scholarly journals Adsorption removal of Cr(VI) by isomeric FeOOH

2019 ◽  
Vol 80 (2) ◽  
pp. 300-307
Author(s):  
Di Zhang ◽  
Jiaxin Liu ◽  
Shibei Zhu ◽  
Huixin Xiong ◽  
Yiqun Xu
Keyword(s):  
Active Sites ◽  
Correlation Coefficients ◽  
Order Kinetic ◽  
Isothermal Adsorption ◽  
Adsorption Mechanisms ◽  
Ph Values ◽  
Adsorption Removal ◽  
Order Kinetic Model ◽  
Pseudo Second Order ◽  
Theoretical Evidence

Abstract The aim of this work is to study the performances of isomeric α-, β-, and γ-FeOOH (goethite, akaganéite and lepidocrocite, including five samples named as Gth1 and Gth2, Aka1 and Aka2, and Lep, respectively) for removing hexavalent chromium (Cr(VI)) from aqueous solutions. The adsorption mechanisms were explored by kinetic and isothermal experiments. Adsorption efficiencies under the different pH values, anions, and the levels of adsorbate and adsorbent were also measured. Results showed that the Cr(VI) adsorption by isomeric FeOOH could be best described by pseudo-second-order kinetic model. The processes of Cr(VI) isothermal adsorption could be greatly fitted by the Langmuir and Freundlich equations with the high correlation coefficients of R2 (>0.92). Also, there were the optimum pH values of 3.0–8.0 for FeOOH to adsorb Cr(VI), and their adsorption capacities were tightly related with the active sites of adsorbents. Cr(VI) adsorptions by these adsorbents were easily influenced by H2PO4–, and then SO42–, while there were little effects by Cl–, CO32– and NO3–. These obtained results could provide a potentially theoretical evidence for isomeric FeOOH materials applied in the engineering treatment of the polluted chromate-rich waters.

Effects of tall fescue biochar on the adsorption behavior of desethyl-atrazine in different types of soil

BioResources ◽  
2021 ◽  
Vol 16 (2) ◽  
pp. 3575-3595
Author(s):  
Wanting Li ◽  
Ruifeng Shan ◽  
Yuna Fan ◽  
Xiaoyin Sun
Keyword(s):  
Tall Fescue ◽  
Adsorption Process ◽  
Exothermic Reaction ◽  
Equilibrium Concentration ◽  
Black Soil ◽  
Adsorption Behavior ◽  
Order Kinetic ◽  
Isothermal Adsorption ◽  
Order Kinetic Model ◽  
Pseudo Second Order

Desethyl-atrazine (DEA) is a metabolite of atrazine that exerts a considerable influence on the environment. In this study, tall fescue biochar was prepared by pyrolysis at 500 °C, and batch experiments were conducted to explore its effect on the adsorption behavior of DEA in red soil, brown soil, and black soil. The addition of biochar increased the equilibrium amount of DEA adsorption for the three soil types. A pseudo-second-order kinetic model most closely fit the DEA adsorption kinetics of the three soils with and without biochar, with a determination coefficient (R2) of 0.962 to 0.999. The isothermal DEA adsorption process of soils with and without biochar was optimally described by the Freundlich and Langmuir isothermal adsorption models with R2 values of 0.98 and above. The DEA adsorption process in the pristine soil involved an exothermic reaction, which became an endothermic reaction after the addition of biochar. Partitioning was dominant throughout the entire DEA adsorption process of the three pristine soils. Conversely, in soils with biochar, surface adsorption represented a greater contribution toward DEA adsorption under conditions of low equilibrium concentration. The overall results revealed that the tall fescue biochar was an effective adsorbent for DEA polluted soil.

scholarly journals Preparation of Activated Biochar-Supported Magnetite Composite for Adsorption of Polychlorinated Phenols from Aqueous Solutions

Water ◽  
2019 ◽  
Vol 11 (9) ◽  
pp. 1899 ◽  
Author(s):  
Jun ◽  
Kim ◽  
Han ◽  
Yoon ◽  
Kim ◽  
...  
Keyword(s):  
Organic Pollutants ◽  
Hydrophobic Interactions ◽  
Order Kinetic ◽  
Adsorption Selectivity ◽  
Adsorption Mechanisms ◽  
Activated Biochar ◽  
Experimental Parameters ◽  
Order Kinetic Model ◽  
Pseudo Second Order ◽  
Cetrimonium Bromide

For this study, we applied activated biochar (AB) and its composition with magnetite (AB-Fe3O4) as adsorbents for the removal of polychlorophenols in model wastewater. We comprehensively characterized these adsorbents and performed adsorption tests under several experimental parameters. Using FTIR, we confirmed successful synthesis of AB-Fe3O4 composite through cetrimonium bromide surfactant. We conducted adsorption tests using AB and AB-Fe3O4 to treat model wastewater containing polychlorophenols, such as 2,3,4,6-Tetrachlorophenol (TeCP), 2,4,6-Trichlorophenol (TCP), and 2,4-Dichlorophenol (DCP). Results of the isotherm and the kinetic experiments were well adapted to Freundlich’s isotherm model and the pseudo-second-order kinetic model, respectively. Main adsorption mechanisms in this study were attributed to non-covalent, π-electron acceptor–donor interactions and hydrophobic interactions judging from the number of chloride elements in each chlorophenol and its hydrophobic characteristics. We also considered the electrostatic repulsion effect between TeCP and AB, because adsorption performance of TeCP at basic condition was slightly worse than at weak acidic condition. Lastly, AB-Fe3O4 showed high adsorption selectivity of TeCP compared to other persistent organic pollutants (i.e., bisphenol A and sulfamethoxazole) due to hydrophobic interactions. We concluded that AB-Fe3O4 may be used as novel adsorbent for wastewater treatment including toxic and hydrophobic organic pollutants (e.g., TeCP).

Fast Removal of Pb2+ from Aqueous Solution by Water Insoluble Konjac Glucomannan

2009 ◽  
Vol 610-613 ◽  
pp. 65-68 ◽  
Author(s):  
Xue Gang Luo ◽  
Feng Liu ◽  
Xiao Yan Lin
Keyword(s):  
Aqueous Solution ◽  
Correlation Coefficients ◽  
Konjac Glucomannan ◽  
Maximum Adsorption Capacity ◽  
Order Kinetic ◽  
Order Kinetic Model ◽  
Langmuir Isotherm Model ◽  
Pseudo Second Order ◽  
Equilibrium Process ◽  
Fast Removal

Konjac glucomannan (KGM) was converted into water insoluble konjac glucomannan (WIKGM) by treating with NaOH through completely deacetylated reaction. Adsorption study was carried out for the adsorption of Pb2+ from aqueous solution using water insoluble konjac glucomannan. The influences of pH, contact time, temperature and initial Pb2+ concentration on the absorbent were studied. Results of kinetic data showed that the Pb2+ adsorption rate was fast and good correlation coefficients were obtained for the pseudo second-order kinetic model. The equilibrium process was described well by the Langmuir isotherm model with maximum adsorption capacity of 9.18 mg/g on WIKGM at 25°C.

Adsorption Removal of Copper and Nickel Ions from Wastewater by Ammonia Modified Cotton Stalks

2014 ◽  
Vol 955-959 ◽  
pp. 2440-2443 ◽  
Author(s):  
Jing Li ◽  
Dong Mei Jia ◽  
Chang Hai Li ◽  
Bao Qing Yu
Keyword(s):  
Copper Ions ◽  
Batch Adsorption ◽  
Order Kinetic ◽  
Optimum Conditions ◽  
Nickel Ions ◽  
Adsorption Removal ◽  
Cotton Stalks ◽  
Order Kinetic Model ◽  
Pseudo Second Order ◽  
Adsorbent Dose

The ammonia modified cotton stalks (CS) were utilized to adsorb the Ni2+and Cu2+ions from wastewaters, and the effect parameters (i.e. pH, contact time, adsorbent dose, and temperature) were also investigated by batch adsorption experiments. The maximum uptake was attained, i.e., 99.4% and 98.8%, respectively, for nickel and copper ions, under the optimum conditions (adsorbent dose: 10 g/L; pH: 6.0 (Ni2+), 5.0 (Cu2+); t: 75min; T: 20 °C) when the initial concentration of heavy metal ions was 20 mg/L. The adsorption process of nickel and copper ions on ammonia modified CS was well described by the pseudo-second-order kinetic model.

Acetylation of Pomelo Peel for the Production of Oil Materials

2014 ◽  
Vol 955-959 ◽  
pp. 2534-2538
Author(s):  
Jun Chen Zou ◽  
Xiao Yan Liu ◽  
Wen Bo Chai ◽  
Xin Ying Zhang ◽  
Yu Sen Liu
Keyword(s):  
Acetic Anhydride ◽  
Correlation Coefficients ◽  
Kinetic Studies ◽  
Sorption Kinetics ◽  
Lubricating Oil ◽  
Order Kinetic ◽  
Pomelo Peel ◽  
Order Kinetic Model ◽  
Pseudo Second Order ◽  
Spilled Oil

Pomelo peel was esterified with acetic anhydride using 4-dimethyl-amino pyridine as a catalyst under reaction temperature of 60 °C and duration of 3 h. At 0.1 g 4-dimethyl-amino pyridine of the catalyst in 80 ml acetic anhydride, the highest sorption values of 14.95 g/g diesel and 18.39 g/g lubricating oil were achieved, which was found to be much higher than raw pomelo peel. FTIR and SEM studies produced evidence for acetylation. The sorption kinetics and reusability were studied. The kinetic studies show good correlation coefficients for a pseudo-second-order kinetic model. This work demonstrated that pomelo peel modified by acetic anhydride is an efficient and environment-friendly biosorbent for the removal of spilled oil.

Removal of Rhodamine B from Wastewater by Rectorite and Sepiolite-Kinetic Study and Equilibrium Isotherm Analyses

2011 ◽  
Vol 183-185 ◽  
pp. 362-366 ◽  
Author(s):  
Jun Li ◽  
Ming Zhen Hu
Keyword(s):  
Rhodamine B ◽  
Low Cost ◽  
Freundlich Isotherm ◽  
Second Order ◽  
Order Kinetic ◽  
Isotherm Equation ◽  
Adsorption Removal ◽  
Equilibrium Data ◽  
Order Kinetic Model ◽  
Pseudo Second Order

Adsorption removal of a cationic dye, rhodamine B (RhB) from water onto rectorite and sepiolite was investigated. The rectorite and sepiolite were characterized by Fourier transform infrared (FT-IR) spectroscopy and scanning electron microscopy (SEM). Attempts were made to fit the isothermal data using Langmuir and Freundlich equations. The experimental results have demonstrated that the equilibrium data are fitted well by a Freundlich isotherm equation. Pseudo-first-order and pseudo-second-order models were considered to evaluate the rate parameters. The experimental data were well described by the pseudo-second-order kinetic model. The results indicate that the rectorite exhibited higher adsorption capacity for the removal of RhB than sepiolite and could be employed as a low-cost alternative in wastewater treatment for the removal of cationic dyes.

scholarly journals Enhanced cadmium removal from water by hydroxyapatite subjected to different thermal treatments

2020 ◽  
Vol 69 (7) ◽  
pp. 678-693
Author(s):  
R. Aouay ◽  
S. Jebri ◽  
A. Rebelo ◽  
J. M. F. Ferreira ◽  
I. Khattech
Keyword(s):  
Electron Microscopy ◽  
Sorption Process ◽  
Maximum Adsorption Capacity ◽  
Order Kinetic ◽  
Cadmium Removal ◽  
Sorption Behaviour ◽  
Adsorption Mechanisms ◽  
Transmission Electron ◽  
Order Kinetic Model ◽  
Pseudo Second Order

Abstract Hydroxyapatite powders were synthesized according to a wet precipitation route and then subjected to heat treatments within the temperature range of 200–800 °C. The prepared samples were tested as sorbents for cadmium in an aqueous medium. The best performances were obtained with the material treated at 200 °C (HAp200), as the relevant sorbent textural features (SBET – specific surface area and Vp – total volume of pores) were least affected at this low calcination temperature. The maximum adsorption capacity at standard ambient temperature and pressure was 216.6 mg g−1, which increased to 240.7 mg g−1 by increasing the temperature from 25 to 40 °C, suggesting an endothermic nature of the adsorption process. Moreover, these data indicated that a thermal treatment at 200 °C enhanced the ability of the material in Cd2+ uptake by more than 100% compared to other similar studies. The adsorption kinetic process was better described by the pseudo-second-order kinetic model. Langmuir, Freundlich, and Dubinin–Kaganer–Radushkevich isotherms were applied to describe the sorption behaviour of Cd2+ ions onto the best adsorbent. Furthermore, a thermodynamic study was also performed to determine ΔH°, ΔS°, and ΔG° of the sorption process of this adsorbent. The adsorption mechanisms were investigated by Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy-transmission electron microscopy (SEM-TEM) observations.

scholarly journals Novel Hydroxyapatite Beads for the Adsorption of Radionuclides from Decommissioned Nuclear Power Plant Sites

2021 ◽  
Vol 11 (4) ◽  
pp. 1746
Author(s):  
Thi Nhung Tran ◽  
Junho Kim ◽  
Joo-Sung Park ◽  
Youngkun Chung ◽  
Jaemun Han ◽  
...  
Keyword(s):  
Nuclear Power ◽  
Power Plants ◽  
Polyvinyl Butyral ◽  
Order Kinetic ◽  
Practical Applications ◽  
Adsorption Mechanisms ◽  
Rate Limiting Step ◽  
Aqueous Environments ◽  
Order Kinetic Model ◽  
Pseudo Second Order

Although a powdered form of hydroxyapatite (p-HdA) has been studied for the adsorption of heavy metals that contaminate the restoration sites of decommissioned nuclear power plants, most of the studies are limited in the laboratory due to the head loss and post-separation in practical applications. Herein, we fabricated a porous bead form of HdA (b-HdA) as a novel adsorbent for removing radionuclides from aqueous environments via a facile synthesis by mixing the p-HdA precursor and polyvinyl butyral (PVB) as a binder and added a sintering process for the final production of a porous structure. The spherical b-HdA with an approximate diameter of 2.0 mm was successfully fabricated. The effectiveness of the b-HdA at removing Co(II) was investigated via the adsorption equilibrium at various experimental temperatures. The b-HdA exhibited the adsorption capacity for Co(II) ions with a maximum of 7.73 and 11.35 mg/g at 293 K and 313 K, respectively. The experimental kinetic data were well described using a pseudo-second-order kinetic model, and the adsorption mechanisms of Co(II) onto the b-HdA were revealed to be a chemisorption process with intraparticle diffusion being the rate-limiting step. In addition, the competitive adsorption onto the b-HdA with the order of U(VI) > Co(II) > Ni(II) > Sr(II) > Cs(I) was also observed in the multi-radionuclides system. Considering the advantages of the size, applicability to the continuous-flow column, and the easy separation from treated water, the b-HdA can be an excellent absorbent with high potential for practical applications for removing radionuclides.

Experimental and Modeling Studies of Sorption of Tetracycline onto Zeolite in the Presence of Copper(II)

2012 ◽  
Vol 512-515 ◽  
pp. 2355-2360 ◽  
Author(s):  
Hong Huang ◽  
Yan Li Zou ◽  
Ya Nan Li
Keyword(s):  
Removal Rate ◽  
Sorption Process ◽  
Order Kinetic ◽  
Adsorption Removal ◽  
Intra Particle Diffusion ◽  
Order Kinetic Model ◽  
Pseudo Second Order ◽  
Equilibrium Process ◽  
Presence And Absence ◽  
Rate Limiting

The sorption performance of tetracycline on zeolite under different conditions was investigated in presence and absence of Cu(Ⅱ).The presence of Cu(Ⅱ) greatly increased the adsorption of tetracycline on zeolite. Adsorption kinetics and adsorption equilibrium isotherms were studied by conducting series of batch experiments. The kinetic analysis indicated that the pseudo-second-order kinetic model was well described the sorption equilibrium process of tetracycline onto zeolite in the presence and absence of Cu(Ⅱ), and intra-particle diffusion was not the only rate-limiting in the sorption process. The qmax value calculated from Langmuir model were 17.37 and 68.26 mg/g in the absence and the presence of Cu(Ⅱ). The value of E calculated from Dubinin-Radushkevich (D-R) model confirmed that the adsorption in the absence and presence of Cu(Ⅱ) were mainly controlled by physical combined with chemical adsorption mechanism. The tetracycline sorption amount decreased in the absence of Cu(Ⅱ) and increased in the presence of Cu(Ⅱ) as the pH increasing. The adsorption removal rate of wastewater containing 0.1 mmol/L tetracycline was 95.5% in the presence of Cu(Ⅱ) and 34.5% in the absence of Cu(Ⅱ) when the dosage of zeolite was 0.05g.

scholarly journals Characterization and Pb(II) removal potential of corn straw- and municipal sludge-derived biochars

2017 ◽  
Vol 4 (9) ◽  
pp. 170402 ◽  
Author(s):  
Shujuan Wang ◽  
Wei Guo ◽  
Fan Gao ◽  
Rui Yang
Keyword(s):  
Aqueous Solutions ◽  
Surface Complexation ◽  
Order Kinetic ◽  
Municipal Sludge ◽  
Corn Straw ◽  
Ph Values ◽  
Adsorption Capacities ◽  
Adsorption Data ◽  
Order Kinetic Model ◽  
Pseudo Second Order

Corn straw- and municipal sludge-derived biochars (CS-BC and MS-BC, respectively) were used to remove Pb(II) from aqueous solutions. Despite being pyrolysed at the same temperature (723 K), MS-BC showed higher porosity and hydrophobicity than CS-BC. The optimum biochar loading and pH values allowing efficient Pb(II) removal (greater than 80%) were 0.2 g l −1 and 7.0, respectively. The presence of PO 4 3− (greater than 0.01 mol l −1 ) significantly affected the adsorptive performance of Pb(II) on the biochar samples. The adsorption data fitted well to a pseudo-second-order kinetic model and a Langmuir model, and the maximum Pb(II) adsorption capacities were 352 and 387 mg g −1 for CS-BC and MS-BC, respectively. The main mechanisms involved in the adsorption of Pb(II) on biochar were electrostatic attraction and surface complexation. When comparing both biochars, CS-BC showed better cost-effectiveness for the removal of Pb(II) from aqueous solutions.

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