Adsorption of Ni(II) on oxidized multi-walled carbon nanotubes: Effect of contact time, pH, foreign ions and PAA

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.

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

Chemical Industry and Chemical Engineering Quarterly ◽

10.2298/ciceq111104025g ◽

2012 ◽

Vol 18 (4-1) ◽

pp. 509-523 ◽

Cited By ~ 10

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.

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

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.295-298.1227 ◽

2013 ◽

Vol 295-298 ◽

pp. 1227-1230 ◽

Cited By ~ 1

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.

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

Global NEST Journal ◽

10.30955/gnj.001984 ◽

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>

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

Radiochimica Acta ◽

10.1515/ract-2017-2922 ◽

2018 ◽

Vol 107 (1) ◽

pp. 67-82 ◽

Cited By ~ 1

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.

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

Fullerenes Nanotubes and Carbon Nanostructures ◽

10.1080/1536383x.2019.1570923 ◽

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

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Error Analysis of Adsorption Isotherm Models for Sulfamethazine onto Multi Walled Carbon Nanotubes

Journal of Pharmaceutical Research International ◽

10.9734/jpri/2018/v25i630121 ◽

2019 ◽

pp. 1-10

Author(s):

Davoud Balarak ◽

Amir Ali Salari

Keyword(s):

Electron Microscopy ◽

Carbon Nanotubes ◽

Error Analysis ◽

Contact Time ◽

Isotherm Models ◽

Transmission Electron ◽

Adsorption Isotherm Models ◽

Equilibrium Data ◽

Multi Walled Carbon Nanotubes ◽

Walled Carbon Nanotubes

In the present study, Multi walled carbon nanotubes (MWCNTs) was used for the adsorption of Sulfamethazine (SMZ) antibiotics. The adsorbent was characterized by scanning electron microscopy, surface area (BET) and transmission electron microscopy. Batch experiments were carried out by varying the parameters like contact time, adsorbent dosage and initial Sulfamethazine concentration at fixed pH and temperature. The equilibrium data were tested with Langmuir, Freundlich, Tempkin, Dubinin–Radushkevich (D–R), Redlich-Peterson (R-P), Sips, Toth and Khan isotherm models at five Error Analysis EABS, X2, ARE, RMSE and SD and it was found that the Langmuir and Toth isotherms best ﬁtted the adsorption of SMZ with highest value of R2 and lowest overall experimental error. Also according to the results, a maximum removal efficiency of 99.1% was obtained at pH of 7 and the contact time of 60 min; initial SMZ concentration 20 mg/L and adsorbent dose 0.8 g/L.

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