiled intricate molecular interactions among the adsorbent components-cellulose, hemicellulose, lignin, and alginate-and the pollutant Cu2+, confirming their physically interactive nature. These findings emphasize the synergistic application of experimental and theoretical approaches, providing a comprehensive understanding of copper adsorption dynamics at the molecular level. This methodology holds promise for unraveling intricate processes across various adsorbent materials in wastewater treatment applications.


Asunto(s)
Olea , Cobre , Aguas Residuales , Adsorción , Alginatos
5.
Cell Mol Biol (Noisy-le-grand) ; 69(13): 241-249, 2023 Dec 10.
Artículo en Inglés | MEDLINE | ID: mdl-38158663

RESUMEN

We are looking into viral components that may contribute to breast cancer in order to find possible therapeutic targets. The Epstein-Barr virus (EBV), which has been found to cause nasopharyngeal carcinoma and Burkitt lymphoma, is thought to play a role in breast cancer. Our series' patients had a median age of 49, with nearly half being under the age of 49. T2 tumors (two to five centimeters in size) make up the vast majority of our collection (60%). Six percent of our patients showed lymph node involvement, with roughly the same number in the N1 and N2 stages (41.17% each). Only 17.64% of people are at the N3 stage. SBR II tumors were the most common (90%). Only 20% of patients have HER2 overexpression, whereas 73.33% have ER expression. EBV was found in 23.33% of breast carcinomas (7 cases/30) after oncoprotein LMP1 expression, but normal surrounding tissues tested negative. We discovered that overexpression of the HER2 protein is inversely related to the two HRs' expression. They have no relationship with EBV infection and, consequently, LMP1 expression. LMP1 expression was not shown to be linked with patient age, tumor grade, tumor size, or lymph node invasion.


Asunto(s)
Neoplasias de la Mama , Infecciones por Virus de Epstein-Barr , Neoplasias Nasofaríngeas , Humanos , Femenino , Herpesvirus Humano 4/metabolismo , Infecciones por Virus de Epstein-Barr/complicaciones , Infecciones por Virus de Epstein-Barr/patología , Neoplasias de la Mama/patología , Carcinoma Nasofaríngeo , Neoplasias Nasofaríngeas/patología
6.
Molecules ; 28(19)2023 Sep 28.
Artículo en Inglés | MEDLINE | ID: mdl-37836682

RESUMEN

Persistent Organic Pollutants (POPs), particularly the indicator polychlorinated biphenyls (PCBs), were first quantified in water and sediments of two wadis, Boujemaâ and Seybouse, as well as in the effluents from a fertilizer and phytosanitary production industrial plant (Fertial). Since these contaminated discharges end in Annaba Bay (Algeria) in the Mediterranean Sea, with a significant level of contamination, all the potential sources should be identified. In this work, this task is conducted by a multivariate analysis. Liquid-liquid extraction and gas chromatography/mass spectrometry (GC-MS) methods were applied to quantify seven PCB congeners, usually taken as indicators of contamination. The sum of the PCB concentrations in the sediments ranged from 1 to 6.4 µg/kg dw (dry weight) and up to 0.027 µg/L in waters. Principal component analysis (PCA) and hierarchical cluster analysis (HCA) were used for the multivariate analysis, indicating that the main sources of PCB emissions in the bay are urban/domestic and agricultural/industrial. The outfalls that mostly contribute to the pollution of the gulf are the Boujemaâ wadi, followed by the Seybouse wadi, and finally by the Fertial cluster and more precisely the annex basin of the plant. Although referring to a specific site of local importance, the work aims to present a procedure and a methodological analysis that can be potentially applicable to further case studies all over the world.


Asunto(s)
Bifenilos Policlorados , Contaminantes Químicos del Agua , Bifenilos Policlorados/análisis , Argelia , Monitoreo del Ambiente , Contaminantes Químicos del Agua/química , Bahías , Sedimentos Geológicos/química
7.
RSC Adv ; 13(22): 15132-15140, 2023 May 15.
Artículo en Inglés | MEDLINE | ID: mdl-37207102

RESUMEN

The main purpose of this research is to theoretically investigate the adsorption of two pharmaceutical molecules, i.e. aspirin and paracetamol, using two composite adsorbents, i.e. N-CNT/ß-CD and Fe/N-CNT/ß-CD nanocomposite polymers. A multilayer model developed by statistical physics is implemented to explain the experimental adsorption isotherms at the molecular scale, so as to overpass some limitations of the classical adsorption models. The modelling results indicate that the adsorption of these molecules is almost accomplished by the formation of 3 to 5 adsorbate layers, depending on the operating temperature. A general survey of the number of adsorbate molecules captured by the adsorption site (npm) suggested that the adsorption process of pharmaceutical pollutants is multimolecular and that each adsorption site can capture several molecules simultaneously. Furthermore, the npm values demonstrated the presence of aggregation phenomena of aspirin and paracetamol molecules during adsorption. The evolution of the adsorbed quantity at saturation confirmed that the presence of Fe in the adsorbent enhanced the removal performance of the investigated pharmaceutical molecules. In addition, the adsorption of the pharmaceutical molecules aspirin and paracetamol on the N-CNT/ß-CD and Fe/N-CNT/ß-CD nanocomposite polymer surface involved weak physical type interactions, since the interaction energies do not overcome the threshold of 25 000 J mol-1.

8.
Chemosphere ; 313: 137355, 2023 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-36455664

RESUMEN

In this paper, the adsorption of the herbicide 2,4-D and the drug ketoprofen on wheat husks Fagopyrum esculentum treated with H2SO4 is experimentally and analytically analyzed. The adsorbent is fully characterized through some techniques such as FT-IR, SEM, and XRD. Adsorption tests are carried out to optimize the performances in terms of adsorbent dosage and solution pH. Subsequently, the impact of temperature is determined through the realization of adsorption isotherms. A multilayer model is employed to microscopically interpret the adsorption mechanism of both the investigated compounds. The modelling analysis shows that the number of molecules bound per adsorption site varied from 0.68 to 2.77 and from 2.23 to 3.59 for ketoprofen and herbicide 2,4-D, respectively. These estimated values testify that an aggregation process occurs during adsorption. The global number of formed layers of each adsorbate is also determined, showing a significant reduction from 5.73 to 2.61 for ketoprofen and from 1.79 to 1.5 for herbicide 2,4-D with the temperature. For a complete understanding of the adsorption mechanism, the saturation adsorption capacity and adsorption energy were calculated and interpreted. Overall, it may be inferred that physical interactions govern how these contaminants adsorb on the tested adsorbent.


Asunto(s)
Fagopyrum , Herbicidas , Cetoprofeno , Contaminantes Químicos del Agua , Triticum , Adsorción , Contaminantes Químicos del Agua/análisis , Espectroscopía Infrarroja por Transformada de Fourier , Ácido 2,4-Diclorofenoxiacético , Cinética , Concentración de Iones de Hidrógeno , Termodinámica
9.
Environ Sci Pollut Res Int ; 30(6): 15789-15796, 2023 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-36173520

RESUMEN

An activated carbon (AC) deriving from sludge is used in this research for the adsorption of two water pollutants, namely Reactive Black 5 (RB5) and Green Alizarin (GA) dyes, at different temperatures. The adsorption capacities varied from 277.2 to 312.69 mg/g for GA and from 225.82 to 256.02 mg/g for RB5. Comparatively, this adsorbent presents good performances in removing these dyes from wastewater. The application of physical models to adsorption experiments is advantageous to provide new insights into the dyes' adsorption mechanism. A dedicated physical adsorption model suggests that RB5 and GA dyes are adsorbed in a monolayer. Moreover, the orientation of RB5 and GA dyes on AC resulted in an angled position, determining a multi-molecular process. In addition, both dyes are adsorbed by the occurrence of an aggregation process, forming a dimer. The impact of temperature can be also interpreted, allowing concluding that it plays a relevant role in removing these dyes. The calculation and interpretation of adsorption energies show that the dyes are removed via an endothermic process, and physical forces are involved.


Asunto(s)
Colorantes , Contaminantes Químicos del Agua , Aguas del Alcantarillado , Carbón Orgánico , Adsorción , Contaminantes Químicos del Agua/análisis , Cinética , Concentración de Iones de Hidrógeno
10.
Environ Sci Pollut Res Int ; 29(41): 62507-62513, 2022 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-35404034

RESUMEN

The work reports a modeling analysis of single-compound and binary adsorption of Pb2+ and Cd2+ ions from polluted water onto the activated carbon at room temperature. The homogeneous model for single adsorption (HM) and the exclusive extended monolayer model for binary adsorption (EEMM) are applied for the interpretation of the experimental data set. The adopted models correlate the entire set of adsorption data, allowing a thorough description of the occurring phenomena. The overall objective of the study is to determine the adsorption mechanisms, also through a comparative analysis between the single-compound and binary modeling data. The parameters of both models are used for to retrieve useful indications about the adsorption of these two ions. In particular, the number of ions adsorbed per single functional groups changed from single-compound to binary adsorption, allowing to explain the competitive behavior of the investigated system. The adsorption energy values vary between 21.39 (Pb2+) and 24.06 kJ/mol (Cd2+), and 27.17 (Pb2+) and 32.59 kJ/mol (Cd2+) in single-compound and binary systems, respectively, indicating that adsorption is a physisorption process.

11.
Int J Mol Sci ; 23(5)2022 Mar 04.
Artículo en Inglés | MEDLINE | ID: mdl-35269972

RESUMEN

Density functional theory (DFT), time-dependent density functional theory (TDDFT), quantum theory of atoms in molecules (QTAIM), and extended transition state natural orbitals for chemical valence (ETS-NOCV) have all been used to investigate the physicochemical and biological properties of curcumin and three complexes, i.e., Cur-M (M = Ni, Cu, and Mg). Based on DFT calculations, the enolic form (Cur-Enol) is more stable than the anti-diketone form (Cur-Anti diketone) favored for complexation. This enolic form stability was explained by the presence of three intramolecular hydrogen bonds according to the QTAIM analysis. Furthermore, the ETS-NOCV technique revealed that the enolic form had more significant antioxidant activity compared with the anti-diketone form. The calculations from the COnductor-like Screening MOdel for Realistic Solvents (COSMO-RS) showed that the dimethyl sulfoxide (DMSO) solvent could dissolve all the curcumin tautomers Cur-Enol, Cur-Anti-diketone and Cur-Cu, Cur-Mg, and Cur-Ni complexes in contrast to benzene, acetone, octanol, ethanol, methanol, and water. Furthermore, except for Cur-Mg, which had a relatively low solubility (14 g/L), all complexes were insoluble in water. Cur-Anti-diketone was considerably more soluble than Cur-Enol in the examined solvents.


Asunto(s)
Curcumina , Curcumina/química , Curcumina/farmacología , Cetonas , Teoría Cuántica , Solubilidad , Solventes/química , Agua
12.
Environ Sci Pollut Res Int ; 29(20): 30184-30192, 2022 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-34997519

RESUMEN

The paper describes a theoretical analysis of the adsorption of nicotinamide and propranolol onto a magnetic-activated carbon (MAC). For a better evaluation of the adsorption mechanism, adsorption isotherms expressing the variation of the adsorption capacity as function of adsorbate concentration were determined at different temperatures ranging from 20 to 45 °C. For both the analytes, experimental tests reveal that adsorption capacity increases with temperature. An advanced multi-layer model derived from the statistical physics is set for the interpretation of the entire adsorption data set. The modelling results show that the propranolol molecules change their adsorption orientation from a mixed (parallel and non-parallel) orientation to a multimolecular process. For nicotinamide, the aggregation of molecules is practically absent, except for the data at lower temperatures. The model allows stating that the adsorption of both the pharmaceutical compounds occurs via the formation of one or two layers on MAC adsorbent, the propranolol showing a higher tendency to form multiple layers. Finally, adsorption energy is estimated suggesting that the adsorption is endothermic and physical interactions are the responsible of the adsorption of both the compounds onto MAC adsorbent.


Asunto(s)
Carbón Orgánico , Contaminantes Químicos del Agua , Adsorción , Cinética , Fenómenos Magnéticos , Niacinamida , Propranolol , Termodinámica , Contaminantes Químicos del Agua/análisis
13.
Environ Sci Pollut Res Int ; 28(24): 30714-30721, 2021 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-33594555

RESUMEN

The paper describes a theoretical analysis of the adsorption of amoxicillin (AMX) onto two activated carbons pyrolysed at either 600 or 700 °C (PAC-600 and PAC-700). Series of experimental data are carried out at different temperatures ranging from 10 to 45 °C, as this is the first key factor to explain the adsorption mechanism of this pollutant. AMX adsorption capacity varied from 275 to 450 mg/g and between 276 and 454 mg/g for PAC-600 and PAC-700, respectively. It can be deduced that the pyrolysis temperature does not play a crucial role in AMX removal capacity of the adsorbents. A comparison with literature data shows that the retrieved adsorption capacities of both the adsorbents are very competitive for an effective water treatment. Physical models are applied to the two experimental data sets showing that a monolayer model with single energy is the best option to explain the AMX adsorption mechanism on both PAC-600 and PAC-700 adsorbents. The interpretation of the theoretical results points out that the AMX was not aggregated during the adsorption process. Under these experimental working conditions, it is noted that AMX is adsorbed almost via a parallel orientation on PAC-600 and PAC-700 adsorbents, reflecting that the adsorption is a multi-interaction mechanism. The model provides an estimation of the adsorption energy that allows the quantification of the interactions between the AMX and both PAC-600 and PAC-700 adsorbent surfaces; in both the cases, physical bindings are involved in AMX adsorption.


Asunto(s)
Contaminantes Químicos del Agua , Purificación del Agua , Adsorción , Amoxicilina , Carbón Orgánico , Cinética , Contaminantes Químicos del Agua/análisis
14.
J Contam Hydrol ; 235: 103725, 2020 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-33035820

RESUMEN

Pump-and-treat technology is among the most used technologies for groundwater remediation. While conventional, vertical wells (VRWs) are well-known and used from long time, horizontal wells (HRWs) have been explored for remediation technologies only in last few decades. HRWs have shown to outperform vertical wells in terms of versatility, productivity and clean-up times under certain conditions. In this paper, the efficacy of an innovative pump-and-treat (P&T) configuration for groundwater remediation obtained by adopting either VRWs or HRWs technology is comparatively tested. A 3D transient finite element model of an unconfined aquifer containing a hexavalent chromium (Cr(VI)) contamination plume is considered to compare a single horizontal well configuration vs a range of spatially-optimised arrays containing vertical wells. A sensitivity analysis aimed at finding the best configuration to minimise the remediation time and the related cost is carried out by comparing different well diameters, D, pumping rates, Q, and position of wells. A comparative cost analysis demonstrates that, for the examined case-study, a single HRW achieves the clean-up goals in the same time span as for a greater number of vertical wells, but at higher price due to the excavation costs.


Asunto(s)
Agua Subterránea , Cromo/análisis , Pozos de Agua
15.
Colloids Surf B Biointerfaces ; 195: 111230, 2020 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-32629072

RESUMEN

Waste of Mytella falcata shell was used as low-cost adsorbent to remove the biocide Basic Green 4 (BG4) from water. Shells were collected form trash nearby the lagoon were Mytella falcata is fished. After clean, dry and crushed, the powder was characterized by scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FT-IR), X-ray powder diffraction (XRD), and X-ray dispersive energy spectroscopy (EDS). Both kinetic and equilibrium adsorption tests are carried out. Adsorbent regenerability was tested during adsorption/desorption cycles, using a UV photo-regeneration process. The maximum adsorption capacity reached 539.24 mg.g-1 (60 °C), which was higher than those retrieved for other materials with similar origin. The kinetic results indicated that the process followed pseudo-second order model. Equilibrium data indicate an increase in BG4 adsorption capacity with temperature and Sips model had better fit for all the investigated temperatures (30, 40, 50 and 60 °C). The regeneration/reuse test indicated that the adsorbent is able to assure a BG4 removal above 70 % during five adsorption/desorption cycles evaluated. Thermodynamic parameters suggested that adsorption is spontaneous, endothermal, governed by chemisorption and with structural changes in the solid surface upon adsorption.


Asunto(s)
Desinfectantes , Contaminantes Químicos del Agua , Adsorción , Concentración de Iones de Hidrógeno , Cinética , Regeneración , Espectroscopía Infrarroja por Transformada de Fourier , Termodinámica , Aguas Residuales , Agua , Contaminantes Químicos del Agua/análisis
16.
Int J Biol Macromol ; 158: 595-604, 2020 May 07.
Artículo en Inglés | MEDLINE | ID: mdl-32387603

RESUMEN

The simultaneous adsorption of three pollutants cobalt (Co), methylene blue (MB) and nickel (Ni) on a modified chitin surface from ternary systems was investigated. Multicomponent experimental adsorption data were determined at 298-328 K and pH 6. These experimental studies indicated that Ni adsorption was higher than those obtained for Co and MB. The multicomponent adsorption mechanism of this ternary system was analyzed with statistical physics theory where a set of new models with different hypotheses was developed and tested. Results showed that an adsorption model assuming that the pollutants Co, MB and Ni were adsorbed on three different types of modified chitin receptor sites was the most appropriate. This model was also utilized to calculate the corresponding adsorption energies to describe the possible interactions between these adsorbates and the surface of modified chitin. A general analysis of trends and magnitude of the model parameters provided a deeper understanding of the ternary adsorption mechanism at molecular level. Macroscopically, the ternary adsorption mechanism was interpreted via a calculation of three thermodynamic functions.

17.
Molecules ; 24(3)2019 Jan 23.
Artículo en Inglés | MEDLINE | ID: mdl-30678133

RESUMEN

: In this study, the mechanisms of methylparaben adsorption onto activated carbon (AC) are elucidated starting from equilibrium and thermodynamic data. Adsorption tests are carried out on three ACs with different surface chemistry, in different pH and ionic strength aqueous solutions. Experimental results show that the methylparaben adsorption capacity is slightly affected by pH changes, while it is significantly reduced in the presence of high ionic strength. In particular, methylparaben adsorption is directly dependent on the micropore volume of the ACs and the π- stacking interactions, the latter representing the main interaction mechanism of methylparaben adsorption from liquid phase. The equilibrium adsorption data are complemented with novel calorimetric data that allow calculation of the enthalpy change associated with the interactions between solvent-adsorbent, adsorbent-adsorbate and the contribution of the ester functional group (in the methylparaben structure) to the adsorbate⁻adsorbent interactions, in different pH and ionic strength conditions. It was determined that the interaction enthalpy of methylparaben-AC in water increases (absolute value) slightly with the basicity of the activated carbons, due to the formation of interactions with π- electrons and basic functional groups of ACs. The contribution of the ester group to the adsorbate-adsorbent interactions occurs only in the presence of phenol groups on AC by the formation of Brønsted⁻Lowry acid⁻base interactions.


Asunto(s)
Adsorción/efectos de los fármacos , Parabenos/química , Termodinámica , Contaminantes Químicos del Agua/química , Calorimetría , Carbono/química , Carbón Orgánico/química , Fenoles/química , Solventes/química , Agua/química , Contaminantes Químicos del Agua/toxicidad
18.
Environ Sci Pollut Res Int ; 26(15): 14755-14765, 2019 May.
Artículo en Inglés | MEDLINE | ID: mdl-29968215

RESUMEN

Effective landfill management and operation require an accurate evaluation of the occurrence and extent of odour emission events, which are among the main causes of resident complaints and concerns, in particular in densely urbanised areas. This paper proposes a fuzzy optimal protection system (FOPS) based on fuzzy logic to manage odour production from a municipal solid waste (MSW) landfill. The case study is a MSW landfill in an old quarry site located 6 km north-west of Naples city centre (Italy). The aim is to reduce the odour nuisance in the area surrounding the landfill where there are several sensitive receptors. FOPS is based on logical relationships between local atmospheric dynamics, number and intensity of odour pollution events detected by certain fixed receptors and odour emission rate via an optimal fuzzy approach. Such system allows to start, in real time, established mitigation actions required to further reduce the odorous emissions from the landfill itself (e.g. spraying of perfumed substances and activation of extraction wells), especially when weather conditions might not be favourable and cause by causing a higher odour perception. The fuzzy system was coupled with the air pollutant transport software CALPUFF to simulate the odour dispersion in the considered area taking into account both different odour emission rates and local weather conditions. FOPS results show that this approach can be very useful as, by measuring the odour concentrations, a significant reduction of the odour exceedances over the thresholds fixed, to minimise the olfactory harassment, was observed in the whole area studied.


Asunto(s)
Odorantes/análisis , Residuos Sólidos/análisis , Contaminación Ambiental , Lógica Difusa , Italia , Eliminación de Residuos , Olfato , Instalaciones de Eliminación de Residuos , Tiempo (Meteorología)
19.
Environ Sci Pollut Res Int ; 25(27): 26793-26800, 2018 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-28929297

RESUMEN

The following paper presents a method to optimise a discontinuous permeable adsorptive barrier (PAB-D). This method is based on the comparison of different PAB-D configurations obtained by changing some of the main PAB-D design parameters. In particular, the well diameters, the distance between two consecutive passive wells and the distance between two consecutive well lines were varied, and a cost analysis for each configuration was carried out in order to define the best performing and most cost-effective PAB-D configuration. As a case study, a benzene-contaminated aquifer located in an urban area in the north of Naples (Italy) was considered. The PAB-D configuration with a well diameter of 0.8 m resulted the best optimised layout in terms of performance and cost-effectiveness. Moreover, in order to identify the best configuration for the remediation of the aquifer studied, a comparison with a continuous permeable adsorptive barrier (PAB-C) was added. In particular, this showed a 40% reduction of the total remediation costs by using the optimised PAB-D.


Asunto(s)
Benceno/química , Restauración y Remediación Ambiental/métodos , Contaminantes Químicos del Agua/química , Adsorción , Costos y Análisis de Costo , Restauración y Remediación Ambiental/economía , Agua Subterránea/química , Italia , Pozos de Agua
20.
Molecules ; 22(12)2017 Dec 20.
Artículo en Inglés | MEDLINE | ID: mdl-29261156

RESUMEN

In this work, equilibrium and dynamic adsorption tests of cadmium Cd (II) on activated carbons derived from different oxidation treatments (with either HNO3, H2O2, or NaOCl, corresponding to GACoxN, GACoxP, and GACoxCl samples) are presented. The oxidation treatments determined an increase in the surface functional groups (mainly the acidic ones) and a decrease in the pHPZC (except for the GACoxCl sample). A slight alteration of the textural parameters was also observed, which was more significant for the GACoxCl sample, in terms of a decrease of both Brunauer-Emmett-Teller (BET) surface area and micropore volume. Adsorption isotherms were determined for all the adsorbents and a significant increase in the adsorption performances of the oxidized samples with respect to the parent material was observed. The performances ranking was GACoxCl > GACoxP > GACoxN > GAC, likely due to the chemical surface properties of the adsorbents. Dynamic tests in a fixed bed column were carried out in terms of breakthrough curves at constant Cd inlet concentration and flow rate. GACoxCl and GACoxN showed a significantly higher value of the breakpoint time, likely due to the higher adsorption capacity. Finally, the dynamic tests were analyzed in light of a kinetic model. In the adopted experimental conditions, the results showed that mass transfer is controlled by internal pore diffusion, in which surface diffusion plays a major role.


Asunto(s)
Cadmio/química , Carbón Orgánico/química , Adsorción , Cationes Bivalentes/química , Cromatografía Liquida , Difusión , Concentración de Iones de Hidrógeno , Cinética , Modelos Químicos , Oxidación-Reducción , Porosidad , Solventes , Propiedades de Superficie , Temperatura , Termodinámica
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