scholarly journals FLY ASH MAGNETIC ADSORBENT FOR CADMIUM ION REMOVAL FROM AN AQUEOUS SOLUTION

2021 ◽  
Vol 185 (1) ◽  
pp. 42-50
Author(s):  
Gabriela BUEMA ◽  
Nicoleta LUPU ◽  
Horia CHIRIAC ◽  
Dumitru Daniel HEREA ◽  
Lidia FAVIER ◽  
...  

The fly ash generated from a Romanian power plant was used as a starting material in this study. The aim of the study was to obtain a low cost material based on the treatment of fly ash with Fe3O4 for utilization as an adsorbent for cadmium ion removal. The adsorbent that was synthesized was characterized using different techniques. The adsorption process was investigated by the batch technique at room temperature. The quantity of cadmium ion adsorbed was measured spectrophotometrically. The experimental data showed that the material can remove cadmium ions at all three working concentrations. The adsorption capacity increased with an increase in concentration, respectively contact time. The results were analyzed through two kinetic models: pseudo first order and pseudo second order. The kinetics results of cadmium adsorption onto a magnetic material are in good agreement with a pseudo second order model, with a maximum adsorption capacity of 4.03 mg/g, 6.73 mg/g, and 9.65 mg/g. Additionally, the pseudo second order model was linearized into its four types. The results indicated that the material obtained show the ability to remove cadmium ions from an aqueous solution.

Author(s):  
Farah Monowara Jahangiri ◽  
Hasina Tasmin Moutushi ◽  
Md. Moniruzzaman ◽  
Sirajul Hoque ◽  
Mohammad Enayet Hossain

Abstract Dried ground roots of water hyacinth (Eichhornia crassipes) were used for removal of Pb(II) from aqueous solution. Batch adsorption experiments were conducted with the dried roots (0.1 g dry weight) using 100 mg/L of Pb(II) aqueous solution adjusted at pH 5.0. Equilibrium was obtained in 90 min with a 92% removal of Pb(II). The effect of contact time, pH, adsorbent dosage, initial metal ion concentration on the adsorption of Pb(II) were also studied. Kinetic studies indicated that the adsorption of Pb(II) followed the pseudo-second-order model with a reaction rate constant (k) of 0.0127 mg/(g.min). Kinetics data conforming to the pseudo-second-order model suggest that chemisorption was the rate-limiting step in the adsorption process. The adsorption data were found to fit best into the Langmuir model (R2 = 0.986). The maximum adsorption capacity was found to be ∼50 mg Pb(II) per g of dried roots. To investigate the feasibility of using the water hyacinth roots in a more realistic situation, wastewaters collected from various sources were also tested with the biosorbent. Significant removal of Pb(II) (∼88% to ∼100%) was observed from the wastewaters at pH 5.0. High adsorption capacity, rapid kinetics, and its low cost make water hyacinth dried roots a good candidate for the removal of Pb(II) from wastewaters.


2013 ◽  
Vol 726-731 ◽  
pp. 2736-2741
Author(s):  
Ming Da Liu ◽  
Ge Tian ◽  
Liang Jie Zhao ◽  
Yao Sheng Wang ◽  
Lei Guo ◽  
...  

Five blast-furnace slags were used as adsorbents to remove Pb (II) from aqueous solution. Kinetic studies showed that the sorption process was best described by pseudo-second-order model. Among Langmuir, Freundlich and Temkin isotherms, the Freundlich isotherm had a better fit with the simulation of the adsorption of Pb (II).


2013 ◽  
Vol 68 (2) ◽  
pp. 441-447 ◽  
Author(s):  
Diego S. Paz ◽  
Alexandre Baiotto ◽  
Marcio Schwaab ◽  
Marcio A. Mazutti ◽  
Mariana M. Bassaco ◽  
...  

In this study papaya seeds were used to remove methylene blue dye from aqueous solution. Papaya seeds were characterized as possessing a macro/mesoporous texture and large pore size. Studies were carried out in batches to evaluate the effect of contact time and pH (2–12) on the removal of dye. It was observed that the adsorption of dye was better in the basic region (pH 12). The equilibrium data were analyzed using Langmuir, Freundlich, Dubinin–Raduschkevich, Tempkin, Jovanovich, Redlich–Peterson, Sips, Toth and Radke–Prausnitz isotherms. The equilibrium data were best described by the Langmuir isotherm with a maximum adsorption capacity of 637.29 mg g–1. Adsorption kinetic data were fitted using the pseudo-first-order and pseudo-second-order model. The adsorption kinetic is very fast and was best described by the pseudo-second-order model.


Author(s):  
Dan Wu ◽  
Yaxiu Zhao ◽  
Qiang Liu ◽  
Chein-Chi Chang ◽  
Wei Hou

Abstract A graphene film deposited on titanium substrate was successfully prepared by a facile solution evaporation method, as electrode exhibiting superior electrosorption property toward methylene blue (MB) from aqueous solution. The fabricated graphene film on titanium substrate was characterized in detail by scanning electron microscopy (SEM) and FTIR techniques. As electrode (GTE) for electrosorption of MB, some experimental parameters, such as applied potential, concentration of electrolyte, solution initial pH and temperature, were systematically investigated and discussed. The experimental results demonstrated that the maximum adsorption capacity using GTE can reach 86.06 mg· g−1 under the optimized conditions of −600 mV of applied potential, pH of 7.5, 293 K and 0.01 mg· L−1 Na2SO4 solution, which is 1.40 times of that obtained under open circuit condition in 10 mg· L−1 MB solution. The adsorption isotherm of MB on GTE was analyzed with Langmuir and Freundlich isotherm equations, Pseudo-first-order model, pseudo-second-order model, and intra-particle diffusion model were applied to depict the adsorption kinetics process. The electrosorption of MB preferably fitted Langmuir isotherm, indicating a single-layer adsorption of MB molecules on graphene film followed pseudo-second-order model. Moreover the electrosorption of MB on GTE was found to be spontaneous and endothermic process. This work would be helpful to design and fabricate high performance carbon-based electrodes for high efficiency electrosorption treatment of dye wastewaters.


Materials ◽  
2020 ◽  
Vol 13 (16) ◽  
pp. 3584
Author(s):  
Gabriela Buema ◽  
Nicoleta Lupu ◽  
Horia Chiriac ◽  
Tiberiu Roman ◽  
Marieta Porcescu ◽  
...  

Wastes are the sustainable sources of raw materials for the synthesis of new adsorbent materials. This study has as objectives the advanced capitalization of fly ash, by sulphuric acid activation methods, and testing of synthesized materials for heavy metals removal. Based on the previous studies, the synthesis parameters were 1/3 s/L ratio, 80 °C temperature and 10% diluted sulphuric acid, which permitted the synthesis of an eco-friendly adsorbent. The prepared adsorbent was characterized through SEM, EDX, FTIR, XRD and BET methods. Adsorption studies were carried out for the removal of Cd2+ ions, recognized as ions dangerous for the environment. The effects of adsorbent dose, contact time and metal ion concentrations were studied. The data were tested in terms of Langmuir and Freundlich isotherm and it was found that the Langmuir isotherm fitted the adsorption with a maximum adsorption capacity of 28.09 mg/g. Kinetic data were evaluated with the pseudo-first-order model, the pseudo-second-order model and the intraparticle diffusion model. The kinetics of cadmium adsorption into eco-friendly material was described with the pseudo-second-order model, which indicated the chemisorption mechanism.


2016 ◽  
Vol 869 ◽  
pp. 735-739
Author(s):  
Elton Marks de Araujo Braz ◽  
Mirna Sales Loiola Rosa ◽  
Maria Rita de Morais Chaves Santos ◽  
Luiz de Sousa Santos Jr. ◽  
Josy Anteveli Osajima ◽  
...  

The constant search for the removal of organic and inorganic pollutants has been largely intensified lately, as has the search for efficient techniques. With that, this work aims to test two filter papers of different origins to identify their interaction with the bright yellow dye and to determine the adsorption capacity of each paper. Various parameters were studied (pH, time, temperature, and concentration) and it was possible to verify that the best interaction conditions between the material and the dye were 180 minutes, pH 2, and temperature of 298 K, with a maximal capacity at approximately 7 mg of dye per gram of material, with a kinetic adjustment to the pseudo-second-order model. Thus, these results prove that the paper interacts with the dye, and it can be used as an adsorbent.


2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Zheng Liu ◽  
Yuling Wei

Activated carbons (ACs) were prepared from pomelo peels by K2CO3 activation and used as an adsorbent (PAC) for the removal of Cu(II) from aqueous solutions. BET, SEM, and FT-IR were employed for the characterization of the obtained ACs. The optimum ACs were reported at activation temperature of 850°C, activation time of 60 min, and impregnation ratio of 3, which had a high surface area (1213 m2/g) and total pore volume (0.57 cm3/g). The resulting ACs were used for the adsorption of Cu(II) from aqueous solutions in the batch mode and yielded a superior adsorption capacity of 139.08 mg/g. The pH of optimum adsorption was determined as 5. Pseudo first-order model, pseudo second-order model, and intraparticle diffusion model were applied to describe the adsorption processes. The adsorption kinetic data were found to follow the pseudo second-order model. The adsorption isotherms data were analyzed using Langmuir, Freundlich, Temkin, and Dubinin–Radushkevich models. The Langmuir model was found to provide the best fit, and the calculated adsorption capacity was 151.35 mg/g.


2020 ◽  
Vol 22 (3) ◽  
pp. 9-16
Author(s):  
Qinye Sun ◽  
Heng Zheng ◽  
Yanhui Li ◽  
Meixiu Li ◽  
Qiuju Du ◽  
...  

AbstractIn this study, activated carbon and humic acid powder were fixed by the cross-linking reaction of sodium alginate. Calcium alginate/activated carbon/humic acid (CAH) tri-system porous fibers were prepared by the wet spinning method and freeze-dried for the removal of tetracycline in aqueous solution. Subsequently, the morphology and structure of CAH fibers were measured by scanning electron microscopy (SEM) and the Brunauer-Emmett-Teller (BET) method. The effect of pH, contact time, temperature and other factors on adsorption behavior were analyzed. The Langmuir and Freundlich isotherm models were used to fit tetracycline adsorption equilibrium data. The dynamics data were evaluated by the pseudo-second-order model, the pseudo-second-order model and the intraparticle diffusion model. Thermodynamic study confirmed that the adsorption of tetracycline on CAH fibers was a spontaneous process.


In this study, the magnetite nanoparticles (MNP) was successfully synthesized from mill scale waste to analyze the removal of Cu (II) ions from the aqueous solution. The micron-sized magnetite was milled using the high energy ball mills (HEBM with the variation of milling hours 3,5 and 7 to produce nano-sized particles. The MNP were measured by X-Rays Diffraction (XRD), Transmission Electron Microscopy (TEM), Brunauer-Emmett-Teller (BET) and Atomic Absorption Spectroscopy (AAS). Studied parameters are contact time, the initial concentration and particle size. The adsorption kinetics was relatively quick and equilibrium is reached at about 30 minutes. In kinetic studies, the pseudo-second-order model was employed. Langmuir model (R2 >0.9987) corresponded with the adsorption isotherm data of Cu (II) ions. The adsorption capacity of Cu (II) ions onto magnetite nanoparticles (MNP) is 11.36 mgg -1 at 7 hours milling hours. Pseudo-second-order model and Langmuir isotherm were obeyed with experimental results.


Author(s):  
S. Starlin Shyla ◽  
R. Mohan Kumar ◽  
M. Singanan

The objective of this study is to investigate the removal of divalent cadmium ions from an aqueous solution using Lantana camara leaves biocarbon (LCBC). Batch experiments are conducted to test the effects of various parameters such as pH, initial metal ion concentration, amount of biocarbon, and contact time on the cadmium removal process at room temperature, which allows establishing as the optimum conditions a pH value of 4.0 and 2.5g/100 mL of biocarbon dose at the equilibrium time of 180 min. The maximum percentage removal of cadmium is 93.30%. Langmuir and Freundlich adsorption isotherms are used to verify the adsorption parameters, and the experimental data is well fitted to the Langmuir model. Analysis of the biosorption kinetics shows that the pseudo-second-order model is well fitted for Cd (II) ions removal. The correlation coefficient (r2) for the second-order model is 0.9848. The results reveal LCBC as an efficient, low cost, and harmless to environment adsorbent for the removal of Cd (II) ions in the biosorption process.


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