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1.
J Environ Manage ; 367: 121942, 2024 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-39067338

RESUMO

This bibliometric analysis offers a comprehensive investigation into membrane distillation (MD) research from 1990 to 2023. Covering 4389 publications, the analysis sheds light on the evolution, trends, and future directions of the field. It delves into authorship patterns, publication trends, prominent journals, and global contributions to reveal collaborative networks, research hotspots, and emerging themes within MD research. The findings demonstrate extensive global participation, with esteemed journals such as Desalination and the Journal of Membrane Science serving as key platforms for disseminating cutting-edge research. The analysis further identifies crucial themes and concepts driving MD research, ranging from membrane properties to strategies for mitigating membrane fouling. Co-occurrence analysis further highlights the interconnectedness of research themes, showcasing advancements in materials, sustainable heating strategies, contaminant treatment, and resource management. Overlay co-occurrence analysis provides temporal perspective on emerging research trends, delineating six key topics that will likely shape the future of MD. These include innovations in materials and surface engineering, sustainable heating strategies, emerging contaminants treatment, sustainable water management, data-driven approaches, and sustainability assessments. Finally, the study serves as a roadmap for researchers and engineers navigating the dynamic landscape of MD research, offering insights into current trends and future trajectories, ultimately aiming to propel MD technology towards enhanced performance, sustainability, and global relevance.


Assuntos
Bibliometria , Destilação , Membranas Artificiais
2.
Curr Microbiol ; 80(1): 52, 2022 Dec 23.
Artigo em Inglês | MEDLINE | ID: mdl-36562822

RESUMO

Pantoea bacteria species cause human animal infections, and contribute to soil and aquatic environmental pollution. A novel bacteriophage, vB_Pd_C23 was isolated from a Tunisian wastewater system and represents the first new phage infecting P. dispersa. Lysis kinetics, electron microscopy, and genomic analyses revealed that the vB_Pd_C23 phage has a head diameter of 50 nm and contractile tail dimensions of 100 nm by 23 nm; vB_Pd_C23 has a linear double-stranded DNA genome consisting of 44,714-bp and 49.66% GC-content. Predicted functions were assigned to 75 open reading frames (ORFs) encoding proteins and one tRNA, the annotation revealed that 21 ORFs encode for unique proteins of yet unknown function with no reliable homologies. This indicates that the new species vB_Pd_C23 exhibits novel viral genes. Phylogenetic analysis along with comparative analyses generating nucleotide identity and similarity of vB_Pd_C23 whole genome suggests that the phage is a candidate for a new genus within the Caudoviricetes Class. The characteristics of this phage could not be attributed to any previous genera recognized by the International Committee on Taxonomy of Viruses (ICTV).


Assuntos
Bacteriófagos , Pantoea , Humanos , Bacteriófagos/genética , Pantoea/genética , Filogenia , Genoma Viral , Genômica , Fases de Leitura Aberta
3.
Water Sci Technol ; 86(6): 1510-1526, 2022 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-36178820

RESUMO

The presence of heavy metals in wastewater has become a serious issue and a global concern for the environment and public health with rapid progress of modern textile industry. To minimize the health risks of heavy metals their complexation to a chelating agent constitute a promising process using membrane separation. We highlight for the first time the use of Keggin type-polyoxometalates (PW12) as complexing agent to eliminate heavy metals from synthetic textile wastewater. Indeed, filtration experiments were performed through the ultrafiltration organic regenerated cellulose membrane (3KDa). Effects of pressure (1-2.5 bar), PW12 concentration (10-50 mg·L-1), salt concentration (10-4-2 M) and pH value (2-12) on cadmium (Cd) and copper (Cu) removal were regularly explored. Experimental data showed that the addition of PW12 improves metal removal efficiency (up to 90%). The addition of NaCl salt significantly decreases the metals retention to 42%. The retention drop is probably due to the competition between Na+ and metals on complexation same negative sites of the PW12 and to the electric double-layer compressing. 24 full factorial design has been used to evaluate the most influencing parameters. The results obtained revealed that the maximum metal retention was 99% for both Cd and Cu.


Assuntos
Metais Pesados , Ultrafiltração , Ânions , Cádmio , Quelantes , Cobre , Polieletrólitos , Cloreto de Sódio , Ultrafiltração/métodos , Águas Residuárias
4.
Water Sci Technol ; 85(6): 1701-1719, 2022 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-35358066

RESUMO

Safe drinking water is a necessity for every human being, but clean water is scarce and not easily available due to natural geochemical factors or industrial pollutant activity. Many issues involving water quality could be greatly improved using clays as adsorbents. We highlight for the first time, the uptake of fluoride from natural water by Laponite, synthetic hectorite clay, in raw and modified state. A series of batch adsorption experiments were carried out to evaluate the adsorption potential of the different parameters. The optimized parameters were: contact time, adsorbent dose and pH. It was found that fluoride uptake from natural water was better using raw Laponite and inorganic-modified Laponite than using organic-modified Laponite clays. Adsorbents were characterized before and after fluoride adsorption by X-ray diffraction, X-ray fluorescence, FTIR, thermo gravimetric analyses and 19F solid state NMR spectroscopy. The experimental data showed that both Langmuir and Freundlich models fitted an adsorption isotherm well. Thermodynamic parameters such as Gibbs free energy (ΔG°), enthalpy (ΔH°), and entropy (ΔS°) were calculated. These parameters indicated that fluoride adsorption onto Laponite was nonspontaneous and endothermic in temperature range between 25 and 45 °C.


Assuntos
Fluoretos , Adsorção , Argila , Humanos , Silicatos , Termodinâmica
5.
Bull Environ Contam Toxicol ; 106(2): 327-333, 2021 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-33247788

RESUMO

Nanoparticle (NPs) toxicity in the plant has drawn considerable attention. Fenugreek plants were cultivated for 16 days in hydroponic experiments and treated with 50 and 100 mg L- 1 titanium oxide (TiO2) NPs of two sizes [23 ± 1.6 nm (D1) and 83 ± 15 nm. (D2)]. The level of Ti in roots was higher than that of leaves and stems of plants treated with 100 mg L- 1 of TiO2 NPs (D1, D2). Ti caused a depletion of Ca and Mn compared with root control. The titane (Ti) damage to root cellular membranes could alter the plant's capacity to absorb and transport some nutrients. In our study, increasing the size of TiO2 NPs produced increases in the contents of Mg, Zn and Mn, and a decline in the contents of Fe and Cu in leaves and stems. In roots, Fe and Cu decreased after TiO2 NPs (D2) exposure. Changes in the fenugreek plant mineral composition were assessed, and physiological disturbances could be directly correlated with exposure to NPs.


Assuntos
Nanopartículas , Trigonella , Minerais , Titânio , Água
6.
Bull Environ Contam Toxicol ; 103(3): 461-467, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31222423

RESUMO

The study aimed to determine the impact of treated domestic wastewater on seed germination, seedling growth and reserve mobilization from Fenugreek (Trigonellafoenum graecum L.). Seeds were germinated by soaking in distilled water (H2O) or wastewater treated with various methods: activated sludge processes (T1), facultative lagoons treatment (T2) and dilution. Results show high levels of organic matter (OM), suspended solids (TSS) and nutrients in TWW (T2) than that of TWW (T1). The embryo length and biomass of fenugreek imbibed by TWW were higher in TWW (T2) compared with TWW (T1). There was more reduction in free amino acids and soluble sugar contents in fenugreek treated with TWW (T1) than treated by TWW (T2). Important solutes leakage is recorded by measuring electric conductivity during seed imbibition with TWW. Improving the quality of wastewater by dilution (50%) stimulated germination of seeds and the growth of the tested plant. Moreover, it significantly reduces the solutes leakage and enhanced seed metabolites accumulation.


Assuntos
Sementes/efeitos dos fármacos , Trigonella/efeitos dos fármacos , Trigonella/metabolismo , Águas Residuárias/toxicidade , Agricultura , Transporte Biológico/efeitos dos fármacos , Biomassa , Monitoramento Ambiental , Germinação/efeitos dos fármacos , Plântula/química , Plântula/efeitos dos fármacos , Plântula/crescimento & desenvolvimento , Plântula/metabolismo , Esgotos/efeitos adversos , Esgotos/química , Trigonella/química , Trigonella/crescimento & desenvolvimento , Eliminação de Resíduos Líquidos , Águas Residuárias/química
7.
Bull Environ Contam Toxicol ; 102(4): 477-485, 2019 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-30887056

RESUMO

The aim of this work was to study the toxicity of nanosheet zinc oxide nanoparticle with the size of 45 nm. The penetration of nanoparticles at an exposure by a localized spray does not make it possible to understand the mechanism of transport and bioavailability of the nanoparticles. In contrast, nanoparticles penetrated, via the roots, as a function of their diameter, the smaller ones having caused leaf stress (by translocation) at low concentrations. So that the choice of method of root application. Plants treated with 50 mg L-1 of ZnO-NPs presented disturbance in leaf due to changes in chlorophyll's biosynthesis. The highest value of the photosynthetic pigments was recorded at 5 mg L-1 of ZnO-NPs. However, the treatment with 50 mg L-1 of ZnO-NPs caused a decrease in the levels of chlorophyll a and b. Moreover, ZnO-NPs leaves significantly enhanced antioxidant enzymes activities.


Assuntos
Antioxidantes/metabolismo , Nanopartículas/toxicidade , Estresse Oxidativo/efeitos dos fármacos , Fotossíntese/efeitos dos fármacos , Trigonella/efeitos dos fármacos , Óxido de Zinco/toxicidade , Disponibilidade Biológica , Clorofila A/biossíntese , Nanopartículas/metabolismo , Folhas de Planta/efeitos dos fármacos , Folhas de Planta/metabolismo , Trigonella/metabolismo , Óxido de Zinco/metabolismo
8.
Bull Environ Contam Toxicol ; 101(3): 326-337, 2018 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-30099613

RESUMO

In the present study, the interactions between nanoparticle (NP) exposure, root application and plants were examined. NPs are potentially responsible for conformational changes in polysaccharides, lipids, proteins, pectin, suberin and lignin molecules. 4 days of treatment with metal oxide caused a statistically significant increase in nicotinamide adénine dinucléotide oxidase activity in mitochondria and cytosol. Following exposure to TiO2NP, even lipid peroxidation levels decreased in the mitochondria (leaves, stem and root) and in the cytosol (leaves and root), although it increased in the cytosol of the stem. Malondialdehyde accumulation was found to be higher in the cytosol compared to the mitochondria of stems, and in the cytosol of leaves and roots. NPs caused alterations in metabolism, antioxidant enzyme activities (guaiacol peroxidase, catalase and ascorbate peroxidase) and the generation of oxidative stress. Effects caused by exposures to NPs were influenced by differences in metabolic responses in plant parts, plant compartments, the period of exposure and the NP doses.


Assuntos
Nanopartículas Metálicas/toxicidade , Titânio/toxicidade , Trigonella/efeitos dos fármacos , Ascorbato Peroxidases/metabolismo , Catalase/metabolismo , Citosol/efeitos dos fármacos , Citosol/metabolismo , Peroxidação de Lipídeos/efeitos dos fármacos , Malondialdeído/metabolismo , Mitocôndrias/efeitos dos fármacos , Mitocôndrias/metabolismo , Complexos Multienzimáticos/metabolismo , NADH NADPH Oxirredutases/metabolismo , Oxirredução , Estresse Oxidativo/efeitos dos fármacos , Peroxidase/metabolismo , Folhas de Planta/efeitos dos fármacos , Folhas de Planta/metabolismo , Raízes de Plantas/efeitos dos fármacos , Raízes de Plantas/metabolismo , Caules de Planta/efeitos dos fármacos , Caules de Planta/metabolismo , Trigonella/metabolismo
10.
Water Environ Res ; 96(1): e10979, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-38264925

RESUMO

This research focuses on boosting seawater pretreatment and desalination through electrocoagulation (EC)/ultrafiltration (UF) and electrocoagulation (EC)/nanofiltration (NF) processes. We first optimized the key parameters of the EC process using aluminum (Al) and iron (Fe) electrodes. Experimental results show EC process is efficient under optimal conditions. Second, membrane filtration using UF (ES10B), NF(UTC60) and NF(200) as post-processing steps to the EC process were experimented with. EC(Al)/NF(UTC60) combination resulted in the highest removal rate of organic matter (COD 98%, TOC 95%, fluorescence [humic and fulvic acids] 68%), optical density (OD600nm 75%, turbidity 70%, conductivity 64%). In terms of major ions removal, up to 55% was achieved as NF decreases conductivity, salinity, and hardness. EC(Al)/NF(UTC60) seawater permeate demonstrated the best results in terms of lowest flux decline (J/Jo = 0.9) and fouling, which was realized by resistance in series and recovery factor rate (%). Additionally, NF(UTC60) fouling reversibility led to a longer lifetime and higher recovery factor (93%). PRACTITIONER POINTS: Pretreatment by hybrid processes was experimented with to enhance the saline water treatment. Organic matter (COD 98%, TOC 95%, fluorescence [humic and fulvic acids] 68%) and turbidity were successfully removed. Salinity and hardness (conductivity 64%) were highly reduced by NF. Flux decline, retention rate, and membrane fouling were studied.


Assuntos
Águas Salinas , Água do Mar , Eletrocoagulação , Eletrodos , Ferro
11.
Environ Sci Pollut Res Int ; 31(31): 43660-43672, 2024 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-38904877

RESUMO

The agricultural sector uses 70% of the world's freshwater. As clean water is extracted, groundwater quality decreases, making it difficult to grow crops. Brackish water desalination is a promising solution for agricultural areas, but the cost is a barrier to adoption. This study investigated the performance of the fertilizer drawn forward osmosis (FDFO) process for brackish water desalination using response surface methodology (RSM) and artificial neural network (ANN) approaches. The RSM model was used to identify the optimal operating conditions, and the ANN model was used to predict the water flux (Jw) and reverse solute flux (Js). Both models achieved high accuracy, with RSM excelling in predicting Js (R2 = 0.9614) and ANN performing better for Jw (R2 = 0.9801). Draw solution (DS) concentration emerged as the most critical factor for both models, having a relative importance of 100% for two outputs. The optimal operating conditions identified by RSM were a DS concentration of 22 mol L-1, and identical feed solution (FS) and DS velocities of 8.1 cm s-1. This configuration yielded a high Jw of 4.386 LMH and a low Js of 0.392 gMH. Furthermore, the study evaluated the applicability of FDFO for real brackish groundwater. The results confirm FDFO's potential as a viable technology for water recovery in agriculture. The standalone FO system proves to be less energy-intensive than other desalination technologies. However, FO exhibits a low recovery rate, which may necessitate further dilution for fertigation purposes.


Assuntos
Agricultura , Fertilizantes , Água Subterrânea , Redes Neurais de Computação , Osmose , Purificação da Água , Água Subterrânea/química , Purificação da Água/métodos , Salinidade
12.
Membranes (Basel) ; 12(9)2022 Sep 08.
Artigo em Inglês | MEDLINE | ID: mdl-36135888

RESUMO

In this work, a flat supported liquid membrane (FSLM) was applied for the extraction of bisphenol A (BPA) from aqueous solutions, using an ionic liquid as a carrier. The liquid membrane consists of tricaprylmethylammonium chloride (aliquat 336®) diluted in 2-octanol. Furthermore, to obtain the best transport efficiency, the impacts of various experimental parameters were investigated. These parameters included aliquat 336® concentration, the concentration of BPA in the feed phase, the pH of the feed phase, the concentration of NaOH in the receiving phase, the polymeric support nature, the percentage of extractant in the organic phase, and the solvent nature. The optimum conditions of the experiment were 50% (v/v) aliquat 336®/2-octanol as the organic phase, a transport time of 8 h, and 1 × 10-2 mol L-1 NaOH as the receiving phase. The BPA was successfully recovered (the recovery percentage was about 89%). Supported liquid membrane-based aliquat 336®/2-octanol displayed an acceptable stability with re-impregnation after 5 days of operation.

13.
Environ Technol ; : 1-19, 2022 Oct 17.
Artigo em Inglês | MEDLINE | ID: mdl-36170044

RESUMO

This study investigates the eco-friendly synthesis of zinc oxide nanoparticles (ZnO NPs) utilizing an aqueous solution of Hibiscus sabdariffa L. flower extract, which is acts as reducing agent as well as capping agent. The Fourier transform infrared spectroscopy (FTIR) results revealed the presence of flavonoids and phenols in the plant extract, indicating that they were the major agents capable of reducing zinc nitrate salt. According to our x-ray diffraction (XRD) results, ZnO-NPs exhibit a particular phase wurtzite structure. The ZnO-NPs are spherical in shape and have an average size of 15 nm, according to the measurements of electron microscope (SEM) and transmission electron microscope (TEM) measurements. Energy dispersion (EDX) analysis demonstrates that the NPs are mainly composed of zinc and oxygen. The zeta potential of these nanoparticles shows that they are very stable. The antibacterial activity of ZnO-NPs was tested using agar dilutions with a variety of gram-positive and gram-negative microorganisms. According to the research results, ZnO-NPs can be established as an extremely specific antibacterial agent for a wide variety of organisms to prevent bacterial growth. Furthermore, the antioxidant properties of ZnO-NPs were determined using the 2,2 diphenyl-1-picrylhydrazyl hydrate (DPPH) radical scavenging approach, and the IC50 value of 38 µg/mL was measured for ZnO-NPs. Furthermore, the biosynthesized ZnO-NPs showed significant catalytic performance of methyl orange (MO) under UV irradiation. Overall, ZnO-NPs in their produced state have excellent potential in biomedical and wastewater treatment applications. Radical scavengers were used to evaluate the role of radicals in the reaction mechanism.

14.
Membranes (Basel) ; 11(1)2021 Jan 18.
Artigo em Inglês | MEDLINE | ID: mdl-33477556

RESUMO

A microporous carboxylate metal-organic framework MIL-100 Fe was prepared as submicron particles by microwave-assisted hydrothermal synthesis (Fe-MOF-MW). This product was explored, for the first time, for the preparation of polylactic acid (PLA) mixed matrix membranes. The produced MOF was characterised by powder X-ray diffraction (PXRD), environmental scanning electron microscopy (ESEM) as well as by thermogravimetric analysis (TGA) and nitrogen adsorption/desorption. The effect of different Fe-MOF-MW concentrations (0.1 and 0.5 wt%) on the membrane properties and performance were evaluated. These membranes were used in the pervaporation process for the separation of methanol/methyl tert-butyl-ether mixtures at the azeotropic point. The influence of the feed temperature and vacuum pressure on the membrane performance was evaluated and the results were compared with PLA pristine membranes. Moreover, the produced membranes have been characterised in terms of morphology, MOF dispersion in the polymeric membrane matrix, wettability, thickness, mechanical resistance and swelling propensity. The presence of Fe-MOF-MW was found to have a beneficial effect in improving the selectivity of mixed matrix membranes towards methanol at both concentrations. The highest selectivity was obtained for the PLA membranes embedded with 0.5 wt% of Fe-MOF-MW and tested at the temperature of 25 °C and vacuum pressure of 0.09 mbar.

15.
C R Biol ; 340(11-12): 499-511, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-29066172

RESUMO

The potential toxicity of nanoparticles in plants is scarce and contradictory. Despite the diversity of research efforts, a detailed explanation of the TiO2NPS effects in plant photosynthesis is still missing. The present work gives a new approach to examine the impact of the TiO2NPs on crop production (development and photosynthesis) and plant protection (tolerance and defense systems) in fenugreek (Trigonella foenum graecum L.). Seedlings were assessed in greenhouse trials to estimate the influence of TiO2NPs on physiological characters for 16 days. They were treated with TiO2NPs at a size less than 20nm. The results revealed that there were no significant effects on seedlings growth and biomass of stem, but a decrease in the fresh weight of leaves after TiO2NPs treatment. Plants treated with 100mg·L-1 of TiO2NPs presented a reduction and chlorosis in leaf area due to a significant decrease in the chlorophyll a and b contents. The highest value of the photosynthetic pigments was recorded at 50mg·L-1 of TiO2NPs. However, the treatment with 100mg·L-1 of TiO2NPs caused a decrease in the levels of chlorophyll a, b and of carotenoids. Both doses of TiO2NPs induced an accumulation of anthocyanins compared to the control after 16 days of seedling development. A nano-stress significantly decreased the flavonoids level, but increased that of polyphenols compared to control after 16 days of exposure. The decrease in the translocation ratio of flavonoids suggests that many of them contain an enediol group, which suggests that they may act as bidentate ligands for anatase TiO2NPs. Accordingly, nano-stressed leaves exhibited significantly enhanced GPOX, CAT and APX activity levels. On the contrary, GPOX and CAT activities were reduced substantially in stems treated with 100mg·L-1 TiO2NPs. The accumulation of MDA was found to be higher in stems than in leaves. This could be explained by the accumulation of nanoparticles in different organs; it could be that the stems are the favored targets of nanoparticles. These results underline the necessity for a deeper estimation of nanoparticle ecotoxicity and particularly concerning their interaction with plants.


Assuntos
Clorofila/química , Titânio/toxicidade , Trigonella/metabolismo , Clorofila A , Flavonoides/metabolismo , Folhas de Planta/efeitos dos fármacos , Plântula/efeitos dos fármacos
16.
Environ Sci Pollut Res Int ; 21(17): 10493-501, 2014 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-24756674

RESUMO

Direct contact membrane distillation (DCMD) process using polyvinylidene fluoride (PVDF) membrane was used for fluoride removal from aqueous solution. This study has been carried out on heat and mass transfer analyses in DCMD. The dusty-gas model was used to analyze the mass transfer mechanism and to calculate the permeate flux. The heat transfer is analyzed based on energy balance, and the different layers are considered as a series of thermal resistances. Mass transfer analysis showed that the transition Knudsen-molecular diffusion is the dominant mechanism to describe the transport of water vapor through the pores of the PVDF membrane. The most significant operating parameter is the feed temperature. The permeate increases sensitively with feed temperature and velocity, and it shows insignificant change with feed salts concentration. Heat transfer analysis showed the conduction through the matrix of the membrane presents the major part of available energy. The increasing feed temperature leads to increase thermal efficiency (TE) and decrease temperature polarization coefficient (TPC). The experimental results are in good agreement with theoretical values. Therefore, it is suggested to work at high feed temperature, which will benefit both the thermal efficiency and permeate flux. The experimental results proved that DCMD process is able to produce almost fluoride-free water suitable for many beneficial uses.


Assuntos
Fluoretos/isolamento & purificação , Poluentes Químicos da Água/isolamento & purificação , Purificação da Água/métodos , Destilação , Fluoretos/análise , Membranas Artificiais , Modelos Químicos , Polivinil , Temperatura , Termodinâmica , Poluentes Químicos da Água/análise
17.
Spectrochim Acta A Mol Biomol Spectrosc ; 131: 169-76, 2014 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-24830630

RESUMO

Understanding the role played by chemical additives such as NaCl salt, acid and Cetylpyridinium Chloride (CPC) surfactant on the interaction between dye and polyelectrolyte contributes to optimization of processes using polyelectrolytes in the removal of dye from aqueous solution. Herein we focus in the interaction between Safranin T, a cationic dye, with two anionic polyelectrolytes, poly(ammonium acrylate) and poly(acrylic acid) using spectrophotometric method and conductivity measurement. In aqueous solution, each of anionic polyelectrolytes forms a complex with the dye and induces a metachromasy indicated by the blue shift of the absorbance of the dye. The stoichiometry of complexes evaluated by the molar ratio method are 1:1 for Safranin T poly(ammonium acrylate) and 2:1 in the case of Safranin T poly(acrylic acid). The effect of additives on the stability of complexes has been studied by varying concentrations of the salt and the surfactant and pH of the solution. The thermodynamic parameters of interaction ΔG, ΔH and ΔS at different temperatures were evaluated to determine the stability constant of the complexes.


Assuntos
Resinas Acrílicas/química , Compostos de Amônio/química , Corantes/química , Fenazinas/química , Ânions/química , Cátions/química , Condutividade Elétrica , Eletrólitos/química , Espectrofotometria
18.
Spectrochim Acta A Mol Biomol Spectrosc ; 79(5): 1528-31, 2011 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-21689968

RESUMO

Interactions of anionic dye Eriochrome Blue Black R (EBBR) with various cationic micelles of surfactants n-alkyltrimethylammonium CnTAB (n=12; 14; 16 and 18) have been investigated spectrophotometrically at 25°C in premicellar and postmicellar region. The results have shown that with increasing the alkyl chain length of surfactants, the maximum absorbance of EBBR shifted to a higher wavelength and the binding constants of EBBR to cationic micelles (Kb) increases. This confirms that the surfactant micelle, which has a longer alkyl hydrocarbon chain, enables greater solubilization of dye. Thus, the hydrophobic interaction of the dye with micelles increases in the order: C12TAB

Assuntos
Compostos Azo/química , Corantes/química , Compostos de Amônio Quaternário/química , Tensoativos/química , Ânions/química , Cátions/química , Interações Hidrofóbicas e Hidrofílicas , Micelas , Espectrofotometria Ultravioleta
19.
J Hazard Mater ; 168(2-3): 1417-21, 2009 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-19376644

RESUMO

Micellar-enhanced ultrafiltration (MEUF) represents a potentially attractive tool for the removal of different contaminants from wastewater. In this study, MEUF was carried out to investigate the retention of Eriochrome Blue Black R (EBBR), an anionic dye, from aqueous stream. N-Alkyltrimethylammonium bromide i.e. dodecyltrimethylammonium bromide (C(12)TAB), tetradecyltrimethylammonium bromide (C(14)TAB), cetyl-trimethylammonium bromide (C(16)TAB) and octadecyltrimethylammonium bromide (C(18)TAB) were taken as cationic surfactants, and NaCl, Na(2)SO(4), Na(2)HPO(4) as electrolytes. A hydrophilic membrane made of cellulose (molecular weight cut-off 10000 Da) was used in a cross-flow ultrafiltration unit. The removal of EBBR was studied as a function of dye and surfactant concentrations, ionic strength, transmembrane pressure and pH. The MEUF experiments showed that the highest dye rejection was about 99% for the used range of dye and surfactant concentrations. This retention depended slightly on dye and surfactant concentrations, ionic strength, pH and transmembrane pressure. However, permeate flux changed significantly with those parameters due mainly to concentration polarisation and osmotic pressure.


Assuntos
Compostos Azo/isolamento & purificação , Micelas , Ultrafiltração/métodos , Poluentes Químicos da Água/isolamento & purificação , Concentração de Íons de Hidrogênio , Concentração Osmolar
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