Anionic Dye Molecules Research Articles

Utilizing excited-state proton transfer fluorescence quenching mechanism, layered rare earth hydroxides enable ultra-sensitive detection of nitroaromatic

Convenient, rapid, and accurate detection of nitroaromatic organic toxins and harmful substances is of great significance in research. In the present study, two-dimensional layered rare-earth hydroxides (LYH) were used as ion-exchange matrix materials, and the anionic fluorescent dye molecules (HPTS) were successfully introduced into the LYH structures in situ via a simple and effective “plug-and-play” strategy, which gave the compounds ultra-sensitive fluorescence sensing detection of nitrobenzene, p-nitrotoluene and p-nitrophenol (Fluorescence response time < 1 sec, and the LOD for nitrobenzene, p-nitrophenol and p-nitrotoluene reached an impressive 349 ppb, 22 ppb and 98 ppb, respectively). Combined with theoretical calculations, we elucidated in detail the fluorescence quenching response mechanism of the LYH-HPTS towards nitroaromatic. Additionally, we also constructed fluorescent paper sensor, which effectively transformed the LYH-HPTS from theoretical detection to device application. The LYH-HPTS material is not only simple to synthesize, cost-effective and stable, but also has the features of fast response, excellent sensitivity and selectivity, and good reproducibility, which provides a new approach for the rapid and accurate detection of nitroaromatic.

Rational Synthesis of Monodisperse Hollow Mesoporous Silica Nanospheres for Selective Adsorption

AbstractMonodisperse hollow mesoporous silica nanospheres with large cavity (62 nm) in the inner core, small mesopores in the outer shell, and high specific surface area of 373 m2/g are successfully synthesized via one‐step dual‐template synthetic approach utilizing dodecyl sulfobetaine and sodium dodecyl benzenesulfonate as double templates. The architectures including particles sizes, outer shell thickness, and hollow structure could be effective regulated by simple adjusting the volume proportion of alcohols in the solution. Besides, the functions of alcohols in determining the critical micelle concentration and polarity of the synthesis system are elaborated. Owing to introduction of amino active sites in the outer shell, the prepared hollow mesoporous silica nanospheres deliver high loading capacity and favorable selectivity towards anionic dye molecules. The maximum uptake amount for methyl orange and eosin Y reaches as high as 359 mg/g and 332 mg/g, respectively.

Porous Salts Containing Cationic Al24 -Hydroxide-Acetate Clusters from Scalable, Green and Aqueous Synthesis Routes.

The solution chemistry of aluminum is highly complex and various polyoxocations are known. Here we report on the facile synthesis of a cationic Al24 cluster that forms porous salts of composition [Al24 (OH)56 (CH3 COO)12 ]X4 , denoted CAU-55-X, with X=Cl- , Br- , I- , HSO4 - . Three-dimensional electron diffraction was employed to determine the crystal structures. Various robust and mild synthesis routes for the chloride salt [Al24 (OH)56 (CH3 COO)12 ]Cl4 in water were established resulting in high yields (>95 %, 215 g per batch) within minutes. Specific surface areas and H2 O capacities with maximum values of up to 930 m2 g-1 and 430 mg g-1 are observed. The particle size of CAU-55-X can be tuned between 140 nm and 1250 nm, permitting its synthesis as stable dispersions or as highly crystalline powders. The positive surface charge of the particles, allow fast and effective adsorption of anionic dye molecules and adsorption of poly- and perfluoroalkyl substances (PFAS).

Comprehensive evaluation of zeolite/marine alga nanocomposite in the removal of waste dye from industrial wastewater

A systematic study integrating laboratory, analytical, and case study field trial was conducted to figure out the effective adsorbent that could be used for the removal of Congo red (CR) dye from industrial wastewater effluent. The ability of the zeolite (Z) to adsorb CR dye from aqueous solutions was evaluated after it was modified by the Cystoseira compressa algae (CC) (Egyptian marine algae). Zeolite, CC algae were combined together in order to form the new composite zeolite/algae composite (ZCC) using wet impregnation technique and then characterized by the aid of different techniques. A noticeable enhancement in the adsorption capacity of newly synthesized ZCC was observed if compared to Z and CC, particularly at low CR concentrations. The batch style experiment was selected to figure out the impact of various experimental conditions on the adsorption behavior of different adsorbents. Moreover, isotherms and kinetics were estimated. According to the experimental results, the newly synthesized ZCC composite might be applied optimistically as an adsorbent for eliminating anionic dye molecules from industrial wastewater at low dye concentration. The dye adsorption on Z and ZCC followed the Langmuir isotherm, while that of CC followed the Freundlich isotherm. The dye adsorption kinetics on ZCC, CC, and Z were agreed with Elovich, intra-particle, and pseudo-second-order kinetic models, correspondingly. Adsorption mechanisms were also assessed using Weber's intraparticle diffusion model. Finally, field tests showed that the newly synthesized sorbent has a 98.5% efficient in eliminating dyes from industrial wastewater, authorizing the foundation for a recent eco-friendly adsorbent that facilitate industrial wastewater reuse.

Bioremoval of fast green FCF dye from aqueous solution using cranberry kernel (Cornus mas L.) as a lignocellulosic biowaste: equilibrium, kinetics, and mechanism

ABSTRACT In this study, the biosorption properties of fast green FCF (FG) dye in an aqueous solution were investigated using cranberry (Cornus mas L.) kernel (CK) as lignocellulosic biowaste. The biosorbent performance of the cranberry (Cornus mas L.) kernel biomass for FG dye molecules was optimized: 500 mg L−1 at natural pH: 6.0 at 25°C. The maximum biosorption capacity for CK biomass was found to be 21.6 mg g−1 from the Langmuir isotherm model. Biosorption thermodynamics showed that FG dye biosorption to CK biomass was spontaneous, entropy-increasing, and endothermic. The kinetic data were described by the PSO and IPD kinetic models. Thermodynamic parameters were calculated, and it was seen that the biosorption process is spontaneous and endothermic. FT-IR spectrum after biosorption provided data supporting the formation of electrostatic interactions, n-π interactions, and H-bonds between anionic FG dye molecules and CK biomass. When the results of this study were evaluated as a whole, it was concluded that CK biosorbent is a natural, abundant, low-cost, effective, and potential biosorbent for the removal of FG dye molecules from wastewater.

Kinetic and isotherm studies of Acid Orange 7 dye absorption using sulphonated mandarin biochar treated with TETA

This study contributes to the current state of knowledge by highlighting the physical–chemical interactions between biochar and dyes. The removal of Acid Orange 7 (AO7) dye by a modified biochar obtained from the wastes of mandarin peels (MPs) has been investigated in this work. A dehydration procedure with 80% H2SO4 under reflux was applied to produce an innovative biochar from MPs and then boiled with H2O2 and followed by boiling with triethylenetetramine to make mandarin biochar-C-TETA (MBCT). FTIR, SEM, EDX, BJH, BET, TGA, and DTA analyses were applied to investigate the MBCT. FTIR analysis showed an additional peak that confirmed the addition of the NH2 group to the MBCT structure. An amorphous carbon structure was also confirmed by XRD analysis. The AO7 dye solution pH was proved to give the best absorption at pH 2.0. Significant removal of AO7 dye 99.07% using an initial concentration of 100 mg/L of AO7 dye and a 0.75 g/L MBCT. The Langmuir (LNR) and Freundlich (FRH) isotherm models investigated the experimental results. The LNR was best suited to handle the working MBCT data. The maximum adsorption capacity (Qm) calculated for the MBCT was 312.5 mg/g using 0.25 g/L of the MBCT. Kinetic studies were conducted using the intraparticle diffusion (IND), film diffusion (FD), pseudo-first-order (PFOR), and pseudo-second-order (PSOR) models. The absorption rate was calculated using the ultimate value of the linear regression coefficient (R2 > 0.99), and the PSOR rate model was found to ideally describe the absorption process. The point of zero charge (pHPZC) was found to be 10.17. The electrostatic attractive-forces between the sorbent surface positively charged sites and negatively charged anionic dye molecules were the primary mechanism of the MBCT sorption of the AO7 dye’s anion absorption. The results indicate that the manufactured MBCT adsorbent may be useful for removing the AO7 dye from wastewater. MBCT can be used repeatedly for up to six cycles without dropping its absorption efficiency.

Chitin nanofiber-coated biodegradable polymer microparticles via one-pot aqueous process

Tailoring the surface of biodegradable microparticles is important for various applications in the fields of cosmetics, biotechnology, and drug delivery. Chitin nanofibers (ChNFs) are one of the promising materials for surface tailoring owing to its functionality, such as biocompatibility and antibiotic properties. Here, we show biodegradable polymer microparticles densely coated with ChNFs. Cellulose acetate (CA) was used as the core material in this study, and ChNF coating was successfully carried out via a one-pot aqueous process. The average particle size of the ChNF-coated CA microparticles was approximately 6 μm, and the coating procedure had little effect on the size or shape of the original CA microparticles. The ChNF-coated CA microparticles comprised 0.2–0.4 wt% of the thin surface ChNF layers. Owing to the surface cationic ChNFs, the ζ-potential value of the ChNF-coated microparticles was +27.4 mV. The surface ChNF layer efficiently adsorbed anionic dye molecules, and repeatable adsorption/desorption behavior was exhibited owing to the coating stability of the surface ChNFs. The ChNF coating in this study was a facile aqueous process and was applicable to CA-based materials of various sizes and shapes. This versatility will open new possibilities for future biodegradable polymer materials that satisfy the increasing demand for sustainable development.

Aminated Covalent Organic Polymers for Anionic Dye Adsorption in Aqueous Systems

Aminated covalent organic polymer (ACOP) was synthesized through a catalyst-free Schiff base reaction involving terephthalaldehyde and melamine, and the prepared ACOP was used for the adsorption of anionic dyes. The prepared ACOP possessed a high specific surface area (582.07 m2/g) with an average pore size of 88.71 Å. Its point of zero charge was determined as pH 8.26. Anionic dye molecules, methyl orange (MO) and orange G (OG), were used to evaluate the dye adsorption efficiency of the prepared ACOP, and it was found that they were adsorbed rapidly on ACOP within 1 min. The maximum adsorption capacities (qm) of the prepared ACOP for MO and OG were 351.9 and 227.9 mg/g, respectively. Furthermore, the results of dye adsorption as a function of the initial pH and presence/absence of cationic dye (methylene blue; MB) revealed that dye adsorption on ACOP proceeded through charge–charge and π–π interactions. The presence of MB along with MO and OG enhanced the dye adsorption capacity because of the synergistic effect of the positively charged quaternized nitrogen atoms in the prepared ACOP. The dye adsorption mechanism was further investigated using Fourier transform infrared (FT-IR) analysis and X-ray photoelectron spectrometry (XPS). The ACOP adsorbent prepared herein using a facile catalyst-free reaction offers rapid adsorption with a high adsorption efficiency over a wide pH range and in the presence of cationic dye. For these reasons, it can be used for environmental remediation, especially in aqueous systems.

Fabrication of Textile-Based Flexible Supercapacitor with a Textile Dye on Polyaniline-Based Composite Electrode for Enhanced Energy Storage

Polyaniline (PANI) is a promising conductive polymer for use in energy storage applications. Here, a one-step hydrothermal method of PANI polymerization on carbon felt electrode was synthesized using an azo dye, a bisulfonated dichloro anionic dye molecule to enhance an efficient textile-based flexible supercapacitor electrode material for energy storage applications. The electrode material synthesized at concentration of 2 mM AY17 exhibits 814.1 F g-1 at the scan rate of 5 mV s-1 with multiwall carbon nanotubes (MWCNTs). Due to electrostatic interaction with the polymer, the presence of high electronegativity Cl atoms in the dye molecule significantly improves the PANI structure's electron donor/acceptor properties. A symmetric supercapacitor exhibits an energy density of 11.7 W h kg−1 at a power density of 300 W kg−1, and it is 4.5 W h kg−1 at 1800 W kg−1 in 3.0 M KCl aqueous electrolyte. The capacitance retention performance value of the symmetric supercapacitor exhibited 81.76% after 2500 cycles.

Salt-modified MXene membrane for ultrafast and efficient cationic and anionic dyes removal

MXene, the two-dimensional (2D) transition metal carbides/nitrides, have gained much attention in the application as membranes since the stacking of MXene nanosheets could realize hydrophilic, nanoscale interlayer spacing with remarkable separation performance. Herein, we reported the simple modification of MXene membranes using chloride salts (NaCl, KCl, and MgCl2), which could substantially improve the performance in the separation of cationic (methylene blue, MB) and anionic (congo red, CR) dyes from aqueous solutions. The salts could reside in the membrane surface and penetrate the interlayer galleries as well as the space within the adjacent MXene nanosheets. As a result, the membrane could possess modified nanochannels and altered surface chemistry that improve water transport and dye molecules' retention. In the case of MB filtration, MXene membrane modified with KCl (MM-KCl) exhibits the highest flux (141 L m−2 h−1) and a complete rejection, attributed to the weaker interaction between the water molecules and potassium ion. On the other hand, MM-MgCl2 demonstrates the best performance (flux of 117 L m−2 h−1 and a ∼100 % rejection) in the CR filtration. This could be related to the stronger interaction of anionic dye molecules with the magnesium cation that has the highest positive charge density. All MXene membranes have high flux-recovery ratios and low reversible and irreversible fouling, showing desirable anti-fouling properties.

Negatively Charged Clay Particles Influence Spectroscopic Properties of Anionic Organic Dyes in Aqueous Colloids

Abstract Aqueous colloids of smectite-type clays have been employed as heterogeneous media for photofunctional dyes, where negatively charged clay particles adsorb cationic and polar dye molecules through electrostatic immobilization. However, we herein demonstrate impacts of negatively charged hectorite clay particles on the spectroscopic behavior of anionic dyes. Anionic Eosin B dissolved in aqueous clay colloids exhibits spectroscopic behavior reflecting the coexisting clay particles. The absorption and fluorescence maxima are red-shifted and the fluorescence is intensified with increasing clay concentration. Removal of the clay particles by ultracentrifugation recovers the spectra of aqueous solution, indicating attractive interactions between the anionic dye molecules and negatively charged clay particles. Moreover, the spectroscopic impacts of the clay particles vary on both the dye species and clay mineral species; spectroscopic properties of Rose Bengal are not greatly affected by the clay particles, and synthetic saponite more influences the absorption and emission spectra of the dyes.

Engineered biochar supported layered double hydroxide-cellulose nanocrystals composite-: Synthesis, characterization and azo dye removal performance

In this work, engineered biochar decorated layered double hydroxides and cellulose nanocrystals (B–CuFe–CNC) biocomposites were synthesized by the facile ultrasonicated-co-precipitation technique. The biocomposite was investigated for purification of Eriochrome Black T (EBT) dye from water. The characterization results showed that the presence of CNC in biochar-layered double hydroxides resulted in a two-dimensional rod-like structure with excellent crystallinity, improved surface functionalities, and provides an attractive platform for the enhanced adsorption of azo anionic dye molecules. The adsorption system was appropriately demonstrated by the BBD-RSM (R2 > 0.994). The biocomposite exhibited higher EBT adsorption in the acidic pH range (2–5) due to strong electrostatic and chemical interactions. The kinetic and isotherm results were well demonstrated by pseudo-second order, Freundlich, and Redlich Peterson models. The maximum adsorption capacity of biocomposite was 876.2 mg/g achieved within 45 min. The spectroscopic analyses imply that the high removal of EBT by biocomposite is mainly governed by electrostatic attraction, hydrogen bonding, and chemical/metal complexation mechanisms. The biocomposite maintained high EBT removal after six successive adsorption cycles and excellent dye adsorption in the different water matrices. The results suggest that tailoring biochar properties with layered double hydroxide and CNC is a promising way for the enhanced removal of dye contaminants from wastewater.

Graphene Oxide-Chitosan Network on a Dialysis Cellulose Membrane for Efficient Removal of Organic Dyes.

Currently, water pollution is a significant health problem for both humans and animals due to large amounts of dye-containing wastewater. Thus, polymer composite membranes (PCMs) are considered as efficient adsorption/filtration membranes that can be utilized for removing organic dyes from contaminated water/wastewater. In this study, the goal is to explore the modification of the interfacial dialysis cellulose (DC) surface through molecular interactions of an active graphene oxide-chitosan (GO-CTS) composite hydrogel (GCCH) network without the use of an external cross-linker toward an effective dye removal ability using a simple casting process and a low-cost adsorption technique, resulting in the formation of a PCM, i.e., GO/CTS/DC membrane (GCD-mems). Concomitantly, the incorporation of the GCCH network (as an active hybrid network) and DC (as a supporting material) is considered as a promising approach toward a dye-removing PCM. As a result, the GCD-mems showed that cellulose robustly interacted via the chemical bonds of the GCCH network by maintaining the three-dimensional (3D) porous layer structures, and the functional surface of the membrane was enhanced toward specific groups for an effective dye removal approach. In addition, there is a significant improvement in dye removal performance after modification of the interfacial DC surface through molecular interactions of GCCH, i.e., high adsorption capacities of cationic and anionic dye molecules on the GCD-mems, compared to the relevant GO-based adsorbents. Also, the dye flux and rejection of the GCD-mems can simultaneously remove both methylene blue and Congo red. In the adsorption, it is appropriate with the pseudo-second-order and Langmuir models corresponding to chemical adsorption and monolayer approaches, as well as physical sieving through the 3D layers of porous channels of GCD-mems during the filtration process. Moreover, the structural stability and sustainability of the PCMs are enhanced during the recycling process, and the use of ethanol in the recycling process further simplifies the process and reduces the cost of the PCMs. Thus, the GCD-mems are encouraged as potential candidates that can be applied directly in the removal of dyes from the wastewater of textile industries or selective dialysis applications.

Synergistic sorption performance of karaya gum crosslink poly(acrylamide-co-acrylonitrile) @ metal nanoparticle for organic pollutants

In this work, we tailor facile hydrogels nanocomposite (HNC) based on sustainable karaya gum for water treatment. Karaya gum crosslink poly(acrylamide-co-acrylonitrile) @ silver nanoparticle (KG-cl-P(AAm-co-AN)@AgNPs) HNC were made by an aqueous free radical in situ crosslink copolymerization of acrylamide (AAm) and acrylic acid (AA) in aqueous solution of KG-stabilized AgNPs. FTIR, XRD, DTA–TGA, SEM, and TEM were used to characterize HNC. The hydrogels' swelling, diffusion, and network characteristics were investigated. The removal efficiency of HNC was found to be 99% at pH 8 for a crystal violet (CV), dose of 0.02 g after 1 h. Dye adsorption by these hydrogels was also investigated in terms of isotherms, and kinetics. The dye's exceptionally high adsorption capacity on HNC for CV removal is explained by H-bonding interactions, as well as dipole-dipole and electrostatic interactions between anionic adsorbent and cationic dye molecules (Qmax, 1000 mg/g). The HNC can be regenerated with 0.1 M HCl and reused at least 10 times maintaining over 68% dye removal. The loading of AgNPs into the polymeric matrix of KG-cl-P(AAm-co-AN) significantly increases the removal percentage of CV dye from its aqueous solution, according to this study.

Adsorption behaviors of modified clays prepared with structurally different surfactants for anionic dyes removal

In this study, the properties and adsorption behaviors of organoclays synthesized with two structurally different surfactants having the same carbon chain length (hexadecyltrimethylammonium bromide (HDTMAB) and benzyldimethylhexadecylammonium chloride (BDHAC)) were evaluated. The structural properties of the synthesized organoclays were examined using Fourier-transform infrared spectroscopy, zeta potential analysis, X-ray diffraction, and N2 adsorption-desorption test. The modified clays with increased surfactant loadings (from 0.5 CEC to 3 CEC) were prepared to find the optimal surfactant loading. As a result, 1.5 cation exchange capacity (CEC) was found to be the optimal surfactant loading. The organoclay prepared using HDTMAB (H-Bt) exhibited the maximum adsorption capacity of 114.3 mg/g for anionic Orange G dye, which was 1.74 times higher than that of the organoclay prepared using BDHAC (B-Bt). Furthermore, in the presence of a mixture of cationic and anionic dye molecules in water, H-Bt tended to remove more of the cationic target compound than B-Bt (i.e., methylene blue (MB)), suggesting that H-Bt can serve as a more efficient adsorbent for the uptake of environmental contaminants in practical scenarios. Moreover, this study examined the effects of surfactant molecules on the structural properties of organoclays and their adsorption behaviors in the uptake of dye molecules.

Mesoporous MnO2 polymorphs as sorbent materials for removal of cationic dyes from water

ABSTRACT Scientists have become interested in treating dye-contaminated water due to the health issues and ecological imbalances caused by the presence of these injurious compounds in water. Herein, two MnO2 polymorphs i.e. ε- and γ-MnO2 were prepared by the comproportionation reaction between KMnO4 and MnCl2. In comparison to γ-MnO2, ε-MnO2 has greater surface area, pore width, and pore volume. According to the thermal study, ε-MnO2 contains more surplus mass in the form of negatively charged surface hydroxyl groups than γ- phase. The adsorption capability of both polymorphs was examined for the removal of both cationic (methylene blue, malachite green and crystal violet) and anionic dyes (eosin yellow). The efficient adsorption for the cationic dyes using ε-MnO2 was occurred in the neutral medium, where it had a highly negative surface as determined by zeta potential measurements. It only took few minutes to complete the removal. The electrostatic interactions of the cationic dye molecules with the OH- groups account for this result. While, complete dye removal (40 min) was occurred in the acidic medium using γ-MnO2. On the other hand, in the neutral medium the adsorption of the anionic dye molecules on the surface of both MnO2 phases was hampered by the repulsion forces. As a result, despite extending the contact time to 180 min and the adsorbent dose to 50 mg, no anionic dye removal was seen. On the contrary, in the acidic medium very fast removal occurs for Eosin Y as the surface of both MnO2 phases acquired a positive charge. The influence of the ionic strength on MB elimination was investigated. The results showed that as the content of NaCl was increased, the removal effectiveness decreased from 100% to 35%. The kinetics of cationic dye adsorption on the ε-MnO2 surface was studied, and it was discovered that the mechanism follows a pseudo-second order model.

Application of titanium dioxide immobilized on a cellulosic material for the photocatalytic degradation of Acid Black 24 dye in a continuous flow cascade reactor.

The aim of this work is the study of the photocatalytic degradation of Acid Black 24 dye (AB24), in a continuous flow cascade reactor, using titanium dioxide (TiO2) immobilized on a cellulosic material. The results obtained demonstrated a synergistic effect of the two phenomena adsorption and photocatalysis. The effects of various parameters that affect the dye removal efficiency were investigated. The best photocatalytic degradation yield of AB24 molecules is obtained in acidic medium because of the strong attraction between the positively charged catalyst and the anionic dye molecules. The optimum times for obtaining the best yields depend on the initial concentration of the dye, the volume of the treated solution, and the feed rate of the reactor. In addition, reusing the catalytic material several times is technically possible; this can decrease the cost of treatment for a possible industrial scale application.

Photocatalytic efficiency of graphene/nickel oxide nanocomposites towards the degradation of anionic and cationic dye molecules under visible light

Simplified synthesis of nickel oxide nanorods (NiO NRs) and graphene/NiO nanocomposites (Grn/NiO NCs) was achieved using a chemical reduction approach of Grn and nickel chloride precursors. The crystalline nature of the prepared NiO NRs and Grn/NiO NCs was investigated using X-ray diffraction analysis, and the surface morphology was examined using transmission electron microscope. We examined the phtocatalytic efficiency of Grn/NiO NCs against anionic and cationic dye molecules. The Grn/NiO NCs showed 100% photocatalytic activity for methylene blue (MB) and methyl orange (MO) dye molecules within 90 and 120 min, respectively. The presence of Grn sheets has enhance the photocatalytic activity of NCs under visible light irradiation by reducing the recombination of excited electrons in the conduction band (CB) with holes in the valence band (VB) when Grn/NiO NCs reacted with dyes. We have developed efficient visible light functionalized Grn/NiO NCs photocatalysts for practical environmental applications using simple and cost-effective approach for large-scale manufacturing.

Bendable poly(vinylidene fluoride)/polydopamine/β-cyclodextrin composite electrospun membranes for highly efficient and bidirectional adsorption of cation and anion dyes from aqueous media

Electrospun fibrous membranes have potential application prospects in various adsorbents. However, challenges remain in the development of flexible adsorbents with multiple adsorption ability and improved efficiency. In this study, we design and fabricate a new class of composite electrospun membranes poly(vinylidene fluoride)/polydopamine/β-cyclodextrin (PVDF/PDA/β-CD) by triggering the self-polymerization of dopamine onto the surface of PVDF electrospun fibers to form PDA coating, and subsequently binding β-CD molecules on the fibers surface via hydrogen bonding as the result of hydroxyl groups on β-CD and abundant catechol groups of PDA. The PVDF/PDA/β-CD fibers exhibit core-shell structure where PVDF as the supporting core component and PDA/β-CD layer as the shell with many functional groups to be capable of adsorbing cationic and anionic dye molecules. Accordingly, the composite membranes possess highly efficient adsorption performance toward methylene blue (MB) and phenolphthalein (PHP). Furthermore, the adsorption behaviors for the two dyes fit well with the pseudo second-order kinetic model. And the electrostatic attraction and π-π stacking mostly promote the adsorption of MB whereas the host-guest inclusion complexation and hydrogen bonding are more likely to favor the PHP adsorption. Most importantly, all composite membranes can be bendable, and display excellent mechanical performances, which endow these membranes easy to operate in practical applications, such as filtration, separation and purification purposes. Our developed method provides a new avenue for electrospun membrane to simultaneously achieve robust mechanical properties and multiple contaminants efficient removal.

Effect of surfactant micelle on the fluorescence efficiency of a water soluble anionic xanthene dye in complex Langmuir-Blodgett (LB) film

Present communication reports the micellar effect on the increased fluorescence efficiency of a fluorescent dye in the complex LB film. In the complex Langmuir monolayer and Langmuir-Blodgett films, anionic Xanthene dye molecules organized differently when the films were prepared below and above the critical micellar concentration (CMC) of Cetyltrimethylammonium Bromide (CTAB) in the mixed solution of the Langmuir Trough. In-situ Brewster Angle Microscopic (BAM) studies showed the visual images of the Langmuir monolayers during the formation of the films. UV–Vis absorption and Fluorescence Spectroscopic studies were employed to study the spectral characteristics of the complex films.