Novel approach in treating industrial wastewater using metal-organic framework nanoparticles impregnated with biosurfactants.

Abstract

Arabian Gulf countries including Qatar are amongst the main oil and gas (O&G) producers globally. A huge amount of water is used during the upstream and downstream processes of oil and gas refiners. As a result, a large quantity of wastewater is produced. Treatment of this wastewater is a critical issue due to the significant amount of wastewater generated and the potential organic and inorganic contaminants it may contain. Hence, developing treatment strategies for industrial wastewater that are adaptive, eco-friendly, costeffective, and efficient is the main challenge toward the environmental protection field and sustainable development of the O&G sector. Nanotechnology is an emerging advanced technology that incorporates various nanoadsorbents for wastewater. Current work in this field is invested in developing new modified nano-adsorbents and studying their efficiency in mopping up several environmental contaminants from wastewater. The main aim of this study was to develop novel nanoparticles to overcome some limitations encountered by efficient nanoadsorbents due to their mobility, which is attributed to rapid particle aggregation. Firstly, different process wastewaters (PWWs) from the O&G industry were collected and characterized to investigate the type and quantity of organic and inorganic contaminants present. The results revealed that the collected PWWs contained high organic contaminants including gasoline range organics (GRO), extractable petroleum hydrocarbons (EPH), polycyclic aromatic hydrocarbons (PAHs), and inorganic contaminants. Two nanoparticles (NPs) were synthesized and characterized by different techniques, namely zeolite imidazole framework-8 (ZIF-8) and iron oxide nanoparticles (IONs). In this study, the adsorptive removals of volatile petroleum hydrocarbons (VPHs) from an aqueous solution by ZIF-8 and IONs were investigated. In this work, the two NPs (ZIF-8 and IONs) were modified by biosurfactant (BS) extracted from hydrocarbon-degrading bacteria isolated from process wastewater. The main aim behind coating ZIF-8 and IONs with BS is to improve their surface properties and enhance the adsorption capacity of mixture VPHs (namely p,o,m-xylene, pentane, ethylbenzene, methyl tert-butyl ether (MTBE), toluene, n-hexane, benzene, octane, decane, 1,2,3-trimethyl benzene, naphthalene, and 1-methyl naphthalene) from an aqueous phase. The characterization results confirmed the successful loading of BS onto ZIF-8 and IONs surfaces, showing a higher capability of VPHs adsorption. The adsorption isotherm results showed that the BSimpregnated ZIF-8 and IONs have higher adsorption capacity than the unmodified ZIF-8 and IONs. Overall, the results of this work deliver deep knowledge in understanding about different interaction mechanisms between ZIF-8 and IONs and BS in addition between ZIF-8 and IONs and VPHs demonstrating the high potentiality of ZIF-8 and IONs modification techniques to adsorb different contaminants.