Effect Of Initial Dye Concentration Research Articles

Utilization of dye-loaded activated carbon as a potential alternative fuel source: a feasibility study through calorific and thermo-gravimetric analysis.

The disodium salt of Rose Bengal [4, 5, 6, 7-tetrachloro-2', 4', 5', 7'-tetraiodofluorescein] commonly finds application in medical procedures and its removal from aqueous solution is difficult owing to its high molecular weight of 1017.67g/mol. Activated carbon was prepared from Prosopis juliflora and immobilized into sodium alginate beads and doped with aniline for enhanced adsorption of Rose Bengal. The effect of initial dye concentration, beads' dosage, contact time, and the temperature over the adsorption of Rose Bengal dye were studied. The optimum conditions derived for maximum dye uptake capacity were 4mg/L of initial dye concentration, contact time of 60min with the adsorbent dosage of 0.2g, and temperature of 303K at neutral pH. The equilibrium data were found to be best fitted for Langmuir -1 model, whereas the kinetics were interpreted through Ho-Mckay's pseudo-second-order equation. The adsorbents were subjected to thermo-gravimetric studies to determine the activation energy under a heating rate of 20°C/min. The activation energy was computed using Broido's plot and was found to be 35.21 ± 0.84kJ/mol for the activated carbon, and 16.77 ± 2.19kJ/mol for the dye-adsorbed beads. The heat capacity was determined through differential scanning calorimetry and was calculated to be 19.41J/g°C for activated carbon and 39.43J/g°C for beads post-adsorption of Rose Bengal dye.

Poly(trimesoyl chloride-melamine) grafted on palygorskite for simultaneous ultra-trace removal of methylene blue and toxic metals

Poly(trimesoyl chloride-melamine) was grafted on palygorskite via in situ interfacial polymerization. The poly(trimesoyl chloride-melamine)-grafted palygorskite (PTMP) composite was characterized by Fourier transform infrared spectroscopy (FTIR), Energy Dispersive X-Ray Spectroscopy (EDX), N2-physisorption, and scanning electron microscope (SEM). The performance of PTMP as an adsorbent was evaluated for the removal of methylene blue dye (MB) in batch and column systems. The effects of initial dye concentration, contact time, temperature and initial pH on the efficiency of MB removal were investigated. A high adsorption efficiency (≈100%) was shown by PTMP removal within 8 min with high Langmuir monolayer capacity of 64.5 mg/g at 25 °C. The mechanisms of adsorption were evaluated by isotherm and kinetic models. The activation energy Ea and different thermodynamic parameters, for example, ΔGo, ΔSo, and ΔHo were calculated. The prepared composite demonstrated to be an efficient adsorbent for simultaneous removal of dye and toxic metals such as As(III), Cr(III), Mo(II), Co(III), Ni(II), and Hg(II). The dye removal was evaluated by a packed bed column system and showed an excellent adsorption performance with 90 min breakthrough at 160 ppm of initial dye concentration.

Sonochemical synthesis, characterization and sorption study of Kaolin-Chitosan-TiO2 ternary nanocomposite: Advantage over conventional method

The present study deals with the successful preparation of kaolin/chitosan/titanium dioxide (KL-CTS-TiO2) ternary hybrid nanocomposite adsorbent using conventional and ultrasound assisted method synthesis. The particle size (observed form TEM image) of TiO2 nanoparticles dispersed in the nanocomposite was found to be around 5 nm for U-KL-CTS-TiO2 nanocomposite (ultrasonically prepared), which is lesser compared to conventionally prepared nanocomposite. The average particle size of U-KL-CTS-TiO2 nanocomposite was observed to be 293 nm which is very less compared to C-KL-CTS-TiO2 nanocomposite (prepared by conventional method) that is 439 nm. The BET surface area of U-KL-CTS-TiO2 nanocomposite was found to be 116.5 m2/g which is significantly higher than the C-KL-CTS-TiO2 nanocomposite (4.95 m2/g). In batch adsorption experiments the effect of initial dye concentration, time, temperature, and adsorbent dose was studied and equilibrium data, adsorption kinetics and adsorption isotherms parameters are reported. The adsorption equilibrium data was best fitted by Freundlich isotherm compared to the Langmuir and Temkin model for U-KL-CTS-TiO2 and C-KL-CTS-TiO2 nanocomposite. The % removal of CV dye for 2 g/L loading of U-KL-CTS-TiO2 and C-KL-CTS-TiO2 nanocomposite was found to be 93.30% and 85.49%, respectively. The higher adsorption in the case of U-KL-CTS-TiO2 nanocomposite is attributed to the physical effects of ultrasound which are responsible for the preparation of finely dispersed KL-CTS-TiO2 nanocomposite compared to conventional method. Finely dispersed KL-CTS-TiO2 nanocomposite provides more sites for the adsorption which in turn enhances the adsorption capacity of CV dye on ultrasonically prepared KL-CTS-TiO2 nanocomposite.

Kinetics, Thermodynamics and Isotherm studies on Adsorption of Eriochrome Black-T from aqueous solution using Rutile TiO2

In this study, rutile phase of TiO2 particles have been synthesized by co-precipitation method and is used as an adsorbent for removal of toxic azo dye Eriochrome black-T (EBT) from aqueous solution. The rutile phase of TiO2 was confirmed by the X-ray powder diffraction pattern. Effect of initial dye concentration, adsorbent dose, pH, agitation speed and temperature on the adsorption process of EBT was examined. Removal of EBT was increased by increasing in adsorbent dose and decrease in initial dye concentration and pH. The optimum conditions resulted were: 25 ppm initial dye concentration, 20 mg adsorbent dose and pH of 2. Using Langmuir, Freundlich and Temkin isotherm models, equilibrium data was determined. The Freundlich model showed the best fit for uptake of the EBT dye, which evident that the process of adsorption of EBT dye onto TiO2 particles was heterogeneous. The kinetic data were analyzed using pseudo-first order, pseudo-second order and intraparticle diffusion equation. The pseudo-second order showed the best fit for the kinetic studies (R2 = 0.999), which ascertains that the adsorption process was of chemisorptions type. The intraparticle diffusion model indicated a linear relationship (R2= 0.99) suggesting the pore diffusion to be a limiting step in the overall adsorption process.

A novel sol–gel synthesis and characterization of MgFe2O4@γ–Al2O3 magnetic nanoparticles using tragacanth gel and its application as a magnetically separable photocatalyst for degradation of organic dyes under visible light

In the current study, for the first time, MgFe2O4@γ–Al2O3 magnetic nanoparticles (MNPs) were synthesized using tragacanth gel as biotemplate through the simple and cost effective novel sol–gel method. The sample was characterized by powder X-ray diffraction (XRD), vibrating sample magnetometer (VSM), Fourier transform infrared spectroscopy (FTIR), field emission scanning electron microscopy (FESEM), elemental mapping and energy dispersive X-ray analysis (EDX). The nanocomposite shows ferromagnetic behavior at room temperature, with a saturation magnetization of 10.15 emu/g and a coercivity of 50 Oe. XRD results show that MgFe2O4@γ–Al2O3 nanoparticles correspond to the tetragonal phase of γ-Al2O3 and cubic spinel structure of MgFe2O4. The present photocatalyst displays notable catalytic activity for the removal of reactive red 195 and reactive orange 122 dyes in water under visible light irradiation. It was established that the catalyst could remove ca. 98% of the reactive red 195 dye and ca. 93% of the reactive orange 122 dye. The effects of initial dye concentration, photocatalyst dosage, and visible light irradiation on dye degradation were assessed. The magnetic photocatalyst can be simply separated by using an external magnet and nearly no decline in photocatalytic efficiency was observed even after recycling five times.

Adsorption of methylene blue from aqueous solutions by cellulose and nanofiber cellulose and its electrochemical regeneration

This study was conducted to evaluate the potential of the bleached bagasse, cellulose, and nanofiber cellulose to remove methylene blue (MB) from aqueous solution. The morphology of adsorbents surface and their functional groups were examined by using scanning electron microscope and Fourier transform infrared spectroscopy techniques, respectively. In a batch mode study at 25°C temperature, the effects of initial dye concentration, contact time, adsorbent dose, and solution pH on adsorption performance were investigated. The results showed that the percent of MB removal increases by increasing pH and also by increasing sorbent dosage and decreasing initial dye concentration. The adsorption kinetics and equilibrium data were in good agreement with the pseudo-second-order kinetic model and Freundlich adsorption isotherm, respectively. The removal of MB was better and more effective with cellulose and cellulose nanofiber as compared with the bleached bagasse. The regeneration of cellulose and nanofiber cellulose loaded with MB was investigated using electrochemical method under different operating conditions. The results showed that the electrochemical process efficiency is more than 60 for regeneration adsorbents. © 2018 Desalination Publications. All rights reserved.

Kinetics, thermodynamics and isotherm studies of malachite green adsorption by modified orange peel

Kinetics, thermodynamics and isotherm studies of malachite green (MG) adsorption by orange peel (OP) modified with ethanol, calcium chloride and sodium hydroxide were performed. Effects of initial dye concentration, temperature and pH on the adsorption were studied at the different contact times. The amounts of MG adsorbed onto OP increased with increasing contact time, initial dye concentration, solution temperature, and pH. Maximum dye adsorption was about 92.90% under all the experimental conditions. Percent desorption of MG from the surface of OP was lower in the alkali and HCl solutions and higher in an acetone-water mixture of 50%. Adsorption kinetics was best fit the pseudo-second order model with correlation coefficients of 0.99 and 1 for the concentrations studied. Thermodynamic results indicated a spontaneous adsorption. Adsorption isotherm obeyed the Langmuir model. The Langmuir adsorption capacity was determined as 14.55 mg g-1. FT-IR and SEM analyses were also recorded before and after the adsorption.

Equilibrium and Kinetics Studies of Gentian Violet Dye Adsorption on to Activated Carbon Prepared From Aldhnan Hull

The present study investigated the key parameters and mechanism affecting the removal of Gentian Violet(GV) dye from aqueous medium, using Activated Carbon(AC) produced from hull of Aldhnan. The AC characterized by FTIR spectra to indicate the surface Characteristic groups of adsorbent affect the adsorption. The pH at point of zero charge showed the anionic nature of adsorbent surface and by using batch mode, the study considering the typical condition for adsorption of GV dye by the AC such as; effect of initial dye concentration, pH and contact time. The adsorption kinetics and equilibrium constants was achieved at 305K and the Langmuir isotherm model fit for the equilibrium data better than Freundlich model. Kinetics of adsorption was studied by testing the data in the pseudo first order (Lagergren Equation) and pseudo second order model and the adsorption of GV dye onto AC obeyed pseudo second order model. Thermodynamic studies exhibit that the adsorption reaction is endothermic in nature and spontaneous.

Methylene Blue Adsorption on a Low Cost Adsorbent-Carbonized Peanut Shell.

Carbonized peanut shell (CPS), a low cost adsorbent was investigated for adsorption of methylene blue from its aqueous solution. Some experimental parameters like the effect of initial dye concentration, initial solution pH, phases contact time and temperature were investigated. Langmuir, Freundlich and Harkins-Jura isotherm models were applied to the experimental data and Langmuir model fitted best. Monolayer adsorption capacity was 5.34 mg/g according to the Langmuir model. Adsorption capacity/uptake of CPS was found comparable to the some other adsorbent materials. The kinetic and intra particle diffusion models were applied to the experimental data. The experimental reaction was progressed via pseudo second order kinetic model. The thermodynamic parameters were also evaluated.

Fixed-bed column performances of azure-II and auramine-O adsorption by Pinus eldarica stalks activated carbon and its composite with zno nanoparticles: Optimization by response surface methodology based on central composite design

A continuous adsorption was used for removal of azure II (AZ II) and auramine O (AO) from aqueous solutions using Pinus eldarica stalks activated carbon (PES-AC) from aqueous solutions. The effects of initial dye concentration, flow rate, bed height and contact time on removal percentage of AO and AZ II were evaluated and optimized by central composite design (CCD) at optimum pH = 7.0. ZnO nanoparticles loaded on activated carbon were also used to remove AO and AZ II at pH = 7.0 and other optimum conditions. The breakthrough curves were obtained at different flow rates, initial dye concentrations and bed heights and the experimental data were fitted by Thomas, Adams–Bohart and Yoon–Nelson models. The main parameters of fixed-bed column including its adsorption capacity at breakthrough point (qb), adsorption capacity at saturation point (qs), mass transfer zone (MTZ), total removal percentage (R%), and empty bed contact time (EBCT) were calculated. The removal percentages calculated for AZ II and AO II were in the range of 51.6–61.1% and 40.6–61.6%, respectively. Bed adsorption capacity (N0) and critical bed depth (Z0) were obtained by BDST model.

Equilibrium, kinetics and thermodynamic adsorption studies of acid dyes on adsorbent developed from kenaf core fiber

Quaternized kenaf core fiber (QKCF) was used as an adsorbent for adsorption of anionic Acid Blue-25 (AB) and anionic Acid Green-25 (AG) dyes. Chemical treatment with (3-chloro-2-hydroxypropyl) trimethylammonium chloride under basic condition was applied in order to alter the surface properties of the raw kenaf core fiber. Adsorption studies were carried out to delineate the effect of initial dye concentration, temperature and pH on removal of dyes. The results show that the percentage removal of Acid Blue-25 and Acid Green-25 dyes were increased by increasing the concentrations of dyes. In addition, the maximum percentage removal was 99.8% and 99.65% for Acid Blue-25 and Acid Green-25, respectively. Langmuir, Freundlich and Temkin isotherm models were applied to analyze the data for dye adsorption at 15℃, 25℃, 35℃, and 45℃. The experimental data were best represented by the Langmuir model with maximum adsorption capacity of 303.03 mg/g and 344.83 mg/g for Acid Blue-25 and Acid Green-25 dyes, respectively, at 15℃, and the kinetic data for both dyes were best represented by the pseudo-second-order kinetic model. Thermodynamic studies indicated that the reactions of Acid Blue-25 and Acid Green-25 dyes were endothermic. It was concluded that QKCF adsorbent can be utilized as an efficient low-cost adsorbent for removal of anionic dyes.

Fabrication of the novel hydrogel based on waste corn stalk for removal of methylene blue dye from aqueous solution

The novel hydrogel based on waste corn stalk was synthetized by aqueous solution polymerization technique with functional monomers in the presence of organic montmorillonite (OMMT) under ultrasonic. In this study, batch adsorption experiments were carried out to research the effect of initial dye concentration, the dosage of hydrogel, stirring speed, contact time and temperature on the adsorption of methylene blue (MB) dye. The adsorption process was best described by the pseudo-second-order kinetic model, which confirmed that it should be a chemical process. Furthermore, we ascertained the rate controlling step by establishing the intraparticle diffusion model and the liquid film diffusion model. The adsorption and synthesis mechanisms were vividly depicted in our work as well. Structural and morphological characterizations by virtue of FTIR, FESEM, and Biomicroscope supported the relationship between the adsorption performance and material’s microstructure. This research is a valuable contribution for the environmental protection, which not only converts waste corn stalks into functional materials, but improves the removal of organic dye from sewage water.

A prototype of novel agro-waste based column bed device for removal of textile dye Optilan Red.

The aim of the study was to assess the potentiality of an agro-waste (sugarcane bagasse) for removal of the textile dye (Optilan Red) using novel column based filtration unit with a packed column of chemically treated sugarcane bagasse. The treated and untreated sugarcane bagasse (biosorbent) were characterized by Fourier transform infrared (FT-IR) spectroscopy. Effect of initial dye concentration on percentage removal of dye, equilibrium adsorption of sugarcane bagasse, kinetic studies, breakthrough point equilibrium and desorption of dye from the column material were studied. An inverse dependence of initial dye concentration on percent removal of dye was observed, whereas the equilibrium adsorption (qe) showed a direct relationship with dye concentration. The time required for reaching breakthrough point was 120 min. Desorption of dye through alkali wash resulted in complete desorption after 1 h washing of the column for its reuse for next cycle. FT-IR analysis shows vibration in valence bands of the hydrogen bond of OH group, and the bands of intra-molecular and intermolecular hydrogen bonds, which results in interaction of treated bagasse with Optilan Red textile dye. The present study showed that more than 93% removal of the dye can be achieved in the concentration range 10-50 ppm (aqueous solution). The removal efficiency of the column remained almost unchanged for the treatment of dye-house wastewater spiked with the dye. The agro-waste based treatment process shows a considerable potential for a low-cost treatment of dye contaminated water.

Efficient removal of coomassie brilliant blue R-250 dye using starch/poly(alginic acid-cl-acrylamide) nanohydrogel

In this study, we have synthesized a starch/poly(alginic acid-cl-acrylamide) nanohydrogel (ST/PL(AA-cl-AAm) NHG) by co-polymerization method which was used as an effective adsorbent for the removal of coomassie brilliant (CB) blue R-250 dye from the aqueous solution. The synthesized nanohydrogel was characterized by FTIR, SEM and TEM techniques. The effect of initial dye concentration, temperature, and agitation time on the adsorption ability of the nanohydrogel was studied comprehensively. The experimental outcomes exhibited that the prepared nanohydrogel had high adsorption tendency to remove the CB from the aqueous solution. The regression coefficient values for Langmuir (0.99), Frendluich (0.93) and Tempkin (0.98) recommended that adsorption process fit to langmuir isotherm. The pseudo-second-order equation showed the better adsorption kinetics of the adsorption process. The feasibility of CB adsorption onto ST/PL(AA-cl-AAm) NHG was also studied thermodynamically and the results indicated that the adsorption was spontaneous and chemical in nature.

CO2-activated porous carbon derived from cattail biomass for removal of malachite green dye and application as supercapacitors

In this study, we developed a feasible and cost-effective method for obtaining porous carbon from cattail biomass as a promising material to be applied in various applications. The obtained carbon was further treated via CO2 activation without any other chemical reagents. The results showed that the as-prepared activated carbon had a high specific surface area of 441.12m2/g after CO2 activation. Besides, the activated carbon showed excellent capacity to adsorb malachite green dye, and the effects of initial dye concentration, adsorption time, initial pH, and adsorption temperature were studied. Moreover, the activated carbon exhibited exceptional electrochemical performance as supercapacitors, with specific capacitance reaching 126.5F/g at a current density of 0.5A/g within a potential range of −1.0 to 0V in a 6M KOH solution. The excellent adsorption capacities and electrochemical performance suggested that the obtained activated carbon could be a promising candidate as an adsorbent and supercapacitor.

Removal of methylene blue by using porous carbon adsorbent prepared from carbonized chestnut shell

Abstract Carbonized chestnut shell was investigated as a low cost adsorbent for the adsorption of methylene blue (MB) from aqueous solution. Some parameters like the effects of initial dye concentration, initial pH value of solution and contact time of phases were investigated. The equilibrium was attained in 120 minutes. The isotherm models of Langmuir, Freundlich and Dubinin Raduskhevich (DR) were applied to the experimental data and Langmuir and DR adsorption models fit better than the Freundlich model. The maximum MB mono adsorption capacity was found to be 5.13 mg × g−1 obtained by Langmuir model. This value of carbonized chestnut shell was comparable to the adsorption capacities of some other adsorbent materials for dyes. The pseudo first order, second order and intra particle diffusion models were chosen for analyzing adsorption rate data. The adsorption reaction progressed according to the pseudo second order kinetic and Weber Morris diffusion was also effective in the adsorption phenomena. The th...

Synthesis and characterization of magnetic nanocomposite of chitosan/SiO2/carbon nanotubes and its application for dyes removal

The adsorption characteristics of Direct Blue 71 (DB71) and Reactive Blue 19 (RB19) from aqueous solution onto novel magnetic nanocomposite of Chitosan/SiO2/CNTs (MNCSC) have been investigated. The morphology of MNCSC was characterized by vibrating sample magnetometer (VSM), field-emission scanning electron microscopy (FESEM), X-ray Diffraction (XRD), fourier transform infrared spectroscopy (FTIR) and thermogravimetric analysis (TGA). The effect of initial dye concentration, contact time, adsorbent dosage and initial pH as experimental parameters on the removal of dyes were investigated. The adsorption experiments indicated the maximum adsorption capacity occurred at pH 6.8 for DB71 and pH 2.0 for RB19. The experimental data were analyzed by isotherm models and equilibrium results were fitted well with the Langmuir isotherm model and the maximum adsorption capacity of the MNCSM was determined to be 61.35 mg/g for DB71 (R2 = 0.996) and 97.08 mg/g for RB19 (R2 = 0.998). Adsorption data were analyzed with three kinetics models and pseudo second-order equation could best describe for adsorption of dyes. Finally, the thermodynamic parameters were determined.

Adsorption Characteristics of Activated Carbon for the Reclamation of Colored Effluents Containing Orange G and New Solid–Liquid Phase Equilibrium Model

Adsorption characteristics of activated carbon for the removal of orange G, an acid dye from aqueous solutions, have been investigated. The effect of initial dye concentration, temperature, and pH on the removal of orange G was investigated. The removal of orange G decreased from 95% to 82%, when the pH was increased from 2 to 12. The study of the effect of temperature and associated thermodynamic properties revealed the process of removal of dye is exothermic and spontaneous. Kinetic and mass transfer studies of the process were also carried out. The experimental data were used to develop a new solid–liquid phase equilibrium isotherm model. The average absolute relative deviation of the experimental data from the proposed model equation was 5.68%. In order to scale up the batch process for the removal of orange G, the concentration versus time data were analyzed to obtain mass transfer coefficient. The liquid-phase volumetric mass transfer coefficient (kLapL) was found to decrease from 0.008057 to 0.0028...

Bioremediation of red azo dye from aqueous solutions by Aspergillus niger strain isolated from textile wastewater

Biological treatment with fungi has proven to be effective in removing color from textile wastewater containing organic contaminants as an eco-friendly established technique. The main purpose of this research is to remove red azo dye from aqueous solution using Aspergillus niger strain. In a direct application, fungal biomass was tested for the decolorization under different environmental conditions such as contact time, bio-sorbent dosage, pH, agitation speed, and initial dye concentration. The highest azo dye removal efficiency was obtained at the pH 9, agitation speed 250, biosorbent dose 3.5g, and contact time 120min. The removal efficiency decreased with the increase in initial dye concentration. Freundlich isotherm model was best fitted when compared to Langmuir isotherm model, as it has a higher correlation coefficient (R2=0.977). At dye concentration 1000mg/L, the net dry biomass of A. niger increased from 0.18 to 0.58g after seven days of incubation at 28±1°C indicating the high biodegradability of fungal strain. Examination with Scanning Electron Microscope (SEM) showed high affinity of A. niger to the direct red azo dye. The statistical analysis using the interactive response surface methodology (IRSM) technique showed that the dye removal efficiency depends mainly on the contact time, pH, and biomass dosage. In contrast, the effect of initial dye concentration and agitation speed on the dye removal was minor.

Degradation and toxicity depletion of RB19 anthraquinone dye in water by ozone-based technologies.

This research investigated the discoloration and mineralization of Reactive Blue 19 (RB19) anthraquinone dye by single ozonation, single UV radiation and ozonation jointed with UV radiation (O3/UV). The problem was approached from two points of view: with the objective of color removal or the mineralization of solution. In each case, the optimum operating conditions were different. Ozonation was the most effective treatment for color removal, while the combined O3/UV treatment was for mineralization. Major intermediates of the dye degradation were identified by gas chromatography/mass spectrometry and a degradation pathway was proposed. In addition, a clear decrease of the toxicity of the dye was achieved at the end of the experiments. The effect of initial dye concentration, pH, ozone dose, and UV radiation on the degradation of the dye and decrease of total organic carbon was investigated, in order to establish the optimal operating conditions to achieve discoloration, mineralization or a combination of both.