Sorption of Th(IV) onto ZnO nanoparticles and diatomite-supported ZnO nanocomposite: kinetics, mechanism and activation parameters

2016 ◽  
Vol 104 (9) ◽  
pp. 635-647 ◽  
Author(s):  
Sabriye Yusan ◽  
Anastasia Bampaiti ◽  
Sema Erenturk ◽  
Fotini Noli ◽  
Mahmut A. A. Aslani ◽  
...  

Abstract In this study, for the first time ZnO nanoparticles and diatomite-supported ZnO nanocomposite have been utilized as adsorbent for the removal of Th(IV) ions from aqueous solutions under different experimental conditions. The Langmuir, Freundlich, Temkin and Dubinin– Radushkevich (D–R) isotherms were used to analyze the equilibrium data. The sorption equilibrium data were fitted well to the Langmuir isotherm with maximum sorption capacities values was found to be 1.105 mmol/g and 0.320 mmol/g for ZnO nanoparticles and diatomite supported ZnO nanocomposite, respectively. Pseudo-first and pseudo-second order equations, Intraparticle diffusion and Bangham’s models were considered to evaluate the rate parameters and sorption mechanism. Sorption kinetics were better reproduced by the pseudo-second order model (R2 > 0.999), with an activation energy (Ea) of +99.74 kJ/mol and +62.95 kJ/mol for ZnO nanoparticles and diatomite-supported ZnO nanocomposite, respectively. In order to specify the type of sorption reaction, thermodynamic parameters were also determined. The evaluated ΔG* and ΔH* indicate the non-spontaneous and endothermic nature of the reactions. The results of this work suggest that both of the used materials are fast and effective adsorbents for removing Th(IV) from aqueous solutions and chemical sorption plays a role in controlling the sorption rate.

2021 ◽  
Vol 55 (5-6) ◽  
pp. 705-722
Author(s):  
JEYAGOWRI BALAKRISHNAN ◽  
YAMUNA RANGAIYA THIAGARAJAN

The present study investigates the potential of Simarouba glauca seed shell powder as a cost-effective adsorbent for the removal of the cationic dyes Malachite green (MG), Methylene blue (MB) and Rhodamine B (RB) from aqueous solutions. The adsorbent was characterized by Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and X-ray diffraction (XRD), as well as by Brunauer–Emmett–Teller (BET) and elemental (CHNS) analyses. Batch mode adsorption studies were carried out varying the experimental conditions, such as initial dye concentration and contact time, adsorbent dose, pH and particle size, in order to assess the adsorbent capacity for the removal of cationic dyes from wastewater. The experimental data were analysed using the Langmuir, Freundlich, Temkin and Dubinin–Radushkevich isotherms. The data fitted well the Langmuir model for the dyes studied. Kinetic data were analysed using the pseudo-first order, pseudo-second order, intraparticle diffusion and Boyd models. The experimental results showed that the pseudo-second order model fitted well.


Author(s):  
Seyedeh Mahsa Seyed Danesh ◽  
Shahab Shariati ◽  
Hossein Faghihian

Objective: In this study, amine functionalized magnetite Kit-6 silica nanocomposite (Fe3O4@SiO2@Kit-6-NH2) was synthesized as an adsorbent for removing Carmoisine food dye from aqueous solutions. Method: The nanocomposite was chemically synthesized and was characterized by X-ray diffraction analysis (XRD), vi-brating sample magnetometer (VSM), energy dispersive X-ray spectroscopy (EDX), scanning electron microscopy (SEM) and Fourier transform infrared spectrometry (FT-IR). Taguchi orthogonal array experimental design method was used to op-timize the experimental conditions including adsorbent amount, pH of solution, amount of salt, the volume of sample and contact time. Pseudo first-order, pseudo second-order, intra-particle diffusion and Elovich kinetic models were investigated to study the kinetic parameters of sorption process. Results: The kinetic data corresponded to the pseudo second-order kinetic model with R2 = 0.9999. Also, adsorption data were analyzed using Langmuir, Freundlich and Temkin isotherm models. The results indicated that the data were well fitted to the Freundlich isotherm model (R2 = 0.9984, n=1.0786). The reusability tests showed the proposed nanocomposite can be used more than 8 cycles with removal efficiency higher than 90%. Conclusion: The applicability study of proposed nanocomposite proved its ability for efficient removal of Carmoisine dye from real aqueous samples.


2017 ◽  
Vol 43 (3) ◽  
pp. 10-16 ◽  
Author(s):  
Krzysztof Kuśmierek ◽  
Paulina Idźkiewicz ◽  
Andrzej Świątkowski ◽  
Lidia Dąbek

AbstractThe usefulness of untreated powdered eggshell as low-cost adsorbent for the removal of pentachlorophenol (PCP) from aqueous solutions was investigated. The most important parameters affecting the adsorption process, including the pH and ionic strength, were examined. The adsorption characteristics of PCP onto eggshell were evaluated in terms of kinetic and equilibrium parameters. The kinetic data were studied in terms of the pseudo-first order, pseudo-second order and intra-particle diffusion kinetic models. The equilibrium data were analyzed using the Langmuir, Freundlich, Sips and Redlich-Peterson isotherm models. The pseudo-second order model best described the adsorption kinetics. Using the Langmuir equation, the monolayer adsorption capacity of eggshell for PCP was found to be 0.127 mg/g. The results showed that PCP can be effectively removed from aqueous solution employing eggshell as a cheap adsorbent.


2017 ◽  
Vol 79 (7) ◽  
Author(s):  
Abdulganiyu Umar ◽  
Mohd Marsin Sanagi ◽  
Ahmedy Abu Naim ◽  
Wan Nazihah Wan Ibrahim ◽  
Aemi Syazwani Abdul Keyon ◽  
...  

In this work, polystyrene modified-chitin was evaluated for the first time as adsorbent for the removal of Orange G from aqueous solutions. Its absorption capacity was compared to that of chitin. BET and FESEM results showed that the polystyrene-modified chitin has higher surface area (12.47 m2/g) compared to chitin (4.92 m²/g). Batch adsorption experiments on the removal of Orange G from aqueous solutions were conducted. The results showed that the polystyrene-modified chitin has improved adsorption capacity compared to chitin. The maximum adsorption of orange G by chitin occurred at pH 2, while that of the polystyrene-modified chitin occurred at pH 6. At an initial concentration of 20 mg/L, the percentages of dye removal were 65.16% and 81.20% for raw chitin (RCH) and polystyrene-modified chitin (MCH), respectively. Kinetics studies for the adsorbents were conducted using pseudo-first-order and pseudo-second-order models. The pseudo-first-order model gives poor fittings for both adsorbents, with low coefficients of determination (R2). The pseudo-second-order model fits the experimental data well, with R2 close to unity. Langmuir and Freundlich models were used to interpret the adsorption isotherms. It was found that Langmuir isotherm conformed better than Freundlich model in the adsorption of selected dye on chitin and the polystyrene-modified chitin, with R2 nearly unity.


2020 ◽  
Vol 11 (3) ◽  
pp. 11042-11053

This research aims to investigate the removal of trypan blue dye from aqueous solutions by employing ground avocado seeds powder, a low-cost biowaste adsorbent (biosorbent), under various experimental conditions. The effect of contact time, initial dye concentration, and adsorbent dose on dye removal were studied. The experimental kinetic data were fitted to pseudo-first-order and pseudo-second-order kinetic models. Results imply that adsorption of trypan blue on the avocado seed adsorbent nicely followed the pseudo-second-order kinetic model. Equilibrium isotherms were analyzed by Langmuir and Freundlich isotherms, where Langmuir isotherm described the isotherm data with a high-correlation coefficient (R2=0.9948) closer to unity, and maximum adsorption capacity was found to be 19.3 mg g−1. The present study results substantiate that ground avocado seeds are a promising adsorbent for the removal of the dye trypan blue from industrial wastewater.


2015 ◽  
Vol 17 (4) ◽  
pp. 701-715 ◽  

<div> <p>The present study investigates the ability of formaldehyde treated <em>Simarouba glauca</em> seed shell powder for removal of methylene blue (MB) from aqueous solutions. Batch adsorption studies were carried out under various experimental conditions such as agitation time, dye concentration, adsorbent dose and pH. The adsorbent was characterized by Fourier Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscopy (SEM), XRD, BET and CHNS analysis. The adsorption data were analysed using Langmuir, Freundlich, Temkin and Dubinin - Radushkevich isotherms. Equilibrium data fitted well to Langmuir isotherm with maximum adsorption capacity of 111.1 mg g <sup>-1</sup>. Adsorption kinetic data were verified using pseudo first order, pseudo second order and Intraparticle diffusion model. The kinetic data were found to fit well with pseudo second order model.</p> </div> <p>&nbsp;</p>


2009 ◽  
Vol 74 (8-9) ◽  
pp. 953-964 ◽  
Author(s):  
Catalin Balan ◽  
Doina Bilba ◽  
Matei Macoveanu

Batch sorption experiments were performed for the removal of chromium(III) ions from aqueous solutions using Romanian Sphagnum moss peat (untreated and treated with NaCl solution) as sorbent. In order to establish the best conditions for the sorption of chromium(III), the influence of initial pH, contact time, peat dose and metal ion concentration was investigated. The Freundlich, Langmuir and Dubinin-Radushkevich models were applied to describe the sorption isotherms and to calculate its constants. The experimental data fitted well to the Langmuir model with a maximum sorption capacity of 18.6 mg Cr(III)/g of peat. The mean free energy of sorption suggests that the binding of Cr(III) on peat occurred through an ion exchange mechanism. The kinetic data evaluated by pseudo-first order and pseudo-second order kinetic models showed that the sorption of chromium onto the peat followed a pseudo-second order rate equation. The chromium(III) could be easily eluted from the loaded peat using 0.10 M HCl and the peat may be reused in several sorption/ desorption cycles. The experimental results indicated the potential of Sphagnum moss peat for removal of Cr(III) from wastewaters.


2016 ◽  
Vol 4 (2) ◽  
pp. 105-112
Author(s):  
Lalchhing puii ◽  
◽  
Seung-Mok Lee ◽  
Diwakar Tiwari ◽  
◽  
...  

A mesoporous silica was synthesized by annealing (3-Aminopropyl) triethoxysilane grafted chitosan at 800˚C. The mesoporous silica was characterized by the XRD (X-ray diffraction) analysis. The BET specific surface area and pore size of silica was found to be 178.42 m2/g and 4.13 nm. The mesoporous silica was then employed for the efficient remediation of aqueous solutions contaminated with Cu(II) under batch and column reactor operations. The mesoporous silica showed extremely high per cent removal of Cu(II) at wide pH range i.e., pH ~2.0 to 7.0. Relatively a fast uptake of Cu(II) was occurred and high percentage removal was obtained at initial concentrations studied from 1.0 to 15.0 mg/L. The equilibrium state sorption data were utilized for the Langmuir and Freundlich adsorption isotherm studies. Moreover, the effect of an increase in background electrolyte concentrations from 0.0001 to 0.1 mol/L NaNO3 was assessed for the uptake of Cu(II) by mesoporous silica. The equilibrium sorption was achieved within 240 min of contact and the kinetic data is best fitted to the pseudo-second-order and fractal like pseudo-second-order kinetic models. In addition, the mesoporous silica was used for dynamic studies under column reactor operations. The breakthrough curve was then used for the non-linear fitting of the Thomas equation and the loading capacity of the column for Cu(II) was estimated.


Author(s):  
Mohamed Nasser Sahmoune ◽  
Krim Louhab ◽  
Aissa Boukhiar

Dead streptomyces rimosus was found to be an effective biosorbent for the removal of chromium from industrial tanning effluents. A sorption level of 65 mg/g was observed at pH 4.8 while the precipitation effect augmented this value at a higher pH range. Chromium desorption increased with decreasing desorption agents pH (including HCl and H2SO4) to a maximum value of 95% at approximately zero pH. The biosorption data of trivalent chromium by streptomyces rimosus has been used for kinetic studies based on fractional power, Elovich, pseudo-first order and pseudo-second order rate expressions. The time-dependent Cr (III) biosorption data were well-described by a pseudo-second-order kinetic model. The intraparticle diffusion is not the rate-limiting step for the whole reaction. It was found that the biosorption equilibrium data fit well with the Langmuir model.


2019 ◽  
Vol 25 (4) ◽  
pp. 341-351
Author(s):  
Aleksandar Zdravkovic ◽  
Novica Stankovic ◽  
Nebojsa Ristic ◽  
Goran Petkovic

The aim of this study was to determine adsorptive properties of acid activated bentonite clay for the removal of Direct Red 173 (DR 173) and Reactive Red 22 (RR 22) dyes from aqueous solutions. Raw and modified clay were characterized by the following methods: Fourier transform infrared spectroscopy (FTIR), X-ray powder diffraction (XRPD), and scanning electron microscopy (SEM). The efficiency of activated clay adsorption was investigated depending on process parameters: the adsorbent dose, pH, temperature, initial dye concentration, and contact time. Experimental data were analyzed by Langmuir, Freundlich, Temkin, and Dubinin-Radushkevich isotherm as well as kinetic models of pseudo-first order, pseudo-second order and intra-particle diffusion. The process of dye adsorption was best described by Langmuir, Temkin, and Dubinin-Radushkevich isotherm (R2 > 0.97). Pseudo-second order model (R2 > 0.99) had the highest correlation with the obtained kinetic results. The positive value of ?H? indicated that adsorption of dyes by activated bentonite clay is endothermic process. The activated bentonite exhibited good regenerative ability in the 0.1 M NaOH solution. Maximum adsorption capacities of acid activated bentonite clay at 25?C for DR 173 and RR 22 dyes were 356.65 and 109.58 ?mol g-1, respectively.


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