Removal of trace thorium(IV) from aqueous solutions using a pseudo-polyrotaxane

2018 ◽  
Vol 0 (0) ◽  
Author(s):  
Huijun Liu ◽  
Shanxia Deng ◽  
Lanlin Lei ◽  
Zhiyuan Feng ◽  
Caixia Qi ◽  
...  

Abstract The adsorption of thorium(IV) was studied using a pseudo-polyrotaxane, which was obtained by the reaction of poly(propyleneglycol) (PPG) and 6-OTs-β-CD. The adsorption of thorium(IV) was examined as a function of the contact time, pH of the solution, adsorbent dose, concentration of thorium(IV) and temperature using batch adsorption experiments. The experimental results suggested that the optimum conditions were found to be at pH 3.5, contact time 40 min, 10 mg adsorbent doses, 20 mg L−1 thorium(IV) concentration and 298 K. The maximum adsorption capacity was found to be 15.366 mg g−1. The thermodynamic parameters (ΔG0<0, ΔH0<0) were calculated, the result showed that the adsorption of thorium(IV) was exothermic and spontaneous process.

Author(s):  
Nnaemeka John Okorocha ◽  
J. Josphine Okoji ◽  
Charles Osuji

The potential of almond leaves powder, (ALP) for the removal of Crystal violet (CV) and Congo red (CR) dyes from aqueous solution was investigated. The adsorbent (ALP) was characterized by FTIR and SEM analysis. Batch adsorption studies were conducted and various parameters such as contact time, adsorbent dosage, initial dye concentration, pH and temperature were studied to observe their effects in the dyes adsorption process. The optimum conditions for the adsorption of CV and CR dyes onto the adsorbent (ALP) was found to be: contact time (100mins), pH (10.0), temperature (343K) for an initial CV dye concentration of 50mg/L using adsorbent dose of 1.0g and contact time (100mins), pH (2.0), temperature (333K) for an initial CR dye concentration of 50mg/L using adsorbent dose 1.0g respectively. The experimental equilibrium adsorption data fitted best and well to the Freundlich isotherm model for both CV and CR dyes adsorption. The maximum adsorption capacity of ALP was found to be 22.96mg/g and 7.77mg/g for the adsorption of CV and CR dyes respectively. The kinetic data conformed to the pseudo-second-order kinetic model. Thermodynamic quantities such as Gibbs free energy (ΔG0), enthalpy (ΔH0) and entropy (ΔS0) were evaluated and the negative values of ΔG0obtained for both dyes indicate the spontaneous nature of the adsorption process while the positive values of ΔH0and ΔS0obtained indicated the endothermic nature and increased randomness during the adsorption process respectively for the adsorption of CV and CR onto ALP. Based on the results obtained such as good adsorption capacity, rapid kinetics, and its low cost, ALP appears to be a promising adsorbent material for the removal of CV and CR dye stuff from aqueous media.


2018 ◽  
Vol 36 (3-4) ◽  
pp. 1112-1143 ◽  
Author(s):  
Mohammad Hossein Karimi Darvanjooghi ◽  
Seyyed Mohammadreza Davoodi ◽  
Arzu Y Dursun ◽  
Mohammad Reza Ehsani ◽  
Iman Karimpour ◽  
...  

In this study, treated eggplant peel was used as an adsorbent to remove Pb2+ from aqueous solution. For this purpose batch adsorption experiments were performed for investigating the effect of contact time, pH, adsorbent dose, solute concentrations, and temperature. In order to assess adsorbent’s physical and chemical properties, Fourier transform infrared spectroscopy, scanning electron microscopy, and energy dispersive X-ray spectroscopy were used. The results showed that the adsorption parameters for reaching maximum removal were found to be contact time of 110 min, adsorbent dose of 0.01 g/ml, initial lead(II) concentration of 70 ppm, pH of 4, and temperature of 25°C. Moreover, for the experiments carried out at pH > 4 the removal occurred by means of significant precipitation as well as adsorption. Furthermore, these results indicated that the adsorption followed pseudo-second-order kinetics model implying that during the adsorption process strong bond between lead(II) and chemical functional groups of adsorbent surface took place. The process was described by Langmuir model (R2 = 0.99; maximum adsorption capacity 88.33 mg/g). Also thermodynamics of adsorption was studied at various temperatures and the thermodynamic parameters including equilibrium constant (K), standard enthalpy change, standard entropy change, and standard free energy changes were obtained from experimental data.


2020 ◽  
Vol 10 (5) ◽  
pp. 1738
Author(s):  
Kay Thwe Aung ◽  
Seung-Hee Hong ◽  
Seong-Jik Park ◽  
Chang-Gu Lee

Polyacrylonitrile (PAN) fibers were prepared via electrospinning and were modified with diethylenetriamine (DETA) to fabricate surface-modified PAN fibers. The surface-modified PAN fibers were used to evaluate their adsorption capacity for the removal of Cu(II) from aqueous solutions. Batch adsorption experiments were performed to examine the effects of the modification process, initial concentration, initial pH, and adsorbent dose on the adsorption of Cu(II). Kinetic analysis revealed that the experimental data fitted the pseudo-second-order kinetic model better than the pseudo-first-order model. Adsorption equilibrium studies were conducted using the Freundlich and Langmuir isotherm models, and the findings indicated that the PAN fibers modified with 85% DETA presented the highest adsorption capacity for Cu(II) of all analyzed samples. Moreover, the results revealed that the Freundlich model was more appropriate than the Langmuir one for describing the adsorption of Cu(II) onto the modified fibers at various initial Cu(II) concentrations. The maximum adsorption capacity was determined to be 87.77 mg/g at pH 4, and the percent removal of Cu(II) increased as the amount of adsorbent increased. Furthermore, the surface-modified PAN fibers could be easily regenerated using NaOH solution. Therefore, surface-modified PAN fibers could be used as adsorbents for the removal of Cu(II) from aqueous solutions.


Alotrop ◽  
2017 ◽  
Vol 1 (1) ◽  
Author(s):  
Melfi Puspita ◽  
M. Lutfi Firdaus ◽  
Nurhamidah Nurhamidah

The problem of environmental polution caused by waste of batik industry lately is increasing, so it needed a method to overcome that problem. The aim of this study was to determine the ability of activated charcoal from coconut fiber palm in adsorbing Reactive Red-120 and Direct Green-26 dyes in waste of batik along with determining the parameters of isotherms adsorption using UV-Vis Spectrophotometer analysis method. Variations of pH, contact time, adsorbent weight and temperature were carried out as variable to obtain optimum conditions of the adsorption process. The optimum of conditions for Reactive Red-120  occured at pH 3 and a contact time of 30 minutes, while Direct Green-26  occurred at pH 4 and a contact time of 40 minutes, with each adsorbent weight 150 mg and the temperature 30 °C. Adsorption isotherms determined by Freundlich and Langmuir models with maximum adsorption capacity (Qmax) were obtained for the Reactive Red-120  was 400 mg/g, while Direct Green-26 is 169 mg/g. 


Molecules ◽  
2020 ◽  
Vol 25 (16) ◽  
pp. 3692
Author(s):  
Oana Buriac ◽  
Mihaela Ciopec ◽  
Narcis Duţeanu ◽  
Adina Negrea ◽  
Petru Negrea ◽  
...  

Platinum is a precious metal with many applications, such as: catalytic converters, laboratory equipment, electrical contacts and electrodes, digital thermometers, dentistry, and jewellery. Due to its broad usage, it is essential to recover it from waste solutions resulted out of different technological processes in which it is used. Over the years, several recovery techniques were developed, adsorption being one of the simplest, effective and economical method used for platinum recovery. In the present paper a new adsorbent material (XAD7-DB30C10) for Pt (IV) recovery was used. Produced adsorbent material was characterized by X-ray dispersion (EDX), scanning electron microscopy (SEM) analysis, Fourier Transform Infrared Spectroscopy and Brunauer-Emmett-Teller (BET) surface area analysis. Adsorption isotherms, kinetic models, thermodynamic parameters and adsorption mechanism are presented in this paper. Experimental data were fitted using three non-linear adsorption isotherms: Langmuir, Freundlich and Sips, being better fitted by Sips adsorption isotherm. Obtained kinetic data were correlated well with the pseudo-second-order kinetic model, indicating that the chemical sorption was the rate-limiting step. Thermodynamic parameters (ΔG°, ΔH°, ΔS°) showed that the adsorption process was endothermic and spontaneous. After adsorption, metallic platinum was recovered from the exhausted adsorbent material by thermal treatment. Adsorption process optimisation by design of experiments was also performed, using as input obtained experimental data, and taking into account that initial platinum concentration and contact time have a significant effect on the adsorption capacity. From the optimisation process, it has been found that the maximum adsorption capacity is obtained at the maximum variation domains of the factors. By optimizing the process, a maximum adsorption capacity of 15.03 mg g−1 was achieved at a contact time of 190 min, initial concentration of 141.06 mg L−1 and the temperature of 45 °C.


2016 ◽  
Vol 675-676 ◽  
pp. 455-458
Author(s):  
Peeyanan Noirod ◽  
Jittapat Lamangthong ◽  
Padarat Ninjiaranai

The aim of this work was to study the adsorption efficiency of chitosan as an adsorbent for triclosan, commercially known as Irgasan, in aqueous solutions. The effects of contact time, pH and temperature were investigated using a batch adsorption technique. Langmuir and Freundlich isotherms were used to analyze the equilibrium data at different absorption conditions. The results showed that the maximum adsorption capacity for chitosan was found in the acidic pH 3 and at a temperature of 65 oC. These results suggested that chitosan can be used as an adsorbent for removal of triclosan from aqueous solutions.


2013 ◽  
Vol 634-638 ◽  
pp. 276-279
Author(s):  
Neng Zhou ◽  
Zhen Zhou ◽  
Yuan Qin ◽  
Chu Jie Zeng

In this paper, the adsorption of heavy metals by biomass, namely dry garlic stem, an environmentally-friendly and natural adsorbent, were studied.The efficiency of the adsorbent was studied under different experimental conditions by varying parameters such as pH, initial concentration and contact time using batch adsorption technique. The results show that at pH 5.50, room temperature, the adsorption time 90 min and the amount of garlic stem 0.5 g, Co2+ have the maximum adsorption capacity. The maximum adsorption capacity of the Co2+ on garlic stem is 14.9 mg/g. At pH 9.50, the adsorption time 90 min and the amount of garlic stem 0.7g, Cd2+ have the maximum adsorption at the same temperature. The maximum adsorption of the Cd2+ is 20.90 mg/g. At pH 10.0, the adsorption time 150 min and the amount of garlic stem 0.3g, Ni2+ have the maximum adsorption at the same temperature. The dry garlic stem is a efficient adsorbent in removing cobalt, cadmium and nickel from aqueous solution.


2013 ◽  
Vol 3 (1) ◽  
pp. 47-54 ◽  
Author(s):  
Ahmed Al-Ghamdi ◽  
Hosam Altaher ◽  
Waid Omar

In this research raw date palm trunk fibers were used to adsorb cadmium ions from aqueous solutions. The date palm trunk fibers are considered as agricultural waste which is available in huge quantities in the Kingdom of Saudi Arabia. In order to assess the feasibility and the efficiency of using this as an adsorbent, a series of experiments were conducted in a batch adsorption method. The effects of the process variables such as fiber size, mixing rate, mixing time, temperature, solution pH and adsorbent dose on the adsorption capacity of date palm fibers were studied. The results obtained indicated that the adsorption capacity of Cd2+ increased from 29.06 to 51.1 mg/g as the particle size decreased from 875 to 100 μm. It was found that the adsorption capacity of Cd2+ decreased in the strong acidic medium and increased rapidly as the solution pH increased from 1.69 to 3.71. The adsorption capacity was observed to have an insignificant change on raising the temperature from 12 to 34 °C and increasing of mixing speed from 100 to 500 rpm. Also, one very important finding of this research is that the equilibrium time of the adsorption process is very short. The maximum adsorption capacity was obtained after 10 minutes.


2018 ◽  
Vol 78 (11) ◽  
pp. 2328-2337 ◽  
Author(s):  
Jéssica C. Zanette ◽  
Márcia T. Veit ◽  
Gilberto C. Gonçalves ◽  
Soraya M. Palácio ◽  
Fernando R. Scremin ◽  
...  

Abstract This study evaluated the prednisone removal from aqueous solutions using adsorption by an activated carbon of vegetal origin (VAC). A central composite rotatable design (CCRD) and the response surface methodology (RSM) were used to verify the influence of the parameters: pH, adsorbent dose and prednisone concentration in a batch adsorption process. Among the analyzed parameters, only the adsorbent dose and the prednisone concentration were statistically significant (α = 0.05) and the critical values obtained were adsorbent dose: 1.87 g/L, pH 7.56 and prednisone concentration: 3.66 mg/L with 77.51% of prednisone removal by VAC. The kinetic study of the adsorption of prednisone reached the equilibrium in 4 h. The pseudo-first-order model described adequately the kinetics data behavior. The equilibrium experimental data obtained at different temperatures showed that the VAC has a maximum adsorption capacity of 18.04 mg/g at a temperature of 30 °C. The prednisone removal decreased by the increasing temperature and the Langmuir isotherm well described the experimental data (R² &gt; 0.98). Thermodynamic results shown that the prednisone removal of aqueous solutions by VAC is spontaneous and favorable process.


2011 ◽  
Vol 396-398 ◽  
pp. 2443-2446
Author(s):  
Neng Zhou ◽  
Zhen Zhou ◽  
Yuan Qin ◽  
Chu Jie Zeng ◽  
Zu Qiang Huang

This study reported the feasibility of adsorption of heavy metals using dry garlic stem, an environmentally-friendly and natural adsorbent.Using batch adsorption technique, the efficiency of the adsorbent was studied under different experimental conditions by varying parameters such as pH, initial concentration and contact time. The results show that at pH 2.03, adsorption temperature 35°C, the adsorption time 90 min and the amount of garlic stem 1.0 g, Pb2+ have the maximum adsorption capacity. The maximum adsorption capacity of the Pb2+ on garlic stem is 28.42 mg/g and the adsorption rate is 94.74%. At pH 4.05, the adsorption time 120 min and the amount of garlic stem 1.0, Cu2+ have the maximum adsorption at the same temperature. The maximum adsorption of the Cu2+ is 20.90 mg/g and the adsorption rate is 69.75%. The dry garlic stem was found to be efficient in removing lead and copper from aqueous solution as compared to other adsorbents already used for the removal of these ions.


Sign in / Sign up

Export Citation Format

Share Document