Dye Adsorption Research Articles (Page 1)

Starch-integrated alginate-based ternary hydrogel beads-loaded with mace extract-arils of Myristica fragrans: Composition-dependent Hertzian elasticity, swelling and adsorptive properties.

The discharge of dye-contaminated industrial wastewater from textile and dye manufacturing industries poses serious environmental and health risks due to the persistence and toxicity of synthetic dyes, particularly azo compounds. Conventional treatment methods are often ineffective for complete dye removal and may produce secondary pollutants. We developed a green biocatalytic approach using laccase immobilized in sodium alginate beads for efficient dye removal. In this study, a soil-derived fungal strain (A19), identified as Aspergillus fumigatus, was screened using sugarcane bagasse as the growth substrate under submerged fermentation. Crude enzyme exhibited a specific activity of 1.122mg/mL, which was purified through ammonium sulphate precipitation followed by Sephadex G-100 chromatography, resulting in a 1.92-fold increase in purity with a 75.57% recovery. SDS-PAGE confirmed the laccase molecular weight to be approximately 69kDa. The purified enzyme was immobilized in sodium alginate beads. This achieved 88.33% decolorization of Congo red and 80.15% of Bromophenol blue within 120h. Adsorption of both dyes followed the Langmuir isotherm model, indicating monolayer binding with maximum adsorption capacities of 0.09mg/g for Congo red and 1.16mg/g for Bromophenol blue. The stability and reusability of laccase were enhanced by immobilization in sodium alginate beads. FTIR analysis confirmed functional group shifts after treatment, and SEM-EDX data revealed elemental changes in dye-treated beads. This study demonstrates a green, cost-effective biocatalytic system using laccase immobilized in alginate beads for synthetic dye removal. The results highlight the enzyme's stability, efficiency, and potential for large-scale industrial wastewater treatment.

Hexavalent chromium and Xylidine Ponceau dye form a binary mixture that is highly hazardous to the environment. The presence of a second pollutant modifies the adsorbent performance towards one or both pollutants, either by synergism or antagonism. This work evaluated the adsorption performance of a chitosan-based adsorbent over a binary mixture of Cr(VI) and Xylidine Ponceau in batch and fixed-bed configurations. The predicted binary isotherm accurately displayed how the adsorption capacity was affected by the concentration of the other pollutant, based on mono-component and binary adsorption data. The Cr(VI) adsorption capacity remained almost unaffected (~ 13.6mg/g) by the presence of Xylidine Ponceau dye. However, Xylidine Ponceau adsorption capacity was significantly affected by chromium due to the selectivity towards this pollutant, decreasing from 26.9 to 11.4mg/g. The kinetics of Xylidine Ponceau adsorption became faster in the presence of chromium, with PFO kinetic constant going from 0.0270 to 0.1148 1/min, suggesting interactions between both species. The breakthrough curve analysis evidenced a large mass transfer zone, indicating high mass transfer resistance. In this system, the used bed fraction was 46%; within this fraction, chromium occupied 31% of the surface, while the dye covered 13%, as accurately estimated by the modified Thomas model.

This review reports the progress on the utilizationof polymers of intrinsic microporosity (PIMs) for the adsorption of pharmaceuticals (PCs) and organic dyes. PIMs are exceptional porous organic polymers that possess copious contortion sites and rigid fused-ring structures induced by spirocentric molecules (two cyclic rings sharing one tetrahedral carbon). The availability of these contortion sites inhibits bond flexibility, bond rotation, and structural relaxation of PIMs in their solid state. This has led to the intrinsic microporosity, high Brunauer-Emmett-Teller and Barrett-Joyner-Halenda surface areas, pore radii, pore volumes, high permeability, high diffusivity, high selectivity, and high thermal stability. PIMs comprise a cascade of girthy ladder-like building blocks connected to the spirocentre as a result of inflexible backbone stereochemistry. Research progress has shown from a thorough literature survey that the adsorptive properties of PIMs and their functionalized analogs have not been extensively explored for the removal of PCs and organic dyes in contaminated water. To date, there exists scanty literature on the adsorption of PCs in contaminated water. In prospect, research efforts have to be intensified so as to establish vast applications of PIMs for the treatment of water contaminated with PCs and organic dyes.

The green synthesis of iron nanoparticles (FeNPs) using plant extracts has attracted considerable attention because of their potential to effectively decolorize dye-containing wastewater. Nevertheless, the underlying mechanism remains a topic of debate, mainly due to the complex composition of the extracts. In this study, we introduced a novel and well-defined model system by employing a single polyphenol, ellagic acid (EA), as both reducing and capping agent to synthesize iron particles (Fe-EA). This strategic approach not only circumvents the compositional variability of conventional plant extracts but also enables a fundamental molecular-level understanding of the adsorption process. The resulting Fe-EA particles exhibited eminent malachite green (MG) removal performance, achieving high removal efficiency (over 86.4% within 10min), which was comparable to that of FeNPs derived from complex pomegranate extracts. Comprehensive characterizations (SEM, EDS, XRD, FTIR, XPS) confirmed that the particles consist of a Fe(II, III)-EA complex self-assembled into unique hollow spherical structures. Adsorption isotherm data were best described by the Langmuir model, indicating homogeneous monolayer adsorption and a maximum calculated capacity of 4149.4mg (g Fe)-1. Thermodynamic parameters revealed that the adsorption process was spontaneous and endothermic. Combined with LC-MS analysis and kinetic studies, the primary removal mechanism was identified as a chemisorption process, governed by the synergy of strong electrostatic attraction and hydrogen bonding. This work provides molecular-level insights that shift the design of green-synthesized iron particles from empirical testing to rational engineering.

Metal-organic frameworks (MOFs) are an emerging class of porous materials with remarkable surface area, tunable pore structures, and diverse chemical functionalities. In this study, we reported the green synthesis and comprehensive characterization of a novel modified NH2-MIL-101 (Cu) derived from 2-aminoterephthalic acid, followed by post-synthetic modification with terephthalaldehyde to improve its adsorption capabilities. The synthesized Cu-MOF exhibited a very high specific surface area (2037.65m2·g-1, BET), a total pore volume of 0.7465cm2·g-1 and mesoporosity with an average pore diameter of 29.06nm. SEM and TEM images showed uniform polyhedral particles with an average particle size of ≈ 85 ± 10nm, while XRD patterns displayed well-defined diffraction peaks with the most intense reflection at ~ 2θ = 28-29°, confirming high crystallinity and preservation of the MIL-101 topology after modification. Under optimized conditions (10mg adsorbent, 10 mL solution, room temperature and appropriate pH), the material exhibited high adsorption capacities of 230.1, 165.2, and 187.4mg·g-1 for crystal violet, methyl orange, and rhodamine B, respectively, attributable to its large porosity and functional surface groups. A plausible mechanism involving electrostatic interaction, π-π stacking, and coordination bonding is proposed for adsorption of dyes onto the modified MOF. The Cu-MOF maintained excellent structural stability and reusability, retaining over 92% of its initial adsorption capacity after five consecutive adsorption-desorption cycles, as confirmed by XRD patterns showing no noticeable framework collapse. This highlights its robustness and potential for sustainable wastewater remediation. In addition to dye removal, the material demonstrated antimicrobial activity, with MIC values of 4, 8, 32 and 128µg/mL for P. aeruginosa, C. albicans, E. coli, and A. fumigatus, respectively, while no inhibition was observed against Gram-positive strains at concentrations up to 4096µg/mL. The antimicrobial effect is likely attributed to Cu2+ ion release and electrostatic interactions leading to membrane disruption and ROS generation. These results highlight the potential of the synthesized Cu-MOF as a multifunctional and eco-friendly candidate for both wastewater treatment and biomedical applications.

This research aims to evaluate the adsorption performance of activated carbon derived from sorghum bagasse through a two-step activation process involving both chemical and physical activation. The sorghum bagasse precursor was first chemically activated using potassium carbonate (K?CO?) as the activating agent, followed by physical activation at 800 °C under an inert atmosphere. The resulting activated carbon was characterized using Scanning Electron Microscopy (SEM) to examine its surface morphology. Adsorption experiments were subsequently conducted employing methylene blue as a model dye at various initial concentrations to determine the adsorption efficiency. The results revealed that the K?CO?-activated sorghum bagasse carbon exhibited excellent adsorption capability, achieving a removal rate of up to 99% for methylene blue. Overall, these findings demonstrate that sorghum bagasse has considerable potential as a sustainable and cost-effective precursor for producing high-quality activated carbon with outstanding dye adsorption performance. Contribution to Sustainable Development Goals (SDGs):SDG 6: Clean Water and SanitationSDG 12: Responsible Consumption and ProductionSDG 13: Climate Action

Dyes, which have mutagenic, embryotoxic, and carcinogenic effects on terrestrial animals and resistance to degradation in the presence of air and light, have emerged as a potent pollutant of water today. Out of all developed methods to treat contaminated water, adsorption remains propitious due to its advantages such as simple process, low cost, ease, eco-friendliness, and reusability. Herein, the adsorbent epichlorohydrin-grafted nanopolyaniline (PANI-g-EC) was synthesized by the ring-opening reaction of epichlorohydrin by nanopolyaniline, where the nanopolyaniline acted as a nucleophile. The grafting of nanopolyaniline was confirmed by Fourier transform infrared (FTIR). The morphology and particle size of PANI-g-EC were examined by field emission-scanning electron microscopy (FESEM) and transmission electron microscopy (TEM), showing a sponge-like structure with an average particle size of 42 nm. The adsorption parameters such as dosage of the adsorbent, initial dye concentration, pH, temperature, and thermodynamic parameters (ΔGo, ΔHo, ΔSo) of the adsorption process were extensively studied for potential application. The maximum adsorption of dyes occurs at 35 °C in the presence of 0.16 g·L-1 adsorbent for 120 min at their respective pH. PANI-g-EC shows pH-selective adsorption of both cationic and anionic dyes with a maximum adsorption capacity of 588.55 mg.g-1 for methylene blue at pH 8 and 317.89 mg.g-1 for methyl orange dye at pH 2. The adsorption process follows the pseudo-second-order reaction kinetics and Langmuir adsorption isotherm. The electrostatic force of attraction is found to be responsible for the adsorption of dyes.

The photoanodes of dye-sensitized solar cells (DSSCs) were studied. Industrial TiO 2 nanoparticles (P25) were used to form the active layer, and hollow ZnO nanoparticles (hollow ZnO) or ZnO powder particles were coated on top of the active layer to form the scattering layer. The hollow ZnO scattering layer helps increase the amount of dye adsorption as the surface area increases and the efficiency of incident light utilization due to high scattering characteristics. As a result, the light absorption of photoanodes with hollow ZnO was about 90% higher than that of DSSC with only TiO 2 film and about 25% higher than that of DSSC with ZnO powder as a scattering layer.

ABSTRACT Huge discharge of dying effluents and their high hazard impact represent a serious threat to the ecosystem. So, this article aims to eliminate the cationic dye malachite green (MG) from an aquatic medium. This study introduces a novel, green, and cost‐effective ball milling approach to synthesize nanomagneto‐graphene oxide (NMGO) nanocomposites with enhanced adsorption capacity for dye removal, showcasing superior performance compared to conventional methods. Characterization of NMGO nanosorbent was performed via X‐ray diffractometer, high‐resolution transmission electron microscopy, scanning electron microscopy linked to electron dispersive X‐ray, Fourier transform infrared spectroscopy, and vibrating sample magnetometer measurements. The maximum MG dye adsorption capacity of NMGO nanosorbent was evaluated as a function of ball milling time interval, Fe 3 O 4 percentage, solution pH, dye concentration, temperature, NMGO dosage, and agitation time. Several mathematical isothermal and kinetic simulations were employed to model the data obtained from experiments and evaluate the superior adsorption abilities of NMGO (in mg/g). The NMGO nanocomposite exhibited a high dye removal capacity, achieving up to 300 mg/g (60%) of MG dye at optimal conditions. Kinetic modeling revealed that the adsorption process follows a pseudo‐second‐order model, with high correlation coefficients ( r 2 = 0.9999). A Langmuir isothermal monolayer was achieved. In thermodynamics expressions, the capturing of MG dye by NMGO was spontaneous (− ΔG° ), exothermic (+ ΔH° ), and highly random at the boundary of phases (+ ΔS° ). In addition, NMGO sorbent exhibited excellent uptake of dye, and preparation of NMGO by ball milling route can remarkably increase he removal capacity of the NMGO towards MG dye removal from aquatic solutions.

Dopamine triacrylamide-crosslinked chitosan/polyacrylic acid cryogels for rapid and efficient adsorption of anionic dyes from wastewater.

Top ten super-adsorbents for removal of textile dyes from wastewater.

High-entropy Fe-based spinel oxide for simultaneous electrochemical desalination and dye adsorption in textile wastewater remediation

Melamine foam xerogel as a dye adsorbent

Since water pollution constitutes a large part of the pollutants spread on the surface of the earth, pollution is unfortunately the most deadly silent weapon in the world today, especially in light of technological progress. Many efforts have been made to get rid of these pollutants. This study aimed to purify water from pollutants and determine the ideal conditions to improve the adsorption process of eosin yellow dye on the surface of activated carbon derived from walnut shells. Several studies have found that different acidity functions, contact times (512 min for dye), and temperatures (ranging from 298 to 328 K) all played an important role. The adsorption curves were also studied as they apply to Temkin and studying the kinetics of the reaction, and the second-order reaction was reached through the R2 value, which was the highest theoretical value by studying the dye in the optimized geometries in the basic case B3LYP and the basis sets 6-311G using density functional theory (DFT). The theoretical features discovered through density functional theory (DFT) simulations such as the HOMO-LUMO value can be used to identify the active sites. The aim of the theoretical study was to know the energy properties of the dye.

PEI-grafted graphene oxide modified phosphogypsum for the adsorption and removal of heavy metals and dyes in wastewater.

Synthesis and characterization of a high-performance supramolecular polymer for the adsorption of anionic dyes and iodine: a comprehensive study

Zero-valent iron nanoparticles synthesized by ultrasound for the adsorption of malachite green dye

Corrigendum to “Adsorption of malachite green dye over synthesized calcium silicate nanopowders from waste materials” [Mater. Sci. Eng. B 295 (2023) 116605

Chitosan/sodium alginate aerogels showing effective adsorption of anionic Congo Red and cationic Methylene Blue dyes for sustainable water treatment.