Fluoride removal using a MgFe hydrotalcite and a MgFe oxide

MRS Advances ◽  
2020 ◽  
Vol 5 (62) ◽  
pp. 3239-3246
Author(s):  
Jessica G López-Castillo ◽  
Guadalupe Macedo-Miranda ◽  
Sonia Martínez-Gallegos ◽  
Eduardo Ordoñez- Regíl ◽  
Sonia Álvarez-García ◽  
...  

AbstractThe present study investigates the adsorption of fluorides (F) by a hydrotalcite MgFe (HT MgFe) and an iron-based metal oxide (MgFe oxide). Both materials were synthesized by the coprecipitation method and were calcined at the same temperature HT MgFe, HTC MgFe, oxide MgFe and oxide MgFeC. Both solids were characterized by the XRD technique. Materials showed typical crystalline forms; in the case of HT MgFe, an octahedral crystalline form and for the oxide MgFe cubic crystalline form, the analysis of the BET method classifies the materials as mesoporous. In the adsorption study, it was determined that the optimal pH for adsorption is 7. Regarding the adsorption kinetics, the HTC MgFe and oxide MgFeC samples were adjusted to the pseudo-second order model, which describes the process as chemiadsorption; meanwhile, for the samples, isotherms were adjusted to the Langmuir model, which describes the material as homogeneous with a strong interaction between the sorbate and the sorbent.

2021 ◽  
Vol 2 ◽  
Author(s):  
Ting Xu ◽  
Rongjun Qu ◽  
Ying Zhang ◽  
Changmei Sun ◽  
Ying Wang ◽  
...  

Amino-thiol bifunctional polysilsesquioxane/carbon nanotubes (PSQ/CNTs) magnetic composites were prepared by sol-gel method with two types of functional siloxanes coating on carboxyl CNTs simultaneously. The composites were served as efficient adsorbents for removing Hg(II) in aqueous solution and the adsorption properties were investigated systematically. The optimal pH of bifunctional composites for Hg(II) removal is at pH 4.5. The thermodynamic fitting curves are more consistent with the Langmuir model and the adsorption capacities of the bifunctional composites for Hg(II) varied from 1.63 to 1.94 mmol g−1 at 25°C according to the Langmuir model. The kinetics curves are more fitted to the pseudo-second-order model and the composites could selectively adsorb Hg(II) in a series of binary metal ions solution. The elution regeneration tests showed that the adsorption rate could still reach 78% after repeat cycle three times. It is expected that the bifunctional PSQ/CNTs magnetic composites can be potentially applied to remove low concentration Hg(II) from waste water.


2019 ◽  

<p>Synthetic dyes have a hurtful effect on human health and the environment. In this work, activated carbon was produced from date stones for use in elimination of methylene blue charged in aqueous solutions. Before that, the adsorbent was characterized by BET method, SEM, X-ray and TGA. The results of the adsorption kinetics are describe better with the pseudo-second order model (R2= 0.998). Frendlich adsorption isotherm model describe better the experimental data than the Langmuir model. The capacity for methylene blue removal was found to be 163.67 mg/g. Batch experiments studies show that the activated carbon produced as of date stones can be used effectively in the treatment of cationic dyes in aqueous solutions.</p>


2017 ◽  
Vol 19 (1) ◽  
pp. 48-53 ◽  
Author(s):  
Łukasz Klapiszewski ◽  
Przemysław Bartczak ◽  
Tomasz Szatkowski ◽  
Teofil Jesionowski

Abstract We demonstrate here that lignin can be successfully combined with silica to create a multifunctional material with considerable sorption capabilities. Experiments were carried out in which a silica/lignin hybrid was used for the removal of lead(II) ions from water solutions. Adsorption kinetics were also determined and preliminary regeneration tests were performed. The effectiveness of the adsorption process depends on the following parameters: contact time of adsorbent and adsorbate (equilibrium times: 5 min for concentration 25 mg/L, 10 min for 50 and 75 mg/L, 60 min for 100 mg/L), pH (optimal pH = 5) and adsorbent mass. The kinetics of the adsorption of lead(II) ions on the SiO2/lignin biosorbent are best described by a pseudo-second-order model. Adsorption isotherms of lead(II) ions were also determined. The experimental data were found to be in agreement with the Langmuir model, and the maximal sorption capacity of the adsorbent with respect to lead(II) was 89.02 mg/g.


2021 ◽  
Vol 19 (9) ◽  
pp. 46-54
Author(s):  
Makarim A. Mahdi ◽  
Aymen A.R. Jawad ◽  
Aseel M. Aljeboree ◽  
Layth S. Jasim ◽  
Ayad F. Alkaim

The AAc/GO nanocomposite hydrogel was successfully employed as a polymeric Nano sorbent of the removal efficiency of M G dye from the model. The complication of the mechanism of the adsorption system was completely exposed by examining how solution pH affects adsorption, Ionic strength isotherm models, kinetic models, and thermodynamics. The adsorption of the MG dye was greatly dependent on the solution pH. The Freundlich model has been demonstrated to be the most accurate in describing the MG dye sorption, whilst the Langmuir model was shown to be the least accurate. Additionally, these integrated mechanisms fit nicely within the framework of a pseudo-second-order model. Additionally, the contact time at equilibrium short (ten minutes) required to MG removes demonstrates the AAc/GO nanocomposite hydrogel can be considered an efficient and potentially useful adsorbent for MG removal from industrial effluents.


2016 ◽  
Vol 17 (1) ◽  
pp. 32-38 ◽  
Author(s):  
Tianli Han ◽  
Xiaoman Zhang ◽  
Xiangqian Fu ◽  
Jinyun Liu

Chitosan nanoparticle (CS NP)-modified MnO2 nanoflakes were presented as a novel adsorbent for fast adsorption of Pb(II) from aqueous solution. Loading dense CS NPs onto mono-dispersive flower-like MnO2 nanostructures reduces the overlap of CS during adsorption, and thus improves the contact of functional adsorption sites on the surface of MnO2 nanoflakes with heavy metal ions. The results show that the removal efficiency of the nanoadsorbents reaches up to 93% in 3 min for Pb(II). In addition, the maximum adsorption capacity, effects of adsorbent dosage and pH value, and the reusability were investigated. The kinetic process and adsorption isotherm fit well with the pseudo-second-order model and Langmuir model, respectively. These findings provide a potential strategy to address the overlap issue of some common nanoadsorbents.


2012 ◽  
Vol 9 (3) ◽  
pp. 1266-1275 ◽  
Author(s):  
J.Raffiea Baseri ◽  
P.N. Palanisamy ◽  
P. Sivakumar

In this research, Polyaniline coated sawdust (Polyaniline nano composite) was synthesized via direct chemical polymerization and used as an adsorbent for the removal of acid dye (Acid Violet 49) from aqueous solutions. The effect of some important parameters such as pH, initial concentration of dye, contact time and temperature on the removal efficiency was investigated in batch adsorption system. The adsorption capacity of PAC was high (96.84 %) at a pH of 3-4. The experimental data fitted well for pseudo second order model. Langmuir model is more appropriate to explain the nature of adsorption with high correlation coefficient. The Energy of activation from arrehenius plot suggested that the adsorption of AV49 onto PAC involves physisorption mechanism.


2013 ◽  
Vol 2013 ◽  
pp. 1-8 ◽  
Author(s):  
M. Rajan ◽  
G. Alagumuthu

This paper examines the kinetics of fluoride removal from water by the adsorbent zirconium-impregnated walnut-shell carbon (ZIWSC), exploring the mechanisms involved. The dependence of the adsorption of fluoride on the pH of the solution has been studied to achieve the optimum pH value and a better understanding of the adsorption mechanism. The presence of bicarbonate ions in aqueous solution was found to affect the fluoride removal indicating that these anions compete with the sorption of fluoride on adsorbents. The kinetic profile has been modeled using pseudo-first-order model, pseudo-second-order model, and intraparticle diffusion model. The kinetic sorption profiles offered excellent fit with pseudo-second-order model. Adsorption isotherms have been modeled by Langmuir, Freundlich, and Temkin equations, and their constants were determined. The equilibrium adsorption data were fitted reasonably well for Freundlich isotherm model. XRD and SEM patterns of the ZIWSC were recorded to get better insight into the mechanism of adsorption process.


2010 ◽  
Vol 156-157 ◽  
pp. 42-45
Author(s):  
Jing Song Wang ◽  
Si Guang Chen ◽  
Zhi Wu Zhou ◽  
Rui Ting Peng

Modified magnetic microspheres were prepared and used to adsorb As ( ) from aqueous solution. The experiments were conducted in a batch system to study the adsorption behavior of As( ) onto these microspheres and the adsorption equilibrium, adsorption isotherm and kinetics were also studied. The experiment results showed that the modified magnetic microspheres are effective to remove As ( ) from aqueous solution, and the percentage removal of As ( ) could reach over 90% at pH 2.0 within 90 min. The pseudo second-order model was found to fit accurately with the experimental data. The adsorption isotherm can be described by Langmuir model.


2014 ◽  
Vol 775-776 ◽  
pp. 749-754
Author(s):  
Mirna Sales Loiola Rosa ◽  
Marcos Pereira Silva ◽  
Alan Icaro Morais ◽  
Maria Rita de Morais Chaves Santos ◽  
Edson Cavalcanti Silva Filho ◽  
...  

The disposal of textile waste in water bodies is exacerbating environmental problems, which led scientists to seek natural materials to develop more sustainable ways. Searching for low cost materials was used to remove the dye in two cellulosic sources (filter papers of different brands). The papers were characterized by XRD which confirmed crystallographic profile similar to cellulose. With the aim of optimizing the best conditions, various tests were performed, where the ideal time was 180 minutes for the paper 1 and 240 minutes for the second paper, both by adjusting the pseudo second-order model. The other parameters studied was the pH, adsorbate-adsorbent systems which have maximum adsorption capacity of 2.76 mg / g at pH 2.02 and 2 mg / g at pH 11 for the paper 1 and 10.57 mg / g pH 4 and 2 mg / g at pH 11 for the paper 2. Both adsorbents had the best fit to the Langmuir model in pHs 2 and 11 at the temperature of 298 K.


2015 ◽  
Vol 752-753 ◽  
pp. 251-256
Author(s):  
Megat Ahmad Kamal Megat Hanafiah ◽  
Noor Fhadzilah Mansur ◽  
Wan Mohd Nazri Wan Ab Rahman ◽  
Mardhiah Ismail

The potential of sodium hydroxide (NaOH) modified Petai Belalang (Leucaenaleucocephala) leaf powder as a biosorbent for methylene blue removal from aqueous solutions was investigated. Adsorption parameters studied include initial dye concentration, pH, dosage, kinetics and isotherms. The pHzpc of chemically treated Leucaenaleucocephala leaf powder was 7.50 and adsorption equilibrium time was achieved after 60 min. The kinetic data was best represented by the pseudo-second order model. The maximum adsorption capacity predicted from Langmuir model was 208.33 mg g-1. This work indicated that NaOH treated Leucaenaleucocephala leaf powder can be an attractive biosorbent for MB removal from diluted industrial wastewater.


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