Modification and characterization of adsorbent materials and CNTs for oil spill cleanup from water (original) (raw)
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Functionalized multi-walled carbon nanotubes for oil spill cleanup from water
Clean Technologies and Environmental Policy
The growing global economy resulted in an incessant increase in transportation and exploitation of oil. Hence, the oil spillage has been considered a serious threat to aquatic and terrestrial ecosystems. Therefore, water purification has been considered a major challenge around the world. There are numerous classical methods available for oil removal from water, but owing to multiple defects and disadvantages, research efforts have focused to find such adsorbents which can improve oil adsorption capability. Traditional adsorbent material typically applied in oil removal includes activated carbon, organoclays, wool, zeolites, etc. These materials suffer from several drawbacks such as low absorption capacity, non-selective absorption, and complicated reusability, whereas nano-adsorbents offer multiple advantages such as having multiple sorption sites, large surface area, short intra-particle diffusion distance, tuneable pore size, and ease of low-temperature modification. Multi-walled...
REVIEW ON THE EFFECTIVENESS OF ADSORBENT MATERIALS IN OIL SPILLS CLEAN UP
During the last decade of the 20 th Century, oil spill pollution has become an essential area of concern on account of its serious environmental impacts and to such an extent of the pollution that it poses a universal threat, therefore, surface water spill or subsurface leakage of petroleum products has been of concern to many industries and governments and NGOs. Exploration, production and transportation of petroleum products, unprofessional discarding of petroleum wastes and stranded oil spills from pipelines, oil wells, underground storage tanks, are the foremost causes of surface and groundwater contamination. This review aims at to highlight the importance of the oil removal from contaminated sites by adsorption method and to present several adsorbents, such as natural organic sorbents, inorganic sorbents and synthetic sorbents, which are applied to treat the oil-contaminated water, their effectiveness as well as constraints and to set one's sight on the recent development of different adsorbents such as Nano carbon tube (CNT's) adsorbents, hence a lot of attention is given to this new type of adsorbent due to their exceptionally high adsorption capacity for oil-water separation and to their high hydrophobicity properties.. In this review discussion is presented on several different areas such as: (i) adsorption capacity; (ii) kinetic modeling and perspectives of the use of each adsorbent, Investigation for series of adsorbent with its characteristics.
Environmental Science: Processes & Impacts, 2014
In this study, multi-walled carbon nanotubes (MWNTs) were employed to remove benzene, toluene, ethylbenzene, and xylenes (BTEX) from low and high salinity water pre-equilibrated with crude oil. The treatment endpoint of crude oil-contaminated water is often controlled by BTEX compounds owing to their higher aqueous solubility and human-health toxicity compared to other hydrocarbons. The MWNT sorbent was extensively characterized and the depletion of the organic sorbate from the produced water was monitored by gas chromatography-mass spectrometry (GC-MS) and total organic carbon (TOC) analyses. The equilibrium sorptive removal of BTEX followed the order: ethylbenzene/o-xylene > m-xylene > toluene > benzene in the presence of other competing organics in produced water. Sorption mechanisms were explored through the application of a variety of kinetics and equilibrium models.
Functionalized carbon nanotubes for hydrocarbon removal from water
This study aims to develop advanced sorbents for the removal of hydrocarbons from surface waters. The mi-croemulsion method was implemented to modify the surface structure of multiwalled carbon nanotube (MWCNTs) by attaching a hydrocarbon tail on its surface. The structural and surface chemistry properties of the prepared adsorbents were studied by different surface analytical techniques such as Brunauer-Emmett-Teller (BET) method, X-Ray diffraction (XRD), Raman-spectroscopy, Fourier-transform infrared spectroscopy (FTIR) and thermogravimetric analysis (TG). Scanning electron microscopy (SEM) was used to study the microstructure and morphology of the samples. Different model hydrocarbon compounds were used for this investigation. The hydrocarbon removal efficiencies of the unmodified and functionalized sorbents were studied by using total organic carbon analyzer (TOC), gas chromatography (GC), and UV-vis spectroscopy (UV-vis) techniques. Surface chemistry studies over raw and microemulsified multiwalled carbon nanotubes (μEMWCNT) revealed that that microemulsion functionalization resulted in changes in the CH bending vibrations of the functionalized MWCNTs as compared to the raw MWCNTs, demonstrating the existence of intermolecular CH-π interactions between the carbon nanotubes and lauric/miristic acid. The experimental results revealed that microemulsion technique as a type of surface functionalization solved one main issue regarding MWCNTs modification as it proved to have a beneficial effect on MWCNTs' hydrophobic properties without the need for additional func-tionalization and substitution steps to attach hydrocarbon side chains. Using kerosene as a hydrocarbon model mixture, compared with raw MWCNTs, the maximum adsorption capacity of μMWCNTs increased by 63.5 %. Additionally, the outcomes indicated that the n-octane adsorption capacities over μEMWCNTs reached 6.07 g/g. The kinetic studies demonstrated that the adsorption process over μMWCNTs could be well described by the pseudo-second-order model with a high correlation coefficient.
Chemosphere, 2016
Oil removal from water is a highly important area due to the large production rate of emulsified oil in water, which is considered one of the major pollutants, having a negative effect on human health, environment and wildlife. In this study, we have reported the application of high quality carbon nanotube bundles produced by an injected vertical chemical vapor deposition (IV-CVD) reactor for oil removal. High quality, bundles, super hydrophobic, and high aspect ratio carbon nanotubes were produced. The average diameters of the produced CNTs ranged from 20 to 50 nm while their lengths ranged from 300 to 500 μm. Two types of CNTs namely, P-CNTs and C-CNTs, (Produced CNTs from the IV-CVD reactor and commercial CNTs) were used for oil removal from water. For the first time, thermogravimetric analysis (TGA) was conducted to measure maximum oil uptake using CNT and it was found that P-CNT can take oil up to 17 times their weight. The effect of adsorbent dosage, contact time, and agitatio...
Modified Jordanian zeolitic tuff in hydrocarbon removal from surface water
Journal of Environmental Management, 2019
This work aims to investigate the potential of Jordanian raw zeolitic tuff (RZT) as oil adsorbent for oil-contaminated water. As hydrophobic properties are the primary determinants of effective oil adsorbents, the hydrophobicity of RZT was enhanced by dealumination process; since the degree of hydrophobicity of zeolites is directly dependent on their aluminum content. The microemulsion modification of the dealuminated zeolitic tuff (TZT) was also applied to increase its hydrophobicity. The raw and modified tuffs were characterized in terms of the surface area and porosity (BET), mineral composition (XRD), microstructure and morphology using scanning electron microscopy (SEM) and Fourier-transform infrared spectroscopy (FTIR). In this work, a mixture of water and kerosene was used to examine the hydrophobic/organophilic character of raw and modified zeolitic tuff. Water/dodecane and water/octane mixtures were used to study the kinetics of the adsorption over zeolitic tuff. The results revealed that the sorption capacity using kerosene as a mixed model (water-oil) was enhanced by three-and four-fold for TZT and micro-emulsified zeolitic (MeTZT) tuff respectively. The adsorption capacity of modified zeolitic was compared with that of activated carbon adsorbents.
Carbon nanotubes - the promising adsorbent in wastewater treatment
Journal of Physics: Conference Series, 2007
Carbon materials are a class of significant and widely used engineering adsorbent. As a new member of the carbon family, carbon nanotubes have exhibited great potentials in applications as composite reinforcements, field emitters for flat panel display, sensors, energy storage and energy conversion devices, and catalysts support phases, because of their extraordinary mechanical, electrical, thermal and structural properties. In particular, the large specific surface areas, as well as the high chemical and thermal stabilities, make carbon nanotubes an attractive adsorbent in wastewater treatment. The adsorption properties of the carbon nanotubes to a series of toxic agents, such as lead, cadmium and 1,2-dichlorobenzene have been studied and the results show that carbon nanotubes are excellent and effective adsorbent for eliminating these harmful media in water. The effects of the morphologies and the surface status on the carbon nanotube adsorption capacities are also discussed.
ACS Applied Materials & Interfaces, 2019
The development of carbon-based membrane adsorbent materials for water treatment has become a hot topic in recent years. Among them, carbon nanotubes (CNTs) are promising materials because of its large surface area, high aspect ratio, great chemical reactivity and low cost. In this work, free-standing CNT adsorbents are fabricated from chemically cross-linked single-walled carbon nanotubes (SWCNTs). We have demonstrated that by controlling the degree of cross-linking, the nanostructure, porous features and specific surface area (SSA) of the resulting materials can be tuned, in turn allowing the control of the adsorption capacities and the improvement of the adsorption performance. The cross-linked CNT adsorbents exhibit a notably selective sorption ability and good recyclability for removal of organics and oils from contaminated water.
Novel carbon-nanotube-based organogels as candidates for oil recovery
Polymer International, 2013
A simple method for synthesis of novel organogels based on multiwalled carbon nanotubes (MWCNTs) is reported. Three classes of organogels were synthesized by crosslinking polymerization of dodecyl methacrylate with various weight percentages of 1,4-butanediol dimethacrylate, vinyl-group-modified MWCNTs or pristine MWCNTs in the presence of 2,2-azoisobutyronitrile as initiator. In this reaction, the carbon nanotubes (CNTs) served simultaneously as an adsorbent, a comonomer and a crosslinking agent. The oil-absorbent containing CNTs showed much higher swelling capacity in oil and organic solvents compared with that without CNTs. Therefore, CNT-based organogels can be introduced as a promising candidate for environmental protection and oil recovery.
Application of Carbon Nanotubes and Graphene-Based Nanoadsorbents in Water Treatment
BioNanoScience, 2023
In this review, CNT-based adsorbents have been extensively used in the adsorption of inorganic and organic pollutants from water and wastewater. The use of nanoadsorbents is an attractive and promising option in the water treatment process due to its high specific surface area and unique physical and chemical properties. They demonstrate excellent adsorption properties due to their high specific surface area, exceptional porosities, hollow and layered structures, numerous internal and external adsorption sites, π-conjugative structure, and ease of chemical activation and functionalization. A wide range of mechanical, physical, and chemical approaches have been used for the modification or functionalization of CNTs to enhance their adsorptive properties in general or to make them selective toward certain classes of pollutants. Depending on the adsorption conditions and the functionalization involved, CNT-based adsorbents can interact with inorganic contaminants through different mechanisms such as surface complexation, electrostatic interaction, ion exchange, physical adsorption, and precipitation. In the case of organic pollutants, besides physical adsorption, π-π and electrostatic interactions play a major role in adsorption. In some cases, chemical bonding between organics and carbon nanotubes has also been reported as a mechanism of interaction. Properties, functionalization, and mechanisms are involved in CNT-based adsorption of pollutants from aqueous media. An insightful overview of the critical parameters that should be considered while using CNT-based adsorbents for water purification is also provided. In the end, some challenges associated with CNT-based adsorbents are presented, along with the potential solutions.