Adsorption of polycyclic aromatic hydrocarbons from wastewater by using silica-based organic–inorganic nanohybrid material

Abstract

Polycyclic aromatic hydrocarbons (PAHs) are a group of priority pollutants, which are classified as persistent hazardous contaminants. Herein, the adsorption of three PAHs, naphthalene (NAP), acenaphthylene (ACN), and phenanthrene (PHN), from wastewater onto NH 2 -SBA-15 organicinorganic nanohybrid material as a function of pH of the media (2-10), sorbent dosage (0.5-3.5 g L À1 ),, and temperature (25-45 W C) were elucidated. The prepared adsorbents were characterized by scanning electron microscope, transmission electron microscopy, X-ray diffractions, and thermogravimetric analysis. Among Langmuir, Freundlich, and Temkin isotherms models, it was found that the Langmuir model gave an excellent overall fit (R 2 > 0.97). The maximum adsorption capacity of 1.92, 1.41, and 0.76 mg g À1 was obtained for NAP, ACN, and PHN, respectively. Adsorption kinetics of PAHs onto NH 2 -SBA-15 was in accordance with the pseudosecond-order model, providing evidence that pore mass transferring was involved. PAHs' adsorption was strongly dependent on temperature, and confirmed the spontaneous and endothermic nature of the process. The optimized sorption condition was successfully applied to the real petroleum refinery wastewater samples and the adsorption capacity of NH 2 -SBA-15 was satisfactory for PAHs' studies as 1.67, 1.06, and 0.24 mg g À1 for NAP, ACN and PHN, respectively. Furthermore, reusability was successfully tested by five sequential recoveries.

Restoration of an Urban Creek Water Quality Using Sand and Biochar Filtration Galleries

“…In some studies, increasing pH (pH< 7 to pH= 9) favored heavy metal and organic pollutants adsorption using different biochar (Tai 1991, Kim et al 2013, Taha et al 2014). On the other hand, removal capacities of biochar declined following increasing solution pH to more than 8 (Balati et al 2015). In this study, effect of pH on heavy metal and NAP removal was not statistically significant which was in accordance with result found by Lamichhane et al (2016).…”

Nanoparticles Used for Extraction of Polycyclic Aromatic Hydrocarbons

“…is is due to accessible active sites of adsorbents for interaction with the analyte; after that, the extracted amount of PAHs was almost constant; hence, the suitable amount of NPs can be optimised [136]. In another study where the silica-based organicinorganic nanohybrid material (NH 2 -SBA-15) was used for removal of naphthalene, acenaphthylene, and phenanthrene from wastewater, the removal efficiency was increased significantly as the adsorbent amount increased due to the increase in the contact surface of the adsorbent and greater availability of adsorbent [146].…”

“…e removal rate of 3 PAHs (naphthalene, acenaphthylene, and phenanthrene) was increased at a lower pH, and this is due to the formation of NH 3+ on the surface of the nanohybrid adsorbent (NH 2 -SBA-15). Consequently, the electrostatic interaction between surface charges of the adsorbent and PAHs increased due to the π-electron-rich character of PAHs [146].…”

Advances in water treatment technologies for removal of polycyclic aromatic hydrocarbons: Existing concepts, emerging trends, and future prospects

“…It has the capability of generating nano‐sized materials with unique properties, which have found application in drug delivery, biosensors as well as in the remediation of different environmental compartments; such as air, water and soil; via clean‐up of environmental pollutants (Adeola et al, 2019; Nsibande, Montaseri, & Forbes, 2019). The adsorption of three PAHs, naphthalene (NAP), acenaphthylene (ACN), and phenanthrene (PHEN), from wastewater using a silica‐based organic–inorganic nanohybrid material (NH 2 ‐SBA‐15) was reported (Balati, Shahbazi, Amini, & Hashemi, 2015). Adsorption kinetics of PAHs by the hybrid followed the pseudo‐second‐order pathway, providing evidence of chemisorption and pore mass transfer.…”