Adsorption treatment and recovery of the hazardous dye, Brilliant Blue FCF, over bottom ash and de-oiled soya

Two waste materials-bottom ash, a power plant waste, and de-oiled soya, an agricultural waste-are meticulously and successfully used as adsorbent for the removal and recovery of a hazardous triphenylmethane dye, Brilliant Blue FCF. Both the materials were characterized by chemical analysis, IR, DTA, SEM and XRD studies. Their physical characteristics like surface area, porosity, density and loss on ignition were also determined. The adsorption of the dye over both materials was achieved under different pH, adsorbate concentration, sieve size, adsorbent dosage, contact time and temperature, etc. conditions. For both the systems Langmuir and Freundlich adsorption isotherm models were applied and, based on these models, useful thermodynamic parameters were calculated. For both the adsorbents, the kinetic measurements indicate that the adsorption process follows first order kinetics and film diffusion and particle diffusion mechanisms are operative at lower and higher concentrations, respectively, in each case. By percolating the dye solution through fixed-bed columns the bulk removal of the Brilliant Blue FCF was carried out and necessary parameters were determined to find out the percentage saturation of both the columns. Recovery of Brilliant Blue FCF was made by eluting dilute NaOH of pH 11 through each column.     

Applicability of waste materials--bottom ash and deoiled soya--as adsorbents for the removal and recovery of a hazardous dye, brilliant green

Deoiled soya, an agricultural waste material, and bottom ash, a waste of power plants, have been successfully used for the removal and recovery of the hazardous water-soluble dye brilliant green from water. To remove the dye from water, batch adsorption studies have been carried out by observing the effects of pH, concentration, amounts of adsorbents, size of adsorbent particles, etc. Attempts have also been made to monitor the adsorption process through Langmuir, Freundlich, Tempkin, and D-R adsorption isotherm models. Relevant thermodynamic parameters have also been calculated from these models. The adsorption process has been found endothermic and feasible at all the temperatures. The kinetics of the adsorption was also recorded and indicates pseudo-second-order kinetics in both cases. Kinetic operations also reveal the involvement of a film diffusion mechanism for the deoiled soya adsorption at all the temperatures, while bottom ash undergoes through a particle diffusion mechanism at only 30 °C and at higher temperatures a film diffusion mechanism operates. Bulk removal of the dye has been carried out through column studies for both adsorbents. Attempts have also been made to recover the dye from exhausted columns by eluting sulfuric acid of pH 3.     

Adsorption of basic fuchsin using waste materials--bottom ash and deoiled soya--as adsorbents

Basic fuchsin, a triaminotriphenylmethane dye, was removed by adsorption utilizing two waste materials--"bottom ash," a power plant waste material, and "deoiled soya," an agriculture waste product. The adsorbents were characterized through IR spectroscopy and differential thermal analysis (DTA). Batch adsorption experiments were carried out by measuring effects of pH, adsorbate concentration, sieve size, amount of adsorbent, contact time, temperature, etc. The results have been verified on the basis of Langmuir and Freundlich adsorption isotherm models and data obtained have been applied to calculate thermodynamic parameters. Specific rate constants for the processes were calculated by kinetic measurements and a pseudo-second-order adsorption kinetics was observed in each case. To identify whether the ongoing process is particle diffusion or film diffusion, the treatment given by Boyd and Reichenberg was employed. To assess the practical utility of the adsorbent, the aqueous adsorbate samples were eluted through fixed-bed columns of respective adsorbents. Attempts were also made to recover the adsorbed dyes by passing suitable solvent through the columns.     

Dye and its removal from aqueous solution by adsorption: A review

In this review article the authors presented up to-date development on the application of adsorption in the removal of dyes from aqueous solution. This review article provides extensive literature information about dyes, its classification and toxicity, various treatment methods, and dye adsorption characteristics by various adsorbents. One of the objectives of this review article is to organise the scattered available information on various aspects on a wide range of potentially effective adsorbents in the removal of dyes. Therefore, an extensive list of various adsorbents such as natural materials, waste materials from industry, agricultural by-products, and biomass based activated carbon in the removal of various dyes has been compiled here. Dye bearing waste treatment by adsorption using low cost alternative adsorbent is a demanding area as it has double benefits i.e. water treatment and waste management. Further, activated carbon from biomass has the advantage of offering an effected low cost replacement for non-renewable coal based granular activated carbon provided that they have similar or better adsorption on efficiency. The effectiveness of various adsorbents under different physico-chemical process parameters and their comparative adsorption capacity towards dye adsorption has also been presented. This review paper also includes the affective adsorption factors of dye such as solution pH, initial dye concentration, adsorbent dosage, and temperature. The applicability of various adsorption kinetic models and isotherm models for dye removal by wide range of adsorbents is also reported here. Conclusions have been drawn from the literature reviewed and few suggestions for future research are proposed.     

Exploration of biomass waste as low cost adsorbents for removal of methylene blue dye: A review

Biomass waste, which is abundantly available has been studied as low cost biosorbent for dye sequestration from waste water. The present review reports on recent development for remediation of methylene blue dye by agricultural waste and fruit peel waste material. The aim of this study was to revise latest literature in the field of dye adsorption and discuss the dye adsorption capacity of different types of adsorbents. The activated carbon prepared from several types of biomass waste material enhances the adsorption efficiency after modification. The variety of activating agents, method of activation, characterization of biosorbent material like SEM, EDAX, BET surface area and FTIR analysis has been explored in the present review. The dye adsorption factors such as effect of pH, agitation time, temperature, adsorbate and adsorbent dose were discussed. The detailed investigation on applicability of isotherm model, kinetic model and thermodynamic parameters has also been presented. The adsorption kinetics and adsorption isotherm model focus on selectivity of adsorbent. Adsorption mechanism, Influence of surface area, influence of pH_pzc and comparative study of biomass waste adsorbent with other adsorbents have been carried out. The use of biomass waste adsorbents is economically feasible, environmental healthy and found to have outstanding removal capacity of dyes.     

Removal of Reactofix Navy Blue 2 GFN from aqueous solutions using adsorption techniques

The wheat husk, an agricultural by-product, has been activated and used as an adsorbent for the adsorption of Reactofix Navy Blue 2 GFN from aqueous solution. In this work, adsorption of Reactofix Navy Blue 2 GFN on wheat husk and charcoal has been studied by using batch studies. The equilibrium adsorption level was determined to be a function of the solution pH, adsorbent dosage, dye concentration and contact time. The equilibrium adsorption capacities of wheat husk and charcoal for dye removal were obtained using Freundlich and Langmuir isotherms. Thermodynamic parameters such as the free energies, enthalpies and entropies of adsorption were also evaluated. Adsorption process is considered suitable for removing color, COD from waste water.     

Low-temperature synthesis of nanoparticle-assembled, transparent, and low-crystallized hydroxyapatite blocks

The mesoporous carbon CMK-3 adsorbent was prepared, characterized, and used for the removal of anionic methyl orange dye from aqueous solution. Adsorption experiments were carried out as batch studies at different contact time, pH, initial dye concentration, and salt concentration. The dye adsorption equilibrium was rapidly attained after 60 min of contact time. Removal of dye in acidic solutions was better than in basic solutions. The adsorption of dye increased with increasing initial dye concentration and salt concentration. The equilibrium data were analyzed by the Langmuir and Freundlich models, which revealed that Langmuir model was more suitable to describe the methyl orange adsorption than Freundlich model. Experimental data were analyzed using pseudo-first-order and pseudo-second-order kinetic models. It was found that kinetics followed a pseudo-second-order equation. Thermodynamic study showed that the adsorption was a spontaneous and exothermic process.     

Utilization of Waste Biomass (Kitchen Waste) Hydrolysis Residue as Adsorbent for Dye Removal: Kinetic,Equilibrium, and Thermodynamic Studies

Kitchen waste hydrolysis residue (KWHR), which is produced in the bioproduction process from kitchen waste (KW), is usually wasted with potential threats to the environment. Herein, experiments were carried out to evaluate the potential of KWHR as adsorbent for dye (methylene blue, MB) removal from aqueous solution. The adsorbent was characterized using FT-IR and SEM. Adsorption results showed that the operating variables had great effects on the removal efficiency of MB. Kinetic study indicated pseudo-second-order model was suitable to describe the adsorption process. Afterwards, the equilibrium data were well fitted by using Langmuir isotherm model, suggesting a monolayer adsorption. The Langmuir monolayer adsorption capacity was calculated to be 110.13 mg/g, a level comparable to some other low-cost adsorbents. It was found that the adsorption process of MB onto KWHR was spontaneous and exothermic through the estimation of thermodynamic parameters. Thus, KWHR was of great potential to be an alternative adsorbent material to improve the utilization efficiency of bioresource (KW) and lower the cost of adsorbent for color treatment.     

Ultrasonic-enhanced synthesis of rubber-based hydrogel for waste water treatment: Kinetic,isotherm and reusability studies

Hydrogel is used as an adsorbent for the removal of dyes and heavy metals in waste water. In this work, different methods of synthesising novel hydrogels from liquid natural rubber (LNR) were investigated. The two different methods were ultrasonic-assisted polymerisation and heating under reflux. Through graft modification, LNR had initially combined with maleic anhydride (MaH) using benzoyl peroxide (BPO) as a radical initiator. After grafting, acrylic acid (AA) was crosslinked onto LNR-g-MaH using N,N-methylenebisacrylamide (MBA) and potassium persulfate (KPS) as a crosslinker and initiator, respectively. The best method between the two different techniques was identified via a five-level-two-factor response surface methodology (RSM). Higher adsorption percentage (93.34%) was observed in the ultrasonic technique. Meanwhile, the effects of adsorbent mass, dye concentration, pH solution and ionic strength were also investigated and results showed that different conditions were found to give different MG dye adsorption rates. The adsorption of MG dyes on hydrogel is dependent on pH and ionic strength solution. This action indicates an ion exchange mechanism. From an isotherm study, it was found that the Freundlich isotherm best fitted the adsorption of MG dyes. Furthermore, the adsorption kinetic data followed the pseudo-second order kinetic model and the reusability of hydrogel was also investigated.     

Removal of malachite green from dye wastewater using mesoporous carbon adsorbent

Mesoporous carbon was synthesized for the removal of a cationic dye malachite green (MG) from aqueous solution. The studies were carried out under various experimental conditions such as contact time, dye concentration, adsorption dose and pH to assess the potentiality of mesoporous carbon for the removal of malachite green dye from wastewater. The sorption equilibrium was reached within 30 min. In order to determine the adsorption capacity, the sorption data were analyzed using linear form of Langmuir and Freundlich equation. Langmuir equation showed higher conformity than Freundlich equation. More than 99% removal of MG was reached at the optimum pH value of 8.5. From kinetic experiments, it was concluded that the sorption process followed the pseudo-first-order kinetic model. This study showed that mesoporous carbon can be recommended as an excellent adsorbent at high pH values.     

Synthesis and characterization of hexagonal boron nitride used for comparison of removal of anionic and cationic hazardous azo-dye: kinetics and equilibrium studies

The purpose of this study was to compare the adsorption behavior of cationic and anionic dyes onto a hexagonal boron nitride (hBN) nanostructure that was rich in a negative charge. Herein, the hBN nanostructure was synthesized using boric acid as a precursor material. The characteristic peaks of the hBN nanostructure were performed using Fourier transform infrared (FT-IR) and Raman spectroscopies. The morphology and the particle size of hBN nanostructure were determined by transmission electron microscopy (TEM) and scanning electron microscopy (SEM). During the studies, various essential adsorption parameters were investigated, such as the initial dye concentration, pH of the dye solution, adsorbent dose, and contact time. Under optimal conditions, the removal of 42.6% Metanil yellow (MY) and 90% Victoria blue B (VBB) from aqueous solution was performed using a 10-mg hBN nanostructure. Furthermore, the equilibrium studies showed that the Freundlich isotherm model fitted well for the removal of MY. However, the Langmuir isotherm model fitted well for the removal of VBB. Moreover, according to the results obtained from the kinetic studies, while the first-order kinetic model was suited for the adsorption of the MY, the second-order kinetic model was found to well fit for the adsorption of VBB.     

Removal of Rhodamine B,a Cationic Dye From Aqueous Solution Using Poly(cyclotriphosphazene-co-4,4′-sulfonyldiphenol) Nanotubes

Poly(cyclotriphosphazene-co-4,4′-sulfonyldiphenol) (PZS) nanotubes were evaluated as an efficient adsorbent for the removal of Rhodamine B (RhB), a cationic dye from aqueous solution. The as-synthesized adsorbent (PZS nanotubes) were characterized by scanning electron microscopy (SEM), transmission electron microscope (TEM), Fourier transform infrared spectroscopy (FTIR) and N₂ adsorption/desorption isotherms. The factors influencing the adsorption efficiency and capacity had been systematically studied. Results showed that the adsorption was highly dependent on temperature, initial RhB concentration and adsorbent dose. Effects of initial solution pH indicate that the adsorption can proceed in both basic and acidic environment. The equilibrium absorption capacity at 25°C can reach up to 35.58 mg/g within 60 min implying the adsorption procedure was highly rapid. The kinetic data was better described by the pseudo-second-order model with the correlation coefficient (R² = 0.9981), and the adsorption process followed Weber's intraparticle model, indicating the adsorption process could be divided into two stages. Results also showed that the adsorption equilibrium obeyed the Langmuir isotherm, and the value of equilibrium parameter R_L suggested that the PZS nanotubes were an efficient adsorbent for the removal of RhB from aqueous solution.     

Residue valorization: Preparation of recyclable organic amine adsorbent using laterite residue

This study focuses on exploiting the main component of traditional nickel metallurgical waste for use as a valuable material that can be applied in the removal of organic amines from water systems. Silicon compounds from metallurgic waste were converted into dissolvable sodium silicate by roasting the waste with alkali. Silica with adsorption capacity was combined with magnetic NiFe cores by the carbonation decomposition of purified silicate solution. The composite magnetic adsorbent was characterized, and its adsorption mechanism for organic amines was investigated. The effects of the initial trimethylamine concentration, contact time and temperature on the adsorption efficiency of the composite adsorbent towards trimethylamine were investigated. It was found that the adsorption fit the Freundlich mode well. The adsorption kinetics can be described by a pseudo-second-order kinetic model. The adsorption capacity reached 55.8 μg/mg at 293 K. The use of metallurgical waste to prepare the magnetic composite adsorbent has three advantages, which include benefiting the environment by reducing the amount of solid waste and costs associated with constructing and maintaining storage facilities, generating valuable products in an economical manner and conveniently recycling used adsorbents to avoid secondary pollution.     

Adsorption of basic dyes from aqueous solution onto pumice powder

The adsorption of methylene blue and crystal violet on pumice powder samples of varying compositions was investigated using a batch adsorption technique. The effects of various experimental parameters, such as adsorbent dosage, initial dye concentration, and contact time, were also investigated. The extent of dye removal increased with decreased initial concentration of the dye and also increased with increased contact time and amount of adsorbent used. Adsorption data were modeled using the Freundlich adsorption isotherm. The adsorption kinetic of methylene blue and crystal violet could be described by the pseudo-second-order reaction model.     

Kinetic of Patent Blue VF Adsorption from Aqueous Solution on Activated Bone Charcoal

The effect of temperature of activation on bone charcoal, used as adsorbent for the removal of Patent Blue VF from water solutions was studied. The adsorbent was characterized by FTIR, XRD, SEM and EDS. The kinetic of adsorption of dye was carried out at 10 °C and 45 °C. Carbonization temperature (600–1000 °C) of the adsorbent has significant effect on the removal of dye from water solutions. The first order kinetic, Elovich, Bangham, parabolic diffusion and power function equations were found to fit the kinetic data. Activation energies of adsorption (Δ≠) have higher values for the charcoal activated at high temperatures and the other thermodynamic parameters like ΔH≠, ΔS≠ and ΔG≠ were also found.     

Removal of nickel from water and synthetic nuclear power plant coolant water by ion exchange resins

A method for the removal of nickel from waste water by adsorption process on ion exchange resin was studied. The percentage removal of nickel depends upon the contact time, pH and dose of adsorbent. Adsorption of nickel on ion exchange resins obeys Freundlich adsorption isotherm. The applicability of Lagergren kinetic model has also been investigated. In order to understand the adsorption behavior of nickel, a number of batch experiments were conducted at various pH values. The results show that the adsorption is maximum in the pH range 2 to 8. The studies showed that the ion exchange resins IRN77 and SKN1 can be used as an efficient adsorbent material for the removal of Ni(II) from water and coolant water.     

Adsorptive performance of MWCNTs for simultaneous cationic and anionic dyes removal; kinetics,thermodynamics, and isotherm study

Disposal of contaminated wastewater causes many serious problems especially when it gets mixed with the ground and seawater. It is, therefore, important to apply any remedial action to eradicate dangerous pollutants from the aqueous effluents and to avoid exposure of this wastewater to aquatic life. The research results discussed herein deal with the removal of Rhodamine B (RhB) and Congo Red (CR) dye from wastewater by using multi-walled carbon nanotubes (MWCNTs) as an adsorbent. Different factors like solid dosage, initial pH and concentration, time, and temperature were studied to understand the behavior and mechanism of adsorption. The maximum adsorption capacity in case of a single component system was found to be 302 mg/g and 300 mg/g for Congo Red and Rhodamine B, respectively. Moreover, the mechanism of adsorption was best described by a pseudo-second-order kinetic model. Thermodynamic parameters showed that adsorption of CR and RhB was exothermic when these were removed from a single dye system. However, the overall process became endothermic for concurrent removal of both dyes from the solution. The research results showed that the MWCNTs could successfully be utilized to remove the dye from the industrial wastewater.     

Adsorption studies on the removal of Vertigo Blue 49 and Orange DNA13 from aqueous solutions using carbon slurry developed from a waste material

Waste material (carbon slurry), from fuel oil-based generators, was used as adsorbent for the removal of two reactive dyes from synthetic textile wastewater. The study describes the results of batch experiments on removal of Vertigo Blue 49 and Orange DNA13 from synthetic textile wastewater onto activated carbon slurry. The utility of waste material in adsorbing reactive dyes from aqueous solutions has been studied as a function of contact time, temperature, pH, and initial dye concentrations by batch experiments. pH 7.0 was found suitable for maximum removal of Vertigo Blue 49 and Orange DNA13. Dye adsorption capacities of carbon slurry for the Vertigo Blue 49 and the Orange DNA13 were 11.57 and 4.54 mg g(-1) adsorbent, respectively. The adsorption isotherms for both dyes were better described by the Langmuir isotherm. Thermodynamic treatment of adsorption data showed an exothermic nature of adsorption with both dyes. The dye uptake process was found to follow second-order kinetics.     

Adsorptive removal of malachite green and Rhodamine B dyes on Fe3O4/activated carbon composite

This study demonstrates the adsorption experiments of toxic dyes malachite green (MG) and Rhodamine B (RB) on Fe₃O₄-loaded activated carbon (AC). AC, which is known to be a high-capacity adsorbent, was aimed to be easily separated from aqueous media by loading it with Fe₃O₄. Fe₃O₄-loaded AC was prepared by the coprecipitation method and named magnetic activated carbon (M-AC), and the produced M-AC was characterized by x-ray diffraction (XRD), thermogravimetric analysis (TGA), and pH_pzc analyses. MG and RB adsorption by the M-AC was performed separately by batch technique and the effects of adsorbent amount, solution pH, and initial dye concentration on the adsorption were explored. Maximum removal efficiencies were found to be 96.11% for MG and 98.54% for RB, and the Langmuir isotherm model was the most fitted isotherm model for the adsorption. The kinetic and thermodynamic studies showed that the adsorption proceeded via the pseudo-second-order kinetic model and endothermic in-nature for both dyes.     

Polyethyleneimine-grafted polyphosphazene microspheres for rapid and efficient capture of anionic dyes from wastewater

Developing novel adsorbent to capture organic contaminants from wastewater rapidly and efficiently is highly desirable for waste treatment and environmental restoration. Herein, we reported a new amino-rich spherical adsorbent (PZS-PEI) for highly-efficient uptake of anionic dyes from aqueous solution. The PZS-PEI adsorbent was fabricated through a two-step process including synthesis of PZS-Cl microspheres via room temperature polymerization of hexachlorocyclotriphosphazene with bis(4-hydroxyphenyl) sulfone and subsequent surface grafting reaction of PZS-Cl microspheres using branched polyethyleneimine (PEI). The microstructure of as-obtained PZS-PEI microspheres was fully characterized by scanning electron microscopy, Fourier transform infrared, X-ray photoelectron spectroscopy, zeta potential, and N₂ adsorption test. The adsorption performance of the PZS-PEI microspheres towards organic dyes was evaluated through carrying out a series of studies including various influence factor analysis, adsorption isotherm, kinetics, and thermodynamics. Results show that the PZS-PEI adsorbent owned good adsorption selectivity towards anionic dyes, and the maximum adsorption capacities for methyl orange (MO), acid chrome blue K, eosin-Y reached 190.29, 152.90, and 92.34 mg/g at 25 °C, respectively. In addition, the uptake behavior of organic dye by the PZS-PEI adsorbent conformed to Freundlich isotherm and pseudo-second order kinetic model, and the adsorption process followed a three-stage intraparticle diffusion mode with an endothermic and spontaneous characteristic. Electrostatic interaction and hydrogen bonding were responsible for the highly-efficient adsorption of the PZS-PEI adsorbent towards typical anionic dye MO.