Adsorbent For Removal Of Dyes Research Articles

Congo red Removal using Microwave assisted Pyrolysis derived Magnetic Hemp hurd Biochar

Industrial hemp hurd (HH) are the residue obtained after the decortication of the hemp plant for fibre production, which is seldom explored for biochar potential and as adsorbent for dye removal. The present study focused on the microwave-assisted pyrolysis (MAP) of HH for biochar production, magnetization and application for Congo red (CR) removal from aqueous solutions. Magnetic hemp hurd biochar (MHB) depicted a heterogeneous surface with 4.84µm pore size, 17.64 m2/g surface area, and 10.05wt. % Fe. CR removal of 92% was achieved under optimum conditions i.e., treatment time: 120min, pH: 8, and initial CR concentration: 10mg/L with MHB dosage of 0.6g/L. The CR adsorption on MHB was well-fitted with the Freundlich isotherm (R2 - 0.971), owing to the heterogeneous surface of MHB. A strong match with pseudo-second order model (R2 - 0.973), indicated chemisorption as the likely adsorption mechanism. MHB exhibited 87% CR removal efficiency after three successive reutilization cycles. The outcomes of CR removal efficiency and MHB reusability indicated its potential application for adsorptive removal of CR from aqueous systems.

Adsorptive Removal of Dyes: A Comparison of Graphene Oxide to Granular Activated Carbon and Zeolite NaY

Synthetic carbon-based compounds are a prevalent wastewater contaminant that can adversely impact water resources due to their potential carcinogenic and toxic effects on aquatic biota and human health. This research investigates the versatility of graphene oxide (GO) as an alternative to commonly used adsorbents (zeolite NaY (NaY) and granular activated carbon (GAC)) for removal of synthetic cationic dyes. Rhodamine B (RhB) and methylene blue (MB), were selected as the target contaminants to represent cationic synthetic dyes with differing molecular sizes and structural compositions. Batch experiments using GO, NaY, and GAC as adsorbents were used to assess both physicochemical interactions between adsorbent surfaces and contaminants, and removal efficiency. GO demonstrated the highest removal efficiency for both target contaminants—at 99% and 86%, respectively—while the lowest removal efficiency was observed for NaY. Langmuir, Freundlich, Temkin, and BET isotherm models were used to describe the adsorption isotherms. Overall, GO demonstrated a more robust and higher removal efficiency of cationic dyes compared with GAC and NaY, indicating the potential of graphene oxide for the removal of complex structured organic contaminants in wastewater treatment.

The amalgamated impact of bimetals, amino groups, and cross-linked structures of MOF on MOF for the removal of cationic dyes

To protect the environment, it is important to develop effective materials/methods for eliminating or decomposing pollutants. Metal-organic frameworks (MOFs) have attracted considerable interest due to their special properties, including their exceptional porosity and customizable architecture, which make them highly adaptable for many applications. In this study, bimetallic (Ce/Zr) NH2-UiO-66@NH2-MIL-125 was prepared and characterized by, X-ray diffraction, field emission scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy, thermogravimetric and BET analysis. The prepared bimetallic (Ce/Zr) NH2-UiO-66@NH2-MIL-125 served as a potent adsorbent for the efficient removal of cationic dyes via electrostatic, hydrogen bonding, ionic bonding, and π–π stacking. The adsorption of RhB and MB dyes by bimetallic (Ce/Zr) NH2-UiO-66@NH2-MIL-125 includes both isothermal and kinetic studies. The equilibrium adsorption data was found to conform to the Langmuir isotherm, whereas the kinetic adsorption process followed a pseudo-second-order model. The cross-linked structure of MOF on MOF enhances the stability of the adsorbent, and has the potential to efficiently adsorb and release organic dyes over multiple cycles. The aforementioned interactions as well as stability and reusability make the bimetallic (Ce/Zr) NH2-UiO-66@NH2-MIL-125 one of the most promising adsorbent for the removal of dyes from water.

Dual cross-linked magnetic gelatin/carboxymethyl cellulose cryogels for enhanced Congo red adsorption: Experimental studies and machine learning modelling

To achieve highly efficient and environmentally degradable adsorbents for Congo red (CR) removal, we synthesized a dual-network nanocomposite cryogel composed of gelatin/carboxymethyl cellulose, loaded with Fe3O4 nanoparticles. Gelatin and sodium carboxymethylcellulose were cross-linked using transglutaminase and calcium chloride, respectively. The cross-linking process enhanced the thermal stability of the composite cryogels. The CR adsorption process exhibited a better fit to the pseudo-second-order model and Langmuir model, with maximum adsorption capacity of 698.19 mg/g at pH of 7, temperature of 318 K, and initial CR concentration of 500 mg/L. Thermodynamic results indicated that the CR adsorption process was both spontaneous and endothermic. The performance of machine learning model showed that the Extreme Gradient Boosting model had the highest test determination coefficient (R2 = 0.9862) and the lowest root mean square error (RMSE = 10.3901 mg/g) among the 6 models. Feature importance analysis using SHapley Additive exPlanations (SHAP) revealed that the initial concentration had the greatest influence on the model’s prediction of adsorption capacity. Density functional theory calculations indicated that there were active sites on the CR molecule that can undergo electrostatic interactions with the adsorbent. Thus, the synthesized cryogels demonstrate promising potential as adsorbents for dye removal from wastewater.

Development of banana pseudo stem cellulose fiber based magnetic nanocomposite as an adsorbent for dye removal

A hybrid hydrogel nanocomposite derived from cellulose fiber extracted from Banana Pseudo Stem (BPS) was developed as an adsorbent material for wastewater treatment. The hydrogel was developed by graft copolymerization of N-hydroxyethylacrylamide on Cellulose Fiber (BPSCF-g-PHEAAm) with potassium peroxodisulphate (KPS) as an initiator and N, N′-methylene bisacrylamide (MBA) as a crosslinker using microwave irradiation. Magnetic nanoparticles generated by an in-situ method were incorporated into the network structure. Fourier Transform Infrared Spectroscopy (FTIR), Powder X-ray Diffraction (XRD), Thermogravimetric analysis (TGA), Vibrating Sample Magnetometer (VSM), Brunauer-Emmett-Teller analysis (BET), Field Emission Scanning Electron Microscopy (FESEM), and Energy Dispersive Spectrometer (EDS) were employed. The adsorption capacities of hydrogel and its nanocomposite were evaluated using Methylene Blue (MB) and Crystal Violet (CV) as model dyes. The parent gel exhibited the maximum absorption capacity of 235, and 219 mg g−1 towards MB and CV respectively which was enhanced to 320 and 303 mg g−1 for the nanocomposite. Adsorption data were best fitted with the pseudo-second-order kinetic model and the Freundlich isotherm model. Negative ΔG° and positive ΔH° indicated spontaneous and endothermic adsorption. Desorption was effective to an extent of 99 % in the HCl medium suggesting high reusability potential of the developed adsorbent material.

Defects-rich MgFe LDH: A high-capacity adsorbent for methyl orange wastewater

Dye pollution is a common pollutant in wastewater that poses a serious threat to human health. Layered double hydroxide (LDH) is a commonly used adsorbent for dye removal. However, its adsorption efficiency is significantly limited by the limited adsorption active sites of the adsorbent. In this paper, a defects-rich MgFe LDH adsorbent for anionic dye wastewater was synthesized by a simple hydrothermal method and alkaline etching. Different analytical techniques, such as XRD, FT-IR, SEM, TEM, XPS, and N2 adsorption-desorption isotherm, were used to verify the chemical composition and surface characteristics of the materials, and the effects of pH, temperature, and contact time on the adsorption effect of methyl orange and the adsorption mechanism were analyzed. Alkaline etching of Al and Zn in the laminate generated defects that expose unsaturated coordination centers and create abundant adsorption sites, which can electrostatically attract and coordinate with dye ions. At 25°C, the adsorption capacity of MgFe LDH with Al etched and MgFe LDH with Zn etched for methyl orange dye reached 1722 mg/g and 1685 mg/g, respectively, much higher than that of MgFe LDH (544 mg/g). This work provides a promising method for the removal of dye wastewater by adsorption and a new idea for the design and development of high-performance dye wastewater adsorbents.

Preparation of metal organic framework by strategy of ligand premodification coupling with dual ligands and adsorption behaviors for organic dyes

The method of ligand premodification coupling with dual ligands to introduce several functional groups can regulate the pore structure of the porous materials to meet different demands and to maintain the integrity of the framework. Amino groups was introduced into organic ligand by reacting with polyethyleneimine and then it was applied as one of the ligands to prepare porous materials. A series of porous materials were synthesized through varying the additional amount of modified ligand and characterized by several techniques such as BET, FTIR, XRD, XPS, SEM and EDS. The prepared materials were then used to remove organic dyes methyl orange (MO), methylene blue (MB) and Congo red (CR) from aqueous solution. The porous materials exhibited larger adsorption capacities and fast adsorption rate for MO and MB as certain modified ligand introduced. Due to steric hindrance of introduced amino chain, the adsorption capacities for CR decreased. The results of adsorption kinetics and adsorption isotherm studies showed that the adsorption process was more in line with pseudo-second kinetic model and Langmuir isotherm. The adsorption selectivity of the material for MB compared to MO could be controlled by altering the amount of modified ligand The prepared porous materials can be used as fascinating adsorbents for removal of dyes from aqueous solution in a wide pH range, and it was attractive and useful from practical viewpoint.

Cellulose-Based Waste in a Close Loop as an Adsorbent for Removing Dyes from Textile Industry Wastewater

In an attempt to reuse fibrous textile waste and, at the same time, to address dye pollution in textile wastewater, waste cotton-based yarn was utilized as a cheap and sustainable adsorbent, as well as a row material for carbon adsorbent production. Unmodified yarn and cotton-based carbon adsorbents were used as adsorbents for dye removal from water. Cotton and cotton/polyester yarn samples underwent thermal modification through carbonization followed by chemical activation with KOH. Various techniques, including scanning electron microscopy, Fourier transform infrared spectroscopy, nitrogen adsorption–desorption isotherms, and surface charge determination, were employed to analyze the morphological and surface characteristics of the cotton-based adsorbents. Adsorption properties were evaluated by testing the removal of selected cationic and anionic dyes from water. The impact of temperature, initial pH and concentration of the dye solution, and contact time on adsorption were investigated, and experimentally obtained data were analyzed using theoretical models. While carbonization alone did not significantly enhance adsorption properties, activated samples exhibited high efficacy in removing both cationic and anionic dyes from water. Despite the negative influence of the polyester component in the carbon precursor on the efficiency of activated samples in removing methyl orange, the results indicated that activated cotton and cotton/polyester yarn could be used to prepare highly efficient adsorbents for the rapid removal of methylene blue from real wastewater samples.

Chitosan‐nTiO2 Nanocomposite Synthesis and its Adsorptive Removal Capacity for Methylene Blue from its Aqueous Solution: Batch Adsorption Study and Modeling

AbstractThe current work used chitosan (CS)‐nTiO2 nanocomposites (CTNCs) prepared with different CS:nTiO2 mass ratios toward the MB dye removal from an aqueous medium in batch method at variable experimental conditions. The stability and competence of the nanocomposites were checked through characterization by SEM, FTIR, XRD, TGA, and BET. The highest removal of MB was 78 % with the adsorbent CS without nTiO2 (CWT), 94.5 % with CS:nTiO2=1 : 1 weight ratio (CTNC1‐1) and 80 % with CS:nTiO2=2 : 1 weight ratio (CTNC2‐1) with 10 mgL−1of MB and 5 gL−1 adsorbent dosages. The experimental observations obeyed the pseudo‐2nd‐order model, and rate‐limiting steps were film diffusions for CWT, CTNC1‐1 and intraparticle diffusion for CTNC2‐1. Monolayer adsorption was established from the isotherm model. Langmuir adsorption capacities for MB were presented as CTNC1‐1 (qL=34.31)>CTNC2‐1 (qL=32.87)>CWT (qL=21.32). The sorption energy, as derived from Dubinin–Radushkevich isotherm model, showed physisorption for all three adsorbents. The scale‐up design is reported. The statistical (R2>0.98) and GA modeling (R2>0.98) successfully predicted the percentage elimination of MB. Thus, CS‐nTiO2 nanocomposites are prepared as novel and environment‐friendly adsorbents for dye removal.

Selective separation of methylene blue from aqueous solution using Mn/Pd decorated chemically modified MoS2 nanocomposites

The presence of dyes in wastewater is posing as serious threat to human health. There are a huge number of physical, chemical, biological and hybrid methods available for the removal of colorants (dyes) from aqueous environment. In this work, we demonstrate the fabrication of new nanocomposites, MoS2-COOH/gly@M (M= Mn, Pd), with high adsorption property fabricated by chemically immobilizing manganese and palladium metallic centers onto the glycine- modified molybdenum disulfide (MoS2) material. The chemical and physical properties of adsorbents were analyzed using Fourier transform infrared spectrometer (FT-IR), thermal gravimetric analysis (TGA), X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM) companied by energy dispersive X-ray and mapping (EDAX & MAP) analyses. Zeta potential (ξ) technique was also used to measure the surface charge of adsorbents. Performances of nanocomposites were investigated on the sewage as adsorbent for dye removal. Synthesized nanocomposites revealed selective adsorption of methylene blue (MB) dye from aqueous mixture of MB and methyl orange (MO). Results displayed the equivalent high adsorption capacity for MB and MO up to 553 and 619 mg/g, respectively (green reaction condition= 120 min contact time, ,25 °C, pH 2.0 and pH 7.0, in the presence of 2 mg adsorbent and 50 mg/L (30 mL) initial concentration of MO and MB). The remarkable adsorption capacity of dye by MoS2-COOH/gly@M (M= Mn, Pd) nanocomposites can be attributed to the intermolecular interactions due to the presence of the amine, hydroxyl, and carboxyl functionalities. To describe the adsorption mechanism of MO and MB dye by synthesized nanomaterials, the pseudo-first-order and pseudo-second-order kinetics were further studied. Isotherm models displayed that the adsorption of MB and MO onto the MoS2-COOH/gly@M (M= Mn, Pd) nanocomposites is more correspondent with the Freundlich model with high-correlation coefficients. The results showed that the electrostatic attraction and H-bonding interaction were the basic cause of the adsorption of these anionic and cationic dyes on the surface of the nanocomposites. One of the distinguished properties of adsorbents is their capability to selectively adsorb MB from an admixture of MO and MB. The adsorption selectively has expanded in the following order: MoS2 < MoS2-COOH/gly@Mn < MoS2-COOH/gly@Pd. Based on the results, this new type of nanocomposites has potential to act as an effective and affordable adsorbent material for dye removal from an industrial sewage.

A comprehensive review on the sequestration of dyes from aqueous media using maize-/corn-based adsorbents

Abstract Corn or maize (Zea mays L.) is the most significant grain crop worldwide after wheat and rice. It is widely cultivated and consumed as food, feed, and industrial raw material, along with the emission of a large quantity of corn waste. Such abundant, renewable, and cheap wastes with unique chemical compositions can be efficiently converted into adsorbents for the elimination of dye-contaminated water. This article represents an extensive review of the use of corn/maize waste-derived adsorbents for the sequestration of dyes from aqueous media. This study addressed the utilization of corn residues, including cob, stalk, straw, husk, and silk, as precursors for adsorbents. The adsorption behaviour, mechanism, and regeneration of the studied corn adsorbent/dye systems were identified. It was observed that the most common forms of corn/maize-derived adsorbents that have been utilized for the sequestration of dyes include biosorbents, biochars, activated carbons, and composites. The highest adsorption capacity (1,682.7 mg/g) for dye (methylene blue) sequestration was obtained using a corn husk composite-based adsorbent. Important findings and future ideas are finally mentioned for the corn/maize-based materials and their application as adsorbents for dye removal.

Obtaining bio-oil and activated carbon from waste pomegranate peels by pyrolysis.

This study aims to produce beneficial products with pomegranate peel waste through pyrolysis. For this purpose, the usability of the liquid product as a biofuel and the solid product as an adsorbent for dye removal was investigated. To characterize the bio-oil and biochar produced under the best pyrolysis conditions, Fourier transforms infrared spectroscopy (FT-IR), Gas chromatography-mass spectrometry (GC-MS), calorific value, Brunauer-Emmett-Teller (BET), and Scanning electron microscopy (SEM) analyses were conducted. When we examine the FT-IR spectrum of the bio-oil, the presence of phenol, alcohol, ketone, and aldehyde groups is seen in the structure. The GC-MS analysis demonstrated that phenol content was 27.9%, aldehyde content was 19%, acid compound content was 18.28%, ketone content was 8.7%, and aromatic compound content was 8.4%. The lower calorific value of bio-oil was determined as 27.33MJ/kg. It was observed that activated carbon produced from biochar at a 3:1 KOH/biochar impregnation ratio and a carbonization temperature of 800°C exhibited the highest surface area (1307 m2/g). In adsorption analysis, it was observed that the adsorption efficiency was higher at pH 9 and 35°C and with 150ppm initial concentration. Langmuir and Freundlich adsorption isotherms were determined, and the high R2 (0.99) was consistent with the Langmuir methylene blue (MB) adsorption model.

The effectiveness of natural adsorbent for removal of dye using two isotherm models

The low-cost and more efficient adsorbents of Azadirachta Indica (Neem) are charcoal, bark; leave and root were investigated for its optimistic de-colorization of wastewater containing a dye. The effect of various parameters such as contact time, pH, temperature and adsorbent dosage has been carried out in this study. Two isotherm models were developed for compliance with Langmuir and Freundlich isotherm. The results of the goodness fit test based on Root Mean Square Error (RMSE), R2 for Langmuir and Freundlich models were given as, for pH (0.9745 – 0.99919), (0.4831 – 0.9999) for Adsorbent Dose is (0.9034 – 0.9221), (0.4689 – 0.9884) for contact time (0.9494 – 0.9513), (0.4677 – 0.9990) and temperature (0.9264 – 0.9349), (0.3755 – 0.5849) respectively. Both models were found to be best fit on decolorization of dye with contact time, pH, temperature and adsorbent dosage. pH 5 value indicated that adsorbent was effective in the removal of dye.

A novel mesoporous carbon nanospheres-based adsorbent material with desirable performances for dyes removal

Nowadays, the reduction of dye contaminants in the aquatic environment has attracted widespread research attention. In this work, a novel mesoporous carbon nanospheres (MCNs)-based material as an adsorbent for dye removal was achieved by the carbonization of a composite of sucrose and aluminum sulfate without involving any hazardous activators. The as-obtained MCNs were analyzed by TG, XRD, FESEM, TEM, Raman, BET and XPS, meanwhile the batch experiments of Congo red (CR), Malachite green (MG) and Methylene blue (MB) on the MCNs were conducted to explore the impact of adsorption conditions on the adsorption process, respectively. Results show that the MCNs exhibit a uniform spherical morphology as well as partially graphitic structure with a large surface area of 449.25 m2/g, a relatively narrow pore size distribution and a high pore volume of 0.57 cm3 g−1. The unique porous structure of the MCNs endows it with high adsorption capabilities for dyes, including CR (1726.60 mg g−1), MG (980.55 mg g−1) and MB (708.82 mg g−1), suggesting its high adsorption capability for both anionic and cationic dyes. Meanwhile, the adsorption process is demonstrated to follow the Langmuir model and pseudo-second-order kinetic model, respectively, and the main adsorption mechanisms may involve pore filling, π-π conjugation, electrostatic attraction and hydrogen bonding. Furthermore, the as-synthesized adsorbent displays good recyclability performance for remaining relatively high sorption performance even after five regeneration cycles.

Boosted capture ability of Rhodamine B by a core-shell composite equipped with spherical porous carbon and copper-based metal-organic framework

Copper-based metal-organic framework (e.g. Cu-BTC) suffer from water instability issue, restricting its practical applications in the adsorptive removal of dyes from aqueous solution. In this exploration, a innovative core-shell porous composite with spherical porous carbon (SPC) and Cu-BTC units, boosting its water stability and Rhodamine B (RhB) uptake capacity. Those novel Cu-BTC@SPC composites have undergone comprehensive characterization, and their structural features have been further evaluated through various analytical techniques, including N2 adsorption-desorption tests, X-ray diffraction analysis, scanning electron microscopy image, Fourier transform infrared spectroscopy analysis, X-ray photoelectron spectroscopy, etc. Remarkably, the structural integrity of the Cu-BTC@SPC composite remained intact even after being immersed in water for a duration of 7 days or subjected to boiling water for 6 h. Through a series of batch tests, we observed that the Cu-BTC@SPC composite exhibited a high capacity for RhB adsorption. The observed phenomenon can be ascribed to the synergistic effects of π-complexation and acid-base interactions present within the SPC and Cu-BTC components. The maximum RhB uptakes over Cu-BTC@SPC can reach 81 mg/g, exceeding some other adsorbents prior publications. Especially, the RhB uptakes capacity of Cu-BTC@SPC decreased by less than 10% after the fifth cycle. The distinctive core-shell structure of Cu-BTC@SPC might be a hopeful adsorbent for dye (e.g. RhB) removal from water.

KMnO4-oxidized whole pine needle based adsorbent for selective and efficient removal of cationic dyes

In the present study, we report the chemical modification of the dried and fallen pine needles (PNs) via a simple protocol using KMnO4 oxidation. The oxidized PNs (OPNs) were evaluated as adsorbents using some cationic and anionic dyes. The successful synthesis of OPNs adsorbent was characterized by various techniques to ascertain its structural attributes. The adsorbent showed selectivity for the cationic dyes with 96.11% removal (P r) for malachite green (MG) and 89.68% P r for methylene blue (MB) in 120 min. Kinetic models namely, pseudo-first order, pseudo-second order, and Elovich were applied to have insight into adsorption. Additionally, three adsorption isotherms, i.e., Langmuir, Freundlich, and Temkin were also applied. The dye adsorption followed a pseudo-second-order kinetic model with R 2 > 0.99912 for MG and R 2 > 0.9998 for MB. The adsorbent followed the Langmuir model with a maximum adsorption capacity (q m) of 223.2 mg/g and 156.9 mg/g for MG and MB, respectively. Furthermore, the OPNs showed remarkable regeneration and recyclability up to nine adsorption-desorption cycles with appreciable adsorption for both the dyes. The use of OPNs as an adsorbent for the removal of dyes from wastewater, therefore, provides an ecologically benign, low-cost, and sustainable solution.

Adsorptive Removal of Dye (Methylene Blue) Organic Pollutant from Water by Pine Tree Leaf Biomass Adsorbent

In this laboratory batch adsorption study, the raw pine tree leaf biomass solid waste adsorbent material was used for the removal of methylene blue (MB) dye from water at different physicochemical process conditions. The characteristics of adsorbents were determined for particle size, surface area, the existence of functional group identification, and the morphology of the adsorbent surface. The adsorption was performed at different process conditions, which include solution pH, dye concentrations, adsorbent doses, and temperature, respectively. In this study, it was found that MB dye adsorption increased with increases in solution pH and adsorbate MB dye concentration but decreased with adsorbent doses and temperature at fixed process conditions. The Langmuir isotherm model was best fitted with the experimental equilibrium data, with a higher linear regression coefficient (R2) value of 99.9% among the two widely used Langmuir and Freundlich adsorption isotherm model equations. The maximum Langmuir monolayer adsorption capacity of raw pine leaf was found to be 36.88 mg/g, which was comparable with other reported adsorbent capacities towards methylene blue (MB) dye adsorption. The value of the separation factor, RL, from the Langmuir isotherm model equation gives an indication of favorable adsorption. Thermodynamic parameters such as standard Gibbs free energy change (ΔG0), standard enthalpy change (ΔH0), and standard entropy change (ΔS0) indicated that the methylene blue (MB) dye adsorption by pine tree leaf biomass was spontaneous and exothermic in nature and that the mechanism of adsorption was mainly physical adsorption. Finally, limitations and future studies are also discussed here. The outcome of this batch adsorption study may result in the valorization of locally available large pine tree leaf residue waste, which could be used in water purification.

Preparation and characterization of PSF porous composite nanofibers via solution-blowing as adsorbent for dye removal

Preparation and characterization of PSF porous composite nanofibers via solution-blowing as adsorbent for dye removal

Effective utilization of discarded reverse osmosis post-carbon for adsorption of dyes from wastewater

In this study, the deployment of post Reverse Osmosis (RO)-carbon as a adsorbent for dye removal from water has been investigated. The post RO-carbon was thermally activated (RO900), and the material thus obtained exhibited high surface area viz. 753 m2/g. In the batch system, the efficient Methylene Blue (MB) and Methyl Orange (MO) removal was obtained by using 0.08 g and 0.13 g/50 mL adsorbent dosage respectively. Moreover, 420 min was the optimized equilibration time for both the dyes. The maximum adsorption capacities of RO900 for MB and MO dyes were 223.29 and 158.14 mg/g, respectively. The comparatively higher MB adsorption was attributed to the electrostatic attraction between adsorbent and MB. The thermodynamic findings revealed the process as spontaneous, endothermic, and accompanied by entropy increment. Additionally, simulated effluent was treated, and >99% dye removal efficiency was achieved. To mimic an industrial perspective, MB adsorption onto RO900 was also carried out in continuous mode. The initial dye concentration and effluent flow rate were among the process parameters that were optimized using the continuous mode of operation. Further, the experimental data of continuous mode was fitted with Clark, Yan, and Yoon-Nelson models. Py-GC/MS investigation revealed that dye-loaded adsorbents could be pyrolyzed to produce valuable chemicals. The cost and low toxicity associated benefits of discarded RO-carbon over other adsorbents reveal the significance of the present study.

Exploring the reusability of cuttlefish bones in sustainable waste management by green synthesis method for methylene blue dye removal

ABSTRACT The use of solid wastes as an adsorbent for dye removal from wastewater is one of the leading steps of sustainable waste management. In this research, the removal of Methylene Blue dye by cuttlefish bone waste was examined by using peppermint extract. Zn-doped cuttlefish bone was prepared by the green synthesis method in laboratory conditions for the comparison of cuttlefish bone in adsorption and ultrasonically-assisted adsorption processes. The results of this study exhibited that Methylene Blue removal with Zn-doped cuttlefish bone was higher than that with cuttlefish bone at all pH values. The qmax values obtained from the Langmuir isotherm model were calculated as 8.96 mg/g and 12.74 mg/g in the adsorption process with cuttlefish bone and Zn-doped cuttlefish bone, respectively. The qmax value relatively improved to 18.05 mg/g in the ultrasonically-assisted adsorption with Zn-doped cuttlefish bone. With the green synthesis, the qmax increased by 1.42 times, while this increase was 2.01 times with the application of the ultrasonically-assisted adsorption process using Zn-doped cuttlefish bone compared to the adsorption process using cuttlefish bone.