Adsorption Of Azo Dyes Research Articles

Activated Carbon/Polyaniline Composite for Azo Dye Adsorption: Kinetics, Equilibrium, Thermodynamics, and Statistical Physics Interpretations

Activated Carbon/Polyaniline Composite for Azo Dye Adsorption: Kinetics, Equilibrium, Thermodynamics, and Statistical Physics Interpretations

Hybrid rGO/Fe3O4 magnetic nanocomposite for anionic and cationic dye removal application

The adsorption removal of anionic and cationic azo dyes with magnetic nanoparticles was an important technological strategy for the purification of dye-contaminated water. The present work highlights the dye adsorption properties of the solvothermally synthesized hybrid reduced graphene oxide‑iron oxide (rGO/Fe3O4) nanocomposite for the efficient adsorption of methyl orange, congo red, metanil yellow, and methylene blue from the aqueous medium. Morphology, and porous characteristics of the material was analysed with FESEM and BET respectively. The magnetic properties of the material viz. M-H, FC, and ZFC were investigated with SQUID-VSM. The BET analysis confirmed the mesoporous structure of the hybrid rGO/Fe3O4 nanocomposite, with a BET-specific surface area of 27.74 m2/g. Dye adsorption experiments of hybrid rGO/Fe3O4 nanocomposite were conducted to analyse the influence of adsorbent dosage, dye concentrations, and pH variations. FTIR spectroscopy was also used to verify the adsorption of azo dyes onto the surface of the rGO/Fe3O4 nanocomposite. Hybrid rGO/Fe3O4 nanocomposite show complete adsorption of methyl orange, congo red, metanil yellow, and methylene blue dyes with adsorption capacities of 58.76, 100.3, 533, and 50 mg/g, respectively in the water medium. Hybrid rGO/Fe3O4 nanocomposite showed excellent adsorption of metanil yellow dye. The adsorbed azo dyes methyl orange, metanil yellow, methylene blue, and congo red by the rGO/Fe3O4 nanocomposite can be easily desorbs from the material indicating its reusability. The magnetic coercivity of the material at 300K was 47.4 Oe, as a result the adsorbent material can be magnetically separated from the purification system. The adsorption process of methyl orange, congo red, metanil yellow, and methylene blue dyes on the rGO/Fe3O4 nanocomposite best fits to the pseudo-second-order kinetics and the Langmuir isotherm model.

Effective adsorption of fluorescent congo red azo dye from aqueous solution by green synthesized nanosphere ZnO/CuO composite using propolis as bee byproduct extract.

The indirect dumping of massive volumes of toxic dyes into water has seriously affected the ecosystem. Owing to the many applications of the designed nanomaterials in the manufacturing process, there is a lot of research interest in synthesizing nanomaterials using green processes. In this research, the byproduct of bee was employed to synthesize nanoparticles (NPs) of ZnO, CuO, and biosynthesized ZnO/CuO (BZC) nanocomposite via utilizing a green and simple approach. To validate the effective fabrication of BZC nanocomposite, various characterization measurements were applied. FTIR analysis identified the functional groups in charge of producing nanoparticles and nanocomposites. Moreover, the existence of ZnO and CuO XRD peaks suggests that the nanocomposites were successfully biosynthesized. The high-resolution XPS spectrum of the BZC nanocomposite's Zn2p3, Cu2p3, and O1s were observed. Our findings indicate the successful engineering of the prepared nanomaterials and BZC nanocomposite. Our findings indicate the successful engineering of the prepared nanomaterials and BZC nanocomposite. For Congo red (CR) fluorescent stain azo dye elimination in water, all adsorption parameters were examined at room temperature. Moreover, the adsorption experiments revealed the removal capacity for uptake CR dye using BZC nanocomposite (90.14mgg-1). Our results show that the BZC nanocomposite exhibited high removal capability for the adsorption of CR dye. The nanosphere adsorbent offered a simple, low-cost, and green approach for water purification and industrial wastewater control.

Superior Adsorptive Removal of Anionic Azo Dyes from Aqueous Solutions Using Sulfonic Acid Group-Modified MIL-101@Graphene Oxide Composite.

It is critical to remove organic contaminants from wastewater released by the printing and dyeing industry for addressing water pollution issue. Therefore, the fabrication of new adsorbents with excellent removal efficiencies is an urgent task. A composite of MIL-101 partially functionalized with -SO3H (MIL-101-SO3H) and graphene oxide (GO) was prepared by assembling MIL-101-SO3H truncated octahedrons on the GO framework. The synthesized MIL-101-SO3H@GO has a superior adsorption efficiency for anionic azo dyes. The maximum adsorption capacities of MIL-101-SO3H@GO-1 for Congo red, methyl orange, acid orange 7, and acid orange G reached 2711.3, 818.8, 551.2, and 319.8 mg/g, respectively, which are considerably higher than those obtained using unmodified MIL-101. This is because additional interactions that promote azo dye adsorption, such as hydrogen bonding between the dye and the sulfonic acid groups of MIL-101-SO3H or the carboxyl groups of GO, were induced, and agglomerate pores that accommodated the dye were formed in the composite. The ultrahigh removal efficiency of the composite for azo dyes is mainly driven by hydrogen bonding, electrostatic interactions, π-π stacking between the MIL-101-SO3H@GO and dye molecules, synergistic interactions at the interface of GO and MIL-101-SO3H microcrystals, and the pore-filling effect. Understanding these driving forces for dye adsorption can contribute to the development of sustainable and functionally modified metal-organic framework composite adsorbents.

Adsorption of azo dye by biomass and immobilized Yarrowia lipolytica; equilibrium, kinetic and thermodynamic studies

One of the major environmental problems we have today is dye pollution, primarily caused by the textile industry. This pollution has detrimental effects on aquatic life, soil fertility, and human health. Many microbial biosorbents have been documented in the literature for the removal of a wide range of azo dyes commonly employed in the textile industry. However, Yarrowia lipolytica NBRC1658 is firstly used as both free and immobilized sorbents for the removal of Reactive yellow 18 (RY18), acid red 18 (AR18) and basic blue 41 (BB41) in this study. The effect of experimental conditions such as pH, biosorbent quantity, dye concentration, contact time, and temperature on dye removal capacity are examined. The research findings demonstrate that the adsorption capacity is higher in biomass compared to immobilized cells. The highest adsorption capacities are observed at pH 2 for RY18 and AR18, while pH 9 is optimal for BB41. Increasing the adsorbent dosage and initial concentration significantly improves the adsorption capacity. The Langmuir model best describes the adsorption process, indicating that the dye attaches to the biosorbent in a single layer, with a uniform biosorbent surface. The removal of the dye occurs through a chemical process on the biosorbent surface, as evidenced by the pseudo-second-order kinetic model. According to thermodynamic analysis, higher temperatures promote greater adsorption of dyes. Our study shows the effectiveness of Yarrowia lipolyica NBRC1658 as a biosorbent in the removal of a wide range of industrial dyes.Graphical

A graft-modified sponge with COFs for wastewater treatment and iodine adsorption

Azo dyes, used in large quantities in drinks, have become a threat to human health. In the treatment of dyes, the method of chemical adsorption is often used due to its simple and efficient features. Covalent organic frameworks (COFs) material with the characteristics of stability and porosity has great potential for the adsorption of azo dyes. However, the application of COFs is severely limited by their poor mechanical properties and hard recovery. By the strategy of in situ growth using the original functional groups of the sponge, COFs are successfully grafted onto melamine sponges to give rise to a porous sponge@COFs material. The material can adsorb up to 621 mg g−1 of Congo red, a common azo dye. In addition, it exhibits strong adsorption of iodine solution with the saturated adsorption of 1504.76 mg g−1. More importantly, sponge@COFs can selectively adsorb azo dyes with S–O- bond. The adsorption mechanism is inferred as the connect of S–O- in the Congo red molecule with O atom of sponge@COFs. Also, the mechanism of iodine adsorption is explained to be due to the coordination of C atoms in COFs with I atom. In addition, as an adsorbent, the material is recoverable, stable and heat resistant. Relying on the stronger performance and lower cost, sponge@COFs is expected to be developed as a new adsorbent.

Sorption and concentration anionic azo dyes on nanomagnetite modified with cationic polyelectrolytes

Using the chemical coprecipitation method, magnetic magnetite nanoparticles (MNP) were synthesized, the surface of which was modified with biocompatible cationic polyelectrolytes polyethylenimine (PEI) and chitosan (Cht). The MNP were characterised by transmission microscopy and zeta potential measurements. The initial MNP have a shape close to spherical and an average size of (10±3) nm. Immobilization of polyelectrolyte on the surface of MNP led to the appearance of aggregates with an interconnected porous network (shell) around individual particles, with average sizes of (12±2) and (15±2) nm for Fe3O4@PEI and Fe3O4@Cht, accordingly. The influence of various experimental parameters, such as pH, extraction time, amount of sorbent and initial dye concentration on the adsorption and desorption of food azo dyes Allure Red AC (E129) and Brilliant Black BN (E151) was studied. It has been shown that under optimal conditions the degree of extraction of these dyes from aqueous solutions is 96-100%, the concentration coefficient is 2.7×103 and sorption capacity of 56 and 94 mg/g for Fe3O4@PEI and 46 and 69 mg/g on Fe3O4@ХТЗ for E129 and E151, respectively. A comparison of sorption isotherms and process kinetics showed that the Langmuir model and pseudo-first order are preferable for describing the sorption of dyes. In the acidic and neutral regions, electrostatic interactions are responsible for sorption, and in the alkaline region, hydrogen bonding and hydrophobic interactions also play a significant role. The proposed sorbents can be used both for the sorption and concentration of dyes in chemical analysis, and for the purification of wastewater from them. Nanomagnetite modified with polyethylenimine, which allows absorbing and concentrating dyes over a wide pH range of 6-9 is preferable for use.

A comprehensive review on adsorptive removal of azo dyes using functional materials

Abstract The shortage of freshwater resources caused by azo dye pollution is an acute global issue, which has a great impact on environmental protection and human health. Therefore, the use of new strategies for designing and synthesizing green, efficient, and economical materials for the removal of azo dyes is required. Among the various methods for removal of azo dyes, adsorption by using advanced functional materials, including nanomaterials, metal oxides, metal oxides–polymer composite, biomaterials, and porous materials, have attracted significant attention over the past few years because of their capabilities of brilliant removal efficiency, high selectivity, quick response, reversibility, flexibility in operation, and less harmful by-products. In this review, we report the adsorption of azo dyes and general design principles underlying the above-mentioned functional materials and, in particular, highlight the fundamental mechanisms and effect of various environmental conditions; also, current challenges and opportunities in this exciting field have been emphasized, including the fabrication, subsequent treatment, and potential future applications of such functional materials.

Adsorption of anionic and cationic azo dyes from wastewater using novel and effective multicomponent adsorbent

Water pollution is rising worldwide, necessitating innovative and effective treatment solutions. This study introduces a multicomponent/multifunctional novel nanocomposite synthesized from polyethyleneimine (PEI), graphene oxide (GO), bentonite clay, and MgFeAl-layered triple hydroxide (LTH), termed as AGO/Bentonite/LTH. In this study, the synthesized AGO/Bentonite/LTH nanocomposite was utilized to remove azo dyes (methyl orange and crystal violet) from contaminated water samples. The novel AGO/Bentonite/LTH nanocomposite was benchmarked against its pristine materials and their binary combinations. The results indicated the superior adsorption performance of the AGO/Bentonite/LTH nanocomposite relative to all other adsorbents synthesized and examined herein. All the synthesized adsorbents were characterized using different techniques in order to reveal their textural properties, functional groups, morphology, thermal stability, and crystallinity before applying them to decontaminate wastewater samples contaminated with methyl orange (MO) and crystal violet (CV). The Langmuir adsorption isotherm model predicted that the maximum adsorption capacities of CV and MO onto the AGO/Bentonite/LTH nanocomposite are 1705.1 and 1171.8 mg/g, respectively. On the other hand, zeta potential, pH, and FTIR studies suggested the existence of multiple mechanisms governing the adsorption of CV and MO onto the AGO/Bentonite/LTH nanocomposite. Thermodynamic results indicated the endothermicity and exothermicity of CV and MO adsorption, respectively. Another interesting finding reported herein is the high reusability of this nanocomposite as demonstrated by the minimal reduction in the removal of these two pollutants with the repetitive use of the nanocomposite. Additionally, the nanocomposite can also be easily and cheaply regenerated via a few rinses with a diluted NaOH aqueous solution. These interesting observations suggest that the synthesized AGO/Bentonite/LTH nanocomposite is a potent material for efficient dye removal from contaminated water bodies.

Waste Iron Dust Derived Iron Oxide Nanoparticles for Efficient Adsorption of Multiple Azo Dyes

Waste Iron Dust Derived Iron Oxide Nanoparticles for Efficient Adsorption of Multiple Azo Dyes

Synthesized rGO/f-MWCNT-architectured 1-D ZnO nanocomposites for azo dyes adsorption, photocatalytic degradation, and biological applications

A study has synthesized a composite of carbonaceous nanomaterials, including functionalized multi-walled carbon nanotubes (f-MWCNT) and reduced graphene oxide (rGO), with 1D-architectured zinc oxide nanorods (ZnO NRs), for applications in adsorption and sunlight-assisted photocatalytic degradation. We modified the composite with 1% w/w rGO and f-MWCNT. We studied the adsorption and photodegradation of azo dyes using ZnO and its nanocomposites. The photocatalysts of RZnO and CZnO nanocomposite degraded RhB, MB, CV, MO, and CR dyes with a degradation percentage of 92 to 97%. The nanocomposite demonstrated superior antimicrobial and antioxidant properties compared to ZnO NRs, highlighting their potential in drug delivery.

Synthesis of iron oxide microparticles with fern leaf morphology: Assessment of the RY-145 azo-dye adsorption

New particulate ceramic materials with outstanding properties are needed for several technological applications. In this work, multibranched hematite (α-Fe2O3) has been synthesized by tuning the experimental conditions for obtaining dendritic microparticles with the morphology of fern leaves. Variations of temperature, precursor (K3[Fe(CN)6]) concentration, and time were performed to synthesize dendritic hematite with the best fractal morphology. These materials were characterized structurally and morphologically by X-ray powder diffraction and electron microscopy (SEM and TEM). In addition, the composition was studied by X-ray dispersive energy analysis (EDX). The well-formed multibranched sample was additionally analyzed by infrared (IR) and Raman spectroscopies, thermal analysis, and N2 gas adsorption at 77 K. Finally, this multibranched sample was evaluated as an adsorbent for the removal of an azoic dye (Reactive Yellow-145: RY-145) under mild conditions (25 °C, atmospheric pressure) and pH 3.5. The results showed the interesting potentiality of this multibranched α-Fe2O3 for the adsorption of azo dyes and revealed the high stability of the adsorbent particles. However, the adsorption capacity of the solid is moderately low (13 – 32 mg/g), and it is worth improving this parameter. A pseudo-second order kinetic model was well adjusted, revealing an external adsorption of RY-145 on multibranched hematite with possible chemisorption.

Adsorption of Azo Dye Onto TiO2 Nanoparticles Prepared by a Novel Green Method: Isotherm and Thermodynamic Study

The current study examined the use of Sansevieria plant leaves extract as an environmentally acceptable, inexpensive, and safe green approach for creating titanium dioxide nanoparticles (NPs). Batch studies have been used to test the particles' capacity to bind to the azo dye congo red (CR), which has been adsorbed from its aqueous solution. The effects of many factors, including the weight of TiO2 NPs, the contact duration to reach equilibrium, the concentration of CR, temperature, and pH, have been investigated. Both the Freundlich and Langmuir models were used to analyze experimental results. According to the high values of the Freundlich model's correlation coefficient R2, it is discovered that the adsorption of CR dye onto nano TiO2 is well-suited. The kinetics analysis for the adsorption trials proposed the pseudo-second-order. Thermodynamic data showed that the CR dye adsorption onto nano TiO2 is a physical process that happens spontaneously and endothermically with increasing unpredictability.

Adsorption of azo dyes and Naproxen by few-layer MXene immobilized with dialdehyde starch nanoparticles: Adsorption properties and statistical physics modeling

Novel Eco-friendly composite materials (DSP-M) were organized by combining few-layer MXene with the hydrophilic biomaterial dialdehyde starch nanoparticles (DASNP) and immobilizing DASNP on the surface of few-layer MXene by the dialdehyde-based cross-linking method. In addition to the study on the adsorption performance and mechanism of prohibited dyes (Rhodamine B, RB and Congo Red, CR) in food industry, the removal and mechanism of non-steroidal anti-inflammatory drug (Naproxen, NPX) residues in pharmaceutical field were also investigated. DSP-M was physiochemically characterized via series of analytical techniques and the dye adsorption isotherms at three temperatures were quantified. The results show that DSP-M exhibited excellent adsorption performance for all three selected adsorbates, and the Langmuir maximum monolayer adsorption capacity were 678.19 mg/L for RB, 754.41 mg/L for CR and 166.71 mg/L for NPX, respectively, and it agreed well with the Langmuir, pseudo–second order and intraparticle diffusion models. The statistical physics model was employed to further explore the adsorptive mechanism. The characteristics of DSP-M after adsorption and the simulation results indicate that the removal of RB, CR and NPX by DSP-M was mainly a physical adsorption process involved with hydrogen bonding, electrostatic force and van der Waals force.

ZnS/CuFe2O4/MXene ternary heterostructure photocatalyst for efficient adsorption and photocatalytic degradation of azo dyes under visible light: Synergistic effect, mechanism, and application

ZnS/CuFe2O4/MXene (ZSCFOM) composite with ternary heterostructures was prepared by solvothermal methods for the first time to effectively adsorb and photodegrade the azo dyes. ZSCFOM mainly adsorbed azo dyes through the hydrogen bonding and electrostatic interactions, with saturated adsorption capacities of 377 mg g−1 for direct brown M and 390 mg g−1 for direct black RN. ZSCFOM exhibited both characteristics of Schott heterostructure and p-n heterostructure, but it is not a simple superposition of the two heterostructures, but rather achieves better photocatalytic property. ZSCFOM performed a higher separation efficiency of electrons and holes than pure CuFe2O4 and pure ZnS. Under visible light, ZSCFOM was more effective in removing the azo dyes than MXene, CuFe2O4, ZnS, CuFe2O4/MXene, ZnS/MXene, and ZnS/CuFe2O4. The migration pathways of photogenerated carriers in ZSCFOM were inferred as that the electrons were concentrated in MXene and conduction band of ZnS, and holes were gathered in valence band of CuFe2O4. MXene served as a cocatalyst to accelerate the separation of electrons and holes. ZSCFOM mainly degraded DBM and DBRN by catalyzing the generation of holes, superoxide radicals, and hydroxyl radicals. The 100% of 0.05 g L−1 azo dyes were removed by ZSCFOM within 30 min from the environmental water systems.

Synthesis and application of iron based metal organic framework for efficient adsorption of azo dyes from textile industry samples

Synthesis and application of iron based metal organic framework for efficient adsorption of azo dyes from textile industry samples

Efficient Adsorption of Anionic Azo Dye in Wastewater with Medulla tetrapanacis Modified by Cationic Surfactant

Efficient Adsorption of Anionic Azo Dye in Wastewater with Medulla tetrapanacis Modified by Cationic Surfactant

Valorization of Annona reticulata biochar by chitosan for the adsorption of Azo dye from Textile effluent

<p>Azo dye is a synthetic aromatic dye which are direct dye frequently used in textile industry to colour fibres. It also contributes to the damage of the environment. This study examines the adsorption biochar made from Annona reticulata to remove azo dye from textile wastewater. To improve the adsorption capacity, biochar valorized by chitosan molecules, Investigations were conducted on the use of chitosan-based materials that are acid-resistant for azo dye adsorption. In the batch experiment, basic operating parameters such as initial Azo dye concentrations, pH, contact time and bed height were assessed. The percentage removal efficiency for Azo dye was recorded as 67.18%, 75.88% and 94.37% for three dissimilar sized columns that were 6cm, 8cm, and 10cm. The UV–visible absorption spectroscopy was used to quantify the decolorization of dyes. The changed surface properties of the adsorbent produced from Annona reticulata were characterized by using SEM, XRD, and FTIR. The effectiveness of the column's adsorption was calculated mathematically by Yoon-Nelson, Thomas, and Adams-Bohart models. The model that best represents equilibrium isotherm data by adsorption had R2 values of 94.63, 86.67 and 96.35 respectively.</p>

Dye removal from simulated and real textile effluent using laccase immobilized on pine needle biochar

Textile industries generate huge amount of water containing harmful azo dyes that have known carcinogenic and mutagenic toxicities. Removal of these azo dyes is an important step in the treatment of wastewater. This work evaluates the potential application of enzyme immobilized biochar for the removal of azo dyes from real and simulated textile effluents. The simulated textile effluent was prepared using azo dyes Congo red, Malachite green and their mixture. Dye removal studies were conducted in batch studies using laccase immobilized biochar and optimization of immobilization was achieved through response surface methodology. In the case of simulated effluent, higher dye removal efficiencies were obtained when added separately (73.8 % for Malachite green dye and 88.1 % for Congo red) in comparison to when mixed together (59.3 % for Malachite green dye and 78.7 % for Congo red). In the case of real textile effluent, the dye removal through an enzyme immobilized system with 100 % removal efficiency was obtained for one of the dye peaks while it was 35.7 % for the other dye present in the effluent along with 33.3 % COD removal. The real textile effluent was analyzed by GC–MS and the presence of one of the metabolite phenol,2,4-bis (1,1-dimethyl ethyl) in the GC–MS spectra indicated degradation of dye Mordant Black. Thus, an enzyme immobilized biochar system can be used for simultaneous dye adsorption and degradation of toxic azo dyes from real effluents.

Thermodynamics of Azo Dye Adsorption on a Newly Synthesized Titania-Doped Silica Aerogel by Cogelation: A Comparative Investigation with Silica Aerogels and Activated Charcoal.

The adsorption isotherms of azo dyes on a newly synthesized titania-doped silica (TdS) aerogel compared to silica aerogels and activated charcoal (AC) are systematically investigated. Monolithic TdS aerogels were synthesized by the cogelation process followed by supercritical drying of tetraethyl orthosilicate (TEOS) as a gel precursor and titanium(IV) isopropoxide (TTIP) as a metal complex precursor for co-polymerization in ethanol solvent. An acid-base catalyst was used for the hydrolysis and condensation of TEOS and TTIP. The effect of Ti4+ doping in a silica aerogel on the mesoporous structure and the adsorption capacity of methylene blue (MB) and crystal violet (CV) dyes were evaluated from the UV-vis absorption spectra. In order to compare the adsorption isotherms, the surface areas of silica and TdS aerogels were first normalized with respect to AC, as adsorption is a surface phenomenon. The azo dye equilibrium adsorption data were analyzed using different isotherm equations and found to follow the Langmuir adsorption isotherm. The maximum monolayer adsorption capacities for the adsorbent TdS aerogel normalized with the AC of the Langmuir isotherm are 131.58 and 159.89 mg/g for MB and CV dyes, respectively. From the Langmuir curve fitting, the Q max value of the TdS aerogel was found to increase by 1.22-fold compared to AC, while it increased 1.25-1.53-fold compared to the silica aerogel. After four cycles, regeneration efficiency values for MB and CV dyes are about 84 and 80%, respectively. The study demonstrates the excellent potential and recovery rate of silica and TdS aerogel adsorbents in removing dyes from wastewater. The pore volume and average pore size of the new aerogel, TdS, were found to be lower than those of the silica aerogel. Thus, a new TdS aerogel with a high capacity of adsorption of azo dyes is successfully achieved.