Preparation of titanate nanoflower for sorption of 75Se(IV) radioisotope from aqueous solution: Equilibrium, kinetic and thermodynamic studies

2015 ◽  
Vol 103 (12) ◽  
Author(s):  
Sahar El-Sayed Abd El-Kader Sharaf El-Deen ◽  
Karam Fatwhi Allan ◽  
Mohamed Holeil ◽  
Gehan El-Sayed Abd El-Kader Sharaf El-Deen

AbstractIn this study, the adsorptive removal of selenium (IV) from aqueous solution by titanate nanoflower (TNF) was prepared via alkaline hydrothermal method. The morphology and crystal phase of the TNF were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), energy dispersive X-ray spectroscope (EDX), selected area electron diffraction (SAED), thermogravimetric analysis (TGA), fourier transform infrared spectroscopy (FTIR) and specific surface area. This study was conducted to determine the influence of various operating parameters such as pH, adsorbate weight, initial anion concentration, contact time and solution temperature on the adsorptive removal of selenium (IV). Equilibrium adsorption data were analyzed using Freundlich, Langmuir and Dubinin–Radushkevich (D–R) isotherm models. The results demonstrated that the adsorption was well described by the Langmuir adsorption isotherm with the maximum adsorption capacity up to 46.52 mg/g at pH 3.5. The adsorption of Se(IV) anions onto the surface of TNF may proceed through outer sphere electrostatic interactions and/or inner-sphere complexation interaction. The kinetic data indicated that the adsorption fit well with the pseudo-second-order kinetic model. The thermodynamic parameters implied that the adsorption process was spontaneous and endothermic in nature.

2011 ◽  
Vol 230-232 ◽  
pp. 1129-1132 ◽  
Author(s):  
Ya Li He ◽  
Tian Hai Wang ◽  
Jun Cao Shi

Batch experiments were carried out to determine the capacity of Bacillus cereus biomass to adsorb Sr(II) ions from aqueous solution with respect to pH, initial Sr(II) concentration, contact time and biomass dose. The experimental data were modeled by Langmuir and Freundlich isotherm models. Langmuir model resulted in the best fit of the adsorption data. The maximum adsorption capacity for Sr(II) was 78.34 mg/g. The best correlation was provided by the second-order kinetic model, implying that chemical sorption was the rate-limiting step. The practical implication of this study is the development of an effective and economic technology for Sr(II) removal from contaminated waters.


2016 ◽  
Vol 75 (2) ◽  
pp. 366-377 ◽  
Author(s):  
Gülay Bayramoğlu ◽  
V. Cengiz Ozalp ◽  
M. Yakup Arıca

Lentinus concinnus biomass was immobilized to carboxyl derivative of cellulose, carboxymethyl cellulose (CMC), in the presence of FeCl3 (0.1 mol L−1) via ionic cross-linking. The beads containing immobilized fungal biomass were incubated at 30 °C for three days to permit growth of the fungus. The free and immobilized fungal biomass were tested for adsorption of Disperse Red 60 (DR-60) from aqueous solution using bare CMC beads as a control system. The maximum adsorption of DR-60 on the free and immobilized fungal biomass was observed at pH 6.0. The adsorption of DR-60 by the free, and immobilized fungal biomass increased as the initial concentration of DR-60 in the medium increased up to 100 mg/L. The maximum adsorption capacity of the CMC beads, the free and immobilized fungal biomass (i.e. composite beads) were found to be 43.4, 65.7, and 92.6 mg g−1 dry sorbents, respectively. The equilibrium of the adsorption system was well described by Langmuir and Temkin isotherm models. Adsorption equilibrium was established in about 1.0 h. The adsorption of DR-60 on the fungal preparations followed pseudo-second-order kinetic model. It was observed that the immobilized fungal biomass has a high potential for the removal of DR-60 as a model dye from aqueous solution.


2018 ◽  
Vol 2017 (1) ◽  
pp. 16-26 ◽  
Author(s):  
Zejun Liu ◽  
Shaoqi Zhou

Abstract In this study, we provide the first documented removal of humic acid (HA) from aqueous solution using polyacrylamide/chitosan (PAAm/CS) semi-IPN hydrogel. The prepared semi-IPN hydrogel was characterized by scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FT-IR). The factors effecting HA adsorption performance were individually tested, including initial pH, ionic strength, contact time, initial HA concentration, and temperature. The results indicated that semi-IPN hydrogel was successfully fabricated and can be applied in a wide pH range, from 3 to 9. Low ionic strength effectively enhanced the adsorption capacity. As the ionic strength increased, this enhancement was less obvious but still positive. The adsorption kinetics were fitted to a pseudo-first-order kinetic model, and the adsorption isotherm was described using the Sips isotherm model. The HA adsorption capacity increased with increasing temperature. The maximum adsorption capacity has the potential to attain 166.30 mg g−1, based on the Sips isotherm at 25 °C. Experiments demonstrated that the HA adsorption process can be primarily attributed to electrostatic interactions, and hydrogen bonding was also involved. Facile synthesis and good adsorptive performance indicate that semi-IPN hydrogel can be used for removing HA from water.


2021 ◽  
Author(s):  
Dianjia Zhao ◽  
Wenkang Ye ◽  
Wenxuan Cui

Abstract As an eco-friendly adsorption material, hydroxyapatite (Ha) have received widely attention from researchers owing to their excellent biocompatibility and adsorption performance. However, the inconvenient in separating Ha powder from adsorbed processes following use has limited their application. Herein, a novel alginate-based composite beads encapsulation with cellulose and Ha (named HCA) was designed to remove Cu(II) from aqueous solution. Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), Scanning electron microscopy (SEM), and X-ray photoelectron spectroscopy (XPS) were used for characteristic analysis. The impacts of samples compositions, various Cu(II) concentration, adsorption equilibrium time, and regeneration performance on the adsorption process were investigated. The results suggested that beads exhibited their maximum adsorption capacity for Cu(II) was obtained to be 64.14 mg/g at pH=5 for 8 h, best fitted into Langmuir isotherm models and the pseudo-second-order kinetic model. In addition, the biocompatible beads not only increase the sorption sites, but also have good regenerability, would be a promising bio-adsorbent for heavy metal ion removal.


2013 ◽  
Vol 295-298 ◽  
pp. 1154-1160 ◽  
Author(s):  
Guo Zhi Deng ◽  
Xue Yuan Wang ◽  
Xian Yang Shi ◽  
Qian Qian Hong

The objective of this paper is to investigate the feasibility of phenol adsorption from aqueous solution by Pinus massoniana biochar. Adsorption conditions, including contact time, initial phenol concentration, adsorbent dosage, strength of salt ions and pH, have been investigated by batch experiments. Equilibrium can be reached in 24 h for phenol from 50 to 250 mg• L-1. The optimum pH value for this kind of biochar is 5.0. The amount of phenol adsorbed per unit decreases with the increase in adsorbent dosage. The existence of salt ions makes negligible influence on the equilibrium adsorption capacity. The experimental data is analyzed by the Freundlich and Langmuir isotherm models. Equilibrium data fits well to the Freundlich model. Adsorption kinetics models are deduced and the pseudo-second-order kinetic model provides a good correlation for the adsorbent process. The results show that the Pinus massoniana biochar can be utilized as an effective adsorption material for the removal of phenol from aqueous solution.


2018 ◽  
Vol 7 (3) ◽  
pp. 966
Author(s):  
Kartik Kulkarni ◽  
Varsha Sudheer ◽  
C R Girish

The potential of agricultural waste cashew nut shells as an adsorbent for removing phenol from wastewater is presented in this paper. The adsorbent was treated with 3M sulphuric acid in order to improve the properties. The experimental parameters such as adsorbent dosage, concentration and temperature were optimized with response surface methodology (RSM). The isotherm data were tested with different isotherm models and it obeyed Freundlich Isotherm showing the multilayer adsorption. The kinetic data satisfied pseudo-first order kinetic model. The maximum adsorption capacity was calculated to be 35.08 mg/g proving the capability of cashew nut shells for removing phenol from wastewater.  


2017 ◽  
Vol 13 (27) ◽  
pp. 425
Author(s):  
Azeh Yakubu ◽  
Gabriel Ademola Olatunji ◽  
Folahan Amoo Adekola

This investigation was conducted to evaluate the adsorption capacity of nanoparticles of cellulose origin. Nanoparticles were synthesized by acid hydrolysis of microcrystalline cellulose/cellulose acetate using 64% H3PO4 and characterized using FTIR, XRD, TGA-DTGA, BET and SEM analysis. Adsorption kinetics of Pb (II) ions in aqueous solution was investigated and the effect of initial concentration, pH, time, adsorbent dosage and solution temperature. The results showed that adsorption increased with increasing concentration with removal efficiencies of 60% and 92.99% for Azeh2 and Azeh10 respectively for initial lead concentration of 3 mg/g. The effects of contact time showed that adsorption maximum was attained within 24h of contact time. The maximum adsorption capacity and removal efficiency were achieved at pH6. Small dose of adsorbent had better performance. The kinetics of adsorption was best described by the pseudo-second-Order model while the adsorption mechanism was chemisorption and pore diffusion based on intra-particle diffusion model. The isotherm model was Freundlich. Though, all tested isotherm models relatively showed good correlation coefficients ranging from 0.969-1.000. The adsorption process was exothermic for Azeh-TDI, with a negative value of -12.812 X 103 KJ/mol. This indicates that the adsorption process for Pb by Azeh-TDI was spontaneous. Adsorption by Azeh2 was endothermic in nature.


2020 ◽  
Vol 2020 ◽  
pp. 1-14
Author(s):  
Nguyen Le My Linh ◽  
Tran Duong ◽  
Hoang Van Duc ◽  
Nguyen Thi Anh Thu ◽  
Pham Khac Lieu ◽  
...  

In the present work, the modified bentonites were prepared by the modification of bentonite with cetyltrimethylammonium bromide (CTAB), both cetyltrimethylammonium bromide and hydroxy-Fe cations and both cetyltrimethylammonium bromide and hydroxy-Al cations. X-ray diffraction (XRD), thermal analysis (TG-DTA), infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), and nitrogen adsorption/desorption isotherms were utilized to characterize the resultant modified bentonites. The modified bentonites were employed for the removal of phenol red dye from aqueous solution. Phenol red adsorption agreed well with the pseudo-second-order kinetic model. The equilibrium data were analyzed on the basis of various adsorption isotherm models, namely, Langmuir, Freundlich, and Dubinin‒Radushkevich models. The highest monolayer adsorption capacity of phenol red at 30°C derived from the Langmuir equation was 166.7 mg·g−1, 125.0 mg·g−1, and 100.0 mg·g−1 for CTAB‒bentonite, Al‒CTAB‒bentonite, and Fe‒CTAB‒bentonite, respectively. Different thermodynamic parameters were calculated, and it was concluded that the adsorption was spontaneous (∆G° < 0) and endothermic (∆H° > 0), with increased entropy (∆S° > 0) in all the investigated temperature ranges.


2009 ◽  
Vol 610-613 ◽  
pp. 65-68 ◽  
Author(s):  
Xue Gang Luo ◽  
Feng Liu ◽  
Xiao Yan Lin

Konjac glucomannan (KGM) was converted into water insoluble konjac glucomannan (WIKGM) by treating with NaOH through completely deacetylated reaction. Adsorption study was carried out for the adsorption of Pb2+ from aqueous solution using water insoluble konjac glucomannan. The influences of pH, contact time, temperature and initial Pb2+ concentration on the absorbent were studied. Results of kinetic data showed that the Pb2+ adsorption rate was fast and good correlation coefficients were obtained for the pseudo second-order kinetic model. The equilibrium process was described well by the Langmuir isotherm model with maximum adsorption capacity of 9.18 mg/g on WIKGM at 25°C.


2016 ◽  
Vol 2016 ◽  
pp. 1-9 ◽  
Author(s):  
America R. Vazquez-Olmos ◽  
Mohamed Abatal ◽  
Roberto Y. Sato-Berru ◽  
G. K. Pedraza-Basulto ◽  
Valentin Garcia-Vazquez ◽  
...  

Adsorption of Pb(II) from aqueous solution using MFe2O4 nanoferrites (M = Co, Ni, and Zn) was studied. Nanoferrite samples were prepared via the mechanochemical method and were characterized by X-ray powder diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), micro-Raman, and vibrating sample magnetometry (VSM). XRD analysis confirms the formation of pure single phases of cubic ferrites with average crystallite sizes of 23.8, 19.4, and 19.2 nm for CoFe2O4, NiFe2O4, and ZnFe2O4, respectively. Only NiFe2O4 and ZnFe2O4 samples show superparamagnetic behavior at room temperature, whereas CoFe2O4 is ferromagnetic. Kinetics and isotherm adsorption studies for adsorption of Pb(II) were carried out. A pseudo-second-order kinetic describes the sorption behavior. The experimental data of the isotherms were well fitted to the Langmuir isotherm model. The maximum adsorption capacity of Pb(II) on the nanoferrites was found to be 20.58, 17.76, and 9.34 mg·g−1 for M = Co, Ni, and Zn, respectively.


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