scholarly journals Study on the adsorption of MnO4- ions onto GO/PVA/Fe3O4 composite

2021 ◽  
Vol 10 (2) ◽  
pp. 104-108
Author(s):  
Thu Le Dieu ◽  
Hoang Tran Vinh

In this study, MnO4- ions are adsorbed onto GO/PVA/Fe3O4 composite. Results showed that after 18 hours, the adsorption process gets equilibrium with the adsorption capacity is 187.8 mg.g-1, the mass of adsorbent is 0.005 g in 10 mL of 200 mg.L-1 MnO4- ions solution. The influence of temperature was also investigated and with the increasing of temperature, the adsorption capacity also increases, so the adsorption is endothermic. The sorption process obeys pseudo-first-order kinetic.

2021 ◽  
Vol 8 (2) ◽  
Author(s):  
Dianxin Li ◽  
Yiqing Yang ◽  
Peng Zhang ◽  
Jiangang Liu ◽  
Tao Li ◽  
...  

The surface of Bacillus megaterium was modified by coating sodium alginate. The modified B. megaterium before and after adsorption were characterized by SEM, FTIR and XPS. The effects of pH, reaction time, initial U(VI) concentration and adsorbent dosage on the adsorption of U(VI) by the modified B. megaterium were studied by batch adsorption experiments. The adsorption process was studied by pseudo-first-order kinetics and pseudo-second-order kinetic models, Langmuir and Freundlich isotherms. The results showed that the maximum adsorption capacity of U(VI) was 74.61 mg g −1 under the conditions of pH 5.0, adsorbent 0.2 g l −1 , 30°C and initial U(VI) concentration of 15 mg l −1 . The adsorption process accords with pseudo-first-order kinetics and Langmuir isotherm. The adsorption capacity of U(VI) by the modified B. megaterium was still higher than 80% after five times of desorption and reuse experiments. In conclusion, the sodium alginate modified B. megaterium was an ideal material for U(VI) biosorption.


2019 ◽  
Vol 4 (12) ◽  
pp. 78-85
Author(s):  
Aboiyaa A. Ekine ◽  
Patience N. Ikenyiri ◽  
O. Hezekiah-Braye

This Research investigated the adsorption capacity of locally prepared adsorbents from Egg shells for the removal of fluoride ion in well water. It evaluated the performance of these adsorbents calcinated at 3000C and modified with 1.0M HNO3 (trioxonitrate (v)) acid. Batch adsorber was used to allow for interaction between adsorbent (grounded Egg shells) with water containing fluoride ion. The batch experiment was performed with particle size of 2.12 contact time (60, 120, 180, 240, 300min), mass dosage (5g, 10g, 15g, 20g) and temperature (250C, 300C, 400C, 500C). The modified adsorbent was characterized to determine the physiochemical properties of grounded Egg shells (GE). Also the chemical composition of the modified adsorbent was analyzed to determine the percentage of calcium element required for the uptake of the fluoride ions in water for calcium as 39.68% for grounded Egg shells (GE). Percentage adsorption increased with increase in contact time, mass dosage and temperature for the adsorbent. The adsorption capacity was also determined which also increased with increase in contact time, temperature but decreased with increase in mass dosage at constant time of 60minutes. The pseudo first-order, pseudo second order and intraparticle diffusion kinetic models were fitted into the experimental results. The results obtained indicated that the pseudo first order and intraparticle diffusion models for the grounded Egg shells (GE) reasonably described the adsorption process very well whereas the pseudo second order model was not suitable for a calcinations temperature of 3000C and particle size of 2.12m. The adsorption isotherms were obtained from equilibrium experiment Performed at temperature of 25, 35, 45 and 550C. The result showed that Langmuir and Freundlich isotherm fitted perfectly the experimental data. However, the negative values of Gibb’s free energy indicated that adsorption was favourable and the positive enthalpy change H0 revealed that adsorption process was endothermic while the positive value of the entropy change signified increased randomness with adsorption.


Molekul ◽  
2020 ◽  
Vol 15 (3) ◽  
pp. 149
Author(s):  
Aldes Lesbani Lesbani ◽  
Normah Normah ◽  
Neza Rahayu Palapa ◽  
Tarmizi Taher ◽  
Roy Andreas ◽  
...  

Layered double hydroxide (LDH) Ni/Al-NO3 was synthesized using a coprecipitation method under base condition following with intercalation using Keggin ion [a-SiW12O40]4- to form Ni/Al-[a-SiW12O40] LDH. The LDHs were characterized using XRD, FTIR, BET, and pHpzc analyses. Furthermore, LDHs were applied as adsorbent of iron(II) from aqueous solution. The adsorption process was studied through the effect of adsorption time, the concentration of iron(II), and temperature adsorption. The results show the interlayer distance of LDHs was increased from 7.408 Å to 10.533 Å after intercalation process. The adsorption of iron(II) on LDHs showed that adsorption of iron(II) on both LDHs follows pseudo first-order kinetic model with R2 value is close to one. The adsorption process was spontaneous, with adsorption capacity up to 36.496 mg g-1.


Author(s):  
Yahui Zhou ◽  
Shaobo Liu ◽  
Yunguo Liu ◽  
Xiaofei Tan ◽  
Ni Liu ◽  
...  

The occurrence of environmental endocrine disrupting chemicals (EDCs) in aquatic environments has caused extensive concern. Graphene-like magnetic sawdust biochar was synthesized using potassium ferrate (K2FeO4) to make activated sawdust biochar and applied for the removal of 17-estradiol (E2). The characterization showed that the surface morphology of five graphene-like magnetic sawdust biochars prepared with different preparation conditions were quite different. The specific surface area and pore structure increased with the increment of K2FeO4 addition. The results have shown that graphene-like magnetic sawdust biochar (1:1/900 °C) had the best removal on E2. The experimental results indicated that pseudo-first-order kinetic model and the Langmuir model could describe the adsorption process well, in which the equilibrium adsorption capacity (qe,1) of 1:1/900 °C were 59.18 mg·g−1 obtained from pseudo-first-order kinetic model and the maximum adsorption capacity (qmax) of 1:1/900 °C were 133.45 mg·g−1 obtained from Langmuir model at 298K. At the same time, lower temperatures, the presence of humic acid (HA), and the presence of NaCl could be regulated to change the adsorption reaction in order to remove E2. Adsorption capacity was decreased with the increase of solution pH because pH value not only changed the surface charge of graphene-like magnetic sawdust biochar, but also affected the E2 in the water. The possible adsorption mechanism for E2 adsorption on graphene-like magnetic sawdust biochar was multifaceted, involving chemical adsorption and physical absorption, such as H-bonding, π-π interactions, micropore filling effects, and electrostatic interaction. To sum up, graphene-like magnetic sawdust biochar was found to be a promising absorbent for E2 removal from water.


2018 ◽  
Vol 250 ◽  
pp. 06001 ◽  
Author(s):  
Nur Farhan Zon ◽  
Ammar Iskendar ◽  
Shamila Azman ◽  
Shazani Sarijan ◽  
Razali Ismail

This study investigates the interactions between chromium (Cr) and microplastic under controlled laboratory conditions using low density polyethylene microbeads as plastic particles. Chromium was added to suspensions of in artificial seawater to investigate heavy metal adsorption on microbeads surface. Polyethylene microbeads proved to have affinity in providing surface area for chromium. It served as an effective sorption surface thus lowering amounts of chromium in seawater through adsorption process. The best percentage of heavy metals adsorbed to microbeads and adsorption capacity was 1.7 µg/g and 8.5 % at 1.0 µg/mL respectively. The maximum adsorption was monitored for 180 hours. Kinetic study was performed and fitted well in pseudo-first-order kinetic. In term of isotherm, dataset was in good agreement with both Langmuir and Freundlich with correlation at 0.977 and 0.9606 respectively. Adsorption of chromium to polyethylene microbeads had important implications for the potential role of microplastics, in this case microbeadschromium contaminated act as a quantified link in aquatic food webs.


2013 ◽  
Vol 650 ◽  
pp. 231-237
Author(s):  
Shu Kui Zhou ◽  
Guang Ming Zeng ◽  
Ying Jiu Liu ◽  
Hai Yang Jiang

The modified carboxymethyl cellulose(CMC) was prepared and explored to adsorb uranium(Ⅵ) ions from aqueous solution in a batch system. The experimental results showed that on the condition of reaction temperature 70~80°C, CMC 30%-35% (w/w), CMC to AA (w/w) of 10:2.5 and reaction time 3.5-4 h, the modification effect was the best. High removal efficient of U(Ⅵ) was obtained 97.1% at temperature of 25°C, pH value of 5.0, dosage of modified CMC 0.1 g/L and contact time of 60 min. It was found that the adsorption process was best described by Freundlich model and pseudo-first-order kinetic model (R2=0.9618), indicating that the adsorption is mainly on the surface of the modified CMC. Thermodynamics parameters of negative value of ΔG0 and positive value of ΔH0 revealed the spontaneity and endothermic nature of the adsorption. The adsorption is primarily due to physical adsorption.


Author(s):  
Kadriye Bozgeyik ◽  
Turkan Kopac

In this study, the equilibrium and the kinetics of Bovine Serum Albumin (BSA) adsorption onto metal oxides such as alumina (Al2O3) and zirconia (ZrO2) were investigated in a batch reactor. The effects of pH and temperature to adsorption rate and the equilibrium were studied. The equilibrium process was described by the Langmuir or the Freundlich isotherm models. The maximum adsorption capacity (Q0) was found as 81.6 mg/g at pH 5 and 20°C for Al2O3 and 26 mg/g at pH 4 and 40°C for ZrO2, respectively. The protein adsorption capacity for ZrO2 increased with increasing pH and temperature, while the protein adsorption capacity of Al2O3 increased with increasing pH and decreasing temperature. The pseudo-first-order and pseudo-second-order kinetic models were used to describe the kinetic data. The rate kinetics of BSA adsorption onto Al2O3 and ZrO2 at all pH and temperatures were best fitted with the pseudo-first-order kinetic model. The electrostatic interactions of BSA with the metal oxide surface were found to be higher at pH 5 for Al2O3 and pH 4 for ZrO2.


2018 ◽  
Vol 2018 ◽  
pp. 1-10 ◽  
Author(s):  
Javier Paul Montalvo Andia ◽  
Lidia Yokoyama ◽  
Luiz Alberto Cesar Teixeira

In the present work, the equilibrium, thermodynamics, and kinetics of boron removal from aqueous solutions by the adsorption on commercial magnesium oxide powder were studied in a batch reactor. The adsorption efficiency of boron removal increases with temperature from 25°C to 50°C. The experimental results were fitted to the Langmuir, Freundlich, and Dubinin–Radushkevich (DR) adsorption isotherm models. The Freundlich model provided the best fitting, and the maximum monolayer adsorption capacity of MgO was 36.11 mg·g−1. In addition, experimental kinetic data interpretations were attempted for the pseudo-first-order kinetic model and pseudo-second-order kinetic model. The results show that the pseudo-second-order kinetic model provides the best fit. Such result suggests that the adsorption process seems to occur in two stages due to the two straight slopes obtained through the application of the pseudo-first-order kinetic model, which is confirmed by the adjustment of the results to the pseudo-second-order model. The calculated activation energy (Ea) was 45.5 kJ·mol−1, and the values calculated for ∆G°, ∆H°, and ∆S° were −4.16 kJ·mol−1, 21.7 kJ·mol−1, and 87.3 kJ·mol−1, respectively. These values confirm the spontaneous and endothermic nature of the adsorption process and indicated that the disorder increased at the solid-liquid interface. The results indicate that the controlling step of boron adsorption process on MgO is of a physical nature.


2021 ◽  
Vol 1195 (1) ◽  
pp. 012048
Author(s):  
A Amador ◽  
R V Canaria ◽  
N Santos ◽  
M Gomez

Abstract Hexavalent chromium is a highly toxic environmental inorganic pollutant. To eliminate toxic Cr (VI) ions in natural waters, polymer inclusion membranes (PIMs) have been developed for highly selective metal ion transport applications. The investigation of the effectiveness of Cr (VI) recovery in aqueous solutions using PIMs with varying amounts of plasticizer was studied. The pseudo-first order (PFO) kinetic model was modified to describe the amount of Cr (VI) ions that have accumulated onto the PIMs at a specific time and to evaluate the performance of the PIMs. A quantitative analysis of the modified PFO a model based on their non-linear representation and using the coefficient of determination indicates that the adsorptive properties of the PIMs are best described by the modified non-linear pseudo-first-order kinetic model (R2 > 0.9748), suggesting that the sorption process is physisorption. To show the applicability of the modified model to other transport studies, modified PFO was fitted into the experimental data that studies the transport of Zn (II) ions onto PIM (R2 > 0.95).


2018 ◽  
Vol 69 (5) ◽  
pp. 1233-1239
Author(s):  
Raluca Madalina Senin ◽  
Ion Ion ◽  
Ovidiu Oprea ◽  
Rusandica Stoica ◽  
Rodica Ganea ◽  
...  

In this study, non-irradiated and weathered multiwalled carbon nanotubes (MWCNTs) obtained through irradiation, were studied as adsorbents for BPA, both nanomaterials being characterized before and after the adsorption process. The objectives of our investigation were to compare the characteristics of non-irradiated and irradiated MWCNTs, to evaluate the adsorption capacity of BPA by pristine and irradiated MWCNTs and to determine the variation of the kinetic, sorption and thermodynamic parameters during sorption process using both sorbents.


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