scholarly journals Chitosan Fiber as Green Material for Removing Cr(VI) and Cu(II) Contaminants:Adsorption Properties,Kinetics and Machanism

2021 ◽  
Author(s):  
shujie Zhang ◽  
Yating Zhang ◽  
Lisong Fu ◽  
Mengke Jing
Keyword(s):  
Adsorption Capacity ◽  
Ph Value ◽  
Copper Ions ◽  
Maximum Adsorption Capacity ◽  
Order Kinetic ◽  
Chemical Adsorption ◽  
Adsorption Effect ◽  
Green Material ◽  
Chromium Ions ◽  
Chitosan Fiber

Abstract Chitosan (CS) fiber is used as a new green material to remove Cu(II) and Cr(VI) in wastewater.Varying factors, including pH value, dosage of CS, reaction time and original Cr (VI) contents and Cu(II) were studied to investigate the Cr (VI) and Cu(II) removal efficiency.The adsorption of two metal ions by chitosan fiber conforms to the second-order kinetic equation, and can be fitted with Langmuir isotherms. The adsorption process is a spontaneous thermal reaction with both physical adsorption and chemical adsorption, and copper ions reach adsorption equilibrium. It takes longer than chromium ions, but the adsorption effect of copper ions is better. The maximum actual adsorption capacity of copper ions is 539.6 mg/g, and the maximum adsorption capacity of chromium ions is 75 mg/g. SEM, FTIR and XRD were used to characterize the physicochemical properties of CS fiber. The result shows that the complex process of the Cr (VI) and Cu(II) removal involves physical and chemical adsorption, CS fiber have exerted significant role in Cr (VI) and Cu(II) removal.

Synthesis and Characterization of Zeolite X Obtained from Coal Gangue for Adsorption of Cu2+

2021 ◽  
Vol 13 (8) ◽  
pp. 1512-1520
Author(s):  
MiaoSen Zhang ◽  
SiYang Wang ◽  
Zheng Hu ◽  
RunZe Zhang ◽  
XiaoLi Wang
Keyword(s):  
Adsorption Capacity ◽  
Adsorption Kinetics ◽  
Ph Value ◽  
Copper Ions ◽  
Removal Rate ◽  
Coal Gangue ◽  
Maximum Adsorption Capacity ◽  
Order Kinetic ◽  
Zeolite X ◽  
Initial Ph

China is a big coal producing country, there are a lot of coal gangue piled up. The zeolite X was synthesized by alkali melting and hydrothermal method based on the coal gangue from Chifeng city, Inner Mongolia. The obtained zeolite X sample is characterized by X-ray diffraction, SEM, EDS spectrum and IR which showed the X zeolite is an octahedral structure with complete crystal shape and uniform grain size. The results of BET showed the specific surface area of zeolite X is 354.8 m2/g and the minimum pore size is 3.8 nm which indicated that the zeolite X belongs to mesoporous materials. The adsorption conditions of the zeolite X adsorbent on copper ions were optimized. A solution containing Cu2+ ions with an initial concentration of 300 mg/L was added to the zeolite X with a dosage of 0.1 g and the initial pH value of the solution was adjusted to 6. Then the solution was oscillated for 120 min at 225 r/min. The maximum adsorption capacity and removal rate were 148.6 mg/g and 99.1%, respectively. The adsorption mechanism was discussed by adsorption kinetics and thermodynamics. The quasi-second order kinetic equation can be well used to describe the adsorption kinetics of zeolite X to Cu2+ (R2 = 0.9994) and Langmuir can well describe the adsorption behavior of zeolite X to Cu2+ (R2 = 0.9995) which showed the adsorption is a monolayer of chemical adsorption. The adsorption capacity of zeolite X to Cu2+ is about 4.0 times that of coal gangue, indicating that the zeolite X has good adsorption capacity.

scholarly journals Preparation of chitosan/amine modified diatomite composites and adsorption properties of Hg(II) ions

2018 ◽  
Vol 77 (5) ◽  
pp. 1363-1371 ◽  
Author(s):  
Yong Fu ◽  
Yue Huang ◽  
Jianshe Hu ◽  
Zhengjie Zhang
Keyword(s):  
Schiff Base ◽  
Contact Time ◽  
Ph Value ◽  
Adsorption Properties ◽  
Maximum Adsorption Capacity ◽  
Order Kinetic ◽  
Adsorption Effect ◽  
Order Kinetic Model ◽  
Pseudo Second Order ◽  
Modified Diatomite

Abstract A green functional adsorbent (CAD) was prepared by Schiff base reaction of chitosan and amino-modified diatomite. The morphology, structure and adsorption properties of the CAD were characterized by Fourier transform infrared spectroscopy, thermogravimetric analysis, scanning electron microscopy and Brunauer Emmett Teller measurements. The effect of pH value, contact time and temperature on the adsorption of Hg(II) ions for the CAD is discussed in detail. The experimental results showed that the CAD had a large specific surface area and multifunctional groups such as amino, hydroxyl and Schiff base. The optimum adsorption effect was obtained when the pH value, temperature and contact time were 4, 25 °C and 120 min, respectively, and the corresponding maximum adsorption capacity of Hg(II) ions reached 102 mg/g. Moreover, the adsorption behavior of Hg(II) ions for the CAD followed the pseudo-second-order kinetic model and Langmuir model. The negative ΔG0 and ΔH0 suggested that the adsorption was a spontaneous exothermic process.

Insights into the mechanism of methylene blue removed by novel and classic biochars

2019 ◽  
Vol 79 (8) ◽  
pp. 1561-1570
Author(s):  
Wei Chen ◽  
Fengting Chen ◽  
Bin Ji ◽  
Lin Zhu ◽  
Hongjiao Song
Keyword(s):  
Methylene Blue ◽  
Adsorption Capacity ◽  
Ph Value ◽  
Low Cost ◽  
Underlying Mechanism ◽  
Maximum Adsorption Capacity ◽  
Experimental Conditions ◽  
Average Pore ◽  
Adsorption Effect ◽  
Magnolia Grandiflora

Abstract The adsorption behavior and the underlying mechanism of methylene blue (MB) sorption on biochars prepared from different feedstocks at 500 °C were evaluated. The biochar feedstocks included Magnolia grandiflora Linn. leaves biochar (MBC), pomelo (Citrus grandis) peel biochar (PBC) and badam shell biochar (BBC). The results of characterizing and analyzing the samples showed that different biochars had different effects on the adsorption of MB. It could be found that MBC had the best adsorption effect on MB due to its largest average pore diameter of 5.55 nm determined by Brunauer-Emmett-Teller analysis. Under the optimal conditions, the maximum adsorption capacities of BBC, PBC and MBC were 29.7, 85.15 and 99.3 mg/g, respectively. The results showed that the amount of adsorption was affected by the pH value. The maximum adsorption capacity of MBC was 46.99 mg/g when it was at pH of 3, whereas for the same experimental conditions the maximum adsorption capacity of BBC and PBC was 25.29 mg/g at pH of 11 and 36.08 mg/g at pH of 7, respectively. Therefore, MBC was found to be a most efficient low-cost adsorbentl for dye wastewater treatment compared with BBC and PBC, and it had the best removal effect under acidic conditions.

scholarly journals A chitosan fiber as green material for removing Cr(VI) ions and Cu(II) ions pollutants

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Shujie Zhang ◽  
Yating Zhang ◽  
Lisong Fu ◽  
Mengke Jing
Keyword(s):  
Metal Ions ◽  
Adsorption Process ◽  
Ph Value ◽  
Copper Ions ◽  
Physical Adsorption ◽  
Thermodynamic Characteristics ◽  
Fiber Material ◽  
Thermal Reaction ◽  
Order Kinetic ◽  
Chromium Ions

AbstractThe application shell uses cellulose as a green and recyclable fiber material, which has great value in the field of water treatment environment. Varying factors, including pH value, dosage of CS, reaction time and original Cr(VI) ions and Cu(II) ions were studied to investigate the Cr(VI) and Cu(II) ions removal efficiency. The obtained shell trichlorocellulose has better permeability to copper ions, which is mainly due to the different oxide states of copper ions and chromium ions in a pH environment, which lead to different combinations. The price of shell cellulose neutralization is relatively low. Metal ions have better absorption properties. The kinetic and thermodynamic characteristics of the adsorption process of copper ions by chitosan yarns were discussed. The adsorption process of copper ions conformed to the quasi-second-order kinetic equation. It can be fitted by Langmuir isotherm. The adsorption of copper ions by the yarn is a spontaneous thermal reaction with both physical adsorption and chemical adsorption. Compared with chromium ions, chitosan fibers have better adsorption of copper ions, which is mainly because the amino groups in chitosan fibers can have good chelation with copper ions. SEM, FTIR, XRD were used to characterize the adsorption of copper ions by chitosan fibers, and the mechanism of the adsorption of metal ions by chitosan fibers was explored.

Adsorption Characteristic of U(VI) on Fe-Immobilized Bentonite

2013 ◽  
Vol 639-640 ◽  
pp. 1300-1306
Author(s):  
Zhen Ping Tang ◽  
Hui Ling ◽  
Shui Bo Xie ◽  
S.Y. Li ◽  
J.S. Wang ◽  
...  
Keyword(s):  
Adsorption Capacity ◽  
Adsorption Mechanism ◽  
Ph Value ◽  
Maximum Adsorption Capacity ◽  
Order Kinetic ◽  
X Ray Diffraction ◽  
Solution Ph ◽  
Adsorption Characteristic ◽  
Order Kinetic Equation

Fe-immobilized bentonite, prepared with bentonite and FeCl3 was used for the adsorption of uranium(VI) in this study, solution pH, ion strength, contact time and temperature were investigated, structural characterization of Fe-immobilized bentonite was assayed by X-ray Diffraction and Fourier Transform Infrared Spectroscopy. Results indicated that the adsorption capacity were strongly affected by the solution pH and ion strength, the adsorption efficiency was 91.8% when pH value was 6 and ion strength was 0.01 mol•L-1, higher or lower pH did not favor the U(VI) adsorption. The adsorption mechanism was discussed by the views of reactive kinetics and thermodynamics along with Scanning Electron Microscope. The adsorption kinetics process was fitted well with the second-order kinetic equation, when the initial U(VI) concentration was less than 38.08mg/L, Langmuir equations could describe the adsorption isotherm of U(VI) well with the maximum adsorption capacity of 169.5mg/g at 303K

scholarly journals Enhanced Phosphate Removal from Water by Honeycomb-Like Microporous Lanthanum-Chitosan Magnetic Spheres

Water ◽  
2018 ◽  
Vol 10 (11) ◽  
pp. 1659 ◽  
Author(s):  
Rong Cheng ◽  
Liang-Jie Shen ◽  
Ying-Ying Zhang ◽  
Dan-Yang Dai ◽  
Xiang Zheng ◽  
...  
Keyword(s):  
Adsorption Capacity ◽  
Active Sites ◽  
Lanthanum Oxide ◽  
Ph Value ◽  
Phosphate Removal ◽  
Phosphate Adsorption ◽  
Maximum Adsorption Capacity ◽  
Order Kinetic ◽  
Magnetic Spheres ◽  
Hierarchical Porous

The removal of phosphate in water is crucial and effective for control of eutrophication, and adsorption is one of the most effective treatment processes. In this study, microporous lanthanum-chitosan magnetic spheres were successfully synthetized and used for the removal of phosphate in water. The characterization results show that the dispersion of lanthanum oxide is improved because of the porous properties of the magnetic spheres. Moreover, the contact area and active sites between lanthanum oxide and phosphate were increased due to the presence of many honeycomb channels inside the magnetic spheres. In addition, the maximum adsorption capacity of the Langmuir model was 27.78 mg P·g−1; and the adsorption kinetics were in good agreement with the pseudo-second-order kinetic equation and intra-particle diffusion model. From the results of thermodynamic analysis, the phosphate adsorption process of lanthanum-chitosan magnetic spheres was spontaneous and exothermic in nature. In conditional tests, the optimal ratio of lanthanum/chitosan was 1.0 mmol/g. The adsorption capacity of as-prepared materials increased with the augmentation of the dosage of the adsorbent and the decline of pH value. The co-existing anions, Cl− and NO3− had little effect on adsorption capacity to phosphate, while CO32− exhibited an obviously negative influence on the adsorption capacity of this adsorbent. In general, owing to their unique hierarchical porous structures, high-adsorption capacity and low cost, lanthanum-chitosan magnetic spheres are potentially applicable in eutrophic water treatment.

scholarly journals Synthesis of a functional biomass lignin-based hydrogel with high swelling and adsorption of Acid Red 73

2021 ◽  
Author(s):  
Shuxia Wei ◽  
Wu Chen ◽  
Zhiming Tong ◽  
Nan Jiang ◽  
Mijia Zhu
Keyword(s):  
Adsorption Capacity ◽  
Single Molecule ◽  
Raw Material ◽  
Maximum Adsorption Capacity ◽  
Order Kinetic ◽  
Structure And Properties ◽  
Sodium Lignosulfonate ◽  
Isothermal Adsorption ◽  
Adsorption Effect ◽  
Initial Concentration

Abstract In this study, sodium lignosulfonate (LS) was used as raw material, acrylamide (AM) and acryloyloxye thyltrimethyl ammonium chloride (DAC) as monomers, and N,N'-methylenebisacrylamide (MBA) as cross-linking agent, the potassium persulfate (KPS)/tetramethylethyl enediamine (TEMED) as oxidation/ reduction initiation system. Synthesis of a functional biomass terpolymer lignin-based hydrogel adsorbent (LAD) with excellent adsorption properties by free radical graft copolymerization. The structure and properties of the prepared LAD were characterized by FT-IR and SEM, and the relationship between structure and properties was studied. The effects of solution pH, adsorption time, hydrogel dosage, initial concentration of dye and temperature on the adsorption of AR 73 by LAD were investigated. LAD adsorbed AR 73 solution with initial concentration of 100mg/L for 2h to reach equilibrium, with equilibrium adsorption capacity and adsorption rate of 47.59mg/g and 95.18%, respectively. The prepared LAD hydrogel has good swelling and deswelling properties, the swelling ratio of water absorption for 2h was 25g/g, and the water loss rate of 120 min in ethanol solvent was 93.51%. The adsorption of AR 73 by LAD was consistent with the Langmuir isothermal adsorption model. It was single-molecule adsorption with a maximum adsorption capacity of 409.84mg/g. The adsorption was a process of spontaneous heat release and entropy reduction.The adsorption kinetics was in accordance with Pseudo-second-order kinetic equation, and the adsorption activation energy was 2.501 kJ/moL. In addition, the mechanism of adsorption is mainly electrostatic, and there are also comprehensive effects of physical, chemical adsorption and hydrogen bond.The LAD hydrogel adsorbent has a significant adsorption effect on AR 73, and can be used as an efficient and recyclable biomass adsorbent for the treatment of anionic dye wastewater.

scholarly journals Study on Adsorption of Nickel and Methylene Blue in Aqueous Solution by Magnetic Carboxylate-Rich Carbon

2021 ◽  
Vol 37 (2) ◽  
Author(s):  
Doan Van Dat ◽  
Nguyen Hoai Thuong ◽  
Tran Thi Kieu Ngan ◽  
Le Thi Thanh Nhi ◽  
Dao My Uyen ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Methylene Blue ◽  
Adsorption Capacity ◽  
Ph Value ◽  
Isotherm Models ◽  
Maximum Adsorption Capacity ◽  
Order Kinetic ◽  
High Adsorption ◽  
Endothermic Process ◽  
High Adsorption Capacity

In this study, magnetic carboxylate-rich carbon material (Fe3O4@CRC) was synthesized via a low-temperature carbonization method and applied as an adsorbent for adsorption of Ni(II) ions and methylene blue (MB) in aqueous solution. The synthesized Fe3O4@CRC was characterized by various techniques (XRD, FTIR, FE-SEM, TEM, EDX, VSM, and BET). The adsorption kinetics, isotherms, thermodynamics, and the effects of key adsorption factors, including the pH value, initial adsorbate concentration, contact time, adsorbent dose and temperature were investigated in detail. The results showed that Fe3O4@CRC exhibited a high adsorption capacity for MB and Ni(II) with the maximum adsorption capacity of 187.26 mg/g and 106.75 mg/g, respectively. The adsorption of MB and Ni(II) on Fe3O4@CRC was a spontaneous and endothermic process, and was best described with the first-order kinetic model, Freundlich (for MB) and Langmuir (for Ni(II)) isotherm models. In addition, Fe3O4@CRC could maintain a high adsorption capacity after many consecutive cycles. Therefore, the Fe3O4@CRC material can be used as a highly efficient adsorbent for the removal of heavy metals and dyes from wastewater due to the advantages of high adsorption performance, easy separation, and good reusability.  

scholarly journals Adsorption of Nitrogen and Phosphorus in Water by Eggshell Modified with FeCl3

2021 ◽  
Vol 245 ◽  
pp. 03081
Author(s):  
Hongcui Li ◽  
Yurong Li ◽  
Feifei Yan ◽  
Xiangzheng Yin
Keyword(s):  
Adsorption Capacity ◽  
Total Nitrogen ◽  
Total Phosphorus ◽  
Ferric Chloride ◽  
Ph Value ◽  
Orthogonal Experiment ◽  
Maximum Adsorption Capacity ◽  
Nitrogen And Phosphorus ◽  
Adsorption Effect ◽  
Adsorption Of Nitrogen

As a kind of domestic waste, eggshell has developed pore structure and good adsorption capacity. The material was selected as adsorbent to study the adsorption of total nitrogen and total phosphorus in water. After being modified by ferric chloride, its adsorption effect is greatly enhanced. The adsorption of nitrogen and phosphorus in water by eggshell modified by ferric chloride was studied under different conditions. The experimental results show that the adsorption capacity after modification is 15% ~ 40% higher than that before modification. The results of orthogonal experiment show that under the following conditions: pH value was 5.00, dosage was 0.050 g, time was 65 min, the maximum adsorption capacity of total phosphorus was 45.34 mg/g; under the following conditions: pH value was 4.50, dosage was 0.100 g, time was 60 min, the maximum adsorption capacity of total nitrogen was 79.91 mg/g.

scholarly journals Fly Ash Coated with Magnetic Materials: Improved Adsorbent for Cu (II) Removal from Wastewater

Materials ◽  
2020 ◽  
Vol 14 (1) ◽  
pp. 63
Author(s):  
Maria Harja ◽  
Gabriela Buema ◽  
Nicoleta Lupu ◽  
Horia Chiriac ◽  
Dumitru Daniel Herea ◽  
...  
Keyword(s):  
Fly Ash ◽  
Adsorption Capacity ◽  
Copper Ions ◽  
Synthetic Wastewater ◽  
Bet Surface Area ◽  
Isotherm Models ◽  
Batch Adsorption ◽  
Maximum Adsorption Capacity ◽  
Copper Adsorption ◽  
X Ray

Fly ash/magnetite material was used for the adsorption of copper ions from synthetic wastewater. The obtained material was characterized by scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDAX), X-ray diffractometer (XRD), Fourier transform infrared spectroscopy (FTIR), Brunauer–Emmett–Teller (BET) surface area, and vibrating sample magnetometer (VSM). Batch adsorption experiments were employed in order to investigate the effects of adsorbent dose, initial Cu (II) concentration and contact time over adsorption efficiency. The experimental isotherms were modeled using Langmuir (four types of its linearization), Freundlich, Temkin, and Harkins–Jura isotherm models. The fits of the results are estimated according to the Langmuir isotherm, with a maximum adsorption capacity of 17.39 mg/g. The pseudo-second-order model was able to describe kinetic results. The data obtained throughout the study prove that this novel material represents a potential low-cost adsorbent for copper adsorption with improved adsorption capacity and magnetic separation capability compared with raw fly ash.

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