Experimental investigation and modeling hybrid nano-porous membrane process for industrial oily wastewater treatment

Development of superhydrophillic tannic acid-crosslinked graphene oxide membranes for efficient treatment of oil contaminated water with enhanced stability

In the present age of industrialization, oil contamination in the waste water has become a huge global concern due to its several negative impacts on human health and aquatic ecosystem. In order to address this problem, a novel oleophobic and super-hydrophilic graphene-based membrane has been developed using simple and cost-effective vacuum filtration methodology. Prior developing the membranes, the graphene oxide (GO) sheets were crosslinked with tannic acid (TA) molecules in order to improve their mechanical and surface properties. To obtain the structural and morphological information of the membranes and their constituents, Field Emission Scanning Electron (FE-SEM) microscopy, X-Ray Diffraction (XRD), FTIR spectroscopy and Raman spectroscopy was used. When tested with simulated oilfield effluent samples, these membranes exhibited significant reduction in the values of chemical oxygen demand (COD), total dissolved solids (TDS), total suspended solids (TSS) and turbidity demonstrating low-oil adhesion and preferable oil rejection rates. Moreover, such crosslinked membranes are highly stable which can withstand the pressure of water filtration. In such a way, TA crosslinked GO membranes present a robust and efficient way to treat oil contaminated water released from various industries which can be reused for numerous further applications.

Synthesis of polyethersulfone (PES)/GO-SiO2 mixed matrix membranes for oily wastewater treatment

The treatment of oily wastewater continues to pose a challenge in industries worldwide. Membranes have been investigated recently for their use in oily wastewater treatment due to their efficiency and relatively facile operational process. Graphene oxide (GO) and silica (SiO₂) nanoparticles have been found to improve membrane properties. In this study, a polyethersulfone (PES) based GO-SiO₂ mixed matrix membrane (MMM) was fabricated, using the phase inversion technique, for the treatment of oil refinery wastewater. The PES/GO-SiO₂ membrane exhibited the highest water flux (2,561 LMH) and a 38% increase in oil removal efficiency by comparison to a PES membrane. Compared to PES/GO and PES/SiO₂ membranes, the PES/GO-SiO₂ MMM also displayed the best overall properties in terms of tensile strength, water permeability, and hydrophilicity.

An investigation on the capability of magnetically separable Fe3O4/mordenite zeolite for refinery oily wastewater purification

Damage to the water resources and environment as a consequence of oil production and use of fossil fuels, has increased the need for applying various technologies and developing effective materials to remove contaminates from oily wastewaters resources. One of the challenges for an economic industrial wastewater treatment is separation and reusability of the developed purifying agents. Development of magnetic materials could potentially facilitate easier and more economic separation of purifying agents. Therefore, herein we have synthesised an efficient and easily recyclable Fe₃O₄/mordenite zeolite using a hydrothermal process to investigate its purification capability for wastewater from Kermanshah oil refinery. The synthesised Fe₃O₄/mordenite zeolite was characterised using XRD, FTIR, SEM, EDX, XRF and BET analysis. XRD result showed that the synthesised Fe₃O₄/mordenite zeolite comprised sodium aluminium silicate hydrate phase [01-072-7919, Na₈(Al₆Si₃₀O₇₂)(H₂O)_9.04] and cubic iron oxide phase [04-013-9808, Fe₃O₄]. Response Surface Method (RSM) combined with Central Composite Design (CCD) was used to identify the optimum operation parameters of the pollutant removal process. The effect of pH, contact time and Fe₃O₄/mordenite zeolite amount on the Chemical Oxygen Demand (COD), Biochemical Oxygen Demand (BOD) and Nephelometric Turbidity Unit (NTU) were investigated. It was found that pH was the most significant factor influencing COD and BOD removal but the quantity of Fe₃O₄/mordenite zeolite was the most influential factor on the turbidity removal capacity. The optimum removal process conditions were identified to be pH of 7.81, contact time of 15.8 min and Fe₃O₄/mordenite zeolite amount of 0.52% w/w. The results show that the regenerated Fe₃O₄/mordenite zeolite can be reused for five consecutive cycles in purification of petroleum wastes.