Adsorption and Photocatalytic Degradation of an Industrial Azo Dye Using Colloidal Semiconductor Nanocrystals

Abstract In this study, mercaptosuccinic acid capped CdSe nanocrystals was successfully synthesized by in-situ medium colloid and used as photocatalyst for the effective photodegradation of methylene blue from aqueous solution under visible light and sunlight irradiations.The particle size and the crystal structure of these nanocrystals were analyzed by different analytical techniques. Dye adsorption prior to photocatalysis using these nanomaterials was studied via the experimental quantification of kinetics and isotherms. These experimental data were modeled including the application of statistical physics theory to analyze the corresponding adsorption mechanism. A maximum adsorption capacity of 27.1 mg/g (80% dye removal) was observed in 10 min using an initial concentration of 30 mg/L. Statistical physics calculations indicated that the adsorption energy was lower than 40 kJ/mol. Itwas also established that the dye adsorption was associated to the electrostatic interactions and hydrogen bonding. Overall, the dye removal was a spontaneous, feasible process and exothermic. Adsorption properties of CdSe-MSA nanocrystals improved the dye photodegradation efficiency under visible light thus achieving up to 80% degradation in 60 min. The synergic effect of adsorption and photocatalytic degradation performance was mainly due to the surface area, small size (3.7 nm) and structural defects (selenium vacancies Se, interstitial of cadmium ICd), which enhanced the response of these nanomaterials inside the visible range for the photocatalytic activity. In summary, these nanocrystals are promising materials to be used in wastewater treatment under sun light for the removal of organic compounds like dyes.

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Vanadium pentoxide 1-D nanostructures applied to dye removal from aqueous systems by coupling adsorption and visible-light photodegradation

RSC Advances ◽

10.1039/c4ra12788a ◽

2015 ◽

Vol 5 (16) ◽

pp. 12000-12006 ◽

Cited By ~ 28

Author(s):

Waldir Avansi ◽

Vagner R. de Mendonça ◽

Osmando F. Lopes ◽

Caue Ribeiro

Keyword(s):

Visible Light ◽

Hydrothermal Method ◽

Vanadium Pentoxide ◽

Dye Removal ◽

Dye Adsorption ◽

Adsorption Properties ◽

Aqueous Systems ◽

One Dimensional ◽

1D Nanostructures

This paper evaluates the photocatalytic and dye adsorption properties of highly crystalline orthorhombic vanadium pentoxide (V2O5) one-dimensional (1D) nanostructures, such as nanowires and nanorods, synthesized by a hydrothermal method.

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Efficient removal of crystal violet dye from aqueous solutions using sodium hydroxide modified avocado shells: kinetics and isotherms modeling

Water Science & Technology ◽

10.2166/wst.2021.451 ◽

2021 ◽

Author(s):

M. Ait Haki ◽

A. Imgharn ◽

N. Aarab ◽

A. Hsini ◽

A. Essekri ◽

...

Keyword(s):

Sodium Hydroxide ◽

Crystal Violet ◽

Electrostatic Interactions ◽

Fourier Transforms ◽

Dye Adsorption ◽

Order Kinetic ◽

Efficient Removal ◽

Ionic Strength Effect ◽

Crystal Violet Dye ◽

Kinetics And Isotherms

Abstract The main objective of this study is to optimize a new composite for the depollution of contaminated water. The sodium hydroxide-modified Avocado shells (NaOH-AS) were firstly prepared, characterized by field-emission-scanning-electron-microscopy (FE-SEM), X-ray energy dispersive spectroscopy (EDS) and Fourier transforms infrared (FT-IR) spectroscopy, and applied for efficient removal of Crystal violet dye (CV) in wastewater. In addition, the adsorption in a batch system of CV dye on the NaOH-AS material was studied. Therefore, we accomplished a parametric study of the adsorption by studying the effect of several important parameters on the decolorizing power of the used material, namely, initial pH, contact time, initial CV dye concentration, temperature, and the ionic strength effect on the CV dye adsorption process were systematically assessed. The highest adsorption efficiency of CV dye (>96.9%) by NaOH-AS was obtained at pH >8. The pseudo-second-order kinetic model gave the best description of the adsorption kinetic of CV dye on the AS and NaOH-AS adsorbents. Besides, the mass transfer of CV dye molecules from the solution to the adsorbent surface occurred in three sequential stages (boundary layer diffusion, intraparticle diffusion and adsorption equilibrium). The adsorption isotherm data were best fitted with the Freundlich model. The adsorption capacity of AS increased from 135.88 to 179.80 mg g−1 after treatment by 1 M NaOH. The thermodynamic study showed that CV dye adsorption onto NaOH-AS was an exothermic and feasible process. The electrostatic interactions acted as the only forces governing the CV adsorption mechanism. The NaOH-AS demonstrated a satisfactory reusability. Therefore, we can state that the as-developed NaOH-AS material has a potential application prospect as an efficient adsorbent for CV dye from wastewaters.

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A Study of The Equilibrium, Kinetics, and Thermodynamics of Malachite Green Dye Adsorption Onto Lignin

10.21203/rs.3.rs-1009760/v1 ◽

2021 ◽

Author(s):

Vani Gandham ◽

UMA Addepally ◽

Bala Narsaiah T

Keyword(s):

Malachite Green ◽

Group Analysis ◽

Dye Adsorption ◽

Second Order ◽

Isotherm Models ◽

Maximum Adsorption Capacity ◽

Order Kinetic ◽

Adequate Treatment ◽

Pseudo Second Order ◽

Kinetics And Isotherms

Abstract Malachite Green (MG), a cationic synthetic dye is considered hazardous when discharged into the water bodies without any adequate treatment. It can affect the multiple segments of the environment leading to irreversible persistent changes. So, there is a need for remediation with cost-effective method to remove dyes from effluents. Adsorption is one such technique to remove dyes from wastewater and is effective and economical. The present study describes the removal of MG cationic dye from wastewater using eco-friendly and biodegradable lignin extracted from hydrothermally treated rice straw by adsorption process. Functional group analysis and morphological characterisation was done to the extracted lignin after quantification. The maximum percent removal of MG 92 ± 0.2 % was observed from a series of batch experiments at optimum process parameters of: contact time 80 min, initial dye concentration 50 ppm, lignin dosage 0.25g, pH 7, temperature 300c and with 100 rpm agitation speed. The adsorption kinetics and isotherms were determined for the experimental data using four kinetic models (pseudo-first-order, second order, pseudo-second-order and intra-particle diffusion model) and two isotherm models (Langmuir and Freundlich). The results suggested that the kinetics data fit to the pseudo-second-order kinetic model with the maximum adsorption capacity 36.7 mg/g and the two isotherm models were applicable for the adsorption of MG onto the lignin. Additionally, the thermodynamic parameters ΔSo, ΔHo and ΔGo were evaluated. Therefore, lignin which is an environmental friendly and low cost carbon material that can be used as an adsorbent for dye removal.

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A Novel Geopolymer Foam Based On ZSM-5 Zeolite Fabricated Using Templating Emulsion/Chemical Foaming Method and Its Application in Batch and Continuous Dye Removal Systems

10.21203/rs.3.rs-1227901/v1 ◽

2022 ◽

Author(s):

Mahboobeh Monjezi ◽

Vahid Javanbakht

Keyword(s):

Adsorption Capacity ◽

Dye Removal ◽

Adsorption Process ◽

Dye Adsorption ◽

Batch Adsorption ◽

Maximum Adsorption Capacity ◽

Continuous Systems ◽

Green Materials ◽

Pseudo Second Order ◽

Chemical Foaming

Abstract Geopolymers as sustainable and environmentally friendly “green materials”, can be synthesized by utilizing waste material and by-products. A porous geopolymer foam adsorbent based on ZSM-5 zeolite was prepared using templating emulsion/chemical foaming method in different conditions and used for dye removal in batch and continuous systems. The parameters affecting the dye adsorption including temperature, concentration, and pH, kinetics, isotherm, and thermodynamics of the process were investigated. The results of the geopolymer foam synthesis showed that thermal pretreatment of the zeolite has a positive effect on the strength and adsorption capacity. Moreover, the increase in sodium silicate more than the stoichiometric reduces the strength and adsorption capacity. The findings obtained from the batch adsorption process showed that the adsorption kinetics of the pseudo-second-order model and the adsorption isotherm of the Temkin model is adjusted with the experimental data. Thermodynamic results indicated that the process of dye adsorption with geopolymer foam is exothermic. The results from continuous experiments indicated more compatibility of the adsorption process with the models of Thomas and Bohart-Adams. The maximum adsorption capacity of methylene blue in batch and continuous processes was 9.82 and 8.17 mg/g. The adsorbent reduction was performed successfully by chemical and thermal processes.

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Highly Effective Covalently Crosslinked Composite Alginate Cryogels for Cationic Dye Removal

Gels ◽

10.3390/gels7040178 ◽

2021 ◽

Vol 7 (4) ◽

pp. 178

Author(s):

Serap Sezen ◽

Vijay Kumar Thakur ◽

Mehmet Murat Ozmen

Keyword(s):

Adsorption Capacity ◽

Dye Removal ◽

Low Cost ◽

Dye Adsorption ◽

Maximum Adsorption Capacity ◽

High Porosity ◽

Order Model ◽

Removal Capacity ◽

Pseudo Second Order ◽

The One

Currently, macroporous hydrogels have been receiving attention in wastewater treatment due to their unique structures. As a natural polymer, alginate is used to remove cationic dyes due to its sustainable features such as abundance, low cost, processability, and being environmentally friendly. Herein, alginate/montmorillonite composite macroporous hydrogels (cryogels) with high porosity, mechanical elasticity, and high adsorption yield for methylene blue (MB) were generated by the one-step cryogelation technique. These cryogels were synthesized by adding montmorillonite into gel precursor, followed by chemical cross-linking employing carbodiimide chemistry in a frozen state. The as-prepared adsorbents were analyzed by FT-IR, SEM, gel fraction, swelling, uniaxial compression, and MB adsorption tests. The results indicated that alginate/montmorillonite cryogels exhibited high gelation yield (up to 80%), colossal water uptake capacity, elasticity, and effective dye adsorption capacity (93.7%). Maximum adsorption capacity against MB was 559.94 mg g−1 by linear regression of Langmuir model onto experimental data. The Pseudo-Second-Order model was fitted better onto kinetic data compared to the Pseudo-First-Order model. Improved porosity and mechanical elasticity yielding enhanced dye removal capacity make them highly potential alternative adsorbents compared to available alginate/montmorillonite materials for MB removal.

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Removal of Tetracycline by Hydrous Ferric Oxide: Adsorption Kinetics, Isotherms, and Mechanism

International Journal of Environmental Research and Public Health ◽

10.3390/ijerph16224580 ◽

2019 ◽

Vol 16 (22) ◽

pp. 4580 ◽

Cited By ~ 3

Author(s):

Ji Zang ◽

Tiantian Wu ◽

Huihui Song ◽

Nan Zhou ◽

Shisuo Fan ◽

...

Keyword(s):

Adsorption Kinetics ◽

Ferric Oxide ◽

Photoelectron Spectroscopy ◽

Electrostatic Interactions ◽

Adsorption Process ◽

Inhibitory Effect ◽

Maximum Adsorption Capacity ◽

Hydrous Ferric Oxide ◽

X Ray ◽

Kinetics And Isotherms

The removal of tetracycline (TC) from solution is an important environmental issue. Here we prepared an adsorbent hydrous ferric oxide (HFO) by adjusting a FeCl3·6H2O solution to neutral pH. HFO was characterized by a surface area analyzer, X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and X-ray photoelectron spectroscopy (XPS), and was used to remove TC from solution. The influence of pH, solid-to-liquid ratio, ionic type, and strength on TC removal was investigated. Adsorption kinetics and isotherms were also determined. HFO after adsorption of TC was analyzed by FTIR and XPS to investigate the adsorption mechanism. The results showed that the adsorption of TC increased from 88.3% to 95% with increasing pH (3.0–7.0) and then decreased. K+ ions had little effect on TC adsorption by HFO. However, Ca2+ and Mg2+ reduced the adsorption of TC on HFO. When the concentrations of Ca2+ and Mg2+ were increased, the inhibitory effect was more obvious. Pseudo-second-order kinetics and the Langmuir model fitted the adsorption process well. The maximum adsorption capacity of TC on HFO reached 99.49 mg·g−1. The adsorption process was spontaneous, endothermic, and increasingly disordered. Combination analysis with FTIR and XPS showed that the mechanism between TC and HFO involved electrostatic interactions, hydrogen interactions, and complexation. Therefore, the environmental behavior of TC could be affected by HFO.

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Kinetic and equilibrium studies on adsorption of Reactive Blue 19 dye from aqueous solutions by nanohydroxyapatite adsorbent

Archives of Environmental Protection ◽

10.1515/aep-2016-0014 ◽

2016 ◽

Vol 42 (2) ◽

pp. 3-11 ◽

Cited By ~ 22

Author(s):

Gabriela Ciobanu ◽

Simona Barna ◽

Maria Harja

Keyword(s):

Dye Removal ◽

Dye Adsorption ◽

Kinetic Studies ◽

Solution Concentration ◽

Batch Adsorption ◽

Maximum Adsorption Capacity ◽

Order Model ◽

Equilibrium Studies ◽

Reactive Blue 19 ◽

Pseudo Second Order

AbstractIn the present study the adsorption of Reactive Blue 19 dye on the hydroxyapatite (HAp) nanopowders was investigated. The batch adsorption experiments were performed by monitoring the adsorbent dosage, contact time, dye solution concentration, pH and temperature. At pH 3 and 20°C, high dye removal rates of about 95.58% and 86.95% for the uncalcined and calcined nanohydroxyapatites, respectively, were obtained. The kinetic studies indicated the dye adsorption onto nanohydroxyapatite samples to follow a pseudo-second order model. The Langmuir isotherm was found to be the best to represent the equilibrium with experimental data. The maximum adsorption capacity of uncalcined and calcined nanohydroxyapatite samples has been found to be 90.09 mg/g and 74.97 mg/g, respectively.

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Equilibrium and Kinetics Study of Adsorption of Crystal Violet onto the Peel ofCucumis sativaFruit from Aqueous Solution

E-Journal of Chemistry ◽

10.1155/2012/457632 ◽

2012 ◽

Vol 9 (3) ◽

pp. 1091-1101 ◽

Cited By ~ 8

Author(s):

T. Smitha ◽

S. Thirumalisamy ◽

S. Manonmani

Keyword(s):

Crystal Violet ◽

Dye Removal ◽

High Efficiency ◽

Ph Value ◽

Dye Adsorption ◽

Second Order ◽

Maximum Adsorption Capacity ◽

Experimental Conditions ◽

Pseudo Second Order ◽

Cucumis Sativa

The use of low-cost, locally available, high efficiency and eco-friendly adsorbents has been investigated as an ideal alternative to the current expensive methods of removing dyes from wastewater. This study investigates the potential use of the peel ofCucumis sativafruit for the removal of crystal violet (CV) dye from simulated wastewater. The effects of different system variables, adsorbent dosage, initial dye concentration, pH and contact time were investigated and optimal experimental conditions were ascertained. The results showed that as the amount of the adsorbent increased, the percentage of dye removal increased accordingly. Optimum pH value for dye adsorption was determined as 7.0. The adsorption of crystal violet followed pseudo-second order rate equation and fit well Langmuir and Freundlich equations. The maximum removal of CV was obtained at pH 7 as 92.15% for adsorbent dose of 0.2 g/50 mL and 25 mg L-1initial dye concentration at room temperature. The maximum adsorption capacity obtained from Langmuir equation was 34.24 mg g-1. Furthermore, adsorption kinetics of (CV) was studied and the rate of adsorption was found to conform to pseudo-second order kinetics with a good correlation (R2> 0.9739). The peel ofCucumis sativafruit can be attractive options for dye removal from diluted industrial effluents since test reaction made on simulated dyeing wastewater show better removal percentage of (CV).

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Magnetic Nanocomposites Containing Low and Medium-Molecular Weight Chitosan for Dye Adsorption: Hydrophilic Property Versus Functional Groups

10.21203/rs.3.rs-684636/v1 ◽

2021 ◽

Author(s):

Masouma Mirzai ◽

Simin Asadabadi

Keyword(s):

Molecular Weight ◽

Dye Removal ◽

Dye Adsorption ◽

Freundlich Isotherm ◽

Polluted Water ◽

Maximum Adsorption Capacity ◽

Adsorptive Removal ◽

Hydrophilic Property ◽

Initial Ph ◽

Property Versus

Abstract The azo dye removal from polluted water is vital from a sustainable viewpoint. In this study, we investigated the influence of chitosan molecular weight on the adsorptive removal of basic blue 41. For preparing nanocomposite containing medium-molecular weight chitosan (NC(M)), cross-linking of chitosan was done using diethylenetriaminepentaacetic acid, silica-modified magnetite nanoparticles and graphene oxide. Techniques including FT-IR, XRD, FESEM, TGA/DTG, VSM and N2 adsorption/desorption isotherm were applied for characterization of NC(M). The adsorption behavior of synthesized NC(M) was compared with as-prepared adsorbent containing low-molecular weight chitosan (NC(L)) (Asadabadi 2021). The experimental design was carried out using the Central Composite Design. The effect of initial pH, temperature and adsorbent concentration on the percentage of dye removal were examined and the optimum values of variables were determined. Despite NC(M) which had maximum 31% dye removal, NC(L) led to approximately 95% adsorptive removal at optimum conditions. An increase in the monomer number of chitosan caused to reduce hydrophilic property of NC(M), which in turn resulted in a repulsion force between adsorbent and dye. However, H-bonding, coulumbic attraction and pi-stacking interactions contributed in the adsorption mechanism of NC(L). The kinetics study showed that about 30 min necessitated reaching the equilibrium and the rate-limiting steps changed from film diffusion to intra-particle diffusion as time passed. The kinetics data were satisfactorily fitted by the modified pseudo-n-order model. The maximum adsorption capacity of NC(L) was obtained 55.87 mg·g− 1. The modified Langmuir-Freundlich isotherm was the best model to reproduce data. NC(L) was recovered seven times without dramatic changes in its adsorption efficiency.

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A Study on Astrazon Black AFDL Dye Adsorption onto Vietnamese Diatomite

Journal of Chemistry ◽

10.1155/2016/8685437 ◽

2016 ◽

Vol 2016 ◽

pp. 1-11 ◽

Cited By ~ 7

Author(s):

Bui Hai Dang Son ◽

Vo Quang Mai ◽

Dang Xuan Du ◽

Nguyen Hai Phong ◽

Dinh Quang Khieu

Keyword(s):

Experimental Data ◽

Adsorption Capacity ◽

Goodness Of Fit ◽

Piecewise Linear ◽

Dye Adsorption ◽

Maximum Adsorption Capacity ◽

Order Kinetic ◽

Initial Concentration ◽

Average Value ◽

Kinetics And Isotherms

In the present paper, the adsorption of Astrazon Black AFDL dye onto Vietnamese diatomite has been demonstrated. The diatomite was characterized by XRD, SEM, TEM, EDS, and nitrogen adsorption/desorption isotherms. The results show that diatomite mainly constituted centric type frustules characterized by pores as discs or as cylindrical shapes. The adsorption kinetics and isotherms of dye onto Vietnam diatomite were investigated. The experimental data were fitted well to both Freundlich and Langmuir in the initial concentration range of 400–1400 mg L−1. The average value of maximum adsorption capacity,qm, calculated from Freundlich equation is statistically similar to the average value of maximum monolayer adsorption capacity calculated from Langmuir equation. The thermodynamic parameters evaluated from the temperature dependent on adsorption isotherms in the range of 303–343 K show that the adsorption process was spontaneous and endothermic. The Webber and pseudo-first/second-order kinetic models were used to analyze the mechanism of adsorption. The piecewise linear regression and Akaike’s Information Criterion were used to analyze experimental data. The results show that the dye adsorption onto diatomite was film diffusion controlled and the goodness of fit of experimental data for kinetics modes was dependent on the initial concentration.

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