Malachite Green Removal Research Articles

Enhanced Remediation of Textile Dyes via Nonmetal-Modified Layered Graphitic Carbon Nitride: Influence of Various Oxygen Precursors

Layered two-dimensional (2D) graphitic carbon nitride (gCN)) doped with nonmetals has been extensively utilized as a photo-electrocatalyst. Herein, gCN doped with Oxygen was synthesized through a thermal polymerization process. The effect of various oxygen forerunners, namely citric acid (CA), oxalic acid (OX), and lactic acid (LA) on the photocatalytic ability of the gCN was analyzed. The proposed O-doped gCN samples basic characteristics were characterized by different analytical analyses. Indeed, the O-gCN has formed a sheet-like nature with a nanometre range, so often called a nanosheet. Superior photocatalytic performance was measured when the gCN was prepared by the CA as the O-precursor; 95% malachite green (MG) removal was attained within a short treatment time of 40min by adding a 20mg photocatalyst. The influences of different parameters of catalyst concentration, different precursors, and initial pH of MG degradation were also studied. The generation of active radicals played a major part in the degradation of the MG dye solution. These findings offer fundamental insight into utilizing the O-gCN for the remediation of textile effluents in water resources. The preparation of enormous metal-free catalysts via non-metal doping toward the environmental clean-up.

Facile synthesis of ZnO/RGO/Fe2O3 using macroalgae Caulerpa taxifolia as green reductor and its application as malachite green removal

This study presents the synthesis of a novel ZnO/rGO/Fe₂O₃ composite using Caulerpa taxifolia as a green reductant for the effective removal of Malachite Green from aqueous solutions. Characterization techniques, including FTIR, SEM, and XRD, confirmed the successful incorporation of ZnO and Fe₂O₃ onto the rGO matrix, enhancing its adsorption properties. The composite achieved an exceptional maximum adsorption capacity of 454.5 mg/g at pH 9, significantly outperforming rGO alone and other adsorbents. The adsorption kinetics followed a pseudo-second-order model, indicating chemisorption as the dominant mechanism, with a high correlation coefficient (R² = 0.999). The adsorption isotherms were best described by the Langmuir model, suggesting monolayer adsorption. Thermodynamic parameters revealed that the process was spontaneous and exothermic, with a Gibbs free energy (ΔGo) of -10.93 kJ/mol at 25 °C. The composite's high adsorption capacity, rapid kinetics, and favorable thermodynamics highlight its potential as an efficient and sustainable adsorbent for dye removal. This research offers a promising approach to water treatment, aligning with environmentally friendly practices and providing a viable solution for mitigating water pollution caused by organic dyes. KEY WORDS: Reduced graphene oxide, Water treatment, Caulerpa taxifolia, Isothermal and kinetic studies, Malachite Green Bull. Chem. Soc. Ethiop. 2025, 39(1), 29-47. DOI: https://dx.doi.org/10.4314/bcse.v39i1.3

Biofabrication of highly effective and easily regenerated CuO nanoparticles as adsorbents for Congo red and malachite green removal

An effective and easily regenerated adsorbent is the one for which scientists are making an effort to explore. In this study, copper oxide nanoparticles (CuO NPs) were synthesized in a green manner from a leaf extract of Moringa stenopetala and used for dye adsorption. XRD, FTIR, and SEM were employed for the characterization of CuO NPs. The crystallite size of the CuO NPs was calculated via Debye–Scherrer equation from the XRD data and was found to be 8.33 nm. The Cu–O bonding bending vibration at 1116 cm− 1 and stretching vibration at 1649 cm− 1 observed from the FTIR data strongly confirmed the formation of CuO NPs. SEM morphology analysis confirmed the formation of nanoparticles with a plate-like morphology and a spherically random orientation. The zero-point charge of CuO NPs was investigated and reported to be at pH 7. The adsorption of dyes on the greenly produced CuO NPs was studied by optimizing different adsorption parameters. The removal efficiencies of the green CuO NPs adsorbent were 99.54% at the optimum conditions (pH, 4; dye concentration, 30 mg/L; amount of adsorbent, 0.25 g; and contact time, 80 min) and 98.33% at the optimum conditions (pH, 11; dye concentration, 20 mg/L; amount of adsorbent, 0.4 g; and contact time, 80 min) for congo red and malachite green, respectively. The adsorption efficiency of the biosynthesized CuO NPs for the mixture of the two dyes was 92.3%. The green synthesized adsorbent was regenerated and able to work effectively for four cycles for the two dyes. The results of the kinetics-type investigation indicate that the adsorption of both dyes by the CuO NPs adsorbent best fits a pseudo-second-order model. The isotherm model-type investigation resulted in the fitting of the Langmuir adsorption isotherm for both the congo red and malachite green dyes.

Enhanced Removal of Malachite Green from Wastewater Using Nonthermal Plasma Gliding Arc Discharge Combined with Ferrate Oxidation

The rapid and complete removal of Malachite Green (MG) dye was effectively achieved by combining potassium ferrate (Fe(VI)) treatment with nonthermal plasma discharge in both deionized water (DIW) and tap water (TW). This study evaluated the decolorization and mineralization efficiencies under varying MG concentrations, Fe(VI) dosages, and pH levels, as well as the impact of radical scavengers on the process. Fe(VI) alone resulted in moderate decolorization (35.01%) and low mineralization (21.46%) at an MG concentration of 50mg/L in DIW. Plasma discharge alone achieved mineralization rates of 20.6% in TW and 24.16% in DIW. While complete decolorization was observed for all initial MG concentrations, it required significantly longer treatment times (>30min). However, the combination of Fe(VI) with plasma (Fe(VI)-Plasma) demonstrated significant synergistic effects, achieving total decolorization and high mineralization rates -up to 92.5% in DIW and 88.7% in TW for 20mg/L MG- at much shorter treatment times. Radical scavenger tests revealed that hydroxyl radicals (OH) were the primary oxidants in MG degradation, followed by superoxide radicals and electrons. These findings suggest that the combined Fe(VI)-Plasma technology is a promising and efficient solution for dye removal, reducing both chemical usage and treatment time.

Liquid metal-embedded magnetic hydrogel beads as novel adsorbents for malachite green removal

Malachite green (MG) is widely used in aquaculture as a parasiticide. It has generated much concern due to its carcinogenesis, mutagenesis, chromosomal fractures, teratogenicity, and respiratory toxicity. Effective methods for removing MG from water or other media are highly needed. Here, liquid metal (LM) is embedded into the magnetic hydrogel to create magnetic LM hydrogel beads with high adsorption capacity. The morphology and physical properties of the LM-embedded magnetic hydrogel beads are characterized using scanning electron microscopy, optical microscopy, and texture analysis methods. The adsorption efficiency of malachite green was assessed using spectrophotometric analysis at a wavelength of 623 nm. The hardness of these hydrogel beads reached a maximum of 4610 g, and its adsorption capacity reached 10 mg/g. Under the optimal condition, 0.05 %wt LM embedded magnetic hydrogel could remove 100 % of MG. This highly efficient magnetic adsorbent for dye removal has considerable potential for rapidly separating toxic contaminants from aquatic animal tissues, providing a cost-effective and straightforward solution to reduce dye pollution in aquatic environments and food products.

Optimized Dewaxed Honeycomb Powder as a Promising and Eco-Friendly Alternative for the Removal of Malachite Green through Fixed Bed Column

Optimized Dewaxed Honeycomb Powder as a Promising and Eco-Friendly Alternative for the Removal of Malachite Green through Fixed Bed Column

Development of graphene oxide and magnesia immobilized kaolin supported dual biopolymeric hybrid material for methyl orange and malachite green removal from water

Industrial usage of various dyes seriously depends on the efficient treatment of industrial effluents. Efficient retention of waste matter using a variety of adsorbent materials has as a result turned into dangerous. In this research article, graphene oxide (GO) cum magnesium oxide (MgO) impregnated kaolin (KA) based chitosan (CS) and pectin (Pect) composite namely GO/MgO/KA/CS-Pect as an adsorbent material for effective methyl orange (MO) and malachite green (MG) removal in aquatic system. The physico-chemical properties like bonding, structural morphology and elemental composition of GO/MgO/KA/CS-Pect were explored with numerous sophisticated instrumental techniques viz., FTIR, SEM, XRD, EDAX and elemental mapping analysis. The influencing parameters of adsorption method, with effect of reaction time, solution pH, dosage, pHzpc, initial MO/MG concentration and temperature were investigated for MO and MG removal under batch scale. The removal of MO and MG rate of the GO/MgO/KA/CS-Pect was incredibly fast and the adsorption kinetic method was driven with intraparticle diffusion (IPD) and pseudo-second-order (PSO) kinetic models. The adsorption isotherm strongly well-adapted with Langmuir isotherm and the maximum removal efficiency of GO/MgO/KA/CS-Pect was found to be 45.50 and 42.00 mg/g for MO and MG respectively within 40 min. The MO and MG uptake by GO/MgO/KA/CS-Pect was majorly owing to chemical adsorption namely electrostatic adsorption, hydrogen bonding and π-π interaction mechanism. The prepared GO/MgO/KA/CS-Pect was productively regenerated with absolute ethanol and could be repetitively reused. This exploration reveals the feasibility and selectivity of the GO/MgO/KA/CS-Pect as genuine adsorbent material for removal of MO and MG from the aquatic system.

Green synthesis of a multifunctional β-cyclodextrin modified polymer sorbent using agrarian wastes of Nelumbo nucifera for the efficient sequestration of toxic dyes from polluted water

This study explores an eco-friendly strategy for the effective removal of toxic dyes Malachite Green, Methylene Blue, and Basic Magenta Dye, from water bodies, utilizing a novel β-Cyclodextrin modified Nelumbo nucifera (β-CDNN) sorbent. The sorbent was characterized using different analytical techniques, to assess its dye sorption capability. The analysis of sorption isotherm data revealed that the Freundlich model most accurately represented the equilibrium data. Kinetic studies indicated that the sorption process followed a pseudo-second-order model. At pH 5–8, the sorbent achieved maximum removal efficiencies of 96.7 %, 94.2 %, and 96.3 % for Malachite Green (402.7 mg/g), Methylene Blue (385.6 mg/g), and Basic Magenta Dye (401.03 mg/g), respectively, at equilibrium time 60 mins for MAG & MEB and 80 mins for MAD. The maximum swelling capacity of β-CDNN was recorded at 180.4 % and selectivity assay was performed via a MAG-AO7 dye mixture. The sorbent reusability was recorded for six consecutive cycles without much loss in efficiency. Additionally, β-CDNN exhibited a removal efficiency of 91.3 % in real dye samples. The findings highlight the rapid dye adsorption capabilities of β-CDNN, establishing it as a versatile, cost-effective, and environmentally friendly solution for water remediation, while also underscoring the beneficial use of bio-waste materials.

Facile synthesis of MIL-100(Fe)-supported zinc oxide quantum dots (ZnO/MIL-100(Fe)) for enhanced Malachite green removal

Abstract In the present study, a synthesis route for ZnO/MIL-100(Fe) composites is proposed through a one-pot synthesis at room temperature with 25% ZnO QDs, where ZnO QDs were prepared in a soft chemical route by aging process. The X-Ray diffraction (XRD) and Fourier transform infrared (FTIR) results indicated that there is a suitability between MIL-100(Fe) and ZnO/MIL-100(Fe). Scanning electron microscope (SEM) image for the composite undergoing a change due to the presence of ZnO QDs. The materials were then utilized as adsorbents and photocatalysts for the removal of Malachite Green (MG) from aqueous solutions. As a result, the adsorption and photocatalytic process of ZnO/MIL-100(Fe) and MIL-100(Fe) fitted well with the pseudo-second-order kinetic model. More specifically, ZnO/MIL-100(Fe) showed better photocatalytic activity than MIL-100(Fe) towards the degradation of these dyes under irradiation with 92% removal. This indicates that the increased photocatalytic performance of ZnO/MIL-100(Fe) is a benefit of the synergistic effect between the semiconductor ZnO QDs and MIL-100(Fe).

Facile Synthesis of Hierarchical Porous ZIF-8/GO Composite with Enhanced Adsorption Capacity for Malachite Green Removal

Facile Synthesis of Hierarchical Porous ZIF-8/GO Composite with Enhanced Adsorption Capacity for Malachite Green Removal

Zinc/Magnesium Ferrite Nanoparticles Functionalized with Silver for Optimized Photocatalytic Removal of Malachite Green.

Water pollution is a major environmental challenge. Due to the inefficiency of conventional wastewater treatment plants in degrading many organic complex compounds, these recalcitrant pollutants end up in rivers, lakes, oceans and other bodies of water, affecting the environment and human health. Semiconductor photocatalysis is considered an efficient complement to conventional methods, and the use of various nanomaterials for this purpose has been widely explored, with a particular focus on improving their activity under visible light. This work focuses on developing magnetic and photoactive zinc/magnesium mixed ferrites (Zn0.5Mg0.5Fe2O4) by sol-gel and solvothermal synthesis methods, which are two of the most important and efficient methods used for the synthesis of ferrite nanoparticles. The nanoparticles (NPs) synthesized by the sol-gel method exhibited an average size of 14.7 nm, while those synthesized by the solvothermal method had an average size of 17.4 nm. Both types possessed a predominantly cubic structure and demonstrated superparamagnetic behavior, reaching a magnetization saturation value of 60.2 emu g-1. Due to the high recombination rate of electrons/holes, which is an intrinsic feature of ferrites, surface functionalization with silver was carried out to enhance charge separation. The results demonstrated a strong influence of adsorption and of the deposition of silver. Several optimization steps were performed during synthesis, allowing us to create efficient catalysts, as proved by the almost full removal of the dye malachite green attaining 95.0% (at a rate constant of 0.091 min-1) and 87.6% (at a rate constant of 0.017 min-1) using NPs obtained by the sol-gel and solvothermal methods, respectively. Adsorption in the dark accounted for 89.2% of the dye removal for nanoparticles prepared by sol-gel and 82.8% for the ones obtained by the solvothermal method. These results make mixed zinc/magnesium ferrites highly promising for potential industrial application in effluent photoremediation using visible light.

Valorization of hydrolyzed banana peel into activated carbons for methylene blue and malachite green removal—equilibrium and kinetic studies

Valorization of hydrolyzed banana peel into activated carbons for methylene blue and malachite green removal—equilibrium and kinetic studies

RGO/ZIF-8 Aerogel for Effective Removal of Malachite Green from Wastewater.

In this study, dopamine-modified graphene aerogel (DGA) is synthesized through a one-step hydrothermal method using graphene oxide as the precursor and dopamine as the reducing agent. Subsequently, in situ immersion synthesis is conducted to obtain ZIF-8 loaded on a dopamine-modified graphene aerogel skeleton (ZDGA), featuring a regular honeycomb interconnected mesoporosity and a high specific surface area of 532.8 m2/g. The synthesized ZDGA exhibited exceptional adsorption performance for the cationic dye malachite green. At room temperature, ZDGA achieved an impressive equilibrium adsorption capacity of 6578.34 mg/g. The adsorption process followed pseudo-secondary kinetics and adhered to the Langmuir model, indicating chemically dominated adsorption on a monomolecular layer. Intraparticle diffusion was the primary rate determinant, with π-π stacking, electrostatic adsorption, hydrogen bonding, and Lewis acid-base interactions serving as the key driving forces. It has an ideal specific surface area and good cycling performance, which highlights its potential application in dye wastewater treatment.

Renewable fuel and value-added chemicals potential of reed straw waste (RSW) by pyrolysis: Kinetics, thermodynamics, products characterization, and biochar application for malachite green removal

This study comprehensively investigates the potential of reed straw waste (RSW) for thermochemical conversion into bioenergy and value-added chemicals. The physicochemical property characterization confirmed the potential of RSW as both a renewable fuel and a source of chemical compounds. The high heating value (17.16 ± 0.20 MJ/kg), average activation energy (253.10–297.04 kJ mol−1), Gibbs free energy (153.45–158.39 kJ mol−1), and enthalpy change (248.10–292.04 kJ mol−1), underscored the significant potential of RSW for bioenergy production through pyrolysis and its compatibility for co-pyrolysis with other waste materials. Pyrolysis product analysis revealed that syngas constituted 42.25–66.48 % of the total three-phase products, with combustible components like H2, CO, and CH4 comprising 84.14–89.77 % of syngas. Bio-oil represented 18.94–35.23 % of the total three-phase products, primarily composed of phenols (30.88–46.04 %), acids (1.12–16.05 %), furans (8.84–14.46 %), ketones (9.34–16.33 %), alcohols (4.59–13.68 %), and aldehydes (5.54–11.10 %). BET and FTIR analysis of the biochar indicated that RSW biochar possessed a well-defined porous structure and abundant surface functional groups, making it capable of achieving a maximum adsorption capacity of 185.35 mg g−1 for the malachite green (MG) dye in the aquatic environment. In summary, this study holds significant implications for mitigating environmental pollution resulting from improper disposal of RSW and promoting its high-value utilization.

Graphene oxide intercalated Alk-MXene adsorbents for efficient removal of Malachite green and Congo red from aqueous solutions

Currently, adsorbents with high adsorption performance for eliminating pollutants from discharged wastewater have received many researchers’ attention. To this aim, a novel AMXGO absorbent was fabricated by intercalating graphene oxide (GO) into alkalized MXene (Alk-MXene) layer which exhibited high efficacy for the removal of cationic Malachite Green (MG) and anionic Congo Red (CR). Analysis of FTIR, XRD, SEM and TG presented that AMXGO absorbent have a typical three-dimensional layer by layer structure and abundant oxygen-containing groups and its thermal stability was remarkably improved. BET results elucidated that AMXGO1 adsorbent has larger specific surface area and pore volume (16.686 m2 g−1, 0.04733 cm3 g−1) as compared to Alk-MXene (4.729 m2 g−1, 0.02522 cm3 g−1). A dependence of adsorption performance on mass ratio between Alk-MXene and GO, initial dye concentration, contact time, temperature and pH was revealed. Maximum adsorption capacity of MG (1111.6 mg/g) and CR (1133.7 mg/g) were particularly found for AMXGO1 absorbent with a mass ratio of 3:1 and its removal for both dyes were higher than 92%. The adsorption process of AMXGO1 adsorbent for both MG and CR complies with pseudo-second-order kinetic model and Freundlich isotherm model. In addition, adsorption mechanism was explored that synergism effects as electrostatic attraction, π-π conjugates, intercalation adsorption and pore filling were the main driving force for the high adsorption performance of dye. Therefore, AMXGO adsorbent has a potential application prospect in the purification of dye wastewater.

Synthesis of a TiO2/zeolite composite: Evaluation of adsorption-photodegradation synergy for the removal of Malachite Green

Preparing by a simple method a versatile and sustainable material that can simultaneously perform effectively as an adsorbent/photocatalyst is a real challenge in wastewater treatment technology. In this work, a composite with 10% (wt%) TiO2 nanoparticles supported on zeolite (TiO2-Zeo) was synthesized by a facile-solid-state dispersion method, and characterized for their physicochemical, phase structure, microstructure, and optical properties. Characterization findings, showed that, for TiO2-Zeo catalyst, the zeolitic matrix preserved its initial structure without any alteration, while its gap energy of 3.23 eV was similar to that of the starting TiO2 material, showing that TiO2 nanoparticles were simply deposited on the surface of the zeolite support. TiO2-Zeo photocatalyst, as well as commercial TiO2 nanoparticles, tested here as a photocatalyst model in view of comparison, were used for the removal of Malachite Green dye (MG) from aqueous solution. The adsorption and photodegradation potential of the catalysts was evaluated under the same operating conditions. It was found that the adsorption kinetics for the two materials were relatively slow, and the pseudo-first-order model can describe accurately the adsorption kinetics data. The equilibrium states were reached after 140 min and 150 min for MG/TiO2-Zeo and MG/TiO2 systems. At 0.5 g.L-1 dose of TiO2-Zeo, the adsorption capacity of MG at equilibrium, and the removal efficiency obtained with 25 mg.L-1 and 35 mg.L-1 were 41.2 mg.g-1 (82.3%), and 46.9 mg.g-1 (65.6%), respectively. Whereas, after 240 min UV irradiation, the obtained values in synergistic adsorption-photodegradation dye removal were superior, namely 47.4 mg.g-1 (92.7%) and 63.6 mg.g-1 (90.2%), respectively. On the other hand, within the range of operating conditions considered, the overall kinetic rate of synergistic adsorption-photodegradation was also simulated using the modified Elovich heterogeneous kinetic model in the two following scenarios: for strong and weak adsorption. Based on the goodness-of-fit criteria values obtained with the two used catalysts, the model appeared globally very consistent with kinetic data in both cases, with a perfect agreement in the strong adsorption case.

Valorization of cardboard waste adsorbents for efficient malachite green removal – equilibrium, kinetics, and thermodynamics

ABSTRACT This work was aimed at evaluating the adsorptive properties of cardboard waste-based adsorbents for malachite green removal. The adsorbents were produced through hydrothermal carbonization and/or phosphoric acid activation and characterized for specific area, surface morphology, and functional groups. Batch adsorption was performed at varying concentrations, contact times, and temperatures. Results show that the activated carbon derived from cardboard waste with surface area of 196 m2/g exhibits a 134 mg/g (31.6%) adsorption capacity of malachite green. On the other hand, the cardboard hydrochar displays a peak capacity at 400 mg/g (94%) due to dye precipitation before the magnitude subsides to 47 mg/g (5.7%) at higher concentration of 820 mg/L. The equilibrium data of activated carbons could be well described by the Langmuir model, while the kinetics fitted well with the pseudo-second order model. The adsorption of malachite green is endothermic and spontaneous at high solution temperature.

Droplet photopolymerization as new strategy for the rapid preparation of hydrogel beads for malachite green removal

Green and efficient preparation of hydrogel beads remains a great challenge. In this study, the hydrogel beads (AGSP) were directly prepared within 10 s from drop-out to drop-down of the droplets in paraffin oil under green LED irradiation using sodium acrylate and acrylamide as the functional monomers, methacrylated carboxymethyl chitosan (CMCSG) as a crosslinker based on carboxymethyl chitosan and poly(ethylene glycol) as porogen. Molar ratios of monomers were modified to optimize the adsorption of hydrogel beads, and the optimal adsorption capacity for malachite green (MG) was 503.33 mg·g−1. Scanning electron microscopy (SEM), thermogravimetric analysis (TGA), X-ray photoelectron spectroscopy (XPS), and fourier transform infrared (FTIR) spectroscopy were used to determine the structural characteristics of the hydrogel beads. The removal of MG by AGSP was investigated and the adsorption kinetics and isotherms were calculated to understand the adsorption mechanism. Our research provides a green and efficient technique for preparing hydrogel beads for dye removal.

Marine macro algae‐derived activated carbon an efficient bio‐sorbent for Malachite green removal from wastewater

AbstractExtensive use of dyes by the textile industries poses a serious threat to the aquatic flora and fauna. Low‐cost bio‐sorbent derived from marine red, Gracilaria verrucosa (RAC), and green macroalgae, Enteromorpha intestinalis (GAC) have been used for effective removal of unsafe Malachite Green (MG) dye. Batch study was conducted to determine the different bio‐sorption parameters such as biochar dosage, pH, initial concentration of MG, and contact time including MG bio‐sorption capacities. The physicochemical characterization results show the presence of lower crystallite sizes, and active functional groups such as carbonyl, hydroxyl, carboxyl, sulfate and amine with the mesoporous morphology of the algal biochar. The FT‐IR, XRD and SEM analyses were also performed to characterize the structural investigation of adsorbents. The kinetics of adsorption such as pseudo‐first‐order and pseudo‐second‐order were analyzed and pseudo‐second‐order confirms about the nature of process to be chemisorption. The bio‐sorption test for 20 mg/L of initial MG at an equilibrium time of 90 min by RAC showed maximum removal efficiency of about 97.49% at pH 8 whereas GAC showed a removal efficiency of 93.37% at pH10. Thus, marine macroalgae RAC and GAC can be a substitute for the commercially available adsorbents for degradation of dyes from textile effluents.

Hydrogen Peroxide Treated Desiccated Coconut Waste as a Biosorbent in Malachite Green Removal from Aqueous Solutions

Hydrogen Peroxide Treated Desiccated Coconut Waste as a Biosorbent in Malachite Green Removal from Aqueous Solutions