Adsorbent For Removal Of Organic Dyes Research Articles

Removal of brilliant blue and direct black-19 dyes from aqueous solutions using walnut husk-derived Fe–Cu bimetallic nanoparticles embedded in multiwalled carbon nanotubes

In present study aqueous extract of walnut husk was used for the simple, cost-effective synthesis of multiwalled carbon nanotubes (MWCNT) embedded with bimetallic iron-copper (Fe–Cu) nanoparticles, which exhibits adsorption capacity of 769.23 mg/g and 804.50 mg/g for Brilliant Blue (BB) dye and Direct Black (DB-19) dye respectively. The MWCNT@Fe–Cu were characterized by using FTIR, BET, FESEM, EDX, and XRD. The adsorption experiments were conducted by varying concentrations (50 ppm–200 ppm), pH (2.0–11.0), contact time (1 min–5 min), and temperature (30 °C–60 °C) to investigate their effect on adsorption. The adsorption data was best fit with the pseudo-second-order kinetics and Langmuir isotherm model, adsorption process was endothermic and spontaneous. The adsorption of each dye up to the 5th adsorption/desorption cycle was >95 %. From the 6th cycle to the 20th cycle the adsorption decreased from 97 % to 60.98 % and 95 % to56.76 % in the case of BB dye and DB-19 dye respectively. The unique feature of adsorbent is its pH independence as it showed more than 90 % removal efficiency in acidic as well basic medium. All findings underscore the effectiveness of synthesized MWCNT@Fe–Cu to be used as a potential adsorbent for organic dyes removal from industrial effluent.

Bentonite-assisted construction of magnesium-silicate-based composite as efficient adsorbent for organic dye removal

Fabricating highly efficient and low-cost absorbents to remove organic contaminants in industrial effluents is urgent yet of great importance. Herein, a facile one-pot hydrothermal approach was developed to successfully construct magnesium silicate and bentonite composite (MS-Bt) with uniform multilayer porous structure by using Bt as structural promoter. The specific surface area of MS-Bt can reach up to 392 m2·g−1 along with an average pore diameter of 2.29 nm and a pore volume of 0.22 cm3·g−1. MS-Bt composite exhibits a maximal adsorption capacity of 253.92 mg·g−1 for methylene blue (MB) in model wastewater treatment. Adsorption behavior fitted well with Langmuir isotherm and pseudo-second-order kinetics adsorption equations. The adsorption pathways of MB on MS-Bt mainly include chemical precipitation by Mg-OH, electrostatic attraction and surface hydroxyl functional group capture. This work is anticipated to give a new insight into constructing organic contaminants adsorbent by using clay mineral material as an auxiliary agent.

Adsorption Properties of UiO-66/Wood Hybrid Adsorbent for Organic Dye Removal

Adsorption Properties of UiO-66/Wood Hybrid Adsorbent for Organic Dye Removal

Designing a novel porous Ti3C2Tx MXene/MOF-based 3D-printed architecture as an efficient and easy recoverable adsorbent for organic dye removal from aqueous solution

ABSTRACT Recently, the 3D-printing approach has received considerable attention in the field of wastewater treatment. This is due to the ability to fabricate adsorbents with fine architectures that are easily recoverable through this technique. Here, the Ti3C2Tx MXene nanosheets were hybridised with zirconium-based metal-organic framework (UiO-66) through a simple in-situ solvothermal synthesis to develop an efficient adsorbent for organic dye removal. To avoid the secondary pollution of the powdery composite as well as to facilitate the recycling of adsorbent, the 3D-printed MXene/UiO-66 architectures with different lattice geometries of grid, star, and honeycomb were produced. The prepared adsorbent underwent thorough XRD, FTIR, SEM-EDS, TEM, BET, and UV-Vis absorption characterisation. Structural characterisations revealed the successful synthesis of MXene/UiO-66 composite with specific surface area of 347.28 m2/g and a large pore volume of 0.26 cm3/g, which was uniformly immobilised over and within the 3D-printed architectures with hierarchical porous structures. The 3D-printed MXene/UiO-66 architecture with honeycomb geometry exhibited desired dye removal performance for both the MO (88.95%) and DR31 (76.98%) dyes. The adsorption kinetic was analysed with different kinetic models and it was found that the adsorption followed the pseudo-first-order model. The 3D-printed MXene/UiO-66 architectures also displayed good reusability and stability after four cycles. This work suggests the 3D-printed MXene/UiO-66 architecture as a potential candidate for the removal of organic pollutants from wastewater and environmental protection.

Ultrasound assisted co-precipitation synthesis Fe3O4 nanoparticles as a magnetic adsorbent for Congo red removal

Magnetite (Fe3O4) nanoparticles were synthesized by the ultrasound assisted co-precipitation method. The synthesized nanoparticles were thoroughly characterized by various analytical tools including XRD, FESEM & TEM, VSM, BET, and FTIR. It was indicated that Fe3O4 nanoparticles have cubic structure. The size of spherical-shape Fe3O4 particles ranges from 10 to 15 nm. The Fe3O4 magnetic nanoparticles were applied as a magnetic adsorbent to remove Congo red from aqueous solution. It is assumed that the adsorption process follows the pseudo-second-order kinetics equation. Equilibrium data fits well with Langmuir model. The maximum adsorption capacity is of 169.8 mg/g. This suggests that the synthesized magnetic nanoparticles could be a promising adsorbent for organic dyes removal in aqueous solutions.

Effective adsorption of crystal violet dye on sugarcane bagasse–bentonite/sodium alginate composite aerogel: Characterisation, experiments, and advanced modelling

A novel sugarcane bagasse–bentonite/sodium alginate (SCB–Ben/SA) composite aerogel was prepared as an effective green adsorbent via blending–cross-linking for the removal of crystal violet (CV) dye from aqueous solution. The equilibrium adsorption capacity of SCB–Ben/SA for CV was 839.9 mg/g at 0.8 mg/mL adsorbent dosage, temperature 303 K, pH 4, and 800 mg/L initial CV concentration, and presented a removal rate of 85%. Adsorption kinetics studied using the novel pseudo-first-order and pseudo-second-order (PFO–PSO) combined model showed that CV adsorption by SCB–Ben/SA was a complex process and did not include a single mechanism, but involved both chemical and physical adsorption reactions; however, chemisorption was the dominant kinetic mechanism. The dynamic characteristics of CV adsorption process achieved through the liquid film around SCB–Ben/SA and the pores inside SCB–Ben/SA was described satisfactorily and conveniently using the novel film–pore mass transfer (FPMT) model. A multilayer adsorption model was applied to further understand the CV adsorption behaviour of SCB–Ben/SA. The number of linked CV molecules per functional group varied from 0.53 to 0.63 for SCB–Ben/SA. The CV molecules were adsorbed on SCB–Ben/SA via mixed orientation. The adsorption isotherms and thermodynamics revealed that the multilayer adsorption process was endothermic and spontaneous. Overall, SCB–Ben/SA was found to be an efficient, low-cost, green, and recyclable adsorbent for organic dye removal.

Effect of CaO/SiO2 compositions on the structure formation of mesoporous calcium silicate (CaSiO3) composite particles as adsorbent for organic dye removal

The primary objective of this paper was to synthesize a calcium silicate (CaSiO3) and investigate the effect of CaO/SiO2 compositions on the structure formation of synthetic material. CaSiO3 was prepared through the solid-state method using CaO from chicken eggshells and commercial SiO2 powder as starting material. To investigate the effect of CaO/SiO2 on the structure of CaSiO3, the different molar ratios of CaO/SiO2 (i.e., 1:1, 1:7, 2:7, and 3:7) were used. BET results show the resulting product has a high specific surface area of 13,18 ±30.53 m2g-1 and a pore size of 15,16 ±18.4 nm obtained as mesoporous material. The obtained CaSiO3 particles, then to be applied for the degradation of dye pollutants in water. The adsorption capacity was evaluated by methylene blue (MB) and brilliant green (BG) degradation. The parameters of CaO/SiO2 mass ratio and contact time on the degradation efficiency of BG and MB were investigated, respectively. The results showed that the best model for BG adsorption onto CaSiO3 was a pseudo-first-order model, whereas the best model for MB adsorption was a pseudo-second-order model.

Construction of 2D porphyrin-based covalent organic framework as adsorbent for organic dyes removal and carbon dioxide adsorption

A porphyrin-based two-dimensional covalent organic framework (TPE-Por-COF) with high stability was synthesized, and the adsorption performance of TPE-Por-COF on organic dyes was studied. The TPE-Por-COF was characterized by X-ray powder diffraction, infrared spectroscopy, solid-state nuclear magnetic resonance, thermogravimetry and N2 adsorption isotherms. TPE-Por-COF has adsorption effect on five dyes: malachite green (MG), methyl violet (MV) and rhodamine B (RhB), coomassie brilliant blue (CBB) and brilliant green (BG). Among them, TPE-Por-COF has the most obvious adsorption effect on malachite green, and the adsorption capacity is as high as 1428.57 ​mg ​g-1. In addition, the CO2 adsorption capacity of TPE-Por-COF is 187 ​mg ​g-1 at 50 ​bar and 323 ​K.

Amidation modified waste polystyrene foam as an efficient recyclable adsorbent for organic dyes removal.

Modifying environmentally harmful waste polystyrene foam as an efficient recyclable adsorbent for organic dyes is important. Amidation modified polystyrene (PS-SD) was prepared by the Friedel-Crafts reaction and N,N'-dicyclohexylcarbodiimide (DCC) dehydration condensation reaction of waste polystyrene foam. PS-SD had highly efficient removal performance for organic dyes in large volume water sample solutions, and equilibrium was achieved in 0.5 h. The maximum adsorption capacities for Methylene blue (MB) and Congo red (CR) were 881.62 and 1,880.91 mg/g, respectively, at room temperature according to the Langmuir adsorption isotherm (R2 > 0.99). The kinetic data of the two dyes followed pseudo-second-order kinetics. The removal percentage remained high (>85%) after eight filtration-regeneration cycles. Experimental results showed that PS-SD was an excellent adsorbent for water treatment with high recyclability and long life.

Cascade electron transfer in ternary CuO/α-Fe2O3/γ-Al2O3 nanocomposite as an effective visible photocatalyst

Highly efficient ternary heterojunction of CuO/α-Fe2O3/γ-Al2O3 was effectively fabricated by a facile and cost effective chemical route. The structural, chemical composition, morphology, optical and photocatalytic properties of as-prepared CuO/α-Fe2O3/γ-Al2O3 photo catalyst were compared to pristine and binary samples by various characterization. Existence of all the dominant peaks of CuO, α-Fe2O3 and γ-Al2O3 are noticeable in XRD spectrum of CuO/α-Fe2O3/γ-Al2O3 ternary photo catalyst which confirms the successful formation of the photocatalyst. SEM and HRTEM results revealed the spherical shape CuO nanoparticles with distorted α-Fe2O3 agglomerated plates which led to complete diffusion with γ-Al2O3. The band gap of ternary nanocomposite was found to be 1.9 eV elucidated by UV-DRS. Brunauer-Emmett-Teller (BET) analysis showed that as-fabricated ternary CuO/α-Fe2O3/γ-Al2O3 nanocomposite exhibited the porous structure with large surface area and small pore volume as compared to pristine γ-Al2O3.due to the unique ternary nanocomposite structure and synergistic effect among various components. The photocatalytic activity was examined by monitoring the deterioration of methyl orange under simulated solar light irradiation. CuO/α-Fe2O3/γ-Al2O3 exhibited superior photocatalytic efficacy as compared to CuO/γ-Al2O3 and α-Fe2O3/γ-Al2O3 binary and pure oxides of γ-Al2O3, CuO and α-Fe2O3. The marvelous photocatalytic activity of CuO/α-Fe2O3/γ-Al2O3 ternary nanocomposite samples can be ascribed to their close contact, strong interfacial hybridization and proficient charge transfer capacity. The electrochemical studies such as linear sweep voltammetry (LSV) and cyclic voltammetry (CV) were carried out to explore the charge transfer behavior and support the high photo activity of ternary nanocomposite CuO/α-Fe2O3/γ-Al2O3. LSV measurements manifested that CuO/α-Fe2O3/γ-Al2O3 exhibited 4.3 folds higher current density than bare γ-Al2O3 which confirmed the faster electron transfer from CuO to γ-Al2O3 via mediated α-Fe2O3 through the interfacial potential gradient in conduction band. Cyclic voltammetry (CV) results showed that pair of anodic and cathodic peaks in CuO/α-Fe2O3/γ-Al2O3 appeared which affirm the efficient increase in photo-induced e−/h+ separation and suppress recombination rate of electron-hole pair. This work demonstrated that CuO/α-Fe2O3/γ-Al2O3 ternary nanocomposite is found to be a promising candidate as an efficient adsorbent for organic dye removal from waste water.

Heterostructured TiO2@HKUST-1 for the enhanced removal of methylene blue by integrated adsorption and photocatalytic degradation

ABSTRACT Aiming at exploring an effective photocatalytic adsorbent for organic dye removal, a series of heterostructured TiO2@HKUST-1 photocatalysts, by incorporating HKUST-1 with different TiO2 nanoparticles loading, were prepared by single-step hydrothermal method. The morphology and surface characteristics of the as-prepared TiO2@HKUST-1were analyzed using SEM, HRTEM, XRD, FTIR, UV–vis DRS, and Photoluminescence techniques. The adsorption-photocatalytic degradation of the model dye methylene blue (MB) on the catalysts was investigated. It was indicated that the introduction of a certain amount of TiO2 on the surface of HKUST-1 could improve the transfer and separation of the photogenerated charge carriers, resulting in the enhanced photocatalytic activity. The optimal 0.02TiO2@HKUST-1 exhibited the highest MB removal rate with about 4.4 and 19.3 times as high MB removal efficiency as that of HKUST-1 and TiO2, respectively. Heterostructured TiO2@HKUST-1 materials for the removal of MB involved the integrated adsorption and visible light photocatalysis. Meanwhile, the composite exhibited good reusability in the process of cyclic experiments. Therefore, this work provides a potential MOF-based photocatalytic adsorbent for organic dye removal.

Hydrolyzed polyacrylamide modified diatomite waste as a novel adsorbent for organic dye removal: Adsorption performance and mechanism studies

Brewery diatomite waste (DW) was reused as a novel adsorbent via being modified by hydrolyzed polyacrylamide (HPAM). The adsorption of hydrolyzed polyacrylamide modified diatomite waste (HPAM-DW) for methylene blue (MB) and reactive yellow (RY) were severally studied and compared. The DW and HPAM-DW were characterized by various methods including Scanning Electron Microscopy (SEM), Energy Dispersive Spectroscopy (EDS), Fourier Transform Infrared Spectroscopy (FTIR) and X-ray diffraction (XRD) to analyze their physical and chemical properties before and after modification. The effects of four adsorption parameters (adsorption time, adsorbent dosage, pH and initial concentration) were also studied. The maximum adsorption capacity of HPAM-DW for MB (at pH 9.0) and RY (at pH 2.0) was 37.12 mg/g and 32.83 mg/g, respectively at 30 °C. Moreover, the adsorption data was fitted by Langmuir, Freundlich and Dubinin-Radushkevich (D-R) adsorption isothermal models, and as a result, Langmuir presents the best correspondence (R2MB = 0.974, R2RY = 0.991). Also, pseudo-first was more responsible than pseudo-second model in reflecting the mechanism of adsorption process (R2MB = 0.997, R2RY = 0.973). Compared with DW, the adsorption efficiency of organic dyes have improved due to the synergistic effect of HPAM and DW. From the investigation, the synthesized HPAM-DW was proved to act as a promising adsorbent to remove the dye waste in the industrial wastewater.

Hierarchical quasi waxberry-like Ba5Si8O21 microspheres: Facile green rotating hydrothermal synthesis, formation mechanism and high adsorption performance for Congo red

Towards the imperative water contamination by organic dyes, uniform hierarchical quasi waxberry-like Ba5Si8O21 microspheres (diameter: 0.65–1.30 µm) consisted of nanorods have been successfully synthesized via a facile eco-friendly and cost-effective rotating hydrothermal process (120 °C, 6.0 h) without any organic additives, templates or surfactants, using abundant BaCl2·2H2O and Na2SiO3·9H2O as the raw materials. Based on the impacts of the process parameters, a probable heat and mass transport enhanced rotating hydrothermal formation mechanism is proposed. The rotating homogeneous hydrothermal reactor provides vigorous macro- and micro-mixing of the solid and solution phase, thus favors the early stage dissolution-recrystallization, formation of the product nuclei at lower temperature, and final self-assembly for uniform waxberry-like microspheres with miniaturization of size. When employed as the adsorbents for the elimination of Congo red (CR) from simulated waste water, the adsorption data are well fitted with Langmuir isothermal model (qm: 1238.7 mg g−1). Meanwhile, the adsorption of CR is well described by the pseudo-second-order kinetic and intra-particle diffusion models, indicating the final diffusion at equilibrium stage within the mesopores of the real rate-limiting step in the whole adsorption process. The recycling test further confirms the Ba5Si8O21 microspheres as highly efficient adsorbents with satisfactory stability and reusability. As a noteworthy methodology, the heat and mass transport enhanced rotating hydrothermal synthesis presents new insights into the hierarchical porous silicate microspheres as a competitive candidate adsorbent for organic dyes removal, and also a potential new platform for heterogeneous catalysis.

Magnesium oxide modified diatomite waste as an efficient adsorbent for organic dye removal: adsorption performance and mechanism studies

ABSTRACTMagnesium oxide modified diatomite waste (MgO-DW) was successfully synthesized. The adsorption behaviors of methylene blue (MB) and acid orange (AO) over MgO-DW were studied. The samples involved were characterized by Fourier transform infrared, scanning electron microscopy, energy dispersive spectrometer, Brunauer Emmett Teller, X-ray diffraction, and zero point of charge analyses. Experimental factors including contact time, adsorbent dosage, pH, and initial dye concentration were explored. Maximum adsorption capacity of MgO-DW for MB (pH 11.0) and AO (pH 2.0) was 25.02 and 35.13 mg/g at 303 K, respectively. The results showed that Langmuir isotherm and pseudo-first-order kinetic models fitted the experimental data better. Regeneration tests confirmed that MgO-DW has promising potential in reusability.

Polydopamine-coated magnetic nanochains as efficient dye adsorbent with good recyclability and magnetic separability

High adsorption ability and good separation functionality are necessary to an excellent adsorbent for organic dye removal from wastewater. In this study, core@shell nanostructured magnetic Fe-Fe2O3@polydopamine (PDA) nanochains (defined as Fe-Fe2O3@PDA NCs) were facilely synthesized through self-polymerization of dopamine on the surface of Fe-Fe2O3 NCs. The dye adsorption performance, recyclability and magnetic separability of the Fe-Fe2O3@PDA NCs were investigated through selecting malachite green (MG) as a model organic dye. The effects of initial MG concentration, initial solution pH, temperature, and contact time on dye adsorption were systematically studied. Results show that the adsorption capacity of the Fe-Fe2O3@PDA NCs for MG was 61.22 mg/g at 25 °C. Both π-π stacking and electrostatic interactions might be responsible for the adsorption of MG on Fe-Fe2O3@PDA NCs. The adsorption kinetic follows both pseudo-second-order kinetic and Weber’s intraparticle diffusion models. And the adsorption isothermal models fit Langmuir well. Besides, the Fe-Fe2O3@PDA NCs exhibit good recyclable adsorption property towards MG dye.

Preparation of sustainable nanocomposite as new adsorbent for dyes removal

Sustainable nanocomposite from chitosan, silk fibroin and hydroxyapatite was investigated as adsorbent for organic dyes removal from waste water. Chitosan/silk fibroin bioactive blend initiated successfully the mineralization of hydroxyapatite rod-like crystals with ~40 nm diameter. The formed nanocomposite was applied for methylene blue (MB) removal from waste water. The adsorption kinetics were fitted with Pseudo-second order kinetic model. Adsorption results well fitted to the Langmuir model and showed maximum adsorption capacity 476 mg/g. The current nanocomposite is sustainable and efficient adsorbent for organic dyes removal from waste water.

Graphene oxide/Fe3O4/chitosan nanocomposite: a recoverable and recyclable adsorbent for organic dyes removal. Application to methylene blue

In this research, the potential of chitosan/Fe3O4/graphene oxide (CS/Fe3O4/GO) nanocomposite for efficient removal of methylene blue (MB) as a cationic dye from aqueous solutions was investigated. For this purpose, first, graphene oxide (GO) was prepared from pencil’s graphite by Hummer’s method, then after, CS/Fe3O4/GO was synthesized via chemical co-precipitation method from a mixture solution of GO, Fe3+, Fe2+ and chitosan. The synthesized CS/Fe3O4/GO was characterized by XRD, VSM and SEM techniques. Also, the various parameters affecting dye removal were investigated. Dye adsorption equilibrium data were fitted well to the Langmuir isotherm rather than Freundlich isotherm. The maximum monolayer capacity (qmax), was calculated from the Langmuir as 30.10 mg · g−1. The results show that, CS/Fe3O4/GO nanocomposite, can be used as a cheap and efficient adsorbent for removal of cationic dyes from aqueous solutions.

New sustainable hybrid material as adsorbent for dye removal from aqueous solutions

Cellulose grafted with soy protein isolate (SPI), sustainable and cost effective material, was investigated as a bioactive material for calcium phosphate mineralization. The formation of hydroxyapatite rod-like nanocrystals with ∼50nmdiameter was confirmed by different characterization tools. Cellulose grafted SPI/hydroxyapatite hybrid was evaluated as recyclable adsorbent for methylene blue (MB) from aqueous solutions using batch adsorption technique. The new sustainable material exhibited adsorption capacity up to 454mg/g. Adsorption data were examined using different kinetics and isotherms to investigate the adsorption mechanism. After four adsorption-desorption cycles, the efficiency of MB removal is ∼95%. These results present new sustainable, cost effective and reusable hybrid material as a promising adsorbent for organic dyes removal from waste water.

Magnetically modified Sargassum horneri biomass as an adsorbent for organic dye removal

Adsorption of five water-soluble dyes of different chemical structures from aqueous solutions was investigated using magnetically responsive brown algae Sargassum horneri. The simple magnetic modification of Sargassum biomass employing microwave-synthesized iron oxide nano- and microparticles enabled rapid and selective separation by means of external magnetic field. The biosorption was studied in a batch system under different conditions. Time necessary to reach equilibrium was less than 2 h for all tested dyes. The adsorption equilibrium data were analyzed by Langmuir and Freundlich isotherm models. The highest maximum adsorption capacity was observed for acridine orange (193.8 mg/g), the lowest one for malachite green (110.4 mg/g). The sorption kinetics could be described by pseudo-second-order model, and the thermodynamic studies indicated exothermic nature of biosorption process in the temperature range studied. It can be concluded that Sargassum horneri biomass, exhibiting a satisfactory efficacy in dye removal, can be used as an effective, low-cost adsorbent.

Magnetically modified Posidonia oceanica biomass as an adsorbent for organic dyes removal

Magnetically modified Posidonia oceanica sea grass dead biomass was employed as an adsorbent of organic dyes. The adsorption of seven water-soluble organic dyes was characterized using Langmuir adsorption model. The highest calculated maximum adsorption capacity was found for Bismarck brown Y (233.5 mg g-1), while the lowest capacity value was obtained for safranin O (88.1 mg g-1). The adsorption processes followed the pseudo-second-order kinetic model and the thermodynamic studies indicated spontaneous and endothermic adsorption.