Adsorption of Polycyclic Aromatic Hydrocarbons from Heavy Naphthenic Oil Using Commercial Activated Carbons. 2. Column Adsorption Studies

Abstract

Continuous adsorption and desorption of polycyclic aromatic hydrocarbons (PAHs) from heavy naphthenic oils (HNOs) were performed using commercial activated carbon on fixed bed experiments. In part 1, HNO samples with high PAH content (ca. 8 wt %) were treated in batch adsorption experiments, showing decrease in PAH concentration to ca. 3%. In this study, successive column experiments were carried out to study the reduction in capacity along continuous cycles and optimal operational conditions. A column simulation model, using the particle parameters obtained in the previous study, was applied to predict breakthrough curves for adsorption and desorption runs. After several cycles of adsorption/desorption, using solvent or inert gas, only a slight decrease in PAH adsorption capacity was observed. Selectivities for PAH adsorption in relation to aromatics adsorption were also estimated from the adsorption breakthrough curves data. A conceptual continuous process was simulated using the proposed model and evaluated based on productivity in terms of volume of treated oil per mass of adsorbent per time, showing a maximum value at space velocity of ca. 4 h–1.

Degradation of Polycyclic Aromatic Hydrocarbons: A Review

“…In fixed-bed column experiments, activated carbon is uesd by Luna et al to carry out continuous adsorption and desorption experiments on PAHs in heavy naphthenic oil. It was found that the PAHs content in samples decreased from 8% to 3% (Luna et al, 2016).…”

“…This process is called adsorption, which includes absorption, adsorption and ion exchange (Khattri and Singh, 2009; Lamichhane et al, 2016; Yuan et al, 2011). Several kinds of adsorbent media such as activated carbon, biochar and modified clay minerals have been largely used to remove PAHs from aqueous solution and to immobilise PAHs in the contaminated soils (Luna et al, 2016).…”

Competitive adsorption of naphthalene and phenanthrene on walnut shell based activated carbon and the verification via theoretical calculation

“…Due to their high toxicity and stability, PAHs are conrmed to be primary pollutants according to the US Environmental Protection Agency (EPA). [1][2][3] Due to the low biodegradability, weak ionization capacity, low water-solubility and vaporization pressure, PAHs are exceedingly resistant to natural degradation processes and have been present in the environment for a long time. Furthermore, because of accumulation in living tissues, PAHs have caused various adverse effects and disorders for human beings, [3][4][5] and urgently need to be removed from water environment.…”

“…To date, many different techniques such as adsorption, occulation, coagulation, membrane ltration, solvent extraction, and biological treatment have been employed to remove PAHs from aqueous solution-solid systems. [3][4][5] Among the various treatments, adsorption based on several types of porous materials, such as activated carbon (AC), activated alumina, ion exchange media, and iron-based media, has been regarded as a promising green technology due to its simple operation, remarkable economic applicability, low-energy demand, and environmental friendliness. [6][7][8] Actually, the types of adsorbent are vital for the adsorption performances towards specic contaminants.…”

Tailored Design of Differently Modified Mesoporous Materials To Deeply Understand the Adsorption Mechanism for Polycyclic Aromatic Hydrocarbons

“…Researchers have made many efforts to develop a variety of methods to eliminate PAHs via chemical, physical, thermal, or biological progresses, for example, adsorption, sedimentation, − oxidation, , biodegradation, − and photocatalysis. − Among these, adsorption is proved to be a promising method for PAHs removal because it is low cost, easy to operate and recycle, and also environmental friendly. In recent years, a number of efficient adsorbents have been developed and utilized to remove PAHs from contaminated water and soil, such as biomass materials, − activated carbons, − graphene, ,− metal–organic frameworks, − and modified mesoporous materials. − Accordingly, several adsorption mechanisms, involving hydrophobic interaction, π–π interaction, and acidic interaction, were proposed to illustrate the adsorption processes and explain the adsorption behavior of different absorbents. Hu et al compared the adsorption performance of hydrophobic and hydrophilic MCM-41 molecular sieves for phenanthrene, and the results showed that the template-containing hydrophobic MCM-41 exhibited a higher adsorption capacity because of the hydrophobic interactions with phenanthrene.…”