Removal Of Malachite Green Dye Research Articles

Green synthesis of Mn3O4 nanoparticles using Costus woodsonii flowers extract for effective removal of malachite green dye

The pollution of organic dyes such as malachite green is one of the globally critical issues, calling for efficient mitigation methods. Herein, we developed green Mn3O4 nanoparticles synthesized using natural compounds extracted from Costus woodsonii flowers under an ultrasound-assisted mode. The materials were characterized using several physicochemical techniques such as Fourier-transform infrared spectroscopy, X-ray diffraction, Energy-dispersive X-ray spectroscopy, scanning electron microscopy, Raman spectroscopy, and N2 adsorption desorption isotherm measurement. The X-ray diffraction and N2 isotherm plots confirmed the presence of tetragonal γ-Mn3O4 phase and mesoporous structure, respectively. Carbonyl groups derived from flavonoids or carboxylic compounds were found in the surface of green Mn3O4 nanoparticles. The effect of pH, contact time, dose, and concentration on the adsorption of malachite green over green Mn3O4 was carried out. The maximum malachite green adsorption capacity for green Mn3O4 nanoparticles was 101–162 mg g−1. Moreover, kinetic and isotherm adsorption of malachite green obeyed Langmuir (Radj.2 = 0.980–0.995) and pseudo first-order models (Radj.2 = 0.996–1.00), respectively. Adsorption of malachite green over green Mn3O4 was a thermodynamically spontaneous process due to negative Gibbs free energy values (ΔGο < 0). Green Mn3O4 nanoparticles offered a high stability through the FR-IR spectra analysis. With a good recyclability of 4 cycles, green Mn3O4 nanoparticles can be used as potential adsorbent for removing malachite green dye from water.

Porous graphitic carbon nitride nanosheets coated with polyfluorene for removal of Malachite green and Methylene blue dyes and Cu (II) ions

Dyes and heavy metal ions are of great interest for environmental studies as they are common pollutants in industrial applications. Therefore, development of innovative adsorbents has received tremendous interest in wastewater treatment studies. In this study, a new hybrid adsorbent (g-C3N4/AFP) was prepared by modifying porous graphitic carbon nitride surface (g-C3N4) with 2-amino fluorene polymer (AFP) and investigated its adsorptive behaviour for removal of representative dyes and heavy metal from aqueous solution. Experimental data obtained from batch tests were analysed using two parameters (Freundlich, Langmuir and Dubinin–Radushkevich) and three parameters (Sips) isotherm models. Langmuir isotherms were the best model to describe the experimental results of Methylene blue (MB) and Malachite green (MG) dye adsorptions, while Freundlich isotherms were the best for Cu (II) ions. Sips isotherm model was found to have the highest regression coefficient (≥0.99) among the two-parameters isotherms studied. The maximum adsorption capacities of g-C3N4 and g-C3N4/AFP were found to be 226.88 and 327.83 for MG, 85.73 and 221.85 for MB and 184.51 and 452.19 mg g−1 for Cu (II), respectively. This increase in adsorption capacity can be explained by the improved textural properties of the new hybrid adsorbent and the presence of multiple functional groups in its structure. A possible adsorption mechanism was suggested using FTIR and pHpzc data.

ZnO/POA functionalized metal-organic framework ZIF-8 nanomaterial for dye removal

In this work, a novel metal-organic framework ZIF-8 is fabricated with poly-o-anisidine/zinc oxide (POA/ZnO) to obtain poly-o-anisidine/zinc-oxide nanohybrid material (PAZ@ZIF-8) via in-situ approach at room temperature. The characteristics of as-prepared nanocomposites were investigated by employing sophisticated techniques such as SEM, TEM, FTIR, XRD, and SEM-EDAX. The PAZ@ZIF-8 nanohybrid material exhibits a significant rational function for the adsorption of highly toxic organic pollutants. The as-synthesized nanohybrid materials are employed to remove Malachite Green (MG) dye from aqueous solutions. PAZ@ZIF-8 has displayed excellent removal efficiency towards the removal of MG dye, and almost 96% of the dye is removed within a very short period as compared to ZIF-8 (34%) and POA/ZnO (61%), respectively. The experiments were carried out at different pH values (3 - 9) and adsorbent amounts (1 - 1.5 mg/g). The Langmuir sorption model is a better fit for the removal of MG dye on PAZ@ZIF-8, and the maximum adsorption capacity of 613 mg/g is observed. The sorption kinetics of MG dye on PAZ@ZIF-8 is well followed by the pseudo-second-order model. PAZ@ZIF-8 has shown excellent recyclability for three consecutive cycles, and almost 90% of the dye is removed in the third cycle. This research will overlay the road to developing innovative nanohybrid 3D-MOF adsorbent systems for detoxification and wastewater treatment.

Removal of Malachite Green Dye from Wastewater Using Natural and Activated Siirt/Koçpınar Clay

Bu araştırmada, genellikle akvaryumculukta, sıklıkla da pamuk ve elyaf gibi ürünlerin boyanmasında kullanılan toksik ve kanserojen bir boyar madde olan malahit yeşilinin atık sulardan Siirt/Koçpınar kili kullanılarak uzaklaştırılması incelenmiştir. Çalışmamızın ilk aşamasında adsorbent herhangi bir modifiyeye maruz bırakılmadan (K1) gerekli çalışmalarda kullanılmış, ardından aynı işlemler nitrik asit ile modifiye edilen adsorbent (K2) ile tekrar edilmiştir. Çalışmada başlangıç pH’ının (2.0 – 8.0 aralığı), adsorbent miktarının (0.05 g - 1 g aralığı), derişimin (50 ppm - 150 ppm aralığı), sıcaklığın (298 K - 323 K aralığı) ve temas süresinin (0 dk. - 120 dk. aralığı) etkinliği de araştırılmış ve elde edilen veriler Langmuir, Freundlich, D-R izoterm modellerine uygulanmıştır. Çalışma sonucunda en iyi verim pH 5 başlangıç değeri ile 0.2 g adsorbent kullanılarak yapılan çalışmalarda elde edilmiş ve çalışma neticesinde de K1 adsorbenti için %63.05, K2 adsorbentin de %91.99 giderim sağlanmıştır. İzoterm hesaplamaları sonucunda Freundlich izoterm modeline ait korelasyon katsayısı tüm sıcaklıklarda 0.98’den büyük bulunmuştur. D-R izoterm modeli yardımıyla hesaplanan D-R adsorpsiyon serbest enerjisi ise her iki kil ve tüm sıcaklıklar için 8 kJ/mol değerinden küçük bulunmuştur. Termodinamik hesaplamalar yardımıyla bulunan Gibbs serbest enerji değerlerinin negatif olması, adsorpsiyon işleminin kendiliğinden meydana geldiğini göstermiştir.

Ultrahigh adsorption by regenerable iron-cobalt core-shell nanospheres and their synergetic effect on nanohybrid membranes for removal of malachite green dye

The accelerated use of an industrial dye (malachite green (MG)) has led to serious deterioration of water bodies. Although, several water treatment methods have been investigated for MG removal, but they are either costly or produce several byproducts. To address these issues, the present research demonstrates the application of reusable iron-cobalt (Fe-Co) core-shell nanospheres against MG removal from water, using batch adsorption and membrane filtration technique. During batch adsorption, almost complete MG removal (99.8%) was observed against significantly high dye concentration (150 ppm) and the maximum adsorption capacity achieved was 270.27 mg g−1. Furthermore, the adsorbent exhibited excellent reusability up to five consecutive cycles. For membrane filtration studies, remarkable MG dye removal efficiency (97%) was achieved through M-0.1 membrane (containing 0.1% Fe-Co loading) along with outstanding water flux rate (214.73 L/m2 h). Additionally, a multi-cycle filtration test for M-0.1 membrane demonstrated high stability in MG dye separation performance and permeate flux throughout three consecutive cycles. All findings confirm the outstanding potential and financial feasibility of Fe-Co nanospheres in the removal of MG dye for both batch adsorption as well as membrane filtration processes.

Removal of Malachite Green Dye from Water Using MXene (Ti3C2) Nanosheets

In the present study, new emerging 2D Mxene nanosheets (MXNSs) were synthesized from MAX phase powders of Ti3AlC2 and then characterized using a scanning electron microscope (SEM) and X-ray diffraction (XRD) to explore the chemical and physical properties of the prepared MXNS. The characterization of the synthesized MXNS indicated the formation of exfoliated 2D MXene nanosheets (Ti3C2) as a result of the HF treatment of the MAX phase, which was confirmed by XRD measurements, as the characteristic peaks of 2D MXene nanosheets were only observed. The synthesized MXNS was then used as a solid adsorbent for removing malachite green dye (MG) from water. The effects of different operational factors such as MXNS dose, solution temperature, time, MG concentration, solution pH, and ionic strength have also been evaluated. The adsorption results showed that the temperature of the solution, as well as its pH, significantly influenced MG removal when using MXNS. The optimum removal was obtained within 150 min, with 20 mg of MXNS at ambient temperature and a pH value of 6.0. The maximum removal capacity obtained was 4.6 mg MG per g of MXNS using 5 mg of MXNS with a removal efficacy of 46.0%, and the minimum removal capacity obtained was 2.5 mg MG per g of MXNS using 20 mg of MXNS with a removal efficacy of 99.1%. Finally, the results displayed that the MXNS solid adsorbent was able to absorb a high percentage of MG and maintained reasonable efficiency for four consecutive cycles, indicating that MXNS could be a promising adsorbent in wastewater remediation and environmental sustainability.

Selective and effective adsorption of malachite green and methylene blue on a non-toxic, biodegradable, and reusable fenugreek galactomannan gum coupled MnO2 mesoporous hydrogel

A new FG-g-AM-cl-MBA-MnO2 hydrogel has been synthesised via a free radical cross-linking reaction using fenugreek gum containing macromolecular galactomannan units, acrylamide, N, N′-methylenebisacrylamide, potassium persulfate, and MnO2 for removal of methylene blue and malachite green dyes from water. Surface morphology of synthesised hydrogel was porous and rough as determined by FESEM. The presence of functional groups and cross-linking mechanism were validated by FTIR spectroscopy. TGA revealed that FG-g-AM-cl-MBA-MnO2 hydrogel is thermally stable up to 700 °C and mass ratio of MnO2 was found to be 25.9%. BET technique gave surface area as 5.59 m2/g with a pore radius of 3.654 nm. The swelling ratio of FG-g-AM-cl-MBA-MnO2 hydrogel was 1862% at 313 K. To evaluate the influence of adsorbent dose, contact time, temperature, pH, and dye concentration on adsorption behaviour of hydrogel several batch experiments were conducted. The hydrogel preferentially removes MG (98.5%) and MB (96.3%) effectively following Langmuir model with 526.31 and 483.09 mg/g adsorption capacity, respectively. The adsorption process followed pseudo-second-order kinetics and thermodynamics study revealed that process is endothermic and spontaneous. The hydrogel retained more than 85% adsorption capacity even after ten cycles of dye adsorption-desorption process and thus, serves as a proficient, reusable, and eco-friendly adsorbent for wastewater remediation.

Experimental and computational studies of microwave-assisted watermelon rind – styrene based molecular imprinted polymer for the removal of malachite green from aqueous solution

A microwave-assisted watermelon rind imprinted biosorbent polymer (MAWIMOS) was successfully synthesized and applied as an effective removal of malachite green (MG) dye from wastewater. The successful incorporation of imprinted cavities into the MAWIMOS was confirmed by scanning electron microscopy (SEM), X-ray diffractometry (XRD), and Fourier transform infrared spectroscopy (FTIR). A sequence of adsorption studies was carried out to evaluate the influence of operational parameters such as contact time, initial analyte concentration and temperature on MG removal by the prepared polymer. Equilibrium dye removal was attained within 60 min, giving a % removal of 95.2% at initial MG concentration of 200 mg/L. This value was much higher than 59.3% recorded with non-imprinted polymer (NIP). Thermodynamic studies revealed the spontaneous and exothermic nature of the adsorption process. Kinetic and equilibrium data fitted better to the pseudo-second-order and Freundlich models, respectively. Density functional theory (DFT) study suggested the main interaction mechanism to be by chelation through charge flow from the adsorbent to the MG in solution; and that MG and styrene monomer formed ordered complexes via π−π interactions when the molar ratio between MG and styrene was 1:5. The high quantity of malachite green removed by the MAWIMOS strongly positions the material as an efficient adsorbent for wastewater treatment.

Malachite green dye removal using ceramsite-supported nanoscale zero-valent iron in a fixed-bed reactor

Abstract In this study, we prepared and characterized ceramsite-supported nanoscale zero-valent iron (nZVI). Malachite green (MG) dye removal from aqueous solutions using a fixed-bed reactor packed with the above composite material was investigated. This research was carried out according to the prophase study of the preparation and characterization of ceramsite material for water treatment using sintering method from solid wastes. The results indicated that ceramsite could be loaded with nZVI, mainly because of its magnetic property. With the decrease in the initial concentration and influent flow rate or the increase in the reaction temperature, the breakthrough curve became less steep. Meanwhile, the breakthrough and saturation points gradually shifted rightward. When the initial concentration was 10 mg·L−1, the reaction temperature was 25°C, and the influent flow rate was 5 mL·min−1, the breakthrough curve presented an irregular “S” shape, the breakthrough and saturation times were 230 and 515 h, respectively. The characterization of MG dye-containing wastewater treatment using ceramsite-supported nZVI in a fixed-bed reactor by employing the Yoon-Nelson kinetic model was superior to those using the Thomas and Adams-Bohart kinetic models, with R 2 &gt; 0.96.

Garlic peel based mesoporous carbon nanospheres for an effective removal of malachite green dye from aqueous solutions: Detailed isotherms and kinetics

Biowaste based nanoadsorbents have gained much attention in the recent times for wastewater decolourization owing to their low cost, high surface area and high adsorption capacities. In the present research, garlic peel based nanoparticles (GCNP) were synthesized at different temperatures by a one step pyrolytic green approach for the effective removal of cationic dye, malachite green from the aqueous medium. The surface properties of Garlic nanoparticles were elucidated by N2 adsorption- desorption and all the GCNP samples were found to exhibit Type IV(a) isotherm indicating the presence of mesopores in carbon matrix. Using BET calculations, highest surface area (380 m2/g) was obtained for GCNP synthesized at 1000 ◦C. Characterization of nanoparticles was done by XRD, EDAX, SEM and FTIR studies before and after the dye treatment. Adsorption studies conducted using different parameters like contact time, concentration and pH and dosage of adsorbent showed removal efficiency above 90% for the contact time of 70 min. Best adsorption experimental results were obtained for GCNP synthesized at 1000 °C ascribable to its high surface area, higher total pore volume (0.26 cm2/g) and higher carbon content. Four adsorption isotherm models were used to validate batch equillibrium studies and the results showed data in good agreement with Langmuir and Freundlich isotherms with maximum Langmuir adsorbtion capactiy to be 373.7 mg/g. Kinetic modelling of the data showed best fit with the Pseudo second order model with rate constant value of 48.726 g mg−1 min−1. Regenerative studies were conducted conducted upto 6 cycles. Also the GC nanoparticles were tested for their compatibility in membrane form wherein, removal efficiency results were obtained for GCNP anchored in polyvinyl difluoride (PVDF) and polysulfone (PSF) membrane matrix for dye adsorption.

Equilibrium, Kinetic and Thermodynamic Studies of Malachite Green Dye Removal using Activated Sludge from Common Effluent Treatment Plant

Disposal of industrial effluents containing synthetic dyes causes a potential hazard to the land and environment and therefore dyes need to be removed before disposal. In the present study, combined effluent treatment plant (CETP) sludge was activated at 200° C for 1 hour and used as an adsorbent for the removal of malachite green dye from wastewater. The adsorbent was characterized by XRF, SEM, XRD and FTIR. Batch studies were carried out under various experimental conditions by varying contact time, dye concentration, adsorption dose, pH and temperature to assess the potentiality of activated sludge for the removal of malachite green dye from wastewater. The results revealed that the removal of malachite green dye was strongly pH dependent and maximum dye removal was observed at equilibrium pH of 8.0. Optimum adsorbent dose and contact time were found to be 10 g/l and 180 minutes respectively. Thermodynamic studies showed the spontaneous and endothermic nature of the adsorption. Adsorption data have also been correlated with different isotherm models. Hence activated sludge can be used as an effective adsorbent for the removal of malachite green dye from wastewater. It could be considered as good replacement of commercially available adsorbent like zeolites, activated carbon etc. due to its significant low cost and high sorption efficiency.

Lignin-inspired porous polymer networks as high-performance adsorbents for the efficient removal of malachite green dye

Herein, a series of porous polymer networks (LPPNs) were prepared from sustainable lignin-derivatized aldehyde monomers. It was interesting to discover that the 4-hydroxy benzaldehyde (H type) was favorable to promote the formation of the porous network LPPN-H with the largest BET surface area (739.4 m2/g) and pore volume (1.78 cm3/g) over that of LPPN-G (G type) and LPPN-S (S type), emphasizing the various geometrical shapes of building blocks significantly affected the porosity properties. The porous networks and abundant functional groups of LPPNs enabled efficient and rapid adsorption of malachite green (MG) dye. Strongly depending on the porosity parameters, LPPN-H gave a higher adsorption capacity for MG (Qmax = 1449.8 mg/g) than LPPN-G and LPPN-S, which exceeded many other reported adsorbents. The adsorption process could be well described by the pseudo-second-order kinetic model and Langmuir isotherm model, respectively. Study in adsorption mechanism demonstrated that the electrostatic force, hydrogen bonding, and π-π stacking interactions existed in MG adsorption onto LPPNs. Besides, LPPN-H exhibited high stability and retained over 90% removal efficiency after 10 cycles. Together with the excellent adsorption behaviors and unique porosity properties, the low-cost and green LPPNs exhibited promising utilization in wastewater purification.

Bioremoval of toxic malachite green from water through simultaneous decolorization and degradation using laccase immobilized biochar

In this study, decolorization and degradation of malachite green dye was studied using the laccase immobilized pine needle biochar. Successful immobilization of biochar was achieved by adsorption and confirmed through scanning electron microscopy and energy dispersive X-ray analysis (SEM-EDX), Fourier transform infrared spectroscopy (FTIR). High laccase binding of 64.4 U/g and high immobilization yield of 78.1% was achieved using 4U of enzyme at pH3 and temperature 30 °C. The immobilized laccase retained >50% relative activity in the pH range 2–7, >45% relative activity at 65 °C and >55% relative activity at 4 °C for 4 weeks. The re-usability of immobilized enzyme was checked with 2, 2′-azino-bis 3-ethylbenzothiazoline-6-sulphonic acid (ABTS) substrate and enzyme retained 53% of its activity after 6 cycles. Immobilized laccase was used for the degradation and decolorization of azo dye malachite green in aqueous solution. More than 85% removal of malachite green dye (50 mg/L) was observed within 5 h. FTIR and high performance liquid chromatography (HPLC) analysis clearly indicated the breakdown of dye and presence of metabolites (leuco malachite green, methanone, [4-(dimethyl amino)pheny]phenyl and 3-dimethyl-phenyl amine) in gas chromatography–mass spectrometry (GC-MS) analysis confirmed the dye degradation. Phytotoxicity analysis indicated that the enzymatic degradation resulted in lesser toxic metabolites than the original dye. Thus, laccase immobilized biochar can be used as an efficient biocatalytic agent to remove dye from water.

Synthesis and Photocatalytic Activity of Ruthenium-Titania for Enhanced Decolorization of Malachite Green under Visible Light Illumination

The photodecolorization of malachite green (MG) dye was effectively done using Ruthenium-doped TiO2 photocatalysts under visible light illumination. X-ray diffraction analysis revealed that anatase and rutile peaks were both found in undoped TiO2 while only anatase peaks were present in Ru-doped TiO2 systems which were calcined at 500°C. The 0.008 Ru-TiO2 photocatalysts calcined at 300°C showed broader peaks compared to those calcined at 500°C. Further increase of calcination temperature to 700°C promotes the transformation of anatase to rutile peaks. The photocatalytic activity of TiO2 was found to increase with the addition of Ruthenium ions, from 20% for undoped TiO2 to 87% for 0.80 Ru-doped TiO2. The maximum photocatalytic removal of MG dye was achieved using 1.50 g∙L-1 of catalyst loading for 0.008 Ru-doped TiO2. The TiO2 photocatalysts prepared at a calcination temperature of 500°C showed higher photodecolorization efficiency compared to those calcined at 300°C and 700°C. Kinetic studies revealed that the photodecolorization of MG using Ru-doped TiO2 followed a first order kinetics.

Adsorption of Malachite Green from Aqueous Solution Using Hydroxyethyl Starch Hydrogel Improved by Graphene Oxide

This study is the first report of the preparation of hydroxyethyl starch (HES) hydrogels rapidly crosslinked with divinyl sulfone in a single step and single pot. To develop the physical and chemical features of hydrogels, Graphene oxide (GO) nanoparticles were combined with the crosslinked HES. In addition to swelling studies, structural characterization of the samples was conducted with a scanning electron microscope (SEM) and transmission electron microscope (TEM), Fourier transform infrared (FTIR) spectroscopy, X-ray diffractometry (XRD), Brunauer–Emmett–Teller (BET) analysis and thermogravimetric analysis (TGA). For the removal of malachite green model dye by GO-HES, the effects of GO content, solution concentration, temperature, contact duration, dosage and pH on varying adsorption features were researched. Additionally, adsorption isotherms, kinetic and thermodynamic systematics were analyzed. The maximum adsorption capacity of GO-HES composite hydrogel was found to be 89.3 mg/g for Langmuir isotherm. The possible adsorption mechanism of the composite hydrogels for malachite green dye involved electrostatic, hydrogen bonding, and π–π interactions. In addition to reasonable cost and simple synthesis method, the prepared composite materials have potential use in wastewater treatment as adsorbents for the removal of dye from aqueous solutions due to efficient adsorption capacity.

Optimization Study of Malachite Green Dye Adsorption by Eggshell Using Response Surface Methodology

Batch adsorption studies for the removal of Malachite green (MG) dye using eggshell was performed. Response Surface Methodology (RSM) was applied to investigate the effect of significant operating parameters on the uptake of the dye molecule. The aim of this study is to determine the potential of eggshell as adsorbent for MG removal and determine the optimum conditions for the adsorption process by using RSM with Central Composite Design (CCD). A 23 full factorial CCD was generated using Design Expert. The effects and interactions of different parameters were evaluated which are contact time (20-60 min), pH (4-8) and adsorbent dosage (0.5-2.0 g). A quadratic model was developed correlating the adsorption variables to the response (percentage of MG removal). Analysis of variance (ANOVA) was used to determine the significant factors on experimental design response. The predicted results obtained were found to be in good agreement (R2 = 0.9388) with the experimental results. The optimum percentage of MG removal was found to be 90.66% with the operating conditions of 40 minutes contact time, pH 6 and 1.25 g of adsorbent dosage. It was suggested that eggshell could be a potential adsorbent in removing MG from aqueous solution.

Efficient adsorption of malachite green dye using novel reduced graphene oxide/β-cyclodextrin epichlorohydrin composite: batch and fixed-bed studies

ABSTRACT 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.

Magnetized chitosan nanocomposite as an effective adsorbent for the removal of methylene blue and malachite green dyes

Herein, a magnetically separable Fe3O4 decorated chitosan was facilely synthesized, systematically characterized, and subsequently employed as a versatile adsorbing material for the adsorption of malachite green and methylene blue dyes. The prepared adsorbent was characteristically examined through Fourier transform infra-red microscopy, scanning electron microscopy with energy-dispersive X-ray analysis, transmission electron microscopy, X-ray diffraction, Brunauere-Emmette-Teller surface area analysis, thermogravimetric analysis, and vibrating-sample magnetometry techniques. The optimum process parameters for MB were observed to be 180 min of contact time, pH 7, and 1.2 g/L of adsorbent dose, and 210 min of contact time, pH 7, and adsorbent dose of 2 g/L was found to be for MG. The time-dependent experimental data were analyzed with different kinetic models, and pseudo-IInd-order was provided the best fit for the adsorption of both the dyes with a high value of the regression coefficient. The adsorption equilibrium data of both the dyes was best explained by Langmuir isotherm, and the maximum sorption capacity of MG and MB was found to be 55.86 and 76.34 mg/g, respectively. Thermodynamic analysis declared that the adsorption of MG and MB onto the Fe3O4 decorated chitosan was endothermic and spontaneous. Moreover, the adsorbent presented good reusability up to three successive ad-/de-sorption cycles, indicating that Fe3O4 decorated chitosan is a promising applicant for treating dye-containing wastewater.

Superior adsorption and removal of aquaculture and bio-staining dye from industrial wastewater using microporous nanocubic Zn-MOFs

The indirect release of excessive amounts of poisonous dyes into water has drastically affected the environment. Thus, in this work, a method to remove dyes from industrial water was investigated using ecofriendly cubic inorganic–organic Zn metal–organic frameworks (CZM). In particular, the room-temperature one-pot synthesis of inorganic–organic Zn-MOF nanocubes with superior adsorption capacity for the removal of malachite green (MG) dye in wastewater samples was studied. The nanocubes featured intergrowing chains with highly accessible surface areas, and uniform micropores could trap MG dye from wastewater. The inorganic–organic frameworks exhibited excellent adsorption capacity for MG. The adsorption conditions, such as the solution pH, played a significant role in generating an active negatively charged surface throughout the Zn-MOF adsorbent, thereby yielding microporous surfaces with strong ability to interact with and take up MG dye. Adsorption experiments revealed the high capacity of CZM for MG removal (953.14 mg g−1), and this capacity was maintained even after multiple reuse cycles. The microporous CZM adsorbent demonstrated a simple and effective model for water purification and the management of industrial wastewater. To the best of our knowledge, this work is the first to report the usage of Zn-MOF adsorbents for the removal of MG dye in wastewater samples.

Preparation of a novel superabsorbent hydrogel based on polyacrylic acid/shellac using gamma irradiation for adsorption removal of malachite green dye

The objective of this study is to prepare a super absorbent hydrogel based on polyacrylic acid and an environmentally friendly material such as shellac to remove malachite green dye from aqueous solution using gamma radiation. The adsorption of malachite green (MG) dyes using polyacrylic acid (PAA)/shellac (SH) hydrogels was studied. These hydrogels were prepared by mixing aqueous solutions of PAA and SH at differing molecular ratios (10%, 20%, and 30% SH content in the final reaction mixture) and varying doses of gamma radiation (10–50 kGy). The water absorption by the PAA/SH hydrogels prepared at a 30-kGy radiation dose increased with an increase in the SH content. The removal of the MG dyes from an aqueous solution using PAA and PAA/SH hydrogels was investigated at different values for selected parameters, such as pH, contact time, SH concentration, and adsorbent dosage. The highest MG adsorption percentage (95.5%) was obtained for the PAA/SH hydrogel with the highest SH content (30%). As the adsorbent dosage increased, the dye adsorption capacity increased, accordingly. The combination of SH and gamma radiation caused the PAA to undergo structural changes verified by X-ray diffraction and Fourier transform infrared spectroscopy. Scanning electron microscopy was employed to investigate the morphology of the PAA/SH hydrogel and revealed that the SH belonging to the PAA matrixes exhibited a homogeneous dispersion. The thermal stability of the hydrogels was investigated by thermogravimetric analysis. The amount of dye adsorbed by the PAA/SH hydrogel was calculated by subtraction based on the ultraviolet–visible (UV–VIS) spectroscopy determination of the concentration of leftover dye in solution using a UV–VIS spectrophotometer.