Simultaneous sorption of As, B, Cr, Mo and Se from coal fly ash leachates by Al3+-pillared bentonite clay: implication for the construction of activated geo-synthetic clay liner

2017 ◽  
Vol 12 (1) ◽  
pp. 186-201 ◽  
Author(s):  
Vhahangwele Masindi ◽  
W. Mugera Gitari ◽  
Hlanganani Tutu
Keyword(s):  
Fly Ash ◽  
Adsorption Isotherm ◽  
Coal Fly Ash ◽  
Bentonite Clay ◽  
Order Kinetic ◽  
Modified Bentonite ◽  
Adsorption Affinity ◽  
Freundlich Adsorption Isotherm ◽  
Order Kinetic Model ◽  
Pseudo Second Order

The present study reports the optimum conditions for intercalating the Al3+ species to bentonite clay matrices and evaluate the potential of using Al3+-modified bentonite clay (Alum-Bent) for removal of oxyanionic species of As, B, Cr, Mo and Se from coal fly ash (FA) leachates. Removal of oxyanionic species was done in batch experimental procedures. Parameters optimized were: contact time, adsorbent dosage, concentration and pH. The adsorption affinity of Al3+-bentonite clay for oxyanionic species varied as follows: B ≈ Se > Mo > Cr ≈ As respectively. The adsorption data fitted better to Langmuir adsorption isotherm than Freundlich adsorption isotherm hence confirming mono-site adsorption. The adsorption kinetics fitted well pseudo-second-order kinetic model hence confirming chemisorption. The fact that most of the oxyanion were adsorbed at pH ≥ pHpzc indicated that both electrostatic and chemical interactions occurred with the clay surface and interlayers. The Al3+-modified bentonite clay successfully removed oxyanion species from generated coal FA leachates. This study shows that Al3+-modified bentonite clay is an effective adsorbent for oxyanion species in coal FA leachates and could be applied as a reactive barrier in coal FA retention ponds.

Adsorption of Pb(II) from Aqueous Solutions on Dithizone-Immobilized Coal Fly Ash

2020 ◽  
Vol 840 ◽  
pp. 57-63
Author(s):  
Dina Fitriana ◽  
Mudasir Mudasir ◽  
Dwi Siswanta
Keyword(s):  
Fly Ash ◽  
Adsorption Isotherm ◽  
Contact Time ◽  
Coal Fly Ash ◽  
Order Kinetic ◽  
Adsorbent Dosage ◽  
Activated Coal ◽  
Concentration Of Ions ◽  
Order Kinetic Model ◽  
Pseudo Second Order

Adsorption of Pb(II) ions onto selective adsorbent of dithizone-immobilized coal fly ash (DCFA) from Holcim, Cilacap, Indonesia has been investigated in batch experiments. Prepared coal fly ash (CFA) modified by immobilization of dithizone previously were characterized by FT-IR and XRD. Several parameters influencing the adsorption of Pb(II) ions such as effect of pH, adsorbent dosage, contact time and initial concentration of ions on the efficiency of the adsorption were studied. The optimum condition of Pb(II) adsorption was found at pH 5, adsorbent dosage 0.1 g, contact time 60 min and initial Pb(II) ions concentration of 60 mg L–1. The adsorption kinetics of Pb(II) ions on DCFA was found to follow a pseudo-second-order kinetic model. The adsorption isotherm data were fitted to the Langmuir model. Kinetics and adsorption isotherm studies suggest that the capacity and affinity of the DCFA in adsorbing Pb(II) ions is significantly improved compared to those of non-immobilized activated coal fly ash (ACFA).

scholarly journals Adsorption of As, B, Cr, Mo and Se from coal fly ash leachate by Fe3+ modified bentonite clay

2015 ◽  
Vol 6 (3) ◽  
pp. 382-391 ◽  
Author(s):  
Masindi Vhahangwele ◽  
Gitari W. Mugera ◽  
Tutu Hlanganani
Keyword(s):  
Fly Ash ◽  
Toxic Elements ◽  
Coal Fly Ash ◽  
Bentonite Clay ◽  
Potentially Toxic Elements ◽  
Subsurface Water ◽  
Modified Bentonite ◽  
Adsorption Affinity ◽  
Adsorbate Concentration ◽  
Five Elements

Fly ash contains the potentially toxic elements As, B, Cr, Mo and Se which upon contact with water may be leached to contaminate surface and subsurface water bodies. This study aims to evaluate the adsorption of these elements from coal fly ash leachates on Fe3+-modified bentonite (Fe-Bent); such modification improved the physicochemical properties of bentonite clay. For optimization of adsorption of the five elements, the effects of time, adsorbent dosage, adsorbate concentration, and pH were optimized. Adsorption affinity of oxyanions followed in the order B = Se > Mo > Cr = As. Experimental data fitted well to Langmuir and Freundlich adsorption isotherms.

scholarly journals Synthesis, Characterization and Application of a Diatomite-Based Composite for the Adsorption of Anionic Dyes in Aqueous Solutions

2021 ◽  
Vol 15 (3) ◽  
pp. 377-388
Author(s):  
Sadek Chentouf ◽  
◽  
Smail Kacha ◽  
Réda Marouf ◽  
Fouad Mekhalef Benhafsa ◽  
...  
Keyword(s):  
Adsorption Isotherm ◽  
In Situ Polymerization ◽  
Order Kinetic ◽  
Anionic Dyes ◽  
Bet Model ◽  
Freundlich Adsorption Isotherm ◽  
Order Kinetic Model ◽  
Pseudo Second Order ◽  
Acid Blue

Synthesis, characterization and application of the polyaniline-diatomite (PAD) composite in the adsorption of Reactive Red 120 (RR 120) and Acid Blue (AB) dyes were carried out. The composite was prepared by the in situ polymerization of aniline. Mass of purified diatomite was mixed with a solution containing aniline dissolved in 2M hydrochloric acid at room temperature. The solid obtained was characterized using the SEM, XRD and FTIR analyses. The kinetic adsorption of dyes was described using the pseudo-second order kinetic model. The adsorption isotherm of the RR 120 dye can be fitted by the Freundlich adsorption isotherm model. However, the adsorption isotherm of the AB dye can be better fitted by the BET model.

Adsorption of Phosphorus by Ce-Modified Lithium Silica Fume

2013 ◽  
Vol 368-370 ◽  
pp. 687-691 ◽  
Author(s):  
Wei Lan Lin ◽  
Jin Chuan Gu ◽  
Wen Yuan Wang ◽  
Yu Heng Wang
Keyword(s):  
Adsorption Isotherm ◽  
Silica Fume ◽  
Adsorption Process ◽  
Ph Value ◽  
Order Kinetic ◽  
Phosphorus Adsorption ◽  
Initial Ph ◽  
Freundlich Adsorption Isotherm ◽  
Order Kinetic Model ◽  
Pseudo Second Order

This is a study about using cerium ions solution to modify lithium silica fume and the phosphorus adsorption by the modified material. The way to modify lithium silica fume and adsorption conditions has been researched. It was found that capacity of adsorption have been improved after modification by the cerium nitrate. In the adsorption test, we studied the effects of the concentration of cerium ions, the calcination temperature, the dosage, initial pH value, reaction temperature and other factors on the adsorption. The results indicated that after modifications by 3% cerium ions , calcinations at 573k, the adsorption of phosphorus can get more than 90% when modified lithium silica fume dosage is 9.6g.l-1 and the concentration of phosphorus solution is 4 mg.l-1. In addition, the Freundlich adsorption isotherm is fit for the description of the phosphorus adsorption. The phosphorus adsorption process was in accord with pseudo-second-order kinetic model.

scholarly journals Bagasse Fly Ash as an Effective Adsorbent: Evaluation of Adsorptive Characteristics for 4-Nitroaniline Removal

2021 ◽  
Vol 7 (05) ◽  
pp. 155-161
Author(s):  
Amarnath P.C & Shashikala K. J. Praveen Kumar D. G., Kalleshappa C.M.,
Keyword(s):  
Fly Ash ◽  
Contact Time ◽  
Order Kinetic ◽  
Batch Experiments ◽  
Bagasse Fly Ash ◽  
Initial Ph ◽  
Order Kinetic Model ◽  
Pseudo Second Order ◽  
Adsorbent Dose ◽  
Maximum Removal

In the present study we explored the adsorptive characteristics of 4-nitroaniline from synthetic aqueous solution onto bagasse fly ash (BFA). Batch experiments were carried out to determine the influence of parameters like initial pH (pH0), adsorbent dose (m), contact time (t) and initial concentration (C0) on the removal of 4-nitroaniline. The maximum removal of 4-nitroaniline was determined to be 98% at lower concentrations (50 mg/L) and 41% at higher concentrations (300 mg/L), using a BFA dosage of 10 g/L at 303K. Kinetic study of 4-nitroaniline removal by BFA was well represented by pseudo second-order kinetic model. The 4-nitroaniline desorption from 4-nitroaniline loaded BFA shows that only 27% and 36% of 4-nitroaniline could be recovered using ethyl alcohol and acetone respectively.

scholarly journals Preparation and Characterization of a Novel Amidoxime-Modified Polyacrylonitrile/Fly Ash Composite Adsorbent and Its Application to Metal Wastewater Treatment

2022 ◽  
Vol 19 (2) ◽  
pp. 856
Author(s):  
Yan Sun ◽  
Xiaojun Song ◽  
Jing Ma ◽  
Haochen Yu ◽  
Gangjun Liu ◽  
...  
Keyword(s):  
Fly Ash ◽  
Adsorption Process ◽  
Single Layer ◽  
Nitrogen Adsorption ◽  
Order Kinetic ◽  
X Ray Diffraction ◽  
Order Kinetic Model ◽  
Pseudo Second Order ◽  
High Degree

The polyacrylonitrile/fly ash composite was synthesized through solution polymerization and was modified with NH2OH·HCl. The amidoxime-modified polyacrylonitrile/fly ash composite demonstrated excellent adsorption capacity for Zn2+ in an aqueous medium. Fourier transform-Infrared spectroscopy, thermogravimetric analysis, nitrogen adsorption, X-ray diffraction, and scanning electron microscopy were used to characterize the prepared materials. The results showed that the resulting amidoxime-modified polyacrylonitrile/fly ash composite was able to effectively remove Zn2+ at pH 4–6. Adsorption of Zn2+ was hindered by the coexisting cations. The adsorption kinetics of Zn2+ by Zn2+ followed the pseudo-second order kinetic model. The adsorption process also satisfactorily fit the Langmuir model, and the adsorption process was mainly single layer. The Gibbs free energy ΔG0, ΔH0, and ΔS0 were negative, indicating the adsorption was a spontaneous, exothermic, and high degree of order in solution system.

KINETICS AND ISOTHERM STUDIES OF Pb(II) IMPRINTED CARBOXYMETHYL CHITOSAN–PECTIN-PEGDE

2017 ◽  
Vol 79 (6) ◽  
Author(s):  
Budi Hastuti ◽  
Dwi Siswanta ◽  
Mudasir Mudasir ◽  
Triyono Triyono
Keyword(s):  
Adsorption Isotherm ◽  
Kinetic Model ◽  
Metal Ion ◽  
Diglycidyl Ether ◽  
Carboxymethyl Chitosan ◽  
Second Order ◽  
Order Kinetic ◽  
Freundlich Adsorption Isotherm ◽  
Order Kinetic Model ◽  
Chelation Reaction

Pectin and chitosan are biomaterials that capable to act as biosorbent. Pectin has active groups, such as carboxyl, methoxyl, and hydroxyl (OH), while chitosan has amine group (–NH2) and hydroxyl (OH) as the active site metal ion absorber. Integration of two biopolymers is conducted by using a suitable cross-linker agents that are expected to form stable and more organized structure. This structure facilitate metal ions to enter and to form chelation reaction. Thus, it has great capacity for metal adsorption. A modified natural adsorbent pectin-chitosan has been synthesized by reacting of -OH group among pectin (Pec) and chitosan with Poly(ethylene glycol) Diglycidyl Ether (PEGDE) crosslinker agent to form a stable and an acidic medium-resistance adsorbent. Prior to increasing the active group of the adsorbent, chitosan was attached with acetate to form Carboxymethyl Chitosan (CMC). Furthermore, the CMC-Pec-PEGDE adsorbent was imprinted with Pb (II) to afford Pb(II) imprinted-CMC-Pec-PEGDE adsorbent in order to improve the selective sorption of Pb(II) metal ion. All of the functional groups attached on the synthesized adsorbents were characterized by Fourier Transform Infrared (FT-IR) Spectrometry. The kinetics and thermodynamics bath sorption of Pb(II) on Pb(II) imprinted-CMC-Pec-PEGDE film adsorbent have been investigated including the optimal condition for adsorption. The pseudo first-order and second-order kinetic model were investigated in order to determine the adsorption mechanism. The results indicated that all of the three adsorbent, CMC, CMC-Pec-PEGDE, and Pb(II) imprinted-CMC-Pec-PEGDE followed a pseudo-second-order kinetic model. Furthermore, adsorption studies of Pb(II) ion on CMC and CMC–Pec-PEGDE found to follow Langmuir adsorption while on imprinted-CMC-Pec-PEGDE followed Freundlich adsorption isotherm. The adsorption isotherm parameters of CMC and CMC-Pec-PEGDE adsorbents were ΔG° of 24.8 and 23.1 kJ mol-1, respectively. While Pb(II) imprinted-CMC-Pec-PEGDE followedisotherm model with ΔG° of 9.6 kJ mol-1.

scholarly journals Preparation and Characterization of Magadiite–Magnetite Nanocomposite with Its Sorption Performance Analyses on Removal of Methylene Blue from Aqueous Solutions

Polymers ◽  
2019 ◽  
Vol 11 (4) ◽  
pp. 607 ◽  
Author(s):  
Mingliang Ge ◽  
Zhuangzhuang Xi ◽  
Caiping Zhu ◽  
Guodong Liang ◽  
Guoqing Hu ◽  
...  
Keyword(s):  
Methylene Blue ◽  
Adsorption Isotherm ◽  
Kinetic Model ◽  
Aqueous Solutions ◽  
Langmuir Adsorption Isotherm ◽  
Order Kinetic ◽  
Langmuir Adsorption ◽  
Adsorption Performance ◽  
Order Kinetic Model ◽  
Pseudo Second Order

The magadiite–magnetite (MAG–Fe3O4) nanocomposite has great potential applications in the field of biomaterials research. It has been used as a novel magnetic sorbent, prepared by co-precipitation method. It has the dual advantage of having the magnetism of Fe3O4 and the high adsorption capacity of pure magadiite (MAG). MAG–Fe3O4 was characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and vibrating sample magnetometer (VSM). The results showed that Fe3O4 nanoparticles were deposited on the interlayer and surface of magadiite. MAG–Fe3O4 was treated as an adsorbent for methylene blue (MB) removal from aqueous solutions. The adsorption properties of MAG–Fe3O4 were investigated on methylene blue; however, the results showed that the adsorption performance of MAG–Fe3O4 improved remarkably compared with MA and Fe3O4. The adsorption capacity of MAG–Fe3O4 and the removal ratio of methylene blue were 93.7 mg/g and 96.2%, respectively (at 25 °C for 60 min, pH = 7, methylene blue solution of 100 mg/L, and the adsorbent dosage 1 g/L). In this research, the adsorption experimental data were fitted and well described using a pseudo-second-order kinetic model and a Langmuir adsorption isotherm model. The research results further showed that the adsorption performance of MAG–Fe3O4 was better than that of MAG and Fe3O4. Moreover, the adsorption behavior of MB on MAG–Fe3O4 was investigated to fit well in the pseudo-second-order kinetic model with the adsorption kinetics. The authors also concluded that the isothermal adsorption was followed by the Langmuir adsorption isotherm model; however, it was found that the adsorption of the MAG–Fe3O4 nanocomposite was a monolayer adsorption.

scholarly journals Sorption of different phenol derivatives on functionalized macroporous nanocomposite of poly (glycidyl methacrylate-co-ethylene glycol dimethacrylate) and acid modified bentonite

2014 ◽  
Vol 79 (10) ◽  
pp. 1249-1261 ◽  
Author(s):  
Sanja Marinovic ◽  
Aleksandra Milutinovic-Nikolic ◽  
Aleksandra Nastasovic ◽  
Marija Zunic ◽  
Zorica Vukovic ◽  
...  
Keyword(s):  
Ethylene Glycol ◽  
Glycidyl Methacrylate ◽  
Ethylene Glycol Dimethacrylate ◽  
Order Kinetic ◽  
Glycol Dimethacrylate ◽  
Modified Bentonite ◽  
Phenol Derivatives ◽  
Order Kinetic Model ◽  
Influence Of Temperature On ◽  
Pseudo Second Order

Macroporous nanocomposite of poly (glycidyl methacrylate-co-ethylene glycol dimethacrylate) and acid modified bentonite was prepared by radical suspension copolymerization. Nanocomposite was functionalized with diethylene triamine (deta), by ring-opening reaction of the pendant epoxy groups. Functionalization was performed in order to enable phenol derivatives sorption. This new, not sufficiently investigated material, with developed porous structure was denoted CP-SA-deta. In this study, the influence of temperature on 4-nitrophenol (4NP) sorption on CP-SA-deta was investigated. The chemisorption was estimated as dominant process since activation energy of sorption of 4NP of 54.8 kJ mol-1 was obtained. After determining the optimal sorption conditions for 4NP, the sorption of 2-nitrophenol (2NP) and 2-chloro 4-nitrophenol (2Cl4NP) on CP-SA-deta was investigated with respect to pH, initial concentration and contact time. The 2NP sorption was seldom tested, while according to our knowledge, the 2Cl4NP sorption was not investigated. The isotherm data were best fitted with Langmuir model, while the sorption dynamics obeyed the pseudo-second-order kinetic model for all derivatives.

Adsorption of Pb(II) on raw and organically modified Jordanian bentonite

Clay Minerals ◽  
2015 ◽  
Vol 50 (4) ◽  
pp. 485-496 ◽  
Author(s):  
I. Hamadneh ◽  
R. Abu-Zurayk ◽  
B. Abu-Irmaileh ◽  
A. Bozeya ◽  
A. H. Al-Dujaili
Keyword(s):  
Exchange Capacity ◽  
Second Order ◽  
Area Measurement ◽  
Order Kinetic ◽  
X Ray Diffraction ◽  
Experimental Conditions ◽  
Modified Bentonite ◽  
X Ray ◽  
Order Kinetic Model ◽  
Pseudo Second Order

AbstractA comparative study using bentonite (BT), hexadecyltrimethylammonium-modified bentonite (BT-HDTMA) and phenyl fatty hydroxamic acid-modified bentonite (BT-PFHA) as adsorbents for the removal of Pb(II) has been proposed. These adsorbents were characterized by X-ray diffraction, X-ray fluorescence, Fourier-transform infrared spectroscopy and surface area measurement. Cation exchange capacity was also determined in this study. The adsorbent capabilities for Pb(II) from aqueous solution were investigated, and the optimal experimental conditions including adsorption time, adsorbent dosage, the initial concentration of Pb(II), pH and temperature that might influence the adsorption performance were also investigated. The experimental equilibrium adsorption data were tested by four widely used two-parameter equations, the Langmuir, Freundlich, Dubinin- Radushkevich (D-R) and Temkin isotherms. The monolayer adsorption capacities of BT, BT-HDTMA and BT-PFHA for Pb(II) were 149.3, 227.3 and 256.4 mg/g, respectively. The experimental kinetic data were analysed by pseudo-first order, pseudo-second order and intraparticle diffusion kinetics models. The experimental data fitted very well with the pseudo-second order kinetic model. Determination of the thermodynamic parameters, ΔG, ΔH and ΔS showed the adsorption to be feasible, spontaneous and exothermic.

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