Removal Of Malachite Green Dye Research Articles

A novel method for biosynthesis of copper oxide nanoparticles using banana blossom and E-waste: characterization and application in malachite green dye removal through response surface methodology optimization

Textile dyes pose a significant threat to water resources, adversely affecting living organisms. Treating such contaminated water demands sophisticated technology, often expensive and requiring meticulous care. The use of copper oxide nanoparticles as a photocatalyst for degrading textile dyes is a promising solution. However, conventional chemical synthesis of copper oxide nanoparticles can be lengthy and environmentally unfriendly. To address this, a green technology approach was adopted in this research. A novel process was developed by extracting copper sulfate solution from E-waste, utilizing it as a precursor. Simultaneously, banana blossom extract (Musa paradisiaca) acted as a reducing agent in the biosynthesis of copper oxide nanoparticles, serving as a biocatalyst for malachite green dye removal. Optical characterization using a UV–Visible spectrophotometer revealed a peak around ~250 nm, indicating the presence of copper oxide. Fourier-transform infrared spectroscopy identified chemical groups within the sample, and X-ray diffraction spectroscopy confirmed its crystalline nature. The morphology of the synthesized copper oxide nanoparticles was investigated using transmission electron microscopy and energy-dispersive X-ray analysis. The potential application of CuO-NP in malachite green dye removal was successfully demonstrated, achieving a dye removal efficiency of 92% under optimal conditions. A quantitative analysis of dye removal was conducted and optimized using response surface methodology and analysis of variance, which indicated significant interactions among the variables. This eco-friendly and cost-effective approach showcases the feasibility of green technology in addressing environmental challenges associated with textile dye contamination.

Enhanced degradation of malachite green through heterogeneous processes using an iron oxide catalyst

Abstract This laboratory-scale study investigated the removal of Malachite Green (MG) dye using the goethite composite (α-FeOOH) (GOE). In the dark, an interaction between MG and GOE, attributed to physical adsorption, was observed, reaching 28 % after 4 h and confirmed by FTIR analysis. The addition of hydrogen peroxide (H2O2) enhanced the thermal process in the MG-GOE system. By varying parameters such as pH, GOE concentration, and H2O2 amount, the MG disappearance rate increased with higher GOE and H2O2 concentrations. Alkaline pH favored dye removal. Under UV light (365 nm), GOE effectively degraded MG, especially at pH 9 (97 % degradation in 180 min). The scavenging of hydroxyl radicals (˙OH) by tert-butanol in the GOE-MG-UV365nm system indicated ˙OH-dominated degradation. Fe(II) formation monitoring supported this result. Additionally, H2O2 addition significantly enhanced photodegradation. Partial mineralization of dye molecules was observed via Total Organic Carbon (TOC) analysis. The kinetics of MG degradation followed pseudo-first order behavior. Overall, this promising process holds potential for recalcitrant environmental pollutant removal.

Exploring the efficacy of Pongamia pinnata-induced silver nanoflowers for efficient adsorptive degradation of malachite green dye

In this study, silver nanoflowers were synthesized due to catalytic reduction of silver ions by phytochemicals of Pongamia pinnata seed cake extract (PSCAgNPs) in 24 h and subsequently used for removal of malachite green (MLG) dye. PSCAgNPs were characterized by UV–Visible spectrophotometry, scanning electron microscopy (SEM), energy-dispersive X ray spectroscopy (EDAX), Fourier Transformed Infrared Spectroscopy (FT-IR), X-Ray Diffraction (XRD) and BET analysis. The synthesized PSCAgNPs were floral in appearance, of size 18.82—23.70 nm with SPR at 430 nm and crystalline in nature. PSCAgNPs adsorbed 90.01 ± 0.17% of 50 mg/L MLG post one factor at a time analysis. Adsorption followed pseudo-second-order kinetics (k1 = 2.5E-03 g/mg.h), was observed as unilayer chemisorption as the equilibrium data best fitted Langmuir isotherm (Langmuir coefficient = 0.1724 L/mg, R2 = 0.9945). Upon interaction of MLG by PSCAgNPs, hydroxylation of MLG leads to formation of MLG carbinol in the first stage of adsorptive degradation, as evident from LCMS chromatograms.Graphical

Enhanced removal of methyl orange and malachite green using mesoporous TO@CTAB nanocomposite: Synthesis, characterization, optimization and real wastewater treatment efficiency.

This study explores the synthesis of a novel titanium oxide-cetyltrimethylammonium bromide (TO@CTAB) nanocomposite for the effective removal of malachite green (MG) and methyl orange (MO) dyes. The optimization of the nanocomposite's performance was carried out using response surface methodology (RSM). The adsorption characteristics were further evaluated through isotherm models, kinetic studies and thermodynamic analyses. The mesoporous nature of TO@CTAB was confirmed through BET analysis, revealing a pore diameter of 4.625nm. The crystalline size of TO@CTAB is 54.78nm, and its crystalline index is 70.84%. The optimal operating conditions were established based on the results obtained from the ANOVA. The Langmuir isotherm model demonstrates superior adsorption performance compared to the Freundlich isotherm model, with adsorption efficiencies of 317.46mg/g for MO and 306.748mg/g for MG. The pseudo-second-order model, with an R2 value of 0.998 and 0.997 for MO and MG, respectively, provides a more accurate and reliable explanation of the adsorption process compared to the pseudo-first-order model. Furthermore, the high reusability and minimal deterioration of TO@CTAB were observed for up to 5 cycles. The analysis of the adsorption mechanism indicates that the adsorption of MG and MO occurs through H-bonding, electrostatic and π-π interactions. A comprehensive cost analysis of the process was conducted to evaluate the cost-effectiveness; total expenditure incurred during the process was determined to be within acceptable limits. TO@CTAB was assessed using real wastewater samples, demonstrating a decolourization efficiency of 82%. Additionally, it resulted in a reduction of COD, BOD, TSS and TDS.

Exploring the Potential of Coriandrum sativum Seed Powder for the Adsorptive Removal of Malachite Green Dye

Exploring the Potential of Coriandrum sativum Seed Powder for the Adsorptive Removal of Malachite Green Dye

Preparation and characterisation of chitosan/bacterial Escherichia coli biocomposite for malachite green dye removal: modeling and optimisation of the adsorption process

ABSTRACT Herein, a new biocomposite was obtained by loading a bacterial suspension of Escherichia coli onto a chitosan matrix to produce a unique biocomposite (chitosan – E. coli) with effective properties for biosorption of malachite green dye from water. The physicochemical characteristics of the chitosan – E. coli biocomposite were studied by employing XRD, FTIR, FESEM-EDX and pHpzc. The optimisation of biosorption conditions was achieved using a Box-Behnken Design (RSM-BBD) to assess the effect of variables on the dye removal: biocomposite dose (0.02–0.1 g/100 mL), pH (4–8) and contact time (10–300 min). The optimal conditions for dye removal (84.3%) were achieved with a chitosan – E. coli dose of 0.1 g/100 mL, and a contact time of 160 minutes with a pH of 8. The equilibrium and kinetic experimental findings show the biosorption of malachite green dye by chitosan – E. coli follows the Langmuir and pseudo-second-order models, respectively. The maximum dye adsorption capacity (q max ) of malachite green for the chitosan – E. coli biocomposite was 164.7 mg/g, where the dye adsorption mechanism was attributed to several effects such as hydrogen bonding, n-π interactions, and electrostatic attraction. Thermodynamic analysis indicated that the biosorption process was spontaneous and endothermic, with a positive enthalpy change (ΔH° = 40.9 kJ/mol) and a negative Gibbs free energy (ΔG°) at all tested temperatures. The biocomposite chitosan – E. coli adsorbent exhibits favourable cationic dye adsorption that is anticipated to have utility for remediation of dye effluent in industrial wastewater.

Enhanced Adsorption and Photocatalytic Activity of Vertically Oriented TiO2 Nanotube Arrays by Li Incorporation

A highly efficient, solid, and easily maneuverable adsorbent and photocatalyst, Li‐incorporated titanate nanotubes that manifest adsorption efficiency of 98.1% and photocatalytic efficiency of 99.6% in 60 min and 97.8% and 98.5%, respectively, in a shorter duration of 20 min, is synthesized by a facile two‐stage electrochemical technique. The modified nanotubes exhibit good cyclic stability of 93.7% photodegradation of malachite green dye after three continuous cycles. The adsorption data show the highest correlation for second‐order pseudo kinetics and Freundlich isotherm, suggesting multilayer chemisorption with an adsorption capacity of kF ≈ 219.51 mg1–1/nL1/ng−1. Fourier transform infrared spectroscopy (FTIR) analysis of the adsorbent before and after the adsorption corroborates the findings. X‐Ray photoelectron spectroscopy reveals the formation of a larger number of oxygen vacancies (Ti3+/Ti2+) that facilitate more carrier release for the production of reactive oxygen species during photocatalysis. X‐Ray diffraction and transmission electron microscopy analysis confirm a secondary rutile phase formation on Li doping that promotes heterogeneous multilayer adsorption. Field‐emission spectroscopic studies reveal a change in the morphology of the doped tubes with porous aggregate formation on the surface. The structural, morphological, and compositional change brought about by Li incorporation facilitates the use of titania nanotubes as an efficient adsorbent cum photocatalyst in the removal of malachite green dye.

Effective removal of malachite green dye by eco-friendly pectin-grafted poly(acrylamide-co-sodium acrylate) hydrogel from aqueous solutions

Effective removal of malachite green dye by eco-friendly pectin-grafted poly(acrylamide-co-sodium acrylate) hydrogel from aqueous solutions

Adsorption of malachite green dyes from aqueous solution by metal organic framework-5 incorporated coal fly ash (MOF-5/CFA)

Dye contamination of water is a global issue with significant environmental and health risks. This research explores the use of metal organic framework-5 (MOF-5) adsorbents modified with coal fly ash to effectively remove malachite green (MG) dye from water, addressing global dye pollution. Preliminary batch adsorption experiments showed that the addition of CFA to MOF-5 significantly increased the removal efficiency of MG dye (77.90 ± 1.74%) compared to using pristine MOF-5 (30.00 ± 2.14%). Batch adsorption studies showed that MG adsorption efficiency increased with shaking rate and contact time but decreased with adsorbent dosage. Temperature study reveals exothermic behavior of adsorption process. MOF-5/CFA adsorbents can be regenerated for up to four cycles. The results demonstrated that the highest adsorption efficiency of 80.32 ± 0.90% was achieved under the following conditions: a stirring speed of 300 rpm, a dosage of 0.3 g of MOF-5/CFA adsorbent, a temperature of 27 °C, 2 h contact time, and an initial dye concentration of 100 mg/L. Analysis of adsorption isotherms and kinetics revealed that the Langmuir isotherm and pseudo-second-order kinetic models provided the most accurate fit to the experimental data. FTIR analysis revealed significant functional groups in the prepared adsorbent and only minor spectral changes in the spent adsorbents. SEM analysis showed a rough, porous MOF-5/CFA surface before dye adsorption, becoming smoother and less porous afterwards. This study demonstrates the promise of MOF-5/CFA as an alternative adsorbent for the removal of MG dyes from water, paving the way for advances in wastewater treatment and the sustainable use of industrial waste materials.

Incorporation of biomass-derived carbon dots and hydrochar into electrospun polylactic acid membranes: A sustainable zero-waste approach to highly efficient methylene blue, malachite green and neutral red dye removal

Recently, biomass-derived carbon dots (CDs) and hydrochar have gained widespread attention for environmental remediation. However, hydrochar is commonly regarded as carbon waste (CW) generated in the manufacture of CDs, and only a few reports have focused on the simultaneous application of CW and CDs. Herein, we propose a sustainable zero-waste approach for efficient dye removal by incorporating CDs and CW into electrospun membranes. CDs and CW were obtained via the one-step solvothermal carbonization of apple peels. The prepared CDs with an average size of 7.36 nm were first added to the electrospinning solution to obtain electrospun polylactic acid (PLA)/CDs fibers, followed by CW-integration via ultrasonication. The optimized PLA/CDs/CW composite exhibited high dye adsorption capacities of 141.99, 130.52, and 110.83 mg/g for neutral red, methylene blue, and malachite green, respectively. These dye adsorption capacities are significantly higher than those of the CD-loaded (70.15 mg/g for MB) or CW-loaded (52.34 mg/g for MB) composites, and are attributable to the rational loading of CDs and CW. Furthermore, the optimized composite exhibited remarkable chemical stability, stable reusability, and the ability to adsorb multiple dyes concurrently. This work provides new perspectives on the development of biomass-derived carbonaceous materials for environmental preservation and remediation.

Utilizing Fe2O3-β-CD magnetic nanocomposite for efficient removal of MG dye and Gunner 500 pesticide from wastewater

Among various techniques used for wastewater treatment, photocatalysis is one of the most preferred technique. Here, synthesis of a magnetic β-Cyclodextrin (β-CD) based Fe2O3 nanocomposite was carried out. The characterization of the synthesized materials were carried out by using P-XRD, TGA-DTA, FT-IR, PL, DRS, XPS,TEM and SEM-EDAX to study their different properties. Model pollutants Malachite green (MG) dye and Gunner 500 pesticide were selected for photocatalytic activity. These model pollutants were analysed in presence of Fe2O3 and Fe2O3-β-CD under visible light. Performance was monitored through measuring removal efficiency using UV–Visible spectrophotometer. 89.4 and 88.0 % degradation was observed with MG in 120 min and Gunner 500 in 100 min. Photocatalytic degradation efficiency was observed with initial pollutant concentration MG (10 mg L−1) and Gunner 500 (10 mg L−1) at neutral pH value. Reaction kinetics was measured and first order rate law is applicable with both pollutants. Probable mechanism and degradation pathway of pollutants were proposed. COD also favours degradation and demineralization. Reusability was also studied.

Novel tempo oxidized polyvinyl alcohol/ cellulose nanocrystal-based nanocomposite membrane for malachite green dye removal.

In this study, in-situ modification by TEMPO oxidation was performed after nanocomposite synthesis to improve its properties toward dye molecule removal. The unoxidized and oxidized polymeric-based nanocomposite was denoted as PNC6 and PNC6O respectively. The nanocomposites were characterized using FESEM, FTIR, contact angle, XRD and BET analysis. Measurements of swelling ratio and chemical stability were also performed to provide insight into the durability of the nanocomposites. The effects of changing variables included contact duration, pH of aqueous solution, initial pollutant concentration, and temperature were observed. The kinetic study showed that the experimental data is best fitted with pseudo-second-order kinetics (R2 = 0.988 and 0.997 respectively), whereas on observing isotherm data, in both unoxidized and oxidized nanocomposite it fits well with Langmuir isotherm (R2 = 0.951 and 0.993 respectively). In addition, the effects on Gibb's free energy, Enthalpy, and Entropy were measured in terms of thermodynamic characteristics, it was established that dye molecules adsorption mechanism is endothermic and spontaneous in behaviour. To check regeneration tendency of the nanocomposite seven consecutive adsorption desorption cycles were run and about 90% and 80%, regeneration ability could be seen in an unoxidized state (PNC6) and an oxidized state (PNC6O) respectively upto 5th cycle after that the tendency get reduced. This study suggests that this novel polymeric nanocomposite can be employed as an efficient and relatively inexpensive adsorbent for dye removal from aqueous solutions.

Synthesis and application of novel sodium carboxy methyl cellulose-g-poly acrylic acid carbon dots hydrogel nanocomposite (NaCMC-g-PAAc/ CDs) for adsorptive removal of malachite green dye

This study aimed on synthesizing novel sodium carboxy methyl cellulose-g-poly acrylic acid carbon dots hydrogel nanocomposite (NaCMC-g-PAAc/ CDs) to remove malachite green (MG) dye from aqueous media. The characterisation of functionalities, morphology, particle size and crystallography of NaCMC-g-PAAc/ CDs nanocomposite both before and after adsorption. The results of the characterization analysis revealed the presence of numerous ionic functionalities such as carboxyl, amino and hydroxyl groups in nanocomposite. The morphological study revealed the presence of porosity, heterogenous and amorphous nature of adsorbent favoring the adsorption of MG. Furthermore, elemental analysis also confirmed the presence of carbon and oxygen as main elemental composition of nanocomposite. The temperature of 30 °C and the nanocomposite (having pHPZC of 3) dose of 0.06 g at pH 10 results in achieving 96.92 % of MG dye removal. The experimental data fits closely with pseudo-second and Freundlich models. The enhanced MG dye adsorption by NaCMC-g-PAAc/ CDs was attributed to different mechanisms such as electrostatic or H-bonding as well as pi-pi interactions. Thermodynamically, the studied process was spontaneous and is of endothermic kind. Overall, the study reveals adsorptive property of novel NaCMC-g-PAAc/ CDs nanocomposite as a promising adsorbent for MG dye adsorption from water.

Corn stalk decorated with magnetic graphene oxide as an efficient adsorbent for the removal of cationic dye from wastewater

In this study, an in situ immersion loading method is employed to introduce graphene oxide (GO) nanosheets and hollow copper ferrite nanospheres into the ordered porous structure of alkali-activated corn stalk (CS). This approach facilitates the construction of a novel magnetic three-dimensional composite sponge (GO/CS/CuFe2O4) utilized for the efficient removal of methylene blue (MB) and malachite green (MG) dyes from wastewater samples. In this hybrid adsorbent, the stacking of GO nanosheets is inhibited due to the ordered porous structure of CS, based on which GO nanosheets are well immobilized and dispersed. In addition, the hollow CuFe2O4 nanospheres and GO nanosheets support each other, further reducing the accumulation of GO, and increasing the specific surface area of the adsorbent. The engineered morphology of GO/CS/CuFe2O4 sponges supports the maximum exposure of the active adsorption sites to the dye solution, promoting the adsorption process. Microscopy and surface analyses show that GO/CS/CuFe2O4 sponges have a rich pore structure with the specific surface area of 289.85 m2·g−1, more than 17 times higher than that of CS, significantly improving their adsorption performance for MB and MG. The maximum adsorption capacity of GO/CS/CuFe2O4 for MB and MG is as high as 243.65 and 231.53 mg/g, respectively, superior to those of many other biomass-based adsorbents. The dye adsorption performance of GO/CS/CuFe2O4 can be well described by the Langmuir adsorption isotherm and pseudo-second-order kinetic model, suggesting the existence of strong monolayer chemisorption. The FTIR and X-ray photoelectron spectroscopy (XPS) analyses show that the dye removal mechanisms observed mainly includ π-π interactions, hydrogen bonding, electrostatic interactions and pore filling. In addition, GO/CS/CuFe2O4 sponges exhibit an excellent magnetic behavior (Ms = 49.52 emu/g), enabling the adsorbent to be recycled by the application of a magnetic field. The adsorption capacities of the adsorbent for MB and MG remain 88.6 % and 90.2 % of the initial adsorption capacity, respectively, even after 10 regeneration cycles, showing its excellent reusability performance. Finally, GO/CS/CuFe2O4 is applied for the removal of MB and MG from real aqueous environments comprising the seawater, tap water and wastewater treatment plant effluent, and the removal rates are observed to be over 90 % of that achieved in deionized water. This study provides new concepts for the sustainable utilization of agricultural waste and natural structure of plants to purify dye containing wastewater.

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.

Novel magnetic chitosan Schiff base impregnated with ZnO for removal of malachite green dye from aqueous environment

Novel magnetic chitosan Schiff base impregnated with ZnO for removal of malachite green dye from aqueous environment

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 50 mg/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 (>30 min). 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 20 mg/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.

Engineered hybrid iron‐cobalt metal oxide nanoparticles for effective adsorption of malachite green dye

AbstractBACKGROUNDHybrid iron and cobalt metal oxide nanoparticles are well known; however, are not optimized in terms of size and stability. We engineered these hybrid nanoparticles using the co‐precipitation method and characterized them by various techniques, which are then used for the effective adsorption and removal of malachite green (MG) dye.RESULTSThe ideal conditions for synthesis are determined to be 50:50 ratio of Fe2O3 and CoO, pH of 11, temperature range of 40 °C–60 °C, and reactant addition time of 20 min. These hybrid nanoadsorbents effectively eliminated MG dye from aqueous solutions. Factors such as initial MG dye concentration, pH of the medium, contact time, temperature, and nanoadsorbent dose were optimized for the MG removal to achieve a maximum removal efficiency of 96.9%. Non‐linear fitting of data indicates that both Langmuir and Freundlich models provided the best fit, suggesting the presence of both monolayer and multilayer adsorption of MG on hybrid nanoparticles. The kinetics of MG dye removal are better controlled by the intraparticle diffusion (IPD) phenomenon. The adsorption of MG onto the hybrid nanoparticles was confirmed to be endothermic, with negative ΔG and positive ΔH values. The optimized synthetic conditions also positively impacted the hybrid nanoparticles which enhanced the adsorption and exhibited ferromagnetic behavior as compared to the superparamagnetic behavior reported in the literature, making them significantly important for dye removal applications.CONCLUSIONThese findings demonstrate the potential of optimized hybrid nanoparticles as effective nanoadsorbents for dye removal applications, with implications for further applications in photocatalysis and sensing. © 2024 Society of Chemical Industry (SCI).

Malachite green dye removal with aluminosilicate nanopowder from aluminum dross and silicomanganese slag

Malachite green is a persistent, bioaccumulative, mutagenic, carcinogenic, and teratogenic dye that poses significant risks in water sources, making its removal from water a critical necessity. This study aims to fabricate a sorbent comprising amorphous aluminosilicate nanopowder utilizing silicomanganese slag (SMS) and secondary aluminum dross (SAD) waste materials to remediate dye-contaminated water. The silica and alumina components of the SMS and SAD were extracted as sodium silicate and sodium aluminate leachates, respectively, through an effective hydrometallurgical conversion process. An empirical formula of Al2O3·2.3SiO2 was deduced from the X-ray fluorescence analysis of the synthesized material. The X-ray diffraction (XRD) pattern indicated the amorphous nature of the synthesized aluminosilicate, with no evidence of nanocrystals or ordered clusters observed via high-resolution transmission electron microscopy (TEM). Based on TEM micrographs, the aluminosilicate particles ranged in size from 20 to 80 nm. The synthesized aluminosilicate nanopowder was utilized to treat wastewater containing malachite green dye, demonstrating a remarkable dye removal efficiency of 97% after a 15-min contact time using 30 mg of adsorbent in a 30 mL dye solution at 200 rpm. The methodology proposed in this study could facilitate the production of amorphous aluminosilicate powder as a high-value product from industrial waste. Studies on its reusability demonstrated that it could remove over 90% of the dye after three cycles of use.

RSM-CCD directed modeling and optimization of a low-cost adsorbent based on sodium dodecyl sulfate for the selective removal of malachite green and methylene blue dyes: Kinetics, isotherm, and thermodynamics analysis

Sodium dodecyl sulfate (SDS) is widely used as a surface modifier to improve the sorption capacity of sorbents due to its high surface area, non-toxicity, biodegradability, and strong affinity for various impurities. The present works aims at investigating the efficiency of hydrogel adsorbent prepared from sodium dodecyl sulfate for treating malachite green (MG) and methylene blue (MB) dyes. An RSM-based central composite design was utilized to optimize the percentage swelling of the four key synthesis parameters: initiator concentration, monomer concentration, crosslinker concentration, and solvent. The optimal process conditions are as follows: 12.5 mM L−1 initiator, 306 mM L−1 monomer, 23 mM L−1 crosslinker, and 14 mM L−1. Additionally, the mechanism of their formation was investigated by various physical methods, viz., FTIR, XRD, Raman, H1-NMR, SEM-EDS, TGA, and BET. The applicability of the adsorbent was examined in detail as a function of time, pH, adsorbent dose, initial dye concentration, and temperature. The optimum conditions are as follows: pH=7, adsorbent amount = 0.1 g/L, and initial dye concentration = 100 mg/L, contact time = 120 min at ambient temperature. The hydrogel exhibits maximum sorption capacities of 137.74 mg g−1 for MG and 373.13 mg g−1 for MB, respectively. The mechanism of dye adsorption has been established, and the kinetic study suggests that the adsorption follows a pseudo-second-order reaction. Furthermore, the adsorption isotherms at different equilibrium conditions fit well with the Langmuir adsorption model, indicating a chemisorption process. Thermodynamic analyses justified the spontaneous and exothermic nature of dye adsorption, primarily through electrostatic interactions. The adsorption–desorption study of the resulting hydrogel exhibited excellent adsorption efficiency of 42.07 % for MG, and 63.35 % for MB, and desorption efficiency of MG was lowered from 55.3 % to 22.63 % and MB from 35.57 % to 18.8 % even after 5 consecutive cycles. Consequently, this sorbent provides a versatile and sustainable solution for treating dyes waste water.