Adsorption Of Malachite Green Dye Research Articles

Zinc oxide decorated plantain peel activated carbon for adsorption of cationic malachite green dye: Mechanistic, kinetics and thermodynamics modeling

Reports have shown that malachite green (MG) dye causes various hormonal disruptions and health hazards, hence, its removal from water has become a top priority. In this work, zinc oxide decorated plantain peels activated carbon (ZnO@PPAC) was developed via a hydrothermal approach. Physicochemical characterization of the ZnO@PPAC nanocomposite with a 205.2 m2/g surface area, porosity of 614.68 and dominance of acidic sites from Boehm study established the potency of ZnO@PPAC. Spectroscopic characterization of ZnO@PPAC vis-a-viz thermal gravimetric analyses (TGA), Fourier Transform Infrared Spectroscopy (FTIR), Powdered X-ray Diffraction (PXRD), Scanning Electron Microscopy and High Resolution – Transmission Electron Microscopy (HR-TEM) depict the thermal stability via phase transition, functional group, crystallinity with interspatial spacing, morphology and spherical and nano-rod-like shape of the ZnO@PPAC heterostructure with electron mapping respectively. Adsorption of malachite green dye onto ZnO@PPAC nanocomposite was influenced by different operational parameters. Equilibrium data across the three temperatures (303, 313, and 323 K) were most favorably described by Freundlich indicating the ZnO@PPAC heterogeneous nature. 77.517 mg/g monolayer capacity of ZnO@PPAC was superior to other adsorbents compared. Pore-diffusion predominated in the mechanism and kinetic data best fit the pseudo-second-order. Thermodynamics studies showed the feasible, endothermic, and spontaneous nature of the sequestration. The ZnO@PPAC was therefore shown to be a sustainable and efficient material for MG dye uptake and hereby endorsed for the treatment of industrial effluent.

Novel alkali intercalated and acid-exfoliated biochars with enhanced surface areas for contaminant adsorption applications

Cost-effective and eco-friendly adsorbents are essential in environmental engineering and biochar is a promising material from the perspective. A novel and efficient surface modification approach involving alkali intercalation and acid exfoliation was designed in this study to enhance the physicochemical properties of biochar. The alkali intercalation process utilizes potassium hydroxide (KOH), while acid exfoliation involves varying HNO3, H2SO4, and H3PO4 concentrations. A simple two-stage pyrolysis process was employed to facilitate the intercalation-exfoliation modification. The modified biochars were characterized using BET, SEM, XRD, etc., to understand physicochemical properties. To quantify the effectiveness of the modifications, adsorption of malachite green dye as a model moiety was investigated. Dye removal sorption rates exceeding 99 % were recorded in the case of the biochars modified through a two-step process using KOH and 0.1MH3PO4. Specifically, the highest contaminant removal of 99.9 % was recorded when 60 mg of the KOH-0.1MH3PO4 biochar was employed, which is significantly higher than unmodified biochar’s 45.41 % removal at a higher dosage of 100 mg. Moreover, the adsorption kinetics revealed that all the modified biochars attained the maximum removal concentrations (∼99 % removal) in a mere 300 min, indicating a tenfold improvement in adsorption rate from unmodified biochar's requirement of over 5000 min. The results achieved through this study provide a cost-effective, fast, and environment-friendly technology for enhancing the adsorption characteristics and performance of biochars toward contaminant removal.

Removal of malachite green from wastewater using date seeds as natural adsorbent; isotherms, kinetics, Thermodynamic, and batch adsorption process design

This research explores the feasibility of using date seeds (DS), an agricultural waste, for the adsorption of malachite green (MG) dye from synthesized wastewater. The characterization of the DS before and after adsorption was accomplished by FTIR, SEM, BET, and EDX measurements. Batch adsorption experiments were investigated for MG dye adsorption from aqueous solution onto the DS. The effect of different parameters such as solution pH, adsorbent dose, contact time, temperature, and the initial dye concentration were studied. The optimum pH, adsorbent dose, temperature, and contact time for the dye removal were found to be 5, 0.1 g, 25 °C, and 30 min, respectively. The equilibrium studies for the data with Langmuir, Freundlich, and Temkin isotherms showed that Freundlich isotherm is the best model to describe the adsorption of MG onto the DS particles which has a heterogeneous surface. It was found that the adsorption process follows a pseudo-second-order kinetic model which revealed that the intra-particle diffusion stage is the rate-controlling stage for the process. The thermodynamic parameters ΔG, ΔS, and ΔH suggest the possibility of chemisorption and physisorption simultaneously and indicate the exothermic and spontaneous characters of the adsorption of MG dye on DS with negative values of ΔH and ΔG.

Preperation of sodium alginate-based SA-g-poly(ITA-co-VBS)/RC hydrogel nanocomposites: And their application towards dye adsorption

A superabsorbent polymer, Sodium Alginate-g-Poly (Itaconic acid-co-Sodium 4-vinyl benzenesulfonate)/ Ricinus communis (SA-g-P(ITA-co-VBS)/ RC) hydrogel, was prepared by free-radical graft co-polymerization for sequestration of toxic malachite green (MG) dye as a cationic dye model. The surface morphological of shape and composition of the prepared hydrogel used have been characterized by FESEM, EDX, TEM, FTIR, X-ray diffraction XRD, and TGA. Optimizing the synthesis conditions for prepared a hydrogel with the highest swelling ratio have been studied, the results show that employing 0.08 g KPS and 0.09 g MBA, 1.0 g ITA, 2.0 g VBS, 1.0 g SA, and 1.0 g RC, the composites greatest swelling capacity in distilled water was 3400 %. It was discovered that the dye adsorption capacity of the polymer was greatly impacted by the monomer VBS level in the hydrogel, which gives it a better ability to swell. The porosity of the hydrogel spheres, thus significantly enhancing the MG adsorption capacity with the rate-limiting controlled by chemical adsorption, intraparticle diffusion, and film diffusion. Study the influence of different reaction conditions on the removal of MG dye from aqueous solution are adsorbent dose, pH, zero-point charge, temperature, thermodynamic adsorption, adsorption isotherm, and kinetic models have been done. Additionally, (SA-g-P(ITA-co-VBS)/RC) demonstrated strong MG dye adsorption capabilities and reusability in at least four adsorption-desorption cycles this process indicating its considerable potential for use as the adsorbent for dye removals from aqueous solution.

Novel Cs-Co3O4@g-C3N4 nanocomposite constructed for malachite green dye adsorption

The present study focuses on synthesizing a novel nanosorbent, Cs-Co3O4@g-C3N4, via the sol–gel method assisted by ultrasonic power. The synthesized ternary composite was found to include the Cs2O, Co3O4 and g-C3N4 phases, Cs, Co, O, N and C elements, 28.68 m2/g surface area as provided by the XRD, EDX –XPS and nitrogen adsorption techniques. In addition, the images of metal oxide nanoparticles dispersed within the g-C3N4 sheets, as evidenced in the TEM results provided visual proof for the composite formation. The effectiveness of this nanosorbent in adsorbing a commonly used dye, Malachite green (MG) was thoroughly studied. The MG dye adsorption performance was investigated using equilibrium and kinetic investigations. The results indicated that the adsorption process followed the Langmuir monolayer isotherm and exhibited second-order kinetics. The adsorption capacity of MG dye was found to be 1472 mg/g, with the primary interaction being attributed to electrostatic attraction. This interaction is enhanced by the smaller size and increased surface area of the Cs-Co3O4@g-C3N4 nanosorbent, leading to superior adsorption. The findings of this study advocate that the newly developed Cs-Co3O4@g-C3N4 nanosorbent has the ability to effectively remove MG dye and other dyes, making it highly relevant for applications in industrial wastewater treatment.

Magnetic hydrochar grafted-chitosan for enhanced efficient adsorption of malachite green dye from aqueous solutions: Modeling, adsorption behavior, and mechanism analysis

Water pollution by organic dyes is one of the most serious environmental problems worldwide. Malachite green (MG) is considered as one the serious organic dyes which is discharged in wastewater by leather and textile manufacturing plants. MG dye can cause severe hazards to the environment and human health. Therefore, the removal of MG dye from wastewater is very important and essential. This study aims to synthesize a new magnetic hydrochar grafted to chitosan (MWSHC@CS) for the removal of MG dye from the aqueous solutions. Transmission electron microscopy (TEM), Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), Brunauer-Emmett-Teller (BET) surface area, and Zeta potential analysis were used to characterize the synthesized MWSHC@CS. Batch experiments were conducted to optimize MG dye adsorption conditions, including adsorbent mass, pH, temperature, initial concentration, and contact time. The results revealed that MWSHC@CS had an excellent removal efficiency (96.47 %) for MG dye at the optimum condition (at m: 20 mg, pH: 7.5, t: 420 min, and T: 298 K). Adsorption isotherms outcomes revealed the MG adsorption data were best fit by the Langmuir model with a maximum adsorption capacity (420.02 mg/g). Adsorption kinetics outcomes exhibited that the adsorption process of MG dye fitted well to the Elovich model. The thermodynamic results revealed that the adsorption process was physical, exothermic, and spontaneous. The adsorption mechanisms of MG onto MWSHC@CS were hydrogen bonding, electrostatic interaction, and π-π interactions. Furthermore, MWSHC@CS showed excellent reusability for the removal of MG over five cycles of adsorption-desorption (83.76 %). In conclusion, the study provides a new, low-cost, and effective magnetic nanocomposite based on chitosan as a promising adsorbent for the high-performance removal of MG dye from aqueous solutions.

A comparative study on the malachite green dye adsorption of chemically synthesized and green MgFe2O4 nanoparticles using gerbera floral waste extract.

The situation of discharging a large amount of dyes from the textile industries has caused many adverse effects on human health and the ecosystems. Emerging bio-nanomaterials represent a new trend in efficient dye removal in aqueous media. Herein, we mention that MgFe2O4 bioprepared using gerbera extract has been successfully used to adsorb malachite green (MG) in water. A comparison was made to determine the dye removal efficiency between biogenic MgFe2O4 (MFOB) and chemical MgFe2O4 (MFOC). The spherical MFOB material exhibited a large surface area of 85.0 m2 g-1 and high crystallinity. The obtained outcomes showed that the highest adsorption capacity of MG dye was 584.49 mg g-1 at a MFOB dose of 0.05 g L-1 and MG concentration of 10 mg L-1. Higher correlation coefficients in the Langmuir isotherm suggested monolayer adsorption of MG. The Box-Behnken design and response surface method were established to optimize MG removal percentage under the conditions, i.e., initial MG concentration (10-30 mg L-1), adsorbent dose (0.02-0.08 g L-1), and pH of dye solution (6-8). MFOB had good reusability with high removal efficiencies after three continuous cycles. Post reuse, this adsorbent still showed excellent stability through the verification of their structural properties in comparison with fresh MFOB, showing potential for practical applications.

Malachite green dye adsorption from wastewater using pine gum-based hydrogel: Kinetic and thermodynamic studies

In this study, a novel Pn-g-poly(AAm) hydrogel was synthesized via free radical polymerization, using pine gum as the backbone material and polyacrylamide as the monomer. By employing response surface methodology and central composite design, various process parameters were optimized, achieving an optimum 1325 % maximum swelling. The optimized quantities were 0.085 g of initiator, 1.4 g of monomer, 0.013 g of crosslinker, and 14 ml of solvent. The physio-chemical characterizations were conducted using XRD, FE-SEM, FTIR, BET, and TGA. BET analysis showed a specific surface area of 34.973 m²/g and a pore volume of 0.104 cc/g. In adsorption studies, the highest removal (97 %) of malachite green (MG) dye was observed at pH 7, a temperature of 25 °C, a contact time of 5 h and 30 min, an adsorbent dose of 0.08 g, a dye concentration of 50 mg/L, and a shaking speed of 150 rpm. The adsorption data followed pseudo-second-order kinetics and Langmuir isotherm models, with a maximum adsorption capacity of 120.772 mg g−1. Furthermore, thermodynamic studies yielded ΔH° at 106.123 KJ/mol and ΔS° at 382.618 J/mol. These results collectively demonstrate the potential of this adsorbent for effectively treating industrial wastewater pollutants.

Neem flower (Azadirachta indica) activated with sintered-CaP for enhanced adsorption of malachite green dye—adsorption, kinetic, and thermodynamic studies

Neem flower (Azadirachta indica) activated with sintered-CaP for enhanced adsorption of malachite green dye—adsorption, kinetic, and thermodynamic studies

Synthesis of carbon nanofiber incorporated with TiO2 nanoparticles for malachite green removal from water: Statistical and kinetics studies

Carbon nanofiber incorporated with titanium nanoparticles (TiO2-CNFs) was designed, characterized, and evaluated for the adsorption of malachite green dye (MG). The experimental variables which impact the malachite green (MG) removal such as dosage of composite (100–600 mg), the concentration of dye (1–30 mg/L), pH level (2–8), and contact time (15–60 min), were systematically optimized. Factorial design analysis was conducted to estimate the significance level of the experimental variables used in the factorial design. MG adsorption equilibrium data fitted to Langmuir isotherm modeling (R2 = 0.996) and high adsorption capacity (qm) of TiO2-CNFs composite was determined as 439.2 mg g−1 from this model under the optimized experimental circumstances as pH 5, solution temperature (23 °C), adsorbent dose (300 mg) and contact duration (30 min). The kinetic findings exhibited relatively higher R2(0.997) for PSO than the PFO model for the adsorption mechanism of MG onto the nanocomposite adsorbent. The primary adsorption mechanisms were proposed as hydrogen bonding and electrostatic attraction between the cationic MG dye and TiO2-CNFs composite. These results revealed that TiO2-CNFs composite was a stable sorbent for MG adsorption and could be used up to six adsorption cycles with insignificant change in its removal capacity. The results exposed that the synthesized TiO2-CNFs composite adsorbent is very efficient for MG adsorption from wastewater.

Response surface methodology-based modeling and optimization of fenugreek gum-based hydrogel for efficient removal of malachite green dye

This research work describes the synthesis of a fenugreek gum (FG)-based hydrogel (FG-g-poly(AAm)) via free radical polymerization for the removal of malachite green (MG) dye from an aqueous solution. The effects of various parameters such as backbone amount, initiator, monomer, cross-linker, and solvent on the percentage swelling were investigated using a 2-level-5-factor central composite half fraction design as an experimental design for response surface methodology. The model was found to be significant with a maximum percentage swelling of 1360%. The formation of a crosslinked network was validated by FTIR, TGA, XRD, BET, and FE-SEM characterization techniques. The surface area and average pore radius of the prepared FG-g-poly(AAm) were found to be 0.695 m2/g and 18.124 Å, respectively. The synthesized FG-g-poly(AAm) hydrogel was examined for the adsorption of MG dye from an aqueous solution as a function of time, pH, adsorbent dose, initial dye concentration, and temperature. The prepared hydrogel showed a maximum sorption capacity of 585 mg/g, as confirmed by pseudo-2nd-order kinetic and Langmuir adsorption models, revealing adsorption's chemisorption nature. The positive values of ΔHo and ΔSo showed that an endothermic process accompanied the adsorption process and had an affinity for dye molecules. The synthesized hydrogel can be used as a candidate for cationic dye removal.

Malachite green dye adsorption by jackfruit based activated carbon: Optimization, mass transfer simulation and surface area prediction

The exposure of basic dye towards human and environment can caused severe adverse effects. Hence, this study aimed (i) to optimize the adsorption of malachite green (MG) dye onto jackfruit peel based activated carbon (JPAC) by using response surface methodology (RSM) and (ii) to simulate the mass transfer process using Polymath mass transfer (PMT) model. The RSM revealed that the optimum activation temperature, activation time and potassium hydroxide (KOH) impregnation ratio, IR to be 782 °C, 1 h and 2.96 g/g which translated into 66.80 mg/g of MG adsorption and 34.52 % of JPAC's yield. The Freundlich isotherm model described the adsorption process the best while the Langmuir monolayer adsorption capacity was computed to be 376.33 mg/g. The kinetic data obeyed the PMT model the best where the rate constant, KPMT decreased from 1.20 to 0.41 h−1 as the MG concentration increased from 25 to 300 mg/L. Also, the PMT model was succeeded in predicting the surface area, aPMT of JPAC to be 807.77 m2/g and this value is comparable with the actual JPAC's mesopores surface area of 714.25 m2/g (error 11.58 %). The adsorption of MG onto JPAC was aided by several functional groups such as primary or secondary alcohol, non-bonded hydroxy group and methoxy through ion-dipole force and dipole-dipole force. Based on thermodynamic parameters, MG-JPAC adsorption system was endothermic in nature (∆H° = 37.12 kJ/mol), had an increment of randomness at solid-liquid interface (∆S° = 0.19 kJ/mol·K), spontaneous in nature (−20.11 kJ/mol) and physisorptionally governed (Ea = 9.46 kJ/mol).

Adsorption of malachite green dye over synthesized calcium silicate nanopowders from waste materials

The synthesis of calcium silicate (CS) nanopowders from marble sawing dust and silica fume using microwave irradiation (MWI)-assisted route has been studied. Coalesced tiny cubes and rods with flower-like shapes in the range of ∼ 150 nm in size with a surface area of 18.357 m2g−1 have been obtained as observed from FE-SEM images and detected by BET measurements, respectively. According to the Langmuir isotherms, increasing the temperature from 30 to 45 °C increases the maximum monolayer adsorption capacity, qmax, from 13.44 to 59.95 mg/g. The kinetic studies indicated that the adsorption kinetics of malachite green dye (MG) over calcium silicate nanopowders followed the pseudo-first-order with a high correlation coefficient (R2) of 0.7901. The experimental results also showed that the MG dye adsorption fitted better with the Freundlich model with a high correlation coefficient (R2 = 0.9474) which suggested the multilayer physisorption process. The calculated thermodynamics parameters (ΔG° = 0.019 to − 2.898 kJ mol−1, ΔS° = 109.83 J mol−1 and ΔH = 32.79 kJ mol−1) declared the adsorption feasibility, with degrees of randomness. In our study, adsorption measurements, schemes, and mechanism have been discussed to shed light on the advances in this field. The MWI route using waste raw materials will significantly lower overhead costs of adsorbent synthesis and will allow development in wastewater treatment.

The Lantana camara L. stem biomass as an inexpensive and efficient biosorbent for the adsorptive removal of malachite green from aquatic environments: kinetics, equilibrium and thermodynamic studies

Plant biomass is one of the available and economic biomaterials used to remove environmental pollutants. The presence of colored compounds in aqueous solutions is one of the problems that can be solved by biological methods. Herein, the efficiency of available and inexpensive biomass obtained from Lantana camara L. stem for cationic dye uptake has been evaluated. The effect of operational factors, including dosage of L. camara L. stem biomass (LSB), pH of the solution, initial concentration of malachite green (MG), and residence time on the optimal conditions of analyte uptake was studied. The experimental data of adsorption studies fit with P-S-O kinetic () and L.I.M (), indicating MG dye adsorption onto LSB occurred in monolayers due to its chemical affinity. The maximum uptake capacity of LSB for the removal of MG dye was 100 mg g−1. Thermodynamic parameters, including (from −2.13 to −2.469 ), (+2.916 ), and (+16.934 ) suggested that the adsorption process was endothermic and spontaneous. The results revealed that LSB considerably has potential for adsorptive removal of cationic dyes such as, MG from aquatic environments.

Malachite Green Dye Adsorption from Aqueous Solution using a Ni/Al Layered Double Hydroxide-Graphene Oxide Composite Material

Ni/Al layered double hydroxide and Ni/Al-graphene oxide composite materials were created using the coprecipitation method. The materials were successfully synthesized and prepared using XRD, FT-IR, and BET studies. The optimal pH as a result of malachite green dye adsorption is pH 4. The kinetics models of all materials follow the pseudo second order model. After being composited with graphene oxide, the maximum adsorption capacity of Ni/Al layered double hydroxide increased from 99.010 to 111.111 mg/g. All materials’ isotherm models adhere to the Langmuir isotherm model. The adsorption process was endothermic and spontaneous. The Ni/Al-graphene oxide composite material has a more stable structure than the Ni/Al layered double hydroxide. The regeneration procedure was repeated five times, and the Ni/Al-graphene oxide composite material did not show a significant decrease until the fifth cycle, when it dropped from 97.561 to 77.046%, however the Ni/Al layered double hydroxide material dropped rapidly from 85.00 to 5.667%.

Adsorption of Melachite Green onto Activated Carbon Prepared from Clerodendrum serratum

The Clerodendrum serratum leaves obtained from nearby Nagai district, it was used as an adsorbent for the removal of malachite green dye from aqueous solution. The various factors affecting adsorption, such as initial dye concentration, contact time, adsorbent dose and initial pH of solution were evaluated on adsorption of malachite green dye on activated Clerodendrum serratum carbon. The equilibrium adsorption isotherms were analyzed by Langmuir and Freundlich equations. Both Langmuir and Freundlich models can describe the adsorption equilibrium but the Langmuir model shows better agreement. The kinetics of the adsorption process was tested by pseudo-first-order, pseudo-second order, Elovich and Intra-particle diffusion models. It was shown that adsorption of malachite green dye could be described by the pseudo-second order kinetic model. Thermodynamic parameters such as Gibbs free energy (G0 ), the enthalpy (H0 ) and the entropy change of sorption (S0 ) have also been evaluated and it has been found that the adsorption process was spontaneous, feasible and endothermic in nature. The results indicated that activated Clerodendrum serratum carbon can be used as an effective and low-cost adsorbent to remove malachite green dye from aqueous solution.

Lagenaria siceraria Stem Nano Carbon Adsorption Kinetics and Thermodynamics of Malachite Green Dye

Among the most significant industrial pollutants are dyes, notably in the textile industry. Many techniques have been put forth to remove colour from wastewater, but adsorption is the most widely accepted since it can be applied on a broad scale. The Malachite Green dye has been removed from aqueous settings using this work’s application of Modified Activated Lagenaria siceraria Stem Nano Carbon (ALSNC). The effects of pH, contact time, starting concentration, and adsorbent quantity were taken into account. Pseudo-first order, pseudo-second order, and intra-particle diffusion kinetic models were among those utilised to examine the mechanism of the adsorption process. Additionally, equilibrium data was fitted to the Radlich-Peterson isotherm model as well as the Langmuir, Freundlich, and Dubinin-Radushkevich, isotherm models. As a result of raising initial dye concentration, pH, and contact duration, the Malachite Green’s ability to bind to surfaces was improved, according to the results. pH 9 was the ideal level. Malachite Green dye adsorption had a qmax of 15.87 mg/g according to the Langmuir model. The Freundlich isotherm model and the pseudo-second order kinetic model obtained the best fitness when taking into account the values of R2 (0.999) and 2. This work has shown that ALSNC can be used as a cost-effective and efficient adsorbent for the removal of Malachite Green from aquatic environments

Equilibrium, kinetic and thermodynamic study for the efficient removal of malachite green dye onto untreated Morus nigra L. (mulberry tree) leaves powder and its biochar

In the present investigation the removal of malachite green (MG) dye from its aqueous solution by batch mode adsorption study onto mulberry leaves powder (MLP) and mulberry leaves biochar (MLB) has been proved to be efficient with removal percentage more than 95 % at 0.3 gm dose in 35.8 mg/L (20 ml) MG dye solution for 35 minutes. In this batch mode adsorption study various parameters like contact time, effect of dose, concentration, temperature and pH have been studied to investigate the effect of such parameters on MG dye adsorption process onto mentioned adsorbents. Among three commonly used isotherms (Langmuir, Freundlich, and Temkin), Freundlich isotherm model is best fit model with R2 = 0.99. The kinetic study reveals that pseudo-second-order kinetic model is best followed having also R2 = 0.99. Thermodynamically, the adsorption process of MG dye onto MLP is endothermic, exothermic onto MLB, and spontaneous in nature. Accordingly, the results obtained have shown that the adsorbents (MLP and MLB) can be used as low cost, rapid, and effective adsorbents for the removal of malachite green dye from its aqueous solution, thus also from wastewater.

Linear and nonlinear modeling of kinetics and isotherm of malachite green dye adsorption to trimellitic-modified pineapple peel

Adsorption is known for toxic dye removal in water, which can utilize a plant-based material to make a low cost and sustainable adsorbent. This study addresses the issue of preparing a cellulose-based adsorbent that is catered to cationic dye property and address inaccurate data interpretation and parameter estimation errors in adsorption analysis. The objective of this research is to overcome these challenges by modifying the surface of cellulose with carboxyl and utilizing original nonlinear equations with errors evaluation within the applied models to interpret the adsorption. In this paper, the pineapple peel cellulose will be reacted with 1,2,4–benzene tricarboxylic acid for malachite green adsorption. Characterization results showed a peak of C = O at 1712 cm−1, confirming the success of the modification. Through analyzing lowest sum of normalized error in linear and nonlinear model fitting, the best fit was obtained from the nonlinear Sips isotherm, with qm = 51.3 mg g−1, KS = 0.016 L/g, and 1/n = 2.0, as well as PSO kinetics k2 = 0.0142 g mg−1 min−1, qe = 24.8 mg g−1 which suggest that the modification of cellulose promotes collaborative adsorption, a mixing mechanism for MG dye adsorption.

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

The synthesis of MOF-5 and its modification have been investigated towards malachite green (MG) dye removal. The modified MOF-5 adsorbents have been prepared using waste-derived siliceous materials, i.e., rice husk ash (RHA) and/or coal fly ash (CFA) at different ratio. The MOF-5/RHA&CFA/2:1 has been chosen as the best adsorbent for MG dye removal from the aqueous solutions. The adsorption characteristics of the modified MOF-5 for MG dye removal was studied varying various parameters. The MG adsorption efficiency increases with increasing the shaking rate and contact time, but remained constant after 300 rpm and 4 h, respectively. The maximum adsorption capacity of 39.47 mg/g was obtained at adsorbent amount of 0.3 g, initial dye concentration of 150 mg/L, temperature of 30 °C, shaking rate of 200 rpm, contact time of 2 h, and original solution pH. The optimum temperature, pH, and amount of adsorbent for effective MG dye adsorption were 40 °C, 11.5, and 0.2 g, respectively. XRD analysis indicated the presence of crystalline materials has become reduced when RHA and CFA were being incorporated in MOF-5. FTIR analysis showed significant functional groups in the spectrum for both prepared and spent adsorbents. The SEM micrograph results revealed the rough surface morphology with many pores on the MOF-5/RHA&CFA/2:1 before MG adsorption and became smooth and less porous after MG adsorption. While BET analysis indicated that the surface area does not affect the MG dye adsorption efficiency. This study showed that modified MOF-5 adsorbents were successfully used for the removal of MG dye.