Adsorption Capacity For Crystal Violet Research Articles

Facile synthesis, growth process, characterisation of a nanourchin-structured α-MnO2 and their application on ultrasonic-assisted adsorptive removal of cationic dyes: A half-life and half-capacity concentration approach

Textile dyes pose a serious threat in terms of water pollution due to its complex aromatic structures and poor degradability. In order to reduce the toxic effects of Crystal Violet (CV) and Methylene Blue (MB), an ultrasonic-assisted dye adsorption using urchin like α-MnO2 nanostructures was studied. The adsorbent was synthesised by hydrothermal method at low-temperature. The crystallinity and morphology were determined to investigate the growth mechanism of α-MnO2 nanourchins which consists of two main stages. The initial stage includes the formation of α-MnO2 microspheres followed by the epitaxial growth of nanoneedles on to the surface of them. The α-MnO2 was characterised by BET, XRD, FT-IR, XPS, SEM, TEM and TGA. At 5.6, the point of zero charge of α-MnO2 nanostructures was determined. The total pore volume and average pore radius were confirmed to be 4.751 × 10−2 cc/g and 10.99 Å respectively from the BET analysis. Batch adsorption experiments were performed to investigate the effect of pH, adsorbent dosage, sonication time, initial dye concentration, temperature, ultrasonic frequency and power. The adsorption mechanism was studied using several isotherm and kinetic models. The adsorption data of CV and MB at equilibrium was observed to adopt the Langmuir isotherm model and pseudo-second order kinetic model. The maximum adsorption capacities for CV and MB were found to be 5882.3 and 5000 mg/g respectively. The thermodynamic study predicted that the process was exothermic for CV and endothermic for MB. The effects of competitive ions, ionic strength and humic acid on the uptake of both the dyes were also investigated. And finally, the reusability of recovered α-MnO2 after dye adsorption was studied up to five cycles for its potential industrial applications.

High-efficient biosorption of dye wastewater onto aerobic granular sludge and photocatalytic regeneration of biosorbent by acid TiO2 hydrosol.

In present study, aerobic granular sludge (AGS) was applied as a high-efficient biosorbent for dye wastewater treatment. The feasibility of acid TiO2 hydrosol as self-clean eluent for the regeneration of dye-loaded AGS and subsequently photo-catalytic degrade desorbed dyes was investigated. Acid TiO2 hydrosol was successfully synthesized and characterized by X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR). Batch sorption experiments suggested that methyl orange (MO) and crystal violet (CV) sorption onto AGS were both fitted well with Langmuir model, and the maximum adsorbed capacities of AGS for MO and CV were 741.6 and 323.6mg/g, respectively. Biosorbent regeneration experiment indicated that adsorbed dyes were successfully desorbed from dye-loaded AGS and subsequently degraded by a self-cleaning acid TiO2 hydrosol (pH at 2.0). It was found that the photodegradation times for MO and CV were 240 and 300min, respectively. Moreover, the AGS retained more than 50 and 70% of its original MO and CV adsorption capacity after the fourth cycle. The result implied that the integration of biosorption with self-cleaning desorption and photocatalytic degradation process could be applied as a feasible technique for dye wastewater practical treatment.

Preparation of microscale zero-valent iron-fly ash-bentonite composite and evaluation of its adsorption performance of crystal violet and methylene blue dyes.

New microscale zero-valent iron adsorbent on fly ash and bentonite matrix for removal of crystal violet (CV) and methylene blue (MB) was synthesized through direct reduction of iron oxide using coke and palm kernel shell. The adsorbent was prepared as cylindrical shaped pellets to remove the CV and MB from the aqueous solution. Nitrogen adsorption-desorption isotherm and scanning electron microscopy (SEM) studies showed that the adsorbent is highly porous, and the iron particles are finely dispersed on the supporting material surfaces. FTIR and UV studies indicated that the C=C bonds in CV and C=N+(CH3)2 bonds in MB were affected in the adsorption process. MB switched to the reduced MBH2 species while CV was reduced to two small-size molecular compounds, explaining the higher CV adsorption in comparison to that of MB. The reduction of these compounds was coupled to the oxidation of Fe0 to Fe2O3 as revealed by XRD characterization of the adsorbent after adsorption. CV and MB adsorption isotherms fitted well with the Langmuir adsorption model. Different adsorption and reduction kinetic models were examined for the MB and CV removal processes. A better fit of the experimental data with the pseudo-second-order model was observed. CV and MB adsorption increased with temperature in the 30-50°C range. At 50°C, adsorption capacities of CV and MB reached to 89.9 and 42.8mg/g, respectively. This new adsorbent showed a superior adsorption capacity for CV and MB when compared to other adsorbents.

Adsorption of Crystal Violet Dye from Aqueous Solution by Poly(Acrylamide-co-Maleic Acid)/Montmorillonite Nanocomposite

Poly(acrylamide-co-maleic acid)/montmorillonite nanocomposites, were synthesized via in situ polymerization with different maleic acid and MMT content. The capability of the hydrogel for adsorption of crystal violet (CV) was investigated in aqueous solutions at different pH values and temperatures. The pseudo-second-order kinetics model could fit successfully the adsorption kinetic data. The effects of maleic acid to acrylamide molar ratio (MAR), weight percent of MMT (MMT%), the pH of medium and the solution temperature (T) on the CV adsorption capacity (q e ) of adsorbents were studied by Taguchi experimental design approach. The results indicated that increasing the MMT% leads to a greater q e . The q e value of adsorbents increased also with increasing both MAR and pH, while reduced when the temperature of medium increased. The relatively optimum conditions to achieve a maximum CV adsorption capacity for P(AAm/MA)/MMT adsorbents were found as: 0.06 for MAR and 5 % of MMT%, medium pH = 7 and T = 20 °C.

Synthesis of acrylic-lignosulfonate resin for crystal violet removal from aqueous solution

A new acrylic-lignosulfonate resin (ALR) was obtained by radical polymerization using calcium lignosulfonate (LS-Ca) and acrylic acid (AA) as raw materials. ALR was characterized using FT-IR, SEM, TG-DSC and N2 adsorption–desorption surface area and pore size analyzer. Batch adsorption, including initial concentration, time, pH, dosage and temperature on the adsorption of crystal violet (CV) by ALR, was systematically studied. The ALR contained porous structure and the specific surface area of ALR was 190.55 m2/g with average pore diameter 11.34 nm. The kinetic and equilibrium data fitted into the pseudo-second-order model and Freundlich isotherm model, respectively. The adsorption process was slightly influenced in the range of pH=3–12. The maximum adsorption capacity of CV was found to be as high as 150.40±4.80mg/g for 24 h at 25 °C. Thermodynamic parameters were evaluated, and their values indicated that adsorption of CV on ALR was an exothermic process and spontaneous.

Assessment of adsorption kinetics for removal potential of Crystal Violet dye from aqueous solutions using Moroccan pyrophyllite

This study involves the adsorption of Crystal Violet (CV) dye adsorbed from solution on the pyrophyllite’s surface. The batch technique was used under a variety of conditions to produce quantitative adsorption, namely amount of adsorbent, dye concentration, contact time, pH solution and temperature. The maximum adsorption capacity of Crystal Violet on pyrophyllite was 9.58mg/g for 10mg/L of CV concentration, pH=6.8 at a temperature 20°C and 1g/L of adsorbent. This study of adsorption kinetics was carried out within framework of three models: intraparticle diffusion, pseudo-first order and pseudo-second order. The experimental isotherm data were analyzed using Langmuir and Freundlich models. Different thermodynamic parameters have shown spontaneous reaction with endothermic nature (The estimated value for ΔG was −7.64kJ/mol at 293K). Various techniques for characterizing the adsorbent were applied including X-ray diffraction (XRD), X-ray fluorescence spectroscopy (XRF), scanning electron microscopy (SEM) and transmission electron microscopy (TEM) coupled by energy dispersive X-ray spectroscopy (EDX). In addition, the regenerated adsorbents technique was reused several times; this demonstrated an economical aspect of using pyrophyllite which underlines the re-use importance considering the material capacity to regenerate.

Particle size effect of raw material on the pore structure of carbon support and its adsorption capability

ABSTRACTIn this study, a series of activated carbons were prepared from Tuncbilek lignite with different particle size by chemical activation. The effect of particle size of lignite on the pore structure of activated carbon and the adsorption kinetics of crystal violet (CV) onto these activated carbons was investigated. BET surface area values of activated carbon samples were determined in the range of 940–1054 m2 g−1. Adsorption capacity of CV onto activated carbons was investigated in a batch system by considering the effects of various parameters such as initial dye concentration, agitation time and adsorption temperature. The Langmuir and Freundlich isotherms were used to describe the adsorption equilibrium studies. The adsorption kinetics of CV has been discussed using the pseudo-first-order, pseudo-second-order and intraparticle diffusion models. Results show that the pseudo-second-order kinetic equation could describe the adsorption kinetics for CV onto activated carbons. Using the thermodynamic equilibrium coefficient obtained at different temperatures and for the initial dye, the thermodynamic constants of adsorption (ΔG°, ΔH° and ΔS°) were also evaluated.

Ultrasonically assisted hydrothermal synthesis of activated carbon–HKUST-1-MOF hybrid for efficient simultaneous ultrasound-assisted removal of ternary organic dyes and antibacterial investigation: Taguchi optimization

Activated carbon (AC) composite with HKUST-1 metal organic framework (AC–HKUST-1 MOF) was prepared by ultrasonically assisted hydrothermal method and characterized by FTIR, SEM and XRD analysis and laterally was applied for the simultaneous ultrasound-assisted removal of crystal violet (CV), disulfine blue (DSB) and quinoline yellow (QY) dyes in their ternary solution. In addition, this material, was screened in vitro for their antibacterial actively against Methicillin-resistant Staphylococcus aureus (MRSA) and Pseudomonas aeruginosa (PAO1) bacteria. In dyes removal process, the effects of important variables such as initial concentration of dyes, adsorbent mass, pH and sonication time on adsorption process optimized by Taguchi approach. Optimum values of 4, 0.02g, 4min, 10mgL−1 were obtained for pH, AC–HKUST-1 MOF mass, sonication time and the concentration of each dye, respectively. At the optimized condition, the removal percentages of CV, DSB and QY were found to be 99.76%, 91.10%, and 90.75%, respectively, with desirability of 0.989. Kinetics of adsorption processes follow pseudo-second-order model. The Langmuir model as best method with high applicability for representation of experimental data, while maximum mono layer adsorption capacity for CV, DSB and QY on AC–HKUST-1 estimated to be 133.33, 129.87 and 65.37mgg−1 which significantly were higher than HKUST-1 as sole material with Qm to equate 59.45, 57.14 and 38.80mgg−1, respectively.

Effect of magnetic laponite RD on swelling and dye adsorption behaviors of κ-carrageenan-based nanocomposite hydrogels

We synthesized novel magnetic nanocomposite hydrogels of κ-carrageenan by incorporating magnetic laponite RD. The magnetite nanoparticles were embedded in laponite RD through in situ method. The structure of nanocomposites were characterized using X-ray diffraction, scanning electron microscopy, transmission electron microscopy, and vibrating sample magnetometer techniques. The swelling of hydrogel nanocomposites was studied and decrease in water absorbency was found by introducing magnetic laponite RD. The results indicated that the water absorbency was independent on pH of swelling media. The magnetic nanocomposites were examined as adsorbents for the removal of crystal violet (CV) from aqueous solutions. The removal of CV was investigated through batch method on the subject of contact time, initial pH of dye solution, ion strength, and initial concentration of CV. The effect of pH revealed that the adsorption process was independent of pH. Compared to the neat κ-carrageenan hydrogel (78 mg/g), the nanocomposites showed high adsorption capacity for CV due to the introduced magnetic laponite RD (164 mg/g). The adsorption isotherm data were modeled by Langmuir, Freundlich, and Dubinin–Radushkevich isotherm models. The correlation of adsorption isotherm data by mentioned models was affected by the content of magnetic laponite RD. Based on Dubinin–Radushkevich isotherm models, the adsorption process was associated with physical adsorption mechanism. Investigation of thermodynamic parameters revealed that the adsorption of CV on nanocomposites was occurred spontaneously.

Poly (Acrylamide-co-Acrylic Acid) Hydrogel Induced by Glow-Discharge Electrolysis Plasma and Its Adsorption Properties for Cationic Dyes

In this paper, poly (acrylamide-co-acrylic acid) (P(AM-co-AA)) hydrogel was prepared in an aqueous solution by using glow-discharge electrolysis plasma (GDEP) induced copolymerization of acrylamide (AM) and acrylic acid (AA), in which N,N'-methylenebisacrylamide (MBA) was used as a crosslinker. A mechanism for the synthesis of P(AM-co-AA) hydrogel was proposed. To optimize the synthesis condition, the following parameters were examined in detail: the discharge voltage, discharge time, the content of the crosslinker, and the mass ratio of AM to AA. The results showed that the optimum pH range for cationic dyes removal was found to be 5.0–10.0. The P(AM-co-AA) hydrogel exhibits a very high adsorption potential and the experimental adsorption capacities for Crystal violet (CV) and Methylene blue (MB) were 2974.3 mg/g and 2303.6 mg/g, respectively. The adsorption process follows a pseudo-second-order kinetic model. In addition, the adsorption mechanism of P(AM-co-AA) hydrogel for cationic dyes was also discussed.

Adsorption of crystal violet on montmorillonite (or iron modified montmorillonite) followed by degradation through Fenton or photo-Fenton type reactions

In this work we demonstrate the feasibility to couple adsorption with Fenton and photo-Fenton process to separate and mineralize crystal violet (CV) dissolved in water. Montmorillonite (MMT) and iron modified montmorillonite (MMT-Fe) were studied as adsorbents and heterogeneous catalysts for Fenton and photo-Fenton like oxidation of cationic dye CV. The clays were characterized by XRD, SEM, EDX, BET surface area and electrophoretic mobility. MMT-Fe presents iron in the interlayer space and oxohydroxide particles on its surface. Both clays present a high CV adsorption capacity that can be modeled by a two-site Langmuir equation. MMT-Fe oxidizes faster and have a higher mineralization rate of adsorbed CV than MMT with Fe(II) or Fe(III) added externally. The oxidation of the adsorbed dye release organics to the solution which are further mineralized in solution. The Fenton oxidation can be modeled by a double exponential decay and photo-Fenton oxidation by a pseudo-first order kinetic model. Photo-Fenton oxidation leads to higher mineralization rates than Fenton.

Triphenylene-modified chitosan: novel high efficient sorbent for cationic and anionic dyes

The first example of triphenylene-modified chitosan 4 was prepared by reacting chitosan with triphenylene aldehyde derivative 3. Its structure and morphology was characterized by elemental analysis, 1H NMR, FTIR, XRD, SEM and AFM image. The triphenylene units in Tp-chitosan 4 appended on the skeleton of chitosan and possessed orderly layered structure. Adsorption experiments of Tp-chitosan 4 indicated that it possessed excellent adsorption capacities for both cationic and anionic dyes [Orange G sodium salt, Brilliant ponceau 5R, Victoria blue B (VB), Crystal violet (CV), Neutral red (NR) and Methylene blue]. The highest adsorption capacities for CV, VB and NR were 5.612, 5.353 and 5.375 mmol/g, respectively. Adsorption kinetics and isotherms analysis showed that the adsorption processes obeyed pseudo second-order model and the Langmuir isotherm equation. The adsorption processes were exothermic and spontaneous. The best pH values for adsorption were pH = 6–8.

Adsorption behavior of crystal violet onto opal and reuse feasibility of opal-dye sludge for binding heavy metals from aqueous solutions

The potential of opal for removing crystal violet (CV) dye and reuse feasibility of opal-CV sludge for binding heavy metals from aqueous solutions were investigated. The adsorbent was characterized by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), X-Ray Diffraction (XRD) and the point of zero charge (pHpzc) analysis. The thermal treatment of opal at temperatures of 300, 400, 500, 700°C increased the pHpzc value from 6.6 to 7.4 and lead to a decrease in the adsorption of CV dye, demonstrating the significance of the functional groups spread over the surface of opal. The equilibrium adsorption data fitted well to the Freundlich model and the kinetic data conformed to the pseudo-second-order model. Intra-particle diffusion was not the sole rate-controlling factor. The maximum adsorption capacity of CV was found to be 101.13mgg−1 at 30°C. The activation energy (Ea) of 13.85kJmol−1 indicated that the adsorption of CV onto opal was a physisorption. Thermodynamic parameters (ΔGΘ, ΔHΘ, and ΔSΘ) were evaluated and revealed that the adsorption process was spontaneous and endothermic in nature. Moreover, the opal-CV sludge was reutilized after calcination at 250°C (O-CV-250) for the removal of heavy metals from aqueous solution. The O-CV-250 had a maximum adsorption capacity of Pb(II) of 20.92mg·g−1 while has almost no adsorption of Ni(II) and Cr(VI). Enrichment of Pb(II) was conducted and almost 65% of the Pb(II) was collected. This work presents an effective approach for the treatment of dye wastewater and reutilization of dye sludge to enrich heavy metals.

Removal of some cationic dyes from aqueous solutions using magnetic-modified multi-walled carbon nanotubes

An adsorbent, magnetic-modified multi-walled carbon nanotubes, was used for removal of cationic dyes crystal violet (CV), thionine (Th), janus green B (JG), and methylene blue (MB) from water samples. Prepared nanoparticles were characterized by SEM, TEM, BET and XRD measurements. The prepared magnetic adsorbent can be well dispersed in the water and easily separated magnetically from the medium after loaded with adsorbate. The influences of parameters including initial pH, dosage of adsorbent and contact time have been investigated in order to find the optimum adsorption conditions. The optimum pH for removing of all the investigated cationic dyes from water solutions was found to be 7.0. The experimental data were analyzed by the Langmuir adsorption model. The maximum predicted adsorption capacities for CV, JG, Th and MB dyes were obtained as 227.7, 250.0, 36.4 and 48.1 mg g −1, respectively. Desorption process of the adsorbed cationic dyes was also investigated using acetonitrile as the solvent. It was notable that both the adsorption and desorption of dyes were quite fast probably due to the absence of internal diffusion resistance.

Starch-derived carbon aerogels with high-performance for sorption of cationic dyes

Environmentally green carbon aerogels have been prepared as adsorbents for dye-containing wastewater. The aerogels were prepared by carbonization of starch aerogels synthesized from soluble starch through a sol–gel process followed by drying at ambient pressure. The Brunauer-Emmett-Teller (BET) surface areas and pore size distribution were measured by N2 adsorption/desorption, and the surface zeta-potential and microstructure of carbon aerogels were characterized using a scanning electron microscope (SEM) and zeta-potential analyzer. SEM images indicate that the carbon aerogels consist of flakes with side length of 60–120 μm and thickness of 3–4 μm. The flakes are irregular in shape and composed of spherical carbon nanoparticles of 10–30 nm. The carbon aerogels have both microporous and mesoporous structures and exhibit high specific surface areas, the highest value is 1571 m2/g. The mean diameter of the micropores is 0.89 nm and that of the mesopores is 2–10 nm. At pH = 10, the carbon aerogels have a zeta-potential of −40 mV and exhibit high adsorption capacities for cationic dyes, such as crystal violet (CV), methyl violet (MV) and methylene blue (MB), from aqueous solution. The largest adsorption capacities for CV, MV and MB are 1515, 1423 and 1181 mg/g, respectively.

Removal of Crystal Violet Dye from Aqueous Solution Using Calcined and Uncalcined Mixed Clay Adsorbents

In this work, calcined and uncalcined mixed clays containing kaolin, ball clay, feldspar, pyrophyllite, and quartz are examined as a potential adsorbent for the removal of crystal violet dye from aqueous solution. These clays are characterized by nitrogen adsorption/desorption isotherms, X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy, and thermo gravimetric analysis (TGA). The kinetics and thermodynamic parameters as well as the effects of the pH, the temperature, and the adsorbent dosage have also been investigated. The experimental results indicate that the Langmuir model expresses the adsorption isotherm better than the Freundlich model. The obtained result showed a tremendous increase in the crystal violet adsorption capacity (1.9 × 10−3 mol g−1) after calcination, which is one order greater than that of the uncalcined mixed clay. The mechanism of the adsorption process is elucidated on the basis of experimental data. The percentage removal of crystal violet dye increases with increasing the pH, the temperature, and the adsorbent dosage. The investigation of kinetic studies indicates that the adsorption of crystal violet on calcined and uncalcined mixed clays could be described by the pseudo-second-order model. The negative Δ G 0 values obtained from the thermodynamic investigation confirm that the adsorption is spontaneous in nature. The adsorption results suggest that the calcined and uncalcined mixed clays can also be used as low cost alternatives to the expensive activated carbon for the removal of dyes from aqueous solution.

Removal of basic dyes from aqueous solution by low-cost adsorbent: Wood apple shell ( Feronia acidissima)

The adsorption of two basic dyes, methylene blue (MB) and crystal violet (CV) on wood apple shell (WAS) were investigated using a batch adsorption technique. A series of experiments were undertaken in an agitated batch adsorber to assess the effect of the system variables such as solution pH, dye concentration and temperature. Removal of dyes was observed to be most effective at higher pH. Freundlich and Langmuir isotherm models were applied to the equilibrium data. The results showed that Langmuir equation fits better than the Freundlich equation. It was observed that the WAS adsorbent showed higher adsorption capacity for crystal violet (130 mg/g) than methylene blue (95.2 mg/g). The FTIR studies indicate that the interaction of dye and WAS surface is via the nitrogen atoms of the adsorbate and oxygen groups of the adsorbent. The adsorption of dyes onto WAS proceeds according to a pseudo-second-order model. Thermodynamic parameters such as free energy (Δ G°), enthalpy (Δ H°) and entropy (Δ S°) were also calculated. The studies show that WAS, a lignocellulosic inexpensive material, can be an alternative to other expensive adsorbents used for dye removal in wastewater treatment.

Geopolymeric adsorbents from fly ash for dye removal from aqueous solution

Adsorbents from coal fly ash treated by a solid-state fusion method using NaOH were prepared. It was found that amorphous aluminosilicate geopolymers would be formed. These fly ash-derived inorganic polymers were assessed as potential adsorbents for removal of some basic dyes, methylene blue and crystal violet, from aqueous solution. It was found that the adsorption capacity of the synthesised adsorbents depends on the preparation conditions such as NaOH:fly-ash ratio and fusion temperature with the optimal conditions being at 1.2:1 weight ratio of Na:fly-ash at 250–350 °C. The synthesised materials exhibit much higher adsorption capacity than fly ash itself and natural zeolite. The adsorption isotherm can be fitted by Langmuir and Freundlich models while the two-site Langmuir model producing the best results. It was also found that the fly ash derived geopolymeric adsorbents show higher adsorption capacity for crystal violet than methylene blue and the adsorption temperature influences the adsorption capacity. Kinetic studies show that the adsorption process follows the pseudo second-order kinetics.