Synthesis and characterization of NaA zeolite nanoparticles from Hordeum vulgare L. husk for the separation of total petroleum hydrocarbon by an adsorption process

Abstract

Hordeum vulgare, commonly known as barley, grows abundantly around an oil refinery in Bahregan, Bushehr, Iran. A mixture of hydrocarbons found in crude oil, total petroleum hydrocarbon (TPH), is one of the most common groups of persistent organic contaminants, and is found in the wastewater from the Bahregan oil refinery. The purpose of this study was to synthesize and characterize NaA zeolite nanoparticles (NaA-ZNPs) formed from H. vulgare husks using a hydrothermal method and research their effectiveness in removal of TPH from original oil waste by an adsorption process. The NaA-ZNPs were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), and the Brunauer–Emmert–Teller (BET) theory. A pure phase of NaA-ZNP with a ratio of Na2O:SiO2=6 was synthesized in three days at room temperature. Adsorption of TPH was studied for both batch and continuous-flow processes. The parameters of time, pH, and adsorbent dosage were studied in the batch process, and flow rate and column height in the continuous process. The results were analyzed with GC–MS. The removal efficiency of the NaA-ZNPs was investigated using statistical test, one-way analysis of variance (ANOVA) SPSS 21 software. In the batch and continuous systems, the highest TPH removal efficiency under optimal conditions was 92.3% and 87.4%, respectively. The project results demonstrated a high potential for use of NaA-ZNPs in treatment or pretreatment of wastewater from oil refineries containing TPH.