Adsorption Of Dye Molecules Research Articles

Stimuli-triggered reversible switching mechanism between H- and J-type supramolecular assemblies of cationic porphyrins adsorbed on tungsten(VI) oxide surface

Supramolecular organic dye–inorganic semiconductor nanocrystal assemblies are potentially useful in a broad range of technologies and applications, including photovoltaic systems, but the molecular basis of the adsorption of dye molecules onto the semiconductor surfaces remains poorly understood. Herein, we investigated the pH-dependent adsorption and conformational change of two cationic porphyrin stereoisomers [5,10-diphenyl-15,20-di([Formula: see text]-methyl-4-pyridyl)porphyrin (cis-DMPyP) and 5,15-diphenyl-10,20-di([Formula: see text]-methyl-4-pyridyl)porphyrin (trans-DMPyP)] on the tungsten(VI) oxide (WO[Formula: see text] colloid nanoparticle in aqueous media by means of UV-vis absorption spectroscopy. In accordance with the combination of a modified Langmuir adsorption model and Kasha’s exciton coupling model, the molecular orientation and stacking arrangement of DMPyP derivatives on the WO[Formula: see text] colloid surface are discussed in detail. In the trans-DMPyP/WO[Formula: see text] aqueous system, trans-DMPyP molecules adopted flat-on orientation with respect to the WO[Formula: see text] colloid surface and eventually formed head-to-tail [Formula: see text]-dimers regardless of pH conditions. cis-DMPyP molecules in the acidic system also lay flat-on and mainly formed [Formula: see text]-dimers on the WO[Formula: see text] colloid surface, whereas ones in the neutral system exhibited a dominant edge-on orientation and had a higher tendency to form face-to-face [Formula: see text]-dimers. Additionally, we have also convincingly demonstrated the pH-triggered switchable [Formula: see text]-stacking geometry of cis-DMPyP molecules from [Formula: see text]- to [Formula: see text]-dimer and vice versa on the WO[Formula: see text] colloid surface. Such findings will undoubtedly provide a pertinent guideline for the rational design of stimuli-responsive organic-inorganic materials.

Investigation of removal of crystal violet dye using novel hybrid technique involving hydrodynamic cavitation and hydrogel

In this work, intensification of removal of crystal violet (CV) dye in terms of total organic carbon (TOC) from aqueous media has been investigated by a novel hybrid treatment technique involving hydrodynamic cavitation (HC), and hydrogel adsorption. Hydrodynamic cavitation (HC) combined with poly-acrylamide (PAM) hydrogel nano-composite was studied for CV dye removal. TiO2 nano-particles embedded poly-acrylamide (PAM) nano-composite hydrogel was prepared by using the ultrasound polymerization technique. Characteristics of TiO2 nano-particles and hydrogel nano-composite were studied by using XRD and TEM analysis respectively. Degradation of CV dye was carried out by hydrodynamic cavitation and subsequent adsorption of dye molecules were carried out in hydrogel adsorption column. Effect of different operating parameters such as inlet pressure to the cavitation device (orifice), the effect of TiO2 loading in PAM hydrogel, effect of hydrogel loading in the adsorption column was studied. For hydrogel loading of 5 g/L and inlet pressure to orifice at 3 bar, the hybrid system intensifies the removal of dye in terms of operating time compared to its individual operation. Studies revealed that the PAM-TiO2 hydrogel obeys the pseudo-second order kinetic model for CV dye adsorption. Two adsorption isotherm models such as Langmuir and Freundlich were evaluated in order to identify the adsorption behavior.

Multifunctional Lanthanide-Based Metal-Organic Frameworks with a Polyheterotopic Ligand: Doped with Ytterbium(III) for Luminescence Enhancement and Selective Dye Adsorption.

The chemistry of metal-organic frameworks has been progressing fast with its exciting potential in multifunctional applications. A series of three-dimensional lanthanide-based metal-organic frameworks, {[Ln(HTPO)(NO3 )(H2 O)]⋅x(CH3 CN)⋅y(H2 O)}n (Ln=Eu (1), Tb (2), Gd (3), Sm (4), Dy (5), Nd (6)), {[Eu(TPO)(HCOO)0.5 ]⋅(H3 O)0.5 }n (7), {[Eu(TPO)(DMF)]⋅(solv)x }n (8; DMF= N,N-dimethylformamide), and {[Eu(TPO)(DMA)]⋅(solv)x }n (9; DMA=dimethylacetamide) were synthesized with semirigid C3 -symmetric ligand tris(4-carboxylphenyl)phosphine oxide (H3 TPO). In these frameworks, the H3 TPO ligand exists in a totally different configuration. Framework 1 exhibits good breathing properties for absorbing more guest molecules through a solvent-induced single-crystal-to-single-crystal (SC-SC) transformation involving a configuration transformation of the organic linker in the framework. The ytterbium ion was doped into 1 to improve the luminescent performance (lifetime and quantum yield) of the red europium emission. Among a series of Eu1-x Ybx TPO samples, Eu0.88 Yb0.12 TPO showed enhanced luminescence intensity (≈5.1 times that of the pure europium system), and the lifetime increased from 1073.08 to 1236.57 μs. Moreover, the porosity of these frameworks allows them to efficiently adsorb dye molecules with high selectivity and efficiency.

Metal-Organic Gels of Catechol-Based Ligands with Ni(II) Acetate for Dye Adsorption.

Metal organic gels (MOGs) are a class of supramolecular complexes, which have attracted widespread interest because of the coupled advantages of inorganic and organic building blocks. A new compound terminated with catechol was synthesized. This new compound can be used to coordinate with Ni2+ to form MOGs. These MOGs show favorable viscoelasticity and wormhole-shaped porous structures, which were confirmed by transmission electron microscope and scanning electronic microscope images. Taking the benefits of porosity into account, the xerogel could serve as an adsorbent to adsorb dye molecules from the aqueous media. The experimental results indicate that xerogels possess good adsorption effect both on anionic and cationic dyes. Exhaustive research has been performed on the adsorption kinetics and isotherms, revealing that the adsorption process accords with the pseudo-second-order model and the Langmuir model.

Green synthesis of the innovative super paramagnetic nanoparticles from the leaves extract of Fraxinus chinensis Roxb and their application for the decolourisation of toxic dyes

Abstract The leaves extract of Fraxinus chinensis Roxb was used for the synthesis of the innovative phytogenic magnetic nanoparticles (PMNPs) without adding toxic surfactants. The formation, morphology, elemental composition, size, thermal stability, structure and magnetic properties of these PMNPs were examined by UV-visible spectrophotometry, FT-IR, XRD, SEM, EDX, TEM, VSM, XPS, BET and TGA. The reactivity of the obtained PMNPs against decolourising toxic dyes, namely, malachite green (MG), crystal violet (CV) and methylene blue (MB), were investigated by UV-vis spectrophotometry. Further, the factors affecting the removal of dyes, including solution pH, adsorbent dosages, initial concentration of dyes, reaction temperature and contact time, were also investigated. The results revealed the decolourisation of 99.12% of MG and 98.23% of CV within 60 min, and 97.52% of MB within 200 min by the PMNPs using dyes concentration of 25 mg/l at pH 6.5 and 298.15 K. The kinetics outcome indicated that the degradation of dyes matched well to the pseudo first-order reaction kinetics model. Furthermore, the probable degradation mechanism of dyes by the PMNPs, including the adsorption of cationic dye molecules onto the negatively charged surface of adsorbent and the oxidation of the Fe° in the solution, were discussed. Thus, the PMNPs can be produced by the bulk and have great potential to be employed for biomedical/environmental remediation.

Strong Dependence of Surface Enhanced Raman Scattering on Structure of Graphene Oxide Film.

Graphene and its derivatives have been demonstrated to be good surface-enhanced Raman scattering (SERS) substrates. However, the literature offers some contrasting views on the SERS effect of graphene-based materials. Thus, understanding the mechanism of the SERS enhancement of graphene is essential for exploring its application as a SERS substrate. In this study, graphene oxide (GO) and chemically reduced graphene oxide (CRGO) films with different morphologies and structures were prepared and applied as SERS substrates to detect Raman dye molecules. The observed enhancement factors can be as large as 10~103. The mechanism of SERS enhancement is discussed. It is shown that the SERS effect was independent of the adsorption of dye molecules and the surface morphologies of graphene-based films. Raman shifts are observed and are almost the same on different graphene-based films, indicating the existence of charge transfer between dye molecules and substrates. The Raman enhancement factors and sensitivities of dye molecules on different films are consistently within the IG/ID ratios of graphene-based substrates, indicating that the dramatically enhanced Raman spectra on graphene-based films are strongly dependent on the average size of sp2 carbon domain.

Removal of water-soluble dyes by conjugated organic skeletons through drainflow-diffusion filtration

This study develops an alternative adsorbent constructed by conjugated organic skeletons, which further comprises polyene segments and polyaromatic hydrocarbons (PAHs) blocks. The adsorbent was prepared through the FeCl3-mediated dehydration of poly(vinyl alcohol) (PVA). The reaction produces pseudo-polyene (p-polyene) segments and subsequently PAHs through further condensation of some of the polyene segments. The resulting conjugated skeletons and iron oxide/chloride species experience mutual penetration to form aggregates. Thereafter, these aggregates were subjected to sulfonation to achieve the adsorbent with pendant oxygen-containing groups to assure a negatively charged surface as well as porous structures via removing iron species. The adsorbent possesses typically rectangular-channels among the aggregates and meso (<50 nm) and macro-voids (>50 nm) inside individual aggregates. The above structural features endow the adsorbent strong capability to remove cationic methylene blue (MB, 10 mg/L) or zwitterion methyl red (MR, 10 mg/L) dyes from water or even from isopropanol through adsorption and pore diffusion and deposition. The best adsorbent demonstrates the rejection rates over 95% and flux above 17 L/min m2 through the first 3 h at a minor pressure drop. Mechanistically, the separation outcome originates from the viscous drain flow to enhance adsorption of dye molecules on the channel wall, which is followed by diffusion of the dye molecules towards meso/macro-voids inside the rod-like aggregates.

Ultrahigh adsorption capacity of starch derived zinc based carbon foam for adsorption of toxic dyes and its preliminary investigation on oil-water separation

Abstract A novel starch derived zinc carbon foam-like (Zn-CFst) material was synthesized and applied for the adsorption of different dyes and oil-water separation. Zn-CFst was characterized by XRD, FTIR, BET, TGA, SEM, TEM and XPS analysis. The adsorbent exhibited an ultra-high adsorption capacity towards Crystal Violet (25000 mg/g), Malachite Green (1200 mg/g) & Congo Red (1428.57 mg/g) and high absorbing capacity towards Castrol 2T (2937%) and Gear oil (2375%). Evidently, Zn-CFst shows excellent results which fitted with Langmuir isotherm and follows the pseudo-second order kinetic model. BET analysis indicated the high mesoporous nature of the sample with an average pore diameter of 31 A. The instrumental analysis of XPS and FTIR have demonstrated the significant role played by Dipole-dipole H-bonding, Yoshida H-bonding, n-π interaction and π-π interaction for the adsorption of experimented cationic and anionic dye molecules. The experimental results indicate that Zn-CFst can be reused after many cycles without the reduction in their efficiency both in adsorption and oil-water separation.

Facile synthesis and characterization of Bi2MoO6/Ag3PO4/RGO composites with enhanced visible-light-driven photocatalytic activity

The visible-light-driven Bi2MoO6/Ag3PO4/RGO composites were fabricated by a facile in situ precipitation and hydrothermal method and characterized. The as-synthesized Bi2MoO6 appears a sheet-like structure, while the cubic Ag3PO4 nanocrystals attached on the surface of Bi2MoO6 with an average diameter of about 10 nm. Both Bi2MoO6 and Ag3PO4 distributed well on the graphene oxide (GO) sheets, which can potentially improve the separation efficiency of photogenerated electron-hole pairs. Additionally, the high-surface-area GO sheets enhanced adsorption of dye molecules, and the photodegradation efficiency of reactive blue 19 (RB-19) dye under visible-light irradiation was as high as 98% in 3 h for Bi2MoO6/Ag3PO4/RGO heterostructure composite. Therefore, the Bi2MoO6/Ag3PO4/RGO photocatalyst can be a favorable alternative for practical use in environmental photocatalysis.

Molecular modeling of cationic dyes adsorption on agricultural Algerian olive cake waste

In this research, the adsorption isotherms of Methylene Blue (MB) and Basic Yellow 28 (BY28) on agricultural Algerian olive cake waste (AAOCW) were modeled at molecular level using statistical physics and COSMO–RS theories. This molecular modeling aimed to demonstrate an alternative way to describe the interactions between dyes and adsorbents. The adsorption equilibrium isotherms of MB and BY28 on AAOCW were constructed at different temperatures. The statistical physics model was used to quantify the number of adsorbed dye molecules per site, the anchorage number, the receptor sites density, the adsorbed quantity at saturation, the concentration at half saturation and the molar adsorption energy. The COSMO–RS theory was used to quantify the interaction energies: Electrostatic, hydrogen bonding and Van der Waals. σ–Profile and σ–potential were calculated to show the ability of each of the two dyes to interact with every adsorbent site. It was demonstrated that statistical physics and COSMO–RS theories are confident ways to elucidate the interactions between dye molecules and adsorbent surface at a molecular level.

Dye Adsorption and Fluorescence Sensing Behaviour About Rare Earth-Indole Carboxylic Acid Complexes

Five rare earth-indole carboxylic acid complexes: [Eu(IAA)2(phen)2]·NO3 (1) (IAA = indole acetic acid, phen = o-phenanthroline); [Nd(IAA)2(phen)2]·NO3 (2); [Er(IBA)3(phen)](phen)·HNO3·H2O (3) (IBA = indole butyric acid); [Ce(IBA)3(phen)](phen)·HNO3·H2O (4); [Dy(IBA)3(phen)](phen)·HNO3·H2O (5) were synthesized and characterized. Then, we reported their properties as dye adsorption and fluorescence sensing for the first time. The fluorescence explorations demonstrated that complex 1 exhibits highly selective and sensitive sensing for nitro aromatic compounds with high sensitivity (1.49 × 107 M−1) and low detection limit (11.40 µM). Meanwhile, these complexes also exhibit stronger selective adsorption of dye molecules (MB and MG) in aqueous solution. This study provides new physical insights into the rational design of lanthanide complexes based on multifunctional materials. We firstly reported five lanthanide complexes and displayed fluorescence sensing and selective adsorption dye properties.

Magnetic, monodisperse titania microspheres with bimodal pore size distribution by a new sol–gel templating method and their photocatalytic activity

A new sol gel templating method was developed for the synthesis of magnetic monodisperse-porous titania microspheres 5.5 µm in size. A bimodal pore size distribution including both mesoporous and macroporous regions was first reported for magnetic titania microspheres. The product obtained by developed method and its AuNP decorated forms were evaluated as photocatalyst for textile-dye degradation in batch fashion. Different from the photocatalytic degradations performed by titania nanoparticles (i.e. P25 or similar types), a decolorization process including two serial stages was observed with the magnetic-porous titania microspheres. In the first stage, the low intraparticular diffusion resistance originated from macropores and the high surface area originated from mesopores provided fast dye adsorption onto the magnetic photocatalyst and a sudden decrease in the dye concentration (i.e. fast decolorization) that was not observed with titania nanoparticles. In the second stage, a slower decolorization occurred due to the slower photochemical degradation of adsorbed dye molecules on the magnetic photocatalyst. Complete removal of dye was achieved at acidic pH, using magnetic titania microspheres. A marked enhancement in the decolorization rate was obtained by the decoration of magnetic titania microspheres with AuNPs synthesized by Martin method.

Study of the effect of variation in temperature and pH on the adsorption process of natural Gardenia yellow dye into TiO2 mesoporous for dye sensitized solar cells using the statistical physics formalism: Physicochemical and thermodynamic investigation

In this paper, three adsorption isotherms of natural yellow Gardenia dye, at three different temperatures and at three pH values, were fitted by models established through statistical physics treatment. A double-layer model with two energies is able to give good fitting of these experimental data. Four physicochemical parameters are involved in the fitting of the experimental adsorption isotherms such as the number of adsorbed dye molecules per site n, the density of receptor sites Nm and the two energetic parameters C1 and C2. From the numerical simulation, the number of molecules per site showed that the adsorbate molecules have two anchorage positions parallel and nonparallel respectively when pH and temperature vary. The variation of the adsorbed quantity at saturation with temperature shows the exothermic nature of aggregation process of the natural Gardenia yellow dye. In the case of variation of pH, the acidic conditions are more favorable for the adsorption process. The numerical values of the calculated adsorption energies have revealed that the Gardenia yellow dye is physisorbed onto TiO2 mesoporous. A new method based on Kelvin equation in liquid phase has been developed to determine the pore size distribution (PSD) of TiO2 mesoporous in comparison with other experimental measurements. The result of PSD shows a significant effect of the variation with temperature and with pH values on the morphology of pore size structure. Finally, the calculated thermodynamic functions such as entropy, free enthalpy and internal energy exhibited that the system evolved spontaneously.

Effect of nanoporous In2O3 film fabricated on TiO2-In2O3 photoanode for photovoltaic performance via a sparking method

A simple and inexpensive sparking method was used to deposit body-centered cubic In2O3 film on TiO2 photoanode for 30–180 min for dye-sensitized solar cells (DSSCs). The effect of nanoporous In2O3 film on photovoltaic performance was investigated. The efficiency of TiO2-In2O3 photoanode with the sparking time for 120 min was the highest of 3.40 and 8.6% rise in conversion efficiency comparing to the TiO2 photoanode device, due to the increasing in short-circuit current density (Jsc) and electron lifetime (Teff). In this research, Jsc improvement was caused by increasing surface area for adsorbed dye molecules. TiO2-In2O3 photoanode exhibited low resistance of charge diffusion (Rct1) at the interface of the redox electrolyte/Pt counter electrode and/or electrical contact between In2O3 nanoparticles by providing an efficient pathway for photogenerated electrons in the DSSCs. Furthermore, the long-term stability of DSSCs showed that TiO2-In2O3 photoanode with 120 min sparking period exhibited the highest efficiency comparing with the pure TiO2 photoanode.

Sequencing coagulation–photodegradation treatment of Malachite Green dye and textile wastewater through ZnO micro/nanoflowers

ABSTRACTSequencing coagulation–photodegradation over ZnO micro/nanoflowers was assessed for Malachite Green (MG) dye removal and followed by the MG-containing textile wastewater treatment. The ZnO micro/nanoflowers were prepared using a facile reflux route and analyzed by various characterization techniques. The flower-like morphological structures of ZnO were witnessed through microscopy analyses. X-ray diffraction findings showed that the prepared ZnO samples were highly crystalline with hexagonal wurtzite structure. The operational parameters including type of coagulant, coagulant dosage, solution pH, photocatalyst dosage and light power exerted their individual influences on the removal of MG dye. The CaCO3 was the best coagulant among the three coagulants tested due to its high formation of precipitates and adsorption of cationic dye molecules. Using CaCO3 as a coagulant, 88.3% MG removal was obtained at coagulant dosage of 160 mg and solution pH of 9.0. Complete removal of MG was found with 0.5 g L−1 ZnO micro/nanoflowers and 105 W light power. The kinetic analysis showed that a Langmuir−Hinshelwood model was in good agreement with dye removal data. Moreover, a complete removal of MG dye and 80.0% of chemical oxygen demand removal over sequencing coagulation–photodegradation were observed for MG-containing textile wastewater treatment. The sequencing coagulation–photodegradation process using ZnO micro/nanoflowers indicated much promise to be an attractive method for textile effluent treatment applications.

A mesoporous metal-organic framework: Potential advances in selective dye adsorption

A new metal-organic framework based on manganous (II) ions and a paddle wheel ligand, H3[Mn3O3(BTB)] (Mn-BTB, HBTB = 1,3,5-tris(4-carboxyphenyl)benzene acid), was synthesized and structurally characterized. Mn-BTB was formed via self-assembly of one-dimensional (1D) helical chains interconnected through the carboxyl groups of the tripodal ligand HBTB to generate a 3D, extended network with a nanotube-like architecture and aperture size of 18.22 Å × 16.40 Å. The 2-fold self-interpenetration significantly enhanced the stability of the framework, although it minimized the empty space to some extent. Mn-BTB contains an accessible volume of 3143.6 Å3 with a 47.1% porosity, which allowed the adsorption of large dye molecules. Cationic dyes (methylene blue (MB) and rhodamine B (RhB)) and an anionic dye (methyl orange (MO)) were examined for selective dye adsorption on Mn-BTB. Mn-BTB with an anionic skeleton was beneficial for the selective adsorption of cationic dyes.

Multi‐walled carbon nanotubes supported amorphous Fe2O3 and Ag2O–Fe2O3 as Fenton catalysts for degradation of maxilon red dye

AbstractTwo Fenton‐like catalysts of iron oxide (Fe2O3) or Fe2O3 doped with silver oxide (Ag2O) and supported on acidified multi‐walled carbon nanotubes (a‐MWCNTs) were successfully prepared by wet impregnation and calcined at 200 °C and noted as Fe2O3/MWCNTs and Ag2O‐Fe2O3/MWCNTs, respectively. These samples were characterized using techniques such as TEM, FTIR, N2 adsorption at ‐196 °C, and XRD. Their catalytic performances were determined through Fenton oxidation process of maxilon red dye (MR) at 25 °C. Fenton degradation results disclosed that the Ag2O‐Fe2O3/MWCNTs nanocomposite has the superior and the faster catalytic degradation rate of dye. This result was due to the synergistic effect that established from the combination of tiny amount of Ag2O with Fe2O3 over a‐MWCNTs support, which prevents the agglomeration of catalyst nanoparticles and enhances the adsorption of dye molecules. A full degradation of dye was obtained within 10 min at 25 °C and the Fenton oxidation capability of Fe2O3/MWCNTs catalyst increased by about 10% after loading ~1wt.% of Ag2O. The catalytic performance was considerably based on pH of solution, H2O2 concentration, and dye concentration. The reusability tests confirmed that Ag2O‐Fe2O3/MWCNTs nanocomposite offers high stability over three consecutive cycles, where over 90% degradation of MR dye was obtained. Finally, Ag2O‐Fe2O3/MWCNTs nanocomposite showed excellent Fenton catalytic oxidation and reusability as compared with Fe2O3/MWCNTs composite in Fenton‐like processes.

AgBr/diatomite for the efficient visible-light-driven photocatalytic degradation of Rhodamine B

The treatment of organic pollution via photocatalysis has been investigated for a few decades. However, earth-abundant, cheap, stable, and efficient substrates are still to be developed. Here, we prepare an efficient visible-light-driven photocatalyst via the deposition of Ag nanoparticles (< 60 nm) on diatomite and the conversion of Ag to AgBr nanoparticles (< 600 nm). Experimental results show that 95% of Rhodamine B could be removed within 20 min, and the degradation rate constant (κ) is 0.11 min−1 under 100 mW/cm2 light intensity. For comparison, AgBr/SiO2 (κ = 0.04 min−1) and commercial AgBr nanoparticles (κ = 0.05 min−1) were measured as well. The experimental results reveal that diatomite acted more than a substrate benefiting the dispersion of AgBr nanoparticles, as well as a cooperator to help harvest visible light and adsorb dye molecules, leading to the efficient visible-light-driven photocatalytic performance of AgBr/diatomite. Considering the low cost ($10 per ton) and large-scale availability of diatomite, our study provides the possibility to prepare other types of diatomite-based efficient photocatalytic composites with low-cost but excellent photocatalytic performance.

Fly ash supported photocatalytic nanocomposite poly(3,4‐ethylenedioxythiophene)/TiO2 for azo dye removal under simulated solar irradiation

ABSTRACTThe main objective of this study was to develop a supported photocatalyst for wastewater treatment with extended efficiency under solar light. For that purpose titanium dioxide (TiO2) was immobilized by sol–gel synthesis on the surface of the waste fly ash (FA). On such prepared composite material, conductive polymer poly(3,4‐ethylenedioxythiophene) was grafted by in situ chemical oxidative polymerization with different oxidants, ammonium persulfate (APS), and iron(III) chloride, FeCl3. Characterization was performed by Fourier transform infrared spectroscopy, scanning electron microscopy, X‐ray diffraction, thermogravimetric analysis, and gas sorption analysis. Photocatalytic activity of composite photocatalyst was evaluated by testing removal efficiency of C.I. Reactive Red 45 (RR45) azo dye in three consecutive photocatalytic cycles under different pH. Discoloration of RR45 was measured using UV/Vis spectroscopy. It was determined that oxidant type plays major role in structure of composite as sample synthesized with APS had higher fraction of polymer and largest pore volume. The same composite had much better photocatalytic efficiency than sample synthesized with FeCl3 oxidant. It was also determined that there is a very strong adsorption of dye molecules on the surface of photocatalyst that quickly causes saturation of photocatalyst and efficiency drop after first cycle. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 46316.

Novel chitosan blended polymers for the removal of rose bengal dye: adsorption isotherms, kinetics and mechanism

Rose bengal (RB), a synthetic dye, discharges into the environment and is harmful to the land as well as to the aquatic water bodies; therefore it is important to safeguard the environment. For the adsorption of rose bengal dye, chitosan being a good biosorbent is blended with two different polymers namely polyvinyl alcohol (PVA) and polyacrylonitrile (PAN). The morphology and the functional groups attached herewith the biosorbents before and after adsorption were confirmed by scanning electron microscope (SEM) and Fourier transform infrared spectroscopy (FTIR) analyses. The adsorption isotherms for the two different biosorbent systems were studied in association with Langmuir, Temkin and Freundlich adsorption isotherms using MATLAB software. The monolayer adsorption capacities of RB dye onto chitosan/PVA and chitosan/PAN were found to be 44.39 and 42.4 mg/g respectively. The adsorbed dye molecules were desorbed from chitosan/PVA and chitosan/PAN using HCl solution; thereby regenerating the biosorbents for furthermore adsorption.