Study on the degradation characteristics of malachite green organic dye using microwave-synthesized MgO/Mg(OH)2 hollow nanoparticles

Advanced equilibrium study on the synthesis and characterization of Mg-doped hydroxyapatite nano-fibers as a potential enhanced adsorbent of Zn (II) and malachite green dye

This study reveals the solvent dependent third-order nonlinear optical (NLO) features of malachite green (MG) dye using Z-scan technique. MG dye is dissolved in polar solvents, including DMF, DMSO, ethanol, acetone, methanol, and 1-propanol. The study employs the Z-scan instrument, using a continuous wave (CW) laser as the excitation source, operating at a wavelength of 650nm. The closed aperture (CA) and open aperture (OA) Z-scan techniques are used to assess the nonlinear indices of refraction (n2) and nonlinear coefficient of absorption (β) of MG dye. MG dye demonstrates both saturable absorption (SA) and reverse saturable absorption (RSA) in the OA Z-scan results, due to negative and positive NLO absorption coefficients. MG dye proves a self-defocusing NLO refractive index while operating under low-power conditions. The third-order NLO susceptibility (χ3) of MG dye in various liquids are calculated to be the order of 10-6 esu. Multilinear regression fit is applied here to investigate the various intermolecular interactions between the solute and solvent. MG dye exhibited large thermo-optic coefficient of the order of 10- 3 K- 1 is observed. The results give important new information about the characteristics of MG dye and indicate potential sources of material for NLO applications in future.

Response surface methodology optimization for sorption of malachite green dye on sugarcane bagasse biochar and evaluating the residual dye for phyto and cytogenotoxicity

The aquatic ecosystem is negatively impacted by organic dye contamination, which is now one of the factors leading to environmental pollution. The present investigation involved the synthesis of nanocellulose (NC) and nanocellulose modified with NiO (NC/NiO) composite using acid hydrolysis and a one-step precipitation technique for NC and NiO, respectively. Malachite green (MG) dye was catalytically removed from an aqueous solution using the two products, which were mechanically homogenized. The produced materials were examined using different characterization techniques, like FTIR, BET, Uv-vis, XRD, SEM-EDX, and TGA. The characterization findings showed the homogeneous distribution of NiO on the NC. With MG dye serving as the model dye, an experiment was conducted to determine the catalyst’s catalytic removal ability. The catalytic degradation experiments validated the significance of NiO and the high catalytic activities of the synthesized NC/NiO composite toward the breakdown of MG dye. The kinetic study of catalytic malachite green (MG) dye removal is well-described by the pseudo-first-order kinetic model. After five reuse cycles, high removal efficiency was noted, demonstrating the composite’s remarkable stability and reusability. As a result, it was determined that the NC/NiO composite was a suitable catalyst for the degradation of a dye (MG) from the aqueous solution in the presence of H2O2, with an apparent rate constant, kapp, greater than 0.519 min−1 and a catalytic efficiency of material by 10 mg catalyst was higher than 99% within 11 min at 48℃.

Synthesis and characterization of MOF-5 incorporated waste-derived siliceous materials for the removal of malachite green dye from aqueous solution

Grafting of copolymer of sodium acrylate (SA) and acrylamide (Am) onto pectin (Pcn) was successfully performed in order to synthesis Pcn-g-P(Am-co-SA) hydrogel using combined microwave-assisted method and potassium persulfate (KPS) as a free radical initiator. The prepared hydrogel was characterized by FTIR, SEM and TGA. This hydrogel was used to remove malachite green (MG) dye from aqueous solutions. The swelling ratio of the best grade of hydrogel was 214 g/g at pH (7). Factors affecting MG dye adsorption on hydrogel (grafting percentages, pH, contact time, hydrogel dosage, dye initial concentration and temperature) were studied, and the reusability study was also investigated which, in turn, showed the high adsorption capacity of hydrogel for MG dye. The adsorption data were fitted well with Langmuir adsorption isotherm model proposing the formation of monolayer of MG dye molecules on the hydrogel’s surface with maximum adsorption capacity (5000 mg/g). Moreover, the thermodynamic studies indicated the spontaneity and exothermic nature of adsorption of MG dye on hydrogel. From the reusability study, it was found that the prepared hydrogel still retains good adsorption properties after eleven successive cycles. Therefore, Pcn-g-P(Am-co-SA) hydrogel was considered as a highly potential adsorbent for MG dye removal from aqueous solutions.

Reduced graphene oxide as an effective adsorbent for removal of malachite green dye: Plausible adsorption pathways

Application of emulsion liquid membrane for removal of malachite green dye from aqueous solution: Extraction and stability studies

A novel ternary composite (RGO-βCD-ECH) consisting of epichlorohydrin (ECH) cross-linked beta-cyclodextrin polymer (βCD-ECH) with reduced graphene oxide (RGO) as a carrier was synthesised and used for the removal of malachite green (MG) dye from water. The adsorption performance was systematically investigated in batch mode, and the optimised parameters were as follows: initial MG dye concentration 100 mg/L, solution pH 8.0, contact time 90 min, adsorbent dosage 0.4 g/L, and temperature 30°C. The adsorption data follow the Langmuir model (R2 = 0.998) and the maximum sorption capacity (qm) was 902.125 mg/g. The kinetic data of adsorption follows the pseudo-second-order kinetic model (R2 = 0.999). The positive value of ΔHo = 102.047 kJ/mol indicates the endothermic nature of the adsorption process. The effects of bed height (2–4 cm) and MG dye flow rate (5–15 mL/min) were investigated in the fixed-bed column study. The exhaustion time (te), breakthrough time (tb), and bed capacity (qbed) of the column increases with bed height increases, and the value decreases with flow rate increases. The most important feature of this adsorbent is it could efficiently and easily regenerate from the MG dye loaded composite with a negligible effect on percentage removal. These characteristics of these novel composites could exhibit a bright future in the application of MG dye removal from wastewater.

New adsorbent films for the biosorption of malachite green (MG) dye from water were prepared using polylactic acid (PLA) as a renewable, degradable and thermoplastic polymer matrix, instead of widely used crosslinked systems. Polyaniline (PANI) and carbon fibers (CFs) were added to PLA through vigorous sonication followed by a casting technique to create electrically conductive PLA-based adsorbent films with enhanced functionality and adsorption properties. The composite films were characterized using scanning electron microscopy, Fourier transform infrared spectroscopy, differential scanning calorimetry, dynamic mechanical thermal analysis, and BET-surface area measurements to identify their functionality as adsorbents for removing MG dye from water. The produced PLA/PANI/CFs composite films exhibited higher electrical conductivity and surface area compared to PLA and PLA/PANI films. The effects of adsorbent film composition, contact time, pH, and dye concentration on adsorption efficiency were assessed. The adsorption test confirmed effective removal of MG dye with maximum adsorption capacities of up to 60.1 mg/g. The isotherm data fitted the Langmuir model with an R2 value of 0.99, implying a chemisorption process. The fabricated biosorbents disclosed the first-order kinetic model with high R2 values and an exothermic reaction with the MG dye, as the process is stimulated by a decrease in temperature. Adsorbent regeneration and the significant effect of various MG concentrations on electric conductivity, which changed by two orders of magnitude, demonstrated the applicability of PLA/PANI/CFs composite films as potential MG dye sensors.

This study investigates the adsorptive removal of malachite green (MG) dye from aqueous solutions using chemically modified lime-peel-based activated carbon (LPAC). The adsorbent prepared was characterized using FTIR, SEM, Proximate analysis and BET techniques, respectively. Central composite design (CCD) in response surface methodology (RSM) was used to optimize the adsorption process. The effects of three variables: activation temperature, activation time and chemical impregnation ratio (IR) using KOH and their effects on percentage of dye removal and LPAC yield were investigated. Based on CCD design, quadratic models and two factor interactions (2FI) were developed correlating the adsorption variables to the two responses. Analysis of variance (ANOVA) was used to judge the adequacy of the model. The optimum conditions of MG dye removal using LPAC are: activation temperature (796 °C), activation time (1.0 h) and impregnation ratio (2.6), respectively. The percentage of MG dye removal obtained was 94.68 % resulting in 17.88 % LPAC yield. The percentage of error between predicted and experimental results for the removal of MG dye is 0.4 %. Model prediction was in good agreement with experimental results and LPAC was found to be effective in removing MG dye from aqueous solution.

Industrial revolution has intensified water pollution due to the indiscriminate discharge of untreated industrial effluents into water bodies, posing a serious threat to the whole ecosystem. Recently, the floating treatment wetlands system (FTWs) technique has been used as one of the most innovative, cost-effective and environment-friendly option for wastewater treatment. The present study is aimed at investigating the Malachite green (MG) dye decolorizing potential of Eichhornia crassipes (water hyacinth) through the development of a bacterial augmented FTWs. To an artificial FTWs, vegetated with E. crassipes and bioaugmented with Pseudomonas putida and Pseudomonas sp., synthetically prepared MG dye enriched wastewater was added. Among all the treatments developed, floating wetlands treatment T2 (consisting of dye, E. crassipes and Pseudomonas putida) performed the best in decolorizing the dye and in reducing values of electrical conductivity (EC), pH and total dissolved solids (TDS) of the treated water. Bacterial inoculation proved fruitful in assisting the increased MG dye decolorization in partnership with E. crassipes and also helped in aquatic plant growth promotion. MG dye toxicity effects were studied through phytotoxicity assay using FTWs treated water on Pisum sativum seeds, and satisfactory results were obtained. From experimental results, it can be seen that Eichhornia crassipes with bacterial inoculation have a strong ability to degrade and decolorize MG dye in textile effluents. We conclude that the plant-microbial assisted FTWs technique can be a unique approach to remediate the textile dye effluents before their release into water bodies.

Chemically prepared activated carbon derived from durian seed (DSAC) was used as adsorbent to adsorb Malachite green (MG) dye. The prepared DSAC was characterized using Brunauer–Emmet–Teller (BET), Fourier transform infrared (FTIR), scanning electron microscope (SEM), and proximate analysis, respectively. Batch adsorption studies were carried out for the removal of MG dye from aqueous solutions by varying operational parameters like contact time, initial MG dye concentration, solution temperature, and initial solution pH. Maximum dye removal of 97 % was obtained at pH 8. Experimental data were analyzed by eight model equations—Langmuir, Freundlich, Temkin, Dubinin–Radushkevich, Radke–Prausnitz, Sips, Vieth–Sladek, and Brouers–Sotolongo isotherms—and it was found that the Freundlich isotherm model fitted the adsorption data the most. Adsorption rate constants were determined using pseudo-first-order and pseudo-second-order rate equations, Elovich, intraparticle diffusion, and Avrami kinetic model. The results clearly showed that the adsorption of MG dye onto DSAC followed the pseudo-second-order model, and the mechanism of adsorption was controlled both by film diffusion and intraparticle diffusion. Thermodynamic parameters such as ∆G, ∆H, and ∆S were also calculated for the adsorption process. The process was found to be spontaneous and endothermic in nature. This work provided an attractive adsorbent for the removal of MG dye from wastewaters.

The presence of dye contamination in waterbodies has emerged as a widespread environmental issue and poses a significant threat to the well-being of humans and the aquatic ecosystem. Nanotechnology has emerged as a promising field in tackling dye pollution. Nanomaterials such as iron oxide nanoparticles have gained considerable interest for potential applications in treating dye-contaminated wastewater. Hence, the current work focuses on the synthesis of iron oxide nanoparticles (FMNP) using the chemical co-precipitation method and its adsorptive performance for removing malachite green (MG) dye from wastewater. The synthesized FMNP was characterized using SEM-EDS, XRD, FTIR, BET, TGA, and Raman analysis. As obtained from SEM and XRD analysis, the FMNP has cubic crystals with an average crystal size of 8.0 nm and a crystallinity of 78.643%. The average pore size, specific surface area, and micropore volume were 4.217 nm, 172.548 m2.g-1, and 0.342 cm3.g-1, respectively. Batch adsorption studies revealed that MG dye adsorption was sensitive to solution pH, initial MG dye concentration, contact time, dosage, and temperature. Under optimum conditions of pH 12, MG dye concentration 50 mg.L-1, contact time 90 min, dosage of 0.2 g.L-1, and at 328.15 K, a maximum removal of 98.814% was attained with a maximum adsorption capacity of 606.06 mg.g-1. MG dye adsorption best fits the Langmuir isotherm and pseudo-second-order kinetics. The economically feasible reusability of the synthesized FMNP is demonstrated by its consistent performance across several cycles. The results demonstrate the significance of using this mesoporous FMNP as an adsorbent for effectively treating dye wastewater.

Enhanced sono-assisted adsorptive uptake of malachite green dye onto magnesium ferrite nanoparticles: Kinetic, isotherm and cost analysis