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1.
J Environ Public Health ; 2020: 5383842, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32774394

RESUMO

Textile industries generate large quantities of dye containing wastewater which pose a serious environmental problem. Currently, biosorbents have become desirable for the removal of dyes from textile effluents. In this study, batch experiments were conducted to investigate the biosorption characteristics of cactus peel on the removal of reactive red dye from aqueous solutions. The effects of solution pH, biosorbent dosage, contact time, and initial concentration were studied. The interaction effects of process variables were analysed using response surface methodology. The results showed that removal efficiency increased as initial dye concentration and solution pH decreased and as biosorbent dosage and contact time increased. The highest removal efficiency (99.43%) was achieved at solution pH, initial dye concentration, biosorbent dose, and contact time of 3.0, 40 mg/l, 6 g, and 120 min, respectively. From regression analysis, the Langmuir isotherm was found to better (R 2 = 0.9935) represent the biosorption process as compared with the Freundlich isotherm (R 2 = 0.9722). Similarly, the pseudo-second-order model was seen to represent very well the biosorption kinetics. The results show that cactus peel has good potential for the removal of reactive red dye.


Assuntos
Cactaceae/química , Corantes/isolamento & purificação , Indústria Têxtil , Eliminação de Resíduos Líquidos/métodos , Poluentes Químicos da Água/isolamento & purificação , Adsorção , Corantes/química , Recuperação e Remediação Ambiental , Concentração de Íons de Hidrogênio , Cinética , Termodinâmica , Poluentes Químicos da Água/química
2.
PLoS One ; 15(6): e0229968, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32497077

RESUMO

Although laccase has been recognized as a wonder molecule and green enzyme, the use of low yielding fungal strains, poor production, purification, and low enzyme kinetics have hampered its large-scale application. Thus,this study aims to select high yielding fungal strains and optimize the production, purification, and kinetics of laccase of Aspergillus sp. HB_RZ4. The results obtained indicated that Aspergillus sp. HB_RZ4 produced a significantly large amount of laccase under meso-acidophilic shaking conditions in a medium containing glucose and yeast extract. A 25 µM CuSO4 was observed to enhance the enzyme yield. The enzyme was best purified on a Sephadex G-100 column. The purified enzyme resembled laccase of A. flavus. The kinetics of the purified enzyme revealed high substrate specificity and good velocity of reaction,using ABTS as a substrate. The enzyme was observed to be stable over various pH values and temperatures. The peptide structure of the purified enzyme was found to resemble laccase of A. kawachii IFO 4308. The fungus was observed to decolorize various dyes independent of the requirement of a laccase mediator system.Aspergillus sp. HB_RZ4 was observed to be a potent natural producer of laccase, and it decolorized the dyes even in the absence of a laccase mediator system. Thus, it can be used for bioremediation of effluent that contains non-textile dyes.


Assuntos
Aspergillus/enzimologia , Biotecnologia/métodos , Corantes/metabolismo , Lacase/metabolismo , Casca de Planta/microbiologia , Biodegradação Ambiental , Corantes/isolamento & purificação , Ativação Enzimática , Inibidores Enzimáticos/farmacologia , Estabilidade Enzimática , Enzimas Imobilizadas/antagonistas & inibidores , Enzimas Imobilizadas/química , Enzimas Imobilizadas/metabolismo , Concentração de Íons de Hidrogênio , Lacase/antagonistas & inibidores , Lacase/química
3.
PLoS One ; 15(2): e0228595, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32027708

RESUMO

Acid orange 74 (AO74) is a chromium-complex monoazo acid dye widely used in the textile industry. Due to being highly toxic and non-biodegradable, it must be removed from polluted water to protect the health of people and the environment. The aim of this study was two-fold: to evaluate the biosorption of AO74 from an aqueous solution by utilizing HCl-pretreated Lemna sp. (HPL), and to examine dye desorption from the plant material. The maximum capacity of AO74 biosorption (64.24 mg g-1) was reached after 4 h at the most adequate pH, which was 2. The biosorption capacity decreased 25% (to 48.18 mg g-1) during the second biosorption/desorption cycle and remained essentially unchanged during the third cycle. The pseudo-second-order kinetics model concurred well with the experimental results of assays involving various levels of pH in the eluent solution and distinct initial concentrations of AO74. NaOH (0.01 M) was the best eluent solution. The Toth isotherm model best described AO74 biosorption equilibrium data. FTIR analysis confirmed the crucial role of HPL proteins in AO74 biosorption. SEM-EDX and CLSM techniques verified the effective biosorption/desorption of the dye during the three cycles. Therefore, HPL has potential for the removal of AO74 dye from wastewaters.


Assuntos
Araceae/metabolismo , Compostos Azo/isolamento & purificação , Biodegradação Ambiental , Corantes/isolamento & purificação , Adsorção , Compostos Azo/toxicidade , Corantes/toxicidade , Ácido Clorídrico , Concentração de Íons de Hidrogênio , Cinética , Indústria Têxtil , Águas Residuárias/química , Poluentes Químicos da Água/isolamento & purificação , Poluentes Químicos da Água/toxicidade
4.
Artigo em Inglês | MEDLINE | ID: mdl-31533527

RESUMO

The dyes used in textile industries are usually difficult to degrade in aquatic environments, being highly toxic to micro fauna and flora. Thus, textile wastewater treatments have been developed, among them, one that stands out is adsorption process. With the rise of nanomaterials applied to adsorption, graphene oxide (GO) shows promise in the removal of dyes. This work aimed to produce a more economical and environmentally friendly GO by reducing H2SO4 concentration during the synthesis. Adsorption tests were performed with methylene blue (MB) and brilliant blue (BB), adsorbent regeneration tests, as well as a kinetic study using real wastewater, and toxicological assays with lettuce seeds. Results showed that the sample produced with less H2SO4 (GO-21) performed better for MB (99% removal) and BB (29% removal); and recycling test showed that despite the decrease in removal efficiency, it remained high in the first cycles. Kinetics showed that equilibrium was reached in 30 min, removing 67.43% of color and 90.23% of the effluent's turbidity. Phytotoxicity assays indicated that the wastewater treated with GO-21 was the least toxic, compared to other wastewater samples analyzed. Therefore, GO has demonstrated its potential to be an effective and less toxic option to treat textile effluents.[Formula: see text].


Assuntos
Corantes/isolamento & purificação , Grafite/síntese química , Alface/efeitos dos fármacos , Águas Residuárias/toxicidade , Poluentes Químicos da Água/isolamento & purificação , Purificação da Água/métodos , Adsorção , Cor , Corantes/química , Biomarcadores Ambientais/efeitos dos fármacos , Grafite/química , Cinética , Indústria Têxtil , Águas Residuárias/química , Poluentes Químicos da Água/química
5.
Food Chem ; 311: 125870, 2020 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-31740270

RESUMO

Fluorescent brightener 52 (FWA52) is a coumarin-based compound, and it is difficult to degrade owing to its high chemical stability. Up to now, several methods have been developed to extract and determine FWAs, but toxic, volatile and harmful organic solvents are often used. In this paper, a novel method for the extraction and analysis of FWA52 is proposed for the first time by in situ formation of hydrophobic deep eutectic solvent (DES) with parabens in aqueous solution. The effects of paraben structure, solution pH, system temperature, extractant dosage and initial FWA52 concentration on the extraction recovery were investigated systematically. It is shown that FWA52 can be extracted by 2-ethylhexyl 4-hydroxybenzoate at ultra-trace level (0.05 µg/L FWA52) at room temperature without using harmful organic solvents, and various coexisting inorganic ions and organic compounds have little effect on the extraction efficiency. Based on these results, a novel and simple strategy is developed for the accurate determination of FWA52 in water. It is found that under the optimal experimental conditions, the linear range of this method is 0.20~25 µg/L (R2 = 0.9995), and the detection limit and the quantity limit are 0.045 µg/L and 0.20 µg/L respectively. This method has been successfully applied for the determination of FWA52 in actual food samples and food contact materials, such as noodles, fish balls, mushroom and paper cups, with a recovery from 82 to 113% and a relative standard deviation (RSD) from 4.7 to 9.9%. In addition, the separation mechanism was investigated by FT-IR and 1H NMR, and was discussed from strong hydrogen bonding between FWA52 and 2-ethylhexyl 4-hydroxybenzoate and the formation of corresponding DES.


Assuntos
Corantes/isolamento & purificação , Análise de Alimentos , Interações Hidrofóbicas e Hidrofílicas , Solventes/química , Limite de Detecção , Espectroscopia de Infravermelho com Transformada de Fourier , Temperatura , Água/química
6.
Chemosphere ; 242: 125197, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31675592

RESUMO

Industrial effluents often contain mixed metal ions and dyes, and it is difficult to efficiently remove both types of contaminants simultaneously. Here, MIL-125-NH2@Ag/AgCl composites were for the first time developed through a facile deposition-photoreduction method for simultaneously removing Cr(VI)/Rhodamine B (RhB)/Malachite Green (MG) ternary system pollutants under visible-light irradiation. The capacities of Cr(VI) reduction dramatically increased to 98.4% in the coexistence of RhB and MG compared to that of binary (Cr(VI)/RhB (69.6%) or Cr(VI)/MG (67.5%)) and single Cr(VI) (29%) systems. In the meantime, the degradation efficiencies of dyes especially RhB in the ternary system were also improved compared to that of their individual systems. On the grounds of all the experimental results, it can be concluded that the efficient light-harvesting and electrons migration in MIL-125-NH2@Ag/AgCl and the synergistic effect of redox reactions between Cr(VI) and dyes hinder the recombination of photo-induced electron-hole pairs, which are responsible for their high photocatalytic activity to eliminate the mixed pollutants. This study provides a new route to construct high-performance photocatalysts for the practical treatment of wastewater containing mixed pollutants.


Assuntos
Cromo/isolamento & purificação , Corantes/isolamento & purificação , Poluentes Ambientais/isolamento & purificação , Luz , Dietilamida do Ácido Lisérgico/análogos & derivados , Fotólise/efeitos dos fármacos , Catálise , Corantes/efeitos da radiação , Poluentes Ambientais/efeitos da radiação , Resíduos Industriais , Dietilamida do Ácido Lisérgico/química , Oxirredução , Rodaminas/isolamento & purificação , Rodaminas/efeitos da radiação , Corantes de Rosanilina/isolamento & purificação , Corantes de Rosanilina/efeitos da radiação , Purificação da Água/métodos
7.
Chemosphere ; 241: 125043, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31683417

RESUMO

Over the past few decades, cyclodextrin-based adsorbents have drawn worldwide attention as new-generation adsorbents for wastewater treatment due to its extraordinary physicochemical properties. This review outlined the recent development in the synthesis of cyclodextrin-based adsorbents as well as highlighted their applications in the removal of heavy metals, dyes, endocrine disrupting chemicals (EDCs), and mixed pollutants from water. The cross-linked and immobilized cyclodextrin-based adsorbents exhibited excellent adsorption performances. The removal of dyes and heavy metals were effectively controlled by ion exchanging, mainly depending upon the pH; while the adsorptions of EDCs always occurred in cyclodextrin cavities and pH-independent. An easier separation process between aqueous and adsorbents could be achieved compared to native cyclodextrin, which promoted the application of cyclodextrin-based adsorbents in practical industry. This review could provide an inspiration for the advanced study in the development of cyclodextrin-based adsorbents for high efficiency wastewater treatment.


Assuntos
Ciclodextrinas/química , Águas Residuárias/química , Poluentes Químicos da Água/isolamento & purificação , Purificação da Água/métodos , Adsorção , Corantes/isolamento & purificação , Metais Pesados/isolamento & purificação
8.
J Chromatogr A ; 1610: 460516, 2020 Jan 11.
Artigo em Inglês | MEDLINE | ID: mdl-31526639

RESUMO

The new approach to the development of planar chromatogram with controlled developing solvent velocity was implemented for gradient reversed-phase chromatography of a test mixture of dyes. The developing solvent components were directly delivered onto the surface of the C18 type of silica adsorbent layer with controlled velocity by moving pipette combined with two syringe pumps. The eluent components were mixed onto the adsorbent layer, so in this way, there was no dwell volume of the developing solvent during gradient chromatogram development. The delivery of the developing solvent solution to the adsorbent layer was adjusted to its absorption rate by the adsorbent layer. Under such conditions, there was no excess of the eluent solution on the surface of the adsorbent layer, so the high performance of the chromatographic system could be obtained. In the paper, the results of the repeatability and reproducibility test of migration distances of selected separated solute zones are presented.


Assuntos
Cromatografia de Fase Reversa/métodos , Cromatografia em Camada Delgada/métodos , Corantes , Solventes/química , Corantes/análise , Corantes/isolamento & purificação
9.
Chemosphere ; 239: 124766, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31527001

RESUMO

Iron (Fe)-doped ZrO2 tetragonal nanoparticles were synthesized by a facile and inexpensive hydrothermal technique, that were doped with Fe3+ ions (0.1, 0.3, and 0.5 mol%) into the host lattice without altering the morphology and crystal structure of the nanoparticles. SEM and TEM investigations indicated that the morphology of ZrO2 nanoparticles did not change even after incorporation of Fe, while the band gap of semiconducting ZrO2 nanoparticles was reduced from 4.97 to 1.77 eV. Such a in band gap was responsible to harvest more photons to stimulate the generation of more electrons in the valence band, thereby enhancing the photoelectrochemical (PEC) water splitting as well as photocatalytic and photoelectrocatalytic activities in the photodegradation of Rhodamine B. The 0.3 mol%-doped ZrO2 electrode showed enhanced photocurrent density (0.07 × 10-3 A/cm2), that was 45-times greater than the pure sample. The electrochemical impedance spectroscopy (EIS) confirmed that 0.3 mol%-doped ZrO2 exhibited the best charge transfer characteristics, which increased with PEC water splitting activity. The maximum photocurrent density and long-term photo-stability were achieved in the light on-off states.


Assuntos
Corantes/isolamento & purificação , Ferro/química , Nanopartículas Metálicas/química , Rodaminas/isolamento & purificação , Zircônio/química , Catálise , Corantes/química , Eletrodos , Poluentes Ambientais/química , Poluentes Ambientais/isolamento & purificação , Fotoquímica/instrumentação , Fotoquímica/métodos , Fotólise , Pontos Quânticos/química , Rodaminas/química , Água/química
10.
Chemosphere ; 239: 124764, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31527004

RESUMO

Electrospun reduced graphene oxide/TiO2/poly(acrylonitrile-co-maleic acid) composite nanofibers (E-spun RGO/TiO2/PANCMA NFs) were fabricated using electrospinning of the dispersive solution of PANCMA, GO and TiO2 followed by post-chemical reduction. The obtained composite nanofibers were compressed in a dialyzer and then used to absorb and degrade malachite green (MG) and leucomalachite green (LMG) from aqueous solution. Compared to the E-spun TiO2/PANCMA and GO/TiO2/PANCMA NFs, the E-spun RGO/TiO2/PANCMA NFs exhibited higher adsorption capacity and photocatalytic degradation ability. Under optimized conditions, 90.6% of MG and 93.7% of LMG from 50 mL aqueous sample solution were adsorbed on the RGO/TiO2/PANMA NFs (3.0 mg fibers) in 2.0 min, and subsequent the 91.4% and 95.2% of MG and LMG adsorbed on the NFs were degradated in 60 min under UV irradiation, respectively. In addition, the E-spun RGO/TiO2/PANMA NFs exhibited good reusability and could be reused in multiple cycles of operations for adsorption and photocatalytic degradation of MG and LMG. This work demonstrated that the electrospun composite nanofibers are promising materials for removal of pollutants from environmental water samples.


Assuntos
Nanofibras/química , Corantes de Rosanilina/isolamento & purificação , Poluentes Químicos da Água/isolamento & purificação , Resinas Acrílicas/química , Adsorção , Catálise , Corantes/química , Corantes/isolamento & purificação , Grafite/química , Processos Fotoquímicos , Corantes de Rosanilina/química , Titânio/química , Raios Ultravioleta , Poluentes Químicos da Água/química
11.
Chemosphere ; 238: 124539, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31470310

RESUMO

The performance and microbial community structure of anaerobic dynamic membrane bioreactor (AnDMBR) treating textile wastewater was investigated. The reactor showed excellent soluble COD and color removal of 98.5% and >97.5%, respectively. Dynamic membrane layer grown over the 3D printed dynamic membrane support showed decent rejection for high molecular weight compounds (>20 kDa); and the total suspended solid rejection by the dynamic layer was >98.8%. Gel permeation chromatography analysis of extracellular polymeric substance (EPS) and effluent samples revealed EPS accounted for more than 76.7% of low molecular weight fractions (<20 kDa) that end up in the effluent. Higher applied flux facilitated the rapid formation dynamic layer which enabled a satisfactory effluent quality. Microbial community analysis revealed that during the operation the archaeal community was relatively stable while obvious changes took place in the bacterial community. Introduction of dye Remazol Brilliant Blue R (RBBR) to the AnDMBR increased the abundances of phyla of Proteobacteria and Spirochaetae whereas fractions of Firmicutes and Euryarchaeota decreased obviously. Furthermore, relative stable abundances of phyla Aminicenantes, Bacteroidetes, Thermotogae and Chloroflexi among the top six phyla detected in the system ensured a healthy anaerobic degradation environment for RBBR wastewater treatment.


Assuntos
Antraquinonas/isolamento & purificação , Antraquinonas/metabolismo , Reatores Biológicos/microbiologia , Membranas Artificiais , Têxteis , Águas Residuárias/química , Anaerobiose , Corantes/isolamento & purificação , Corantes/metabolismo , Matriz Extracelular de Substâncias Poliméricas/microbiologia , Proteobactérias/metabolismo , Spirochaeta/metabolismo , Poluentes Químicos da Água/isolamento & purificação , Poluentes Químicos da Água/metabolismo
12.
Carbohydr Polym ; 229: 115512, 2020 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-31826502

RESUMO

In recent decades, increased industrial activities have led to the release of various pollutants, such as toxic heavy metals, inorganic anions, and organics. It is imperative but challenging to develop an eco-friendly treatment technology with easy operation, low cost, and high efficiency. Here, we describe a design of magnetic purifier, which has biomass-based structure by blending attapulgite/chitosan (ATP/CS) composite with bacterial cellulose nanofibrils (BCNs). Compared to similar materials reported previously, our product exhibited efficient adsorption capacities towards various metal ions including Pb2+, Cu2+, and Cr6+, and anionic organic dyes including Congo red. The adsorption process could be well fitted by Langmuir isotherm and pseudo-second order equation. Additionally, the adsorption capacity only decreased less than 8% after five adsorption-desorption cycles. We expect our design will inspire more efforts to build a multifunctional water purifier with simple operation, and hopefully effectively remove pollutants from wastewater in future practical applications.


Assuntos
Bactérias/química , Celulose/química , Corantes/química , Compostos de Magnésio/química , Imãs/química , Metais Pesados/química , Compostos de Silício/química , Poluentes Químicos da Água/química , Adsorção , Corantes/isolamento & purificação , Água Doce/química , Cinética , Metais Pesados/isolamento & purificação , Poluentes Químicos da Água/isolamento & purificação
13.
J Colloid Interface Sci ; 560: 825-837, 2020 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-31711669

RESUMO

The capacity of an adsorbent to bind and remove dye from solution greatly depends on the type of functionalization present on the nanoparticles surface, and its interaction with the dye molecules. Within this study, nitrogenous silane nanoparticles were hydrothermally synthesized resulting in the formation of rapid and highly efficient adsorbents for concentrated mixed dyes. The amorphous silane nanoparticles exhibited a monolayer based mechanism of mixed dye adsorption with removal capacities between 416.67 and 714.29 mg/g of adsorbent. Dye removal was predominantly due to the electrostatic attraction between the positively charged silane nanoparticles (13.22-8.20 mV) and the negatively charged dye molecules (-54.23 mV). Addition of H. annuus extract during synthesis resulted in three times the surface area and 10 times increased pore volume compared to the positive control. XPS analysis showed that silane treatments had various nitrogen containing functionalities at their surface responsible for binding dye. The weak colloidal stability of silane particles (13.22-8.20 mV) was disrupted following dye binding, resulting in their rapid coagulation and flocculation which facilitated the separation of bound dye molecules from solution. The suitability for environmental applications using these treatments was supported by a bacterial viability assay showing >90% cell viability in treated dye supernatants.


Assuntos
Corantes/isolamento & purificação , Helianthus/química , Nanopartículas/química , Nitrogênio/química , Extratos Vegetais/química , Silanos/química , Poluentes Químicos da Água/isolamento & purificação , Adsorção , Bactérias/efeitos dos fármacos , Bactérias/crescimento & desenvolvimento , Corantes/química , Meio Ambiente , Nanopartículas/administração & dosagem , Poluentes Químicos da Água/química
14.
Mar Drugs ; 17(11)2019 Nov 13.
Artigo em Inglês | MEDLINE | ID: mdl-31766228

RESUMO

Microalgae produce a variety of compounds that are beneficial to human and animal health. Among these compounds are carotenoids, which are microalgal pigments with unique antioxidant and coloring properties. The objective of this review is to evaluate the potential of using microalgae as a commercial feedstock for carotenoid production. While microalgae can produce some of the highest concentrations of carotenoids (especially astaxanthin) in living organisms, there are challenges associated with the mass production of microalgae and downstream processing of carotenoids. This review discusses the synthesis of carotenoids within microalgae, their physiological role, large-scale cultivation of microalgae, up- and down-stream processing, commercial applications, natural versus synthetic carotenoids, and opportunities and challenges facing the carotenoid markets. We emphasize legal aspects and regulatory challenges associated with the commercial production of microalgae-based carotenoids for food/feed, nutraceutical and cosmetic industry in Europe, the USA, the People's Republic of China, and Japan. This review provides tools and a broad overview of the regulatory processes of carotenoid production from microalgae and other novel feedstocks.


Assuntos
Antioxidantes/farmacologia , Carotenoides/farmacologia , Microalgas/metabolismo , Animais , Antioxidantes/isolamento & purificação , Carotenoides/isolamento & purificação , Corantes/isolamento & purificação , Corantes/farmacologia , Humanos
15.
Int J Mol Sci ; 20(22)2019 Nov 09.
Artigo em Inglês | MEDLINE | ID: mdl-31717564

RESUMO

A new magnetic nanocomposite called MIL-100(Fe) @Fe3O4@AC was synthesized by the hydrothermal method as a stable adsorbent for the removal of Rhodamine B (RhB) dye from aqueous medium. In this work, in order to increase the carbon uptake capacity, magnetic carbon was first synthesized and then the Fe3O4 was used as the iron (III) supplier to synthesize MIL-100(Fe). The size of these nanocomposite is about 30-50 nm. Compared with activated charcoal (AC) and magnetic activated charcoal (Fe3O4@AC) nanoparticles, the surface area of MIL-100(Fe) @Fe3O4@AC were eminently increased while the magnetic property of this adsorbent was decreased. The surface area of AC, Fe3O4@AC, and MIL-100(Fe) @Fe3O4@AC was 121, 351, and 620 m2/g, respectively. The magnetic and thermal property, chemical structure, and morphology of the MIL-100(Fe) @Fe3O4@AC were considered by vibrating sample magnetometer (VSM), thermogravimetric analysis (TGA), zeta potential, X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), Brunner-Emmet-Teller (BET), and transmission electron microscopy (TEM) analyses. The relatively high adsorption capacity was obtained at about 769.23 mg/g compared to other adsorbents to eliminate RhB dye from the aqueous solution within 40 min. Studies of adsorption kinetics and isotherms showed that RhB adsorption conformed the Langmuir isotherm model and the pseudo second-order kinetic model. Thermodynamic amounts depicted that the RhB adsorption was spontaneous and exothermic process. In addition, the obtained nanocomposite exhibited good reusability after several cycles. All experimental results showed that MIL-100(Fe) @Fe3O4@AC could be a prospective sorbent for the treatment of dye wastewater.


Assuntos
Carvão Vegetal/química , Corantes/isolamento & purificação , Imãs/química , Nanocompostos/química , Rodaminas/isolamento & purificação , Poluentes Químicos da Água/isolamento & purificação , Adsorção , Óxido Ferroso-Férrico/química , Nanocompostos/ultraestrutura , Nanotecnologia , Propriedades de Superfície , Termodinâmica , Águas Residuárias/análise , Purificação da Água
16.
J Photochem Photobiol B ; 200: 111631, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31630045

RESUMO

In this work, over the course of four seasons (12 months), we have monitored the fluorescence quantum efficiency (η) from two sets (S1 and S2) of fresh natural dye extracts from the leaves of Tradescantia pallida purpurea. The natural dye was extracted in aqueous solutions from leaves collected from regions with a predominance of shade (S1) and sun (S2) during the day. The thermo-optical parameter fractional thermal load (φ) was measured using conical diffraction (CD) patterns caused by thermally driven self-phase modulation, for η determination in both sets of solutions. Fluorescence measurements corroborate the CD results, and the η values are, on average, slightly higher (~ 11%) in the summer than in the other seasons for both sets of samples (S1 and S2). In addition, the experimental results are presented using natural dye extracted from Tradescantia pallida purpurea as a fungicide probe in Fusarium solani, Sclerotinia sclerotiorum, and Colletotrichum gloeosporioides fungi. The promising fungicide results obtained for the aqueous natural dye extract were compared with those obtained for other natural dyes and fungi. The fungi tested are of the necrotrophic group and constitute important pathosystems in Brazil, causing diseases in several crops that synthetic fungicides often cannot control or do so with low efficiency.


Assuntos
Antifúngicos/química , Corantes/química , Extratos Vegetais/química , Tradescantia/química , Antifúngicos/isolamento & purificação , Antifúngicos/farmacologia , Corantes/isolamento & purificação , Corantes/farmacologia , Fungos/efeitos dos fármacos , Folhas de Planta/química , Folhas de Planta/metabolismo , Refratometria , Estações do Ano , Tradescantia/metabolismo
17.
Environ Sci Pollut Res Int ; 26(30): 31344-31353, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31471849

RESUMO

Simultaneous removal of coexisting metals and dyes from industrial wastewaters is challenging, and the mutual effects behind the co-adsorption of these pollutants remain unclear. Herein, interlayer-expanded MoS2 (IE-MoS2) nanosheets prepared by a one-pot simple and scalable method were tested to simultaneously remove toxic metals and cationic dyes. The adsorption capacities of IE-MoS2 nanosheets were 499, 423, 500, 355, and 276 mg/g for Pb(II), Cu(II), methylene blue, malachite green, and rhodamine B, respectively, in a mono-contaminant system. Interestingly, the sequestration amount of Pb(II) was dependent on the concentrations of dyes in the binary Pb(II)-dye systems, while uptake of cationic dyes was almost not influenced by coexisting Pb(II). The simultaneous adsorption mechanism was further confirmed by spectroscopic methods. The IE-MoS2 nanosheets were easily regenerated and reused for six adsorption-desorption cycles without structure destruction, thus avoiding the potential hazards of nanomaterial to the ecosphere. More interestingly, high-efficiency uptake of Pb(II) from intentionally contaminated natural water and model textile effluent was obtained by using a column filled with IE-MoS2 nanosheets. In summary, IE-MoS2 nanosheets with facile and scalable synthesis method, efficient adsorption performance, and excellent reusability showed potential promise for the integrative treatment of complex wastewater bearing both metals and organic pollutants.


Assuntos
Corantes/isolamento & purificação , Dissulfetos/química , Metais/isolamento & purificação , Molibdênio/química , Nanoestruturas/química , Eliminação de Resíduos Líquidos/métodos , Poluentes Químicos da Água/isolamento & purificação , Adsorção , Cátions , Azul de Metileno/química , Azul de Metileno/isolamento & purificação , Rodaminas/química , Rodaminas/isolamento & purificação , Corantes de Rosanilina/química , Corantes de Rosanilina/isolamento & purificação , Indústria Têxtil , Águas Residuárias/química
18.
Int J Biol Macromol ; 141: 1035-1043, 2019 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-31520702

RESUMO

In this work, natural polysaccharide product sodium alginate (SA) served as templates to prepare porous calcium silicate (CS) hydroxyapatite (HA) composite microspheres (CHCM) with high specific surface area by a new route combining ion exchange and calcination. CHCM played an important role in the fields of environmental protection with its large specific surface area, excellent adsorptive property, high mechanical strength and good regeneration performance. In order to explore its treatment capacity of wastewater, a series of eriochromeblue black R (EBBR) adsorption experiments were carried out. The equilibrium data fitted well with the Langmuir isotherm with a maximum adsorption capacity of 76.80 mg/g. Electrostatic interaction, ionic bonds and physical adsorption were responsible for the interactions between the EBBR and CHCM. Meanwhile, the CHCM maintained complete spherical and almost undamaged in the regeneration experiments, which confirmed its stability for cyclical usage. This paper demonstrates the role of natural polysaccharide product sodium alginate serving as templates to prepare useful products with potential wide applications.


Assuntos
Alginatos/química , Compostos de Cálcio/química , Corantes/química , Corantes/isolamento & purificação , Durapatita/química , Silicatos/química , Purificação da Água/métodos , Água/química , Adsorção , Cinética , Termodinâmica , Poluentes Químicos da Água/química , Poluentes Químicos da Água/isolamento & purificação
19.
Environ Sci Pollut Res Int ; 26(31): 31834-31845, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31489543

RESUMO

A novel multi-functional and environmental friendly tannic acid polymer (Fe3+-TA-HCHO) with Fe3+ and formaldehyde as double crosslinking agents together with cysteine as heteroatom source was prepared by a one-pot hydrothermal method. Characterization with transmission electron microscope (TEM), scanning electron microscopy (SEM), Fourier transform infrared spectrometer (FT-IR), and elemental analysis demonstrated that the Fe3+-TA-HCHO possessed uniform structure and particle size as well as plentiful functional groups. The resulted Fe3+-TA-HCHO material as a adsorbent to remove methylene blue, sunset yellow, Pb2+, Hg2+, and AsO33- from water. The results suggested that Fe3+-TA-HCHO polymer (pHpzc is 2.33) showed different adsorption properties for anionic pollutants (sunset yellow and AsO33-) and cationic pollutants (methylene blue, Pb2+, and Hg2+). The material exhibited remarkable selectivity for adsorption and separation of pollutants. The maximum adsorption capacities calculated from Langmuir model for methylene blue, Pb2+, and Hg2+ were 154.32, 819.67, and 699.30 mg g-1, respectively. This is the first time that tannic acid polymer is synthesized by double crosslinking method, which not only developed a promising adsorbent for selective removal of cation pollutants, but also opened up a new avenue for synthesis and application of tannic acid polymer.


Assuntos
Reagentes para Ligações Cruzadas/química , Formaldeído/química , Polímeros/síntese química , Taninos/química , Poluentes Químicos da Água/isolamento & purificação , Adsorção , Ânions , Compostos Azo/química , Compostos Azo/isolamento & purificação , Cátions , Corantes/química , Corantes/isolamento & purificação , Reagentes para Ligações Cruzadas/síntese química , Ferro/química , Chumbo/química , Chumbo/isolamento & purificação , Mercúrio/química , Mercúrio/isolamento & purificação , Azul de Metileno/química , Azul de Metileno/isolamento & purificação , Microscopia Eletrônica de Varredura , Espectroscopia de Infravermelho com Transformada de Fourier , Poluentes Químicos da Água/química
20.
Int J Biol Macromol ; 141: 626-635, 2019 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-31494166

RESUMO

Bio-resources have a very significant role in current research approach for the synthesis of benign functionalized biological macromolecules for their stable structural integrity and inherent nature-inspired potentialities. Here, chitosan is used as a core moiety for designing of a porous adsorbent after the attachment of salicylaldehyde to remove the toxic dyes. Salicylaldehyde linked chitosan, with excellent surface porosity, lightweight, non-glucose and low-cost feature, makes it as an efficient adsorbent. The dye loaded material is very easy to remove from the top of the water as it is suspended on water. The physico-chemical characterizations are done by FTIR, rheology, SEM and swelling study. The removal efficiency is 98% and 99% for Crystal Violet and Rose Bengal from water respectively. The thorough adsorption with mechanistic approach shows the Freundlich model as an appropriate one and follows closely pseudo-second-order kinetics model. Thermodynamic study reveals the endothermic nature of the process. Moreover, the reusability of Salicylaldehyde linked Chitosan shows its persistence with the same amount and concentration of dyes in water up to three consecutive cycles. So, the chitosan based macromolecules can be a sustainable candidate in the current scenario for the removal of dyes without the dislocation of the water container.


Assuntos
Aldeídos/química , Quitosana/química , Corantes/química , Corantes/isolamento & purificação , Adsorção , Concentração de Íons de Hidrogênio , Cinética , Temperatura
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