scholarly journals COMPARISON OF OXIDIZED CARBON NANOTUBES EFFICIENCIES FOR BENZENE AND TOLUENE REMOVAL FROM AQUEOUS SOLUTION

2018 ◽  
Vol 55 (4C) ◽  
pp. 311
Author(s):  
Le Huu Quynh Anh

Carbon nanotubes (CNTs) have been widely used as adsorbent in environmental treatment, especially for pollutants and volatile organic compounds (VOCs). The purpose of this work is to develop materials based on functionalized multiwalled carbon nanotubes (MWCNTs) for Benzene and Toluene removal. This will exploit adsorption propertiesof modified MWCNTS for Benzene and Toluene. In the first study, adsorption capacity of pristine MWCNTs to Benzene and Toluene in aqueous solution was investigated through isotherm study. The qe values of CNTs for Benzene and Toluene were 45,5 mg.g-1 and 56.3 mg.g-1, respectively and a contact time of 120 min. The modification of three oxidized MWCNTs were performed with acid solution (HNO3/H2SO4), hydrogen peroxide (H2O2) and sodium hypochlorite (NaOCl). The modified MWCNTs materials (CNT-COOH,CNT-NaOCl,CNT-H2O2) were characterized by Fouriertransform infrared spectroscopy (FT-IR). The effects of functional groups on the MWCNTs on the adsorption capacity of Benzene, Toluene in aqueous solution were studied and compared to pristine MWCNTs. The results demonstrated that the efficiency of adsorption was significantly enhanced with oxidized CNTs, and following the order CNTs-NaOCl > CNTs-H2O2> CNTs-H2SO4> pristine CNTs.

2019 ◽  
Vol 889 ◽  
pp. 216-222 ◽  
Author(s):  
Huu Quynh Anh Le ◽  
Dinh Tuan Phan

The volatile organic compounds (VOCs) contribute to serious air pollution problems in Viet Nam. Many studies have investigated in air quality monitoring and treatment, in order to determine the average concentrations of Benzene, Toluene, Ethylbenzene and Xylene (BTEX). Carbon nanotubes (CNTs) have been widely used as adsorbent in environmental treatment, especially for VOCs. This paper aims to determine the adsorption capacity of multiwalled carbon nanotubes for removal of BTEX from air samples. In preliminary study, the effects of various parameters during adsorption experiments were monitored such as flow rate, temperature and BTEX concentrations in air samples. The equipment for BTEX removal was developed by our research team consisting of filter columns, air sample bags, adsorption cartridge. The air samples containing BTEX were conducted directly through a cartridge packed with adsorbent. The adsorption experiments were carried out under various operating conditions such as temperature (30 - 40°C), gas concentration (0,57 - 4,77 mg/L) and the gas flow rate (10 - 90 mL/min). In addition, isotherm studies of CNTs for BTEX removal were achieved by using Langmuir and Freundlich models. The results showed that the experimental parameters were optimized at a flow rate of 30 mL/min and an ambient temperature at 30°C. The adsorption capacity of CNTs increased proportionally with BTEX concentrations. The specific affinity of CNTs for BTEX from air samples was in order of X > E > T > B. The experimental isotherm data were well-fit with the Langmuir model for Benzene and Xylene removal, and the Freundlich model for Toluene and Ethylbenzene adsorption. The CNTs presented highly potential application for BTEX adsorption thanks to their microporous structure and high surface area.


Toxics ◽  
2021 ◽  
Vol 9 (6) ◽  
pp. 139
Author(s):  
Xiaoyu Sheng ◽  
Junkai Wang ◽  
Wei Zhang ◽  
Qiting Zuo

Microplastics are ubiquitous in aquatic environments and interact with other kinds of pollutants, which affects the migration, transformation, and fate of those other pollutants. In this study, we employ carbamazepine (CBZ) as the contaminant to study the influence of polyethylene (PE) microplastics on the adsorption of CBZ pollutants by multiwalled carbon nanotubes (MCNTs) in aqueous solution. The adsorption capacity of CBZ by MCNTs in the presence of PE microplastics was obviously lower than that by MCNTs alone. The influencing factors, including the dose of microplastics, pH, and CBZ solution concentration, on the adsorption of CBZ by MCNTs and MCNTs−PE were thoroughly investigated. The adsorption rate of CBZ by MCNTs decreased from 97.4% to 90.6% as the PE microplastics dose increased from 2 g/L to 20 g/L. This decrease occurred because the MCNTs were coated on the surface of the PE microplastics, which further decreased the effective adsorption area of the MCNTs. This research provides a framework for revealing the effect of microplastics on the adsorption of pollutants by carbon materials in aqueous environments.


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.


2018 ◽  
Vol 2018 ◽  
pp. 1-13 ◽  
Author(s):  
Kodanda Rama Rao Chebattina ◽  
V. Srinivas ◽  
N. Mohan Rao

The aim of the paper is to investigate the effect of size of multiwalled carbon nanotubes (MWCNTs) as additives for dispersion in gear oil to improve the tribological properties. Since long pristine MWCNTs tend to form clusters compromising dispersion stability, they are mildly processed in a ball mill to shorten the length and stabilized with a surfactant before dispersing in lubricant. Investigations are made to assess the effect of ball milling on the size and structure of MWCNTs using electron microscopy and Raman spectroscopy. The long and shortened MWCNTs are dispersed in EP 140 gear oil in 0.5% weight. The stability of the dispersed multiwalled carbon nanotubes is evaluated using light scattering techniques. The antiwear, antifriction, and extreme pressure properties of test oils are evaluated on a four-ball wear tester. It is found that ball milling of MWCNTs has a strong effect on the stability and tribological properties of the lubricant. From Raman spectroscopy, it is found that ball milling time of up to 10 hours did not produce any defects on the surface of MWCNTs. The stability of the lubricant and the antiwear, antifriction, and extreme pressure properties have improved significantly with dispersion shortened MWCNTs. Ball milling for longer periods produces defects on the surface of MWCNTs reducing their advantage as oil additives.


2017 ◽  
Vol 147 (6) ◽  
pp. 1598-1607 ◽  
Author(s):  
Tian Shi ◽  
Jun Peng ◽  
Jianqiu Chen ◽  
Cheng Sun ◽  
Hua He

2019 ◽  
Vol 77 (9) ◽  
pp. 4631-4653
Author(s):  
Islam Mohamed Abdelmonem ◽  
Essam Metwally ◽  
Tharwat Essa Siyam ◽  
Farid Abou El-Nour ◽  
Abdel-Rahman Mahmoud Mousa

Nanomaterials ◽  
2019 ◽  
Vol 9 (6) ◽  
pp. 890 ◽  
Author(s):  
Gabriela Kamińska ◽  
Mariusz Dudziak ◽  
Edyta Kudlek ◽  
Jolanta Bohdziewicz

Grainy Hal-CNT composites were prepared from powder halloysite nanoclay (Hal) and carbon nanotubes (CNTs). The effect of the amount and type of CNTs, as well as calcination temperature on morphology and properties of Hal-CNT composites and their adsorption capacity of anthracene (ANT), were studied. The surface topography of granules was heterogenous, with cracks and channels created during granulation of powder clay and CNTs. In FTIR, spectra were exhibited only in the bands arising from halloysite, due to its dominance in the granules. The increase in the heating temperature to 550 °C resulted in mesoporosity/macroporosity of the granules, the lowest specific surface area (SSA) and poorest adsorption potential. Overall, SSA of all Hal-CNT composites were higher than raw Hal, and by itself, heated halloysite. The larger amount of CNTs enhanced adsorption kinetics due to the more external adsorption sites. The equilibrium was established with the contact time of approximately 30 min for the sample Hal-SWCNT 85:15, while the samples with loading 96:4, it was 60–90 min. Adsorption isotherms for ANT showed L1 type, which is representative for the sorbents with limited adsorption capacity. The Langmuir model described the adsorption process, suggesting a monolayer covering. The sample Hal-SWCNT 85:15 exhibited the highest adsorption capacity of ANT, due to its highest SSA and microporous character.


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