Adsorption kinetics and thermodynamics of hydrophobic natural organic matter (NOM) removal from aqueous solution by multi-wall carbon nanotubes

2013 ◽  
Vol 13 (2) ◽  
pp. 273-285 ◽  
Author(s):  
A. Naghizadeh ◽  
S. Nasseri ◽  
A. M. Rashidi ◽  
R. Rezaei Kalantary ◽  
R. Nabizadeh ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Aqueous Solution ◽  
Organic Matter ◽  
Natural Organic Matter ◽  
Adsorption Kinetics ◽  
Chemical Vapor ◽  
Freundlich Isotherm ◽  
Order Kinetic ◽  
Operational Conditions ◽  
Multi Wall Carbon Nanotubes

The objective of this research was to study the efficiency of Multi-Walled Carbon Nanotubes (MWCNTs) for the adsorption of hydrophobic natural organic matter (NOM) from aqueous solution under different operational conditions of contact time, pH, initial concentration of NOM and temperature. MWCNTs were synthesized via chemical vapor deposition (CVD) with average diameter of 10–50 nm. The results illustrated that both as-prepared and functionalized MWCNTs showed high adsorption capacity for the NOM studied. Functionalization of MWCNT affected the surface area and introduced oxygen-containing functional groups to the surface of MWCNT which depressed the adsorption of NOM onto MWCNTs-COOH. The obtained data were studied using Freundlich, Langmuir and BET isotherms; NOM adsorption data had the best conformity to the Freundlich isotherm. Kinetic studies were performed and the adsorption kinetics successfully followed the pseudo-second-order kinetic model. Thermodynamic parameters such as free energy change (ΔG°), enthalpy change (ΔH°) and entropy change (ΔS°) were determined and evaluation of them showed that the adsorption process for NOM is general spontaneous, endothermic and thermodynamically favorable.

Amino-Functionalized Multi-Walled Carbon Nanotubes as Novel Adsorbents for Selective Adsorption of Anionic Dyes in Aqueous Solution

NANO ◽  
2015 ◽  
Vol 10 (05) ◽  
pp. 1550065 ◽  
Author(s):  
Hui Huang ◽  
Jingang Yu ◽  
Wei Liu ◽  
Xinyu Jiang
Keyword(s):  
Carbon Nanotubes ◽  
Aqueous Solution ◽  
Adsorption Kinetics ◽  
Organic Dyes ◽  
Selective Adsorption ◽  
Order Kinetic ◽  
Equilibrium Isotherms ◽  
Anionic Dyes ◽  
Multi Walled Carbon Nanotubes ◽  
Walled Carbon Nanotubes

In this study, amino-functionalized multi-walled carbon nanotubes ( MWCNTs - NH 2) were successfully synthesized via an improved method and used for removal of organic dyes in aqueous solution. The synthesized MWCNTs - NH 2 were characterized by Fourier transform infrared (FTIR) spectroscopy, thermogravimetric analysis (TGA), scanning electron microscope (SEM), etc. The adsorption capacity and selectivity of MWCNTs - NH 2 for organic dyes was evaluated using rhodamine B ( RhB ), malachite green (MG), methyl orange (MO) and congo red (CR) as models. The selective adsorption toward anionic dyes was found for the MWCNTs - NH 2, and MO was selected as a typical anionic dye to deeply investigate the adsorption kinetics, equilibrium isotherms and thermodynamic parameters of the adsorption process. The adsorption kinetics and equilibrium isotherms data fitted well with the pseudo-second-order kinetic equation and Langmuir isotherm model. The thermodynamics study revealed that the adsorption of MO onto MWCNTs - NH 2 was spontaneous, exothermic and physisorptive in nature. The results indicated that MWCNTs - NH 2 are promising nanomaterials for removal of anionic dyes from industrial wastewater.

Studies on Adsorption of Tyrosine on Multi-Wall Carbon Nanotubes

2011 ◽  
Vol 179-180 ◽  
pp. 1396-1401
Author(s):  
Zhi Biao Feng ◽  
Ren Jiao Han ◽  
Jing Long Wang
Keyword(s):  
Carbon Nanotubes ◽  
Aqueous Solution ◽  
Adsorption Process ◽  
Freundlich Isotherm ◽  
Sorption Process ◽  
Multi Wall Carbon Nanotubes ◽  
Different Temperatures ◽  
Pseudo Second Order ◽  
Rate Controlling Step ◽  
Mechanism Of Sorption

The thermodynamics and kinetics properties and mechanism of sorption process were studied for adsorpting tyrosine in aqueous solution with multi-wall carbon nanotubes (MWCNTs), and the adsorption isotherms at different temperatures were determined. The results showed that the adsorption of the tyrosine in aqueous solution obeys well with the Freundlich isotherm, The thermodynamic parameters indicated that the adsorption reaction was a spontaneous, exothermal and decreasing entropy process,and the adsorption process had an obvious physisorption characteristic.The pseudo-second-order equation provided the best correlation for the adsorption process, being in agreement with adsorption as the rate controlling step.

REMOVAL OF STRONTIUM (II) FROM AQUEOUS SOLUTION USING FUNCTIONALIZED CARBON NANOTUBES

2012 ◽  
Vol 11 (02) ◽  
pp. 1250019 ◽  
Author(s):  
RAJESH KUMAR ◽  
S. K. JAIN
Keyword(s):  
Carbon Nanotubes ◽  
Polluted Water ◽  
Order Kinetic ◽  
Environmental Application ◽  
Functionalized Carbon Nanotubes ◽  
Multi Wall Carbon Nanotubes ◽  
Adsorption Data ◽  
Order Kinetic Model ◽  
Pseudo Second Order ◽  
Ft Ir

This study was carried out to evaluate the environmental application of functionalized carbon nanotubes through the experimental removal of strontium (II) from water. The aim was to find the optimal condition for the removal of strontium from water under different conditions such as initial concentration of strontium, contact time and neutral pH. The functionalized multi wall carbon nanotubes (f-MWCNT) were characterized by FT-IR and scanning electron microscopy (SEM). The adsorption isotherms were correlated to Freundlich and Langmuir models and it was found that the adsorption data could be fitted better by Langmuir model than Freundlich one. The kinetic data shows that the adsorption describes well with the pseudo-second order kinetic model. Functionalized MWCNT can be used as good adsorbent for the removal of the strontium ions from polluted water according to results.

scholarly journals Adsorption and Equilibrium Studies on the Removal of Methyl Red from Aqueous Solution Using White Potato Peel Powder

2017 ◽  
Vol 72 ◽  
pp. 52-64 ◽  
Author(s):  
Conrad K. Enenebeaku ◽  
Nnaemeka J. Okorocha ◽  
Uchechi E. Enenebeaku ◽  
Ikechukwu C. Ukaga
Keyword(s):  
Aqueous Solution ◽  
Dye Adsorption ◽  
Freundlich Isotherm ◽  
Batch Adsorption ◽  
Maximum Adsorption Capacity ◽  
Order Kinetic ◽  
Methyl Red ◽  
Potato Peel ◽  
White Potato ◽  
Equilibrium Studies

The potential of white potato peel powder for the removal of methyl red (MR) dye from aqueous solution was investigated. The adsorbent 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 dye adsorption process. The optimum conditions for the adsorption of MR onto the adsorbent (WPPP) was found to be contact (80 mins), pH (2) and temperature (303K) for an initial MR dye concentration of 50mg/l and adsorbent dose of 1.0g. The experimental equilibrium adsorption data of the (MR) dye fitted best and well to the Freundlich isotherm model. The maximum adsorption capacity was found to be 30.48mg/g for the adsorption of MR. The kinetic data conforms to the pseudo – second order kinetic model.

Mathematical Modelling for Copper and Lead Adsorption on Coffee Grounds

2017 ◽  
Author(s):  
Jurgita Seniūnaitė ◽  
Rasa Vaiškūnaitė ◽  
Kristina Bazienė
Keyword(s):  
Heavy Metals ◽  
Mathematical Modelling ◽  
Adsorption Kinetics ◽  
Adsorption Process ◽  
Freundlich Isotherm ◽  
Sorption Process ◽  
Second Order ◽  
Order Kinetic ◽  
Coffee Grounds ◽  
Pseudo Second Order

Research studies on the adsorption kinetics are conducted in order to determine the absorption time of heavy metals on coffee grounds from liquid. The models of adsorption kinetics and adsorption diffusion are based on mathe-matical models (Cho et al. 2005). The adsorption kinetics can provide information on the mechanisms occurring be-tween adsorbates and adsorbents and give an understanding of the adsorption process. In the mathematical modelling of processes, Lagergren’s pseudo-first- and pseudo-second-order kinetics and the intra-particle diffusion models are usually applied. The mathematical modelling has shown that the kinetics of the adsorption process of heavy metals (copper (Cu) and lead (Pb)) is more appropriately described by the Lagergren’s pseudo-second-order kinetic model. The kinetic constants (k2Cu = 0.117; k2Pb = 0,037 min−1) and the sorption process speed (k2qeCu = 0.0058–0.4975; k2qePb = 0.021–0.1661 mg/g per min) were calculated. After completing the mathematical modelling it was calculated that the Langmuir isotherm better reflects the sorption processes of copper (Cu) (R2 = 0.950), whilst the Freundlich isotherm – the sorption processes of lead (Pb) (R2 = 0.925). The difference between the mathematically modelled and experimen-tally obtained sorption capacities for removal of heavy metals on coffee grounds from aqueous solutions is 0.059–0.164 mg/l for copper and 0.004–0.285 mg/l for lead. Residual concentrations of metals in a solution showed difference of 1.01 and 0.96 mg/l, respectively.

Natural Organic Matter Stabilizes Carbon Nanotubes in the Aqueous Phase

2007 ◽  
Vol 41 (1) ◽  
pp. 179-184 ◽  
Author(s):  
Hoon Hyung ◽  
John D. Fortner ◽  
Joseph B. Hughes ◽  
Jae-Hong Kim
Keyword(s):  
Carbon Nanotubes ◽  
Organic Matter ◽  
Natural Organic Matter ◽  
Aqueous Phase

Synthesis of Carbon Nanotubes on a Moving Substrate by Laser-Induced Chemical Vapor Deposition

2005 ◽  
Author(s):  
Kinghong Kwok ◽  
Wilson K. S. Chiu
Keyword(s):  
Carbon Nanotubes ◽  
Chemical Vapor Deposition ◽  
Deposition Rate ◽  
Vapor Deposition ◽  
Substrate Surface ◽  
Carbon Film ◽  
Chemical Vapor ◽  
Multi Wall Carbon Nanotubes ◽  
Vapor Deposition Technique ◽  
Synthesis Of Carbon Nanotubes

An open-air laser-induced chemical vapor deposition technique has been successfully used to rapidly deposit pillars of carbon nanotube forest on a moving glass substrate. A CO2 laser is used to heat a traversing fused quartz rod covered with metal particles inside a hydrocarbon environment. Pyrolysis of hydrocarbon precursor gas occurs and subsequently gives rise to the growth of multi-wall carbon nanotubes on the substrate surface. The experimental results indicate that nanotube growth kinetics and microstructure are strongly dependent on the experimental parameters such as laser power. The typical deposition rate of carbon nanotubes achieved in this study is over 50 μm/s, which is relatively high compared to existing synthesis techniques. At high power laser irradiation, carbon fibers and carbon film are formed as a result of excessive formation of amorphous carbon on the substrate. High-resolution transmission and scanning electron microscopy, and x-ray energy-dispersive spectrometry are used to investigate the deposition rate, microstructure and chemical composition of the catalytic surface and the deposited carbon nanotubes.

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