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).

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.

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 Carbonized Lanthanum-Based Metal-Organic Framework with Parallel Arranged Channels for Azo-Dye Adsorption

Nanomaterials ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 1053
Author(s):  
Krzysztof Cendrowski ◽  
Karolina Opała ◽  
Ewa Mijowska
Keyword(s):  
Kinetic Model ◽  
Adsorption Kinetics ◽  
Hydrophobic Interactions ◽  
Metal Organic Framework ◽  
Second Order ◽  
Order Kinetic ◽  
Order Kinetic Model ◽  
Metal Organic ◽  
Pseudo Second Order ◽  
Organic Framework

In this contribution, the synthesis of the metal−organic framework (MOF) based on lanthanum that exhibits trigonal prism shape is presented. The length of a single side of this structure ranges from 2 to 10 μm. The carbonized lanthanum-based organic framework (CMOF–La) maintained the original shape. However, the lanthanum oxide was reshaped in the form of rods during the carbonization. It resulted in the creation of parallel arranged channels. The unique structure of the carbonized structure motivated us to reveal its adsorption performance. Therefore, the adsorption kinetics of acid red 18 onto a carbonized metal−organic framework were conducted. Various physicochemical parameters such as initial dye concentration and pH of dye solution were investigated in an adsorption process. The adsorption was found to decrease with an increase in initial dye concentration. In addition, the increase in adsorption capacity was noticed when the solution was changed to basic. Optimal conditions were obtained at a low pH. Kinetic adsorption data were analyzed using the pseudo-first-order kinetic model, the pseudo-second-order kinetic model and the intraparticle diffusion model. The adsorption kinetics were well fitted using a pseudo-second-order kinetic model. It was found that the adsorption of anionic dye onto CMOF–La occurs by hydrophobic interactions between carbonized metal-organic framework and acid red 18.

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.

scholarly journals Al-Waste-Based Zeolite Adsorbent Used for the Removal of Ammonium from Aqueous Solutions

2018 ◽  
Vol 2018 ◽  
pp. 1-11 ◽  
Author(s):  
Ruth Sánchez-Hernández ◽  
Isabel Padilla ◽  
Sol López-Andrés ◽  
Aurora López-Delgado
Keyword(s):  
Aqueous Solutions ◽  
Order Kinetic ◽  
Equilibrium Isotherms ◽  
First Order ◽  
Experimental Parameters ◽  
Aqueous Effluents ◽  
Order Kinetic Model ◽  
Pseudo Second Order ◽  
Pseudo First Order ◽  
Zeolite Adsorbent

This work evaluates the use of a synthetic NaP1 zeolite obtained from a hazardous Al-containing waste for the removal of ammonium (NH4+) from aqueous solutions by batch experiments. Experimental parameters, such as pH (6–8), contact time (1–360 min), adsorbent dose (1–15 g/L), and initial NH4+ concentration (10–1500 mg/L), were evaluated. Adsorption kinetic models and equilibrium isotherms were determined by using nonlinear regression. The kinetic was studied by applying both the pseudo-first-order and pseudo-second-order models. The equilibrium isotherms were analyzed according to two-parameter equations (Freundlich, Langmuir, and Temkin) and three-parameter equations (Redlich–Peterson, Sips, and Toth). The results showed that the NH4+ uptake on NaP1 was fast (15 min) leading to a high experimental sorption capacity (37.9 mg/g). The NH4+ removal on NaP1 was a favorable process that followed the pseudo-first-order kinetic model. The NH4+ adsorption was better described by the Sips (54.2 mg/g) and Toth (58.5 mg/g) models. NaP1 zeolite from Al-waste showed good NH4+ sorption properties, becoming a potential adsorbent to be used in the treatment of contaminated aqueous effluents. Thus, a synergic effect on the environmental protection can be achieved: the end of waste condition of a hazardous waste and the water decontamination.

scholarly journals Preparation of Cotton Fibers Modified With Aromatic Heterocyclic Compounds and Study of Cr(VI) Adsorption Performance

2021 ◽  
Author(s):  
Zhiyu Huang ◽  
Peng Wu ◽  
Yankun Yin ◽  
Xiang Zhou ◽  
Lu Fu ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Metal Ion ◽  
Low Cost ◽  
Order Kinetic ◽  
Adsorption Mechanisms ◽  
Adsorption Capacities ◽  
Equilibrium Data ◽  
Order Kinetic Model ◽  
Langmuir Isotherm Model ◽  
Pseudo Second Order

Abstract In order to prepare low-cost and environmentally friendly adsorbent materials for adsorption of heavy metal ion, two kinds of novel modified cottons (C-4-APD and C-2-APZ) were obtained by introducing 4-aminopyridin and 2-aminopyrazine into the surface of degreasing cotton, respectively, and used for the removal of Cr(VI) ions from aqueous solution. The two modified cottons were characterized by Scanning Electron Microscopy (SEM), Fourier Transform Infrared Spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS), which confirmed the amino groups, pyridine groups and pyrazine groups grafted onto the surface of modified cottons. The maximum adsorption capacities of C-4-APD and C-2-APZ were 73.78 mg/g and 61.34 mg/g, respectively, at the optimum pH of 6 and an initial concentration of 200 mg/g. Kinetic and isotherm studies were carried out to investigate the adsorption behavior of the modified cottons on Cr(VI) ions. The results showed that the adsorption of Cr(VI) ions by modified cottons followed a pseudo-second-order kinetic model, the equilibrium data were in good agreement with the Langmuir isotherm model, and electrostatic and chemisorption may be the main adsorption mechanisms. The recovery and reuse of modified cotton were achieved by washing with 2 wt% thiourea-hydrochloric acid solution (0.5 mol/L concentration of HCl), and the adsorption capacities of C-4-APD and C-2-APZ were maintained above 90% and 80%, respectively, after six cycles.

scholarly journals Removal and Adsorption Mechanism of Tetracycline Using Manganese-modified Cotton Straw Biochar in an Aqueous Solution

2021 ◽  
Author(s):  
Xiao Liu ◽  
Shaoyang Shi ◽  
Xuefei Hu ◽  
Tao Sun ◽  
Juanxiang Zhang ◽  
...  
Keyword(s):  
Rural Areas ◽  
Electrostatic Interactions ◽  
Adsorption Process ◽  
Solution Concentration ◽  
Order Kinetic ◽  
Adsorption Effect ◽  
Adsorption Mechanisms ◽  
Aqueous Environments ◽  
Order Kinetic Model ◽  
Pseudo Second Order

Abstract Farming in China’s rural areas leads to antibiotic pollution in waterbodies making it a grave issue. Cotton straw biochar (CSBC) was prepared by oxygen-limited pyrolysis at 400 °C (CSBC400) and 600 °C (CSBC600); and Mn-modified CSBC (MCSBC) was produced by the KMnO4 wrapping method for tetracycline (TC) removal from aqueous solutions. The effects of temperature, initial solution concentration, pH, ion type, and ionic strength on TC adsorption were investigated. The adsorption process of the biochars achieved an equilibrium state after 360 min, and the highest equilibrium adsorption amount (13.254 mg/g) was found for MCSBC. The kinetic adsorption process, which was dominated by chemisorption, was well-described by the pseudo-second-order kinetic model. The adsorption was a non-homogeneous heat absorption process, and the adsorption isotherm data fitting was compatible with the Freundlich model. A better adsorption effect of MCSBC was observed when the pH was < 4. Monovalent cations (Na+, K+, NH4+, and Ca2+) had a facilitative effect on the adsorption process. The adsorption mechanisms of TC by MCSBC included pore diffusion, H bonding, electrostatic interactions, and π–π accumulation. Therefore, MCSBC has a good adsorption capacity for TC and can be used for the treatment of TC-based pollutants in aqueous environments.

scholarly journals Effective adsorption of direct Red 23 by sludge biochar-based adsorbent: adsorption kinetics, thermodynamics and mechanisms study

2021 ◽  
Author(s):  
Ruqing Jiang ◽  
Guangwei Yu ◽  
Pamphile Ndagijimana ◽  
Yu Wang ◽  
Futian You ◽  
...  
Keyword(s):  
Adsorption Kinetics ◽  
Electrostatic Interactions ◽  
Removal Rate ◽  
Order Kinetic ◽  
Solution Ph ◽  
Adsorption Mechanisms ◽  
Equilibrium Data ◽  
Order Kinetic Model ◽  
Solid Adsorbents ◽  
Pseudo Second Order

Abstract Using solid adsorbents, such as biochar, has been a potential practice to remove the pollutants from water bodies to render the water safer for potential usage. A potential application of sludge biochar-based adsorbent (SBA) obtained by pyrolysis with hydrothermal treatment was developed to adsorb Direct Red 23 (DR23) from wastewater. The results showed that the synthesized SBA (0.5 g/L) in the adsorption of DR23 at low concentration (&lt;20 mg/L), the DR23 were totally removed from the aqueous solution. PH had a limited effect on the adsorption, while an increase in temperature was shown to have a large enhancing effect. The adsorption kinetics were the best fit by the pseudo-second-order kinetic model, while the equilibrium data were best fitted by the Langmuir isotherm. A maximum saturation adsorption capacity of SBA of 111.98 mg/g was achieved. SBA could then be regenerated by pyrolysis, and after three cycles, SBA still retained the good adsorption ability of DR23, a removal rate exceeding 97% was achieved. Functional groups, pores, π-π bond, and electrostatic interactions are the key to the adsorption mechanisms. The results proved that SBA would be a promising material in the removal application of dyes in printing and dyeing wastewater.

scholarly journals Modelling of the adsorption of chlorinated phenols on polyethylene and polyethylene terephthalate microplastic

2020 ◽  
Vol 85 (5) ◽  
pp. 697-709
Author(s):  
Maja Loncarski ◽  
Aleksandra Tubic ◽  
Marijana Kragulj-Isakovski ◽  
Branislav Jovic ◽  
Tamara Apostolovic ◽  
...  
Keyword(s):  
Polyethylene Terephthalate ◽  
Hydrophobic Interactions ◽  
Sorption Process ◽  
Aquatic Environments ◽  
Order Kinetic ◽  
Chlorinated Phenols ◽  
Adsorption Affinity ◽  
Order Kinetic Model ◽  
Pseudo Second Order

The role of microplastics (MPs) on the fate and transport of various pollutants in water matrices is of major concern, but it is still relatively under investigated. In order to consider the conditions in real aquatic environments, the changes to polyethylene (PE) structure during the fabrication of microplastic particles for specific uses should not be neglected. Thus, this work considers isolated PE from two types of personal care products, which are possible sources of microplastic contamination in aquatic environments. The adsorption affinity of these PE microplastics towards ionisable compounds was compared with those of standards of PE and polyethylene terephthalate (PET), using chlorinated phenols (4-chlorophenol, 2,4-dichlorophenol, 2,4,6-trichlorophenol and pentachlorophenol) as adsorbates. The pseudo-second order kinetic model described well the sorption process for all chlorinated phenols on all four types of MPs (R2 range: 0.900?0.998). The kinetic study showed that sorption rates are mainly controlled by hydrophobic interactions and molecule size. Adsorption isotherms were best described by the Freundlich model for all MPs. The obtained results indicate that MPs could serve for the transport of chlorinated phenols through ambient waters.

Hard coal as a potential low-cost adsorbent for removal of 4-chlorophenol from water

2016 ◽  
Vol 73 (8) ◽  
pp. 2025-2030 ◽  
Author(s):  
Krzysztof Kuśmierek ◽  
Katarzyna Zarębska ◽  
Andrzej Świątkowski
Keyword(s):  
Adsorption Process ◽  
Low Cost ◽  
Kinetic Studies ◽  
Hard Coal ◽  
Order Kinetic ◽  
Experimental Parameters ◽  
Order Kinetic Model ◽  
Pseudo Second Order ◽  
Related Compounds ◽  
Potential Use

The potential use of raw hard coals as low-cost adsorbents for the removal of 4-chlorophenol (4-CP) from aqueous solutions was examined. The effect of experimental parameters such as the pH and salt presence was evaluated. The kinetic studies showed the equilibrium time was found to be 2 h for all of the adsorbents and that the adsorption process followed the pseudo-second order kinetic model. The adsorption isotherms of the 4-CP on the hard coals were fitted to the Langmuir, Freundlich, Langmuir–Freundlich, Sips and Redlich–Peterson equations. Based on the results obtained, hard coals appear to be a promising adsorbent for the removal of some hazardous water pollutants, like 4-CP and related compounds.

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