The influence of pH, contact time, ionic strength, temperature, and fullerene on the adsorption of Cu(II) onto magnetic multi-walled carbon nanotubes

2019 ◽  
Vol 27 (4) ◽  
pp. 317-322
Author(s):  
Peng Liu ◽  
Yun Xue ◽  
Fuqiu Ma
Keyword(s):  
Carbon Nanotubes ◽  
Ionic Strength ◽  
Contact Time ◽  
Multi Walled Carbon Nanotubes ◽  
Walled Carbon Nanotubes ◽  
Influence Of Ph

Adsorption of perfluorooctane sulfonate on carbon nanotubes: influence of pH and competitive ions

2014 ◽  
Vol 69 (7) ◽  
pp. 1489-1495 ◽  
Author(s):  
Yue Bei ◽  
Shubo Deng ◽  
Ziwen Du ◽  
Bin Wang ◽  
Jun Huang ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Ionic Strength ◽  
Perfluorooctane Sulfonate ◽  
Suppressive Effect ◽  
Research Attention ◽  
Low Concentrations ◽  
Multi Walled Carbon Nanotubes ◽  
Enhanced Adsorption ◽  
Walled Carbon Nanotubes ◽  
Influence Of Ph

Perfluorooctane sulfonate (PFOS) is one of the persistent organic pollutants that has aroused global concern. Carbon nanotubes (CNTs) have drawn much research attention due to their unique properties. This study was aimed to investigate the adsorption behaviour of PFOS with relation to CNTs and clarify their interactions. Electrostatic repulsion suppressed the sorption of PFOS to multi-walled carbon nanotubes (MWCNTs), resulting in low sorption at high pH. With the increase of anion concentration, the removal of PFOS decreased by 20 to 30% because ionic strength changed the aggregation of the MWCNTs. Unlike inorganic anions, cationic metals including Cu(II) and Pb(II) had a significant impact on the sorption of PFOS onto the MWCNTs. At low concentrations of Cu(II) and Pb(II), PFOS removal decreased due to the suppressive effect of ionic strength, while the removal of PFOS increased rapidly with increasing metal concentrations, especially for functionalized MWCNTs. The enhanced adsorption of PFOS at high Cu(II) and Pb(II) concentrations was attributed to the adsorbed cationic metals which might further adsorb PFOS.

Adsorption of Th(IV) on the modified multi-walled carbon nanotubes using central composite design

2019 ◽  
Vol 107 (5) ◽  
pp. 377-386 ◽  
Author(s):  
Cansu Endes Yılmaz ◽  
Mahmoud A.A. Aslani ◽  
Ceren Kütahyalı Aslani
Keyword(s):  
Carbon Nanotubes ◽  
Central Composite Design ◽  
Contact Time ◽  
Adsorption Process ◽  
Freundlich Isotherm ◽  
Thorium Concentration ◽  
Multi Walled Carbon Nanotubes ◽  
Pseudo Second Order ◽  
Walled Carbon Nanotubes ◽  
Central Composite

Abstract Adsorption of thorium onto nitric acid modified multi-walled carbon nanotubes was investigated by central composite design as a function of contact time, pH, initial thorium concentration and temperature. The results showed that optimum uptake capacity was 65.75±2.23 mg·g−1 with respect to pH=4, initial thorium concentration of 100 mg·L−1, 25 °C and 15 min contact time. Thermodynamic parameters [standard enthalpy (ΔH0), entropy (ΔS0), and free energy (ΔG0)] were calculated, and the results indicated that adsorption was endothermic. Langmuir, Freundlich and Dubinin-Radushkevich isotherms have been investigated in order to characterize the adsorption process in the range of 25–100 mg·L−1 initial thorium concentration. The Freundlich isotherm is the best suited as a model because it has the highest correlation coefficient (R2=0.9485). The pseudo-second order kinetics well defined the adsorption process.

scholarly journals Evaluation of multi-walled carbon nanotubes performance in adsorption and desorption of hexavalent chromium

2012 ◽  
Vol 18 (4-1) ◽  
pp. 509-523 ◽  
Author(s):  
Mina Gholipour ◽  
Hassan Hashemipour
Keyword(s):  
Carbon Nanotubes ◽  
Hexavalent Chromium ◽  
Contact Time ◽  
Second Order ◽  
Desorption Process ◽  
Kinetics Models ◽  
Initial Ph ◽  
Multi Walled Carbon Nanotubes ◽  
Pseudo Second Order ◽  
Walled Carbon Nanotubes

In this study, the removal of hexavalent chromium from aqueous solutions using multi-walled carbon nanotubes (MWCNTs) has been investigated as a function of adsorbent dosage, initial Cr(VI) concentration, initial pH, contact time and temperature. Low pH, low initial concentrations of Cr(VI), increasing contact time and high temperature were found as optimal conditions. A comparison of kinetics models applied to the adsorption of Cr(VI) ions on the MWCNTs was evaluated for the pseudo first-order, the pseudo second-order, and Elovich kinetics models, respectively. Pseudo second-order kinetics model was found to correlate the experimental data well. Equilibrium isotherms were measured experimentally and results show that data were fitted well by the BET model. Thermodynamic parameters were estimated and results suggest that the adsorption process is spontaneous, physical and endothermic. The reversibility of Cr(VI) adsorption onto MWCNTs by desorption process and the effect of operating factors such as regeneration solution characteristics, contact time and temperature on this process was investigated. Results show that MWCNTs are effective Cr(VI) adsorbents and can be reused through many cycles of regeneration without any high decreasing in their performance.

Multi Wall Carbon Nanotube Surface Modification and Adsorption Performance of Cu2+

2013 ◽  
Vol 295-298 ◽  
pp. 1227-1230 ◽  
Author(s):  
Reyila Abuduwayiti ◽  
Cheng Tun Qu ◽  
Tao Yu ◽  
Bo Yang
Keyword(s):  
Carbon Nanotubes ◽  
Adsorption Capacity ◽  
Contact Time ◽  
Effect Factors ◽  
Initial Concentration ◽  
Mixed Acid ◽  
Adsorption Performance ◽  
Capacity Change ◽  
Multi Walled Carbon Nanotubes ◽  
Walled Carbon Nanotubes

Mixed acid processed Multi-walled carbon nanotubes （MWCNTs）were used as adsorbent to adsorb Cu2+ in artificial wastewater in this . In this study, the effect factors of Cu2+ adsorption capacity, such as initial concentration of Cu2+, absorbent contact time and dosage, etc were investigated respectively in the solution at neutral pH. The results show that population of -OH is increased on surface of mixed acid processed MWCNTs; and at condition of 30 °C, pH 6，as the increase in concentration and contact time, there is an increase in adsorption capacity of two adsorbents(processed and unprocessed)，and the Cu2+ adsorption rate increased with the increase in adsorbent dosage. In addition, the considered adsorption capacity change was obtained when processed MWCNTs was used.

Effects of ionic strength and temperature on the aggregation and deposition of multi-walled carbon nanotubes

2017 ◽  
Vol 51 ◽  
pp. 248-255 ◽  
Author(s):  
Lixin Wang ◽  
Xuezhi Yang ◽  
Qi Wang ◽  
Yuxuan Zeng ◽  
Lei Ding ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Ionic Strength ◽  
Multi Walled Carbon Nanotubes ◽  
Walled Carbon Nanotubes

scholarly journals Response surface methodology, modeling to improve mercury removal from aqueous solutions using L-Cysteine functionalized Multi-walled Carbon Nanotubes

2019 ◽  
Vol 21 (1) ◽  
pp. 64-69
Keyword(s):  
Carbon Nanotubes ◽  
Response Surface Methodology ◽  
Aqueous Solutions ◽  
Response Surface ◽  
Removal Efficiency ◽  
Mercury Concentration ◽  
Contact Time ◽  
Mercury Removal ◽  
Multi Walled Carbon Nanotubes ◽  
Walled Carbon Nanotubes

<p>The aim of this study was to evaluate the mercury removal from aqueous solutions by using L-Cysteine functionalized Multi-walled Carbon Nanotubes. The effect of pH, adsorbent dose, contact time and mercury concentration in removal efficiency was evaluated. Multi -walled carbon nanotubes were functionalized with L-cysteine. The Response Surface Methodology (RSM) was used to find the optimum process parameters. The results showed that an increase in contact time, pH and adsorbent dosage resulted in an increase of the adsorption rate. However, removal efficiency decreases by increasing mercury concentration. The highest and lowest removal efficiencies of mercury were 89% and 17%, respectively. The maximum adsorption rate was occurring at 120 min. It is concluded that L-Cysteine functionalized multi-walled carbon nanotubes is an effective adsorbent for removal from aqueous solutions.</p>

Development and application of carbon nanotubes reinforced hydroxyapatite composite in separation of Co(II) and Eu(III) ions from aqueous solutions

2018 ◽  
Vol 107 (1) ◽  
pp. 67-82 ◽  
Author(s):  
Reda R. Sheha ◽  
Saber I. Moussa ◽  
Mohamed A. Attia ◽  
Sedeeq A. Sadeek ◽  
Hanan H. Someda
Keyword(s):  
Carbon Nanotubes ◽  
Aqueous Solutions ◽  
Sorption Capacity ◽  
Contact Time ◽  
Packed Column ◽  
Maximum Sorption Capacity ◽  
Hydroxyapatite Composite ◽  
Maximum Sorption ◽  
Multi Walled Carbon Nanotubes ◽  
Walled Carbon Nanotubes

Abstract Multi-walled carbon nanotubes/strontium hydroxyapatite (MWCNT/SH) composite was synthesized, where CNTs were applied to improve the properties of HAP and increase the reinforcement of the composite. The composite CNTs/Sr-HAP and its precursor Sr-HAP were successfully applied in removal of Co(II) and Eu(III) ions from aqueous solutions. Sorption of Co(II) and Eu(III) onto the synthesized sorbents was investigated as a function of contact time and pH. The synthesized sorbents highly removed the studied radionuclides from their aqueous solutions with necessary time of 6 h to reach equilibrium. The maximum sorption capacity was 33.31 and 48.93 mg g−1 for Co(II) sorption onto Sr-HAP and CNTs/Sr-HAP composite at pH 4.5, while it was 115.74 and 127.11 mg g−1 for sorption of Eu(III) onto Sr-HAP and CNTs/Sr-HAP composite at pH 2.5, respectively. Desorption of Co(II) and Eu(III) from loaded samples was studied using various eluents and maximum recovery was obtained using FeCl3 and HCl solutions. Co(II) was completely separated from Eu(III) by a ratio of 85.1 % using Cd(NO3)2 as an eluent in CNTs/Sr-HAP composite packed column.

Adsorption of sulfamethazine by multi-walled carbon nanotubes: effects of aqueous solution chemistry

RSC Advances ◽  
2015 ◽  
Vol 5 (32) ◽  
pp. 25541-25549 ◽  
Author(s):  
Quanquan Yang ◽  
Guangcai Chen ◽  
Jianfeng Zhang ◽  
Helian Li
Keyword(s):  
Carbon Nanotubes ◽  
Aqueous Solution ◽  
Ionic Strength ◽  
Electrostatic Interactions ◽  
Solution Chemistry ◽  
Adsorption Mechanisms ◽  
Multi Walled Carbon Nanotubes ◽  
Walled Carbon Nanotubes

The adsorption of SMZ by MWCNTs was studied under varied pH, ionic strength, cations and anions in solution. The results indicated that hydrophobic and electrostatic interactions were the main adsorption mechanisms, and π–π interaction also played an important role.

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