PVDF membrane for oil-in-water separation via cross-flow ultrafiltration process

The objective of this study is to investigate the potential of ultrafiltration polyvinylidene fluoride (PVDF)-titanium dioxide (TiO2) membrane for oil-in-water separator. PVDF polymeric matrix membrane is excellent in term of chemical and thermal stabilities, which make it very promising to be used as a membrane matrix for water separation. However, poor hydrophilic property of the PVDF has led to the severe fouling during operation. Thus, current work was performed to investigate the effect of incorporation of two additives i.e. polyvinylpyrrolidone (PVP) and polyethylene glycol (PEG) in PVDF-TiO2 membrane, which fabricated using dry/wet phase inversion technique. Membranes characterizations were performed using field emission scanning electron microscopy (FESEM), atomic force microscopy (AFM), contact angle and UV-vis spectrophotometer. Accordingly, modified PVDF membrane possessed good hydrophilicity property when the additives were added into PVDF-TiO2 membrane matrix. In term of filtration performance, the experimental results showed that oil rejection using PVDF-TiO2/PVP membrane were ~99.7%, which met the requirement for discharge. On the other hand, PVDF-TiO2/PEG membrane was shown more enhancement in terms of permeate flux by given over 64 (L/m2h) at pressure of 2 bar gauge

Preparation and characterization of PPSU membranes with BiOCl nanowafers loaded on activated charcoal for oil in water separation

Bismuth oxychloride nanowafers were synthesized and loaded on activated charcoal (BiOCl-AC) and were used as a novel additive to prepare polyphenylsulfone (PPSU) ultrafiltration (UF) membranes along with polyvinylpyrrolidone (PVP) as a pore forming agent by phase inversion technique. The BiOCl nanowafers were characterized by using scanning electron microscope (SEM) and Fourier transform infrared spectroscopy (FTIR). The PPSU hybrid membranes were characterized by SEM studies. The cross sectional images of the membranes along with the elemental mapping of membrane surface were assessed by using SEM and Energy Dispersive Spectroscopy (EDS). Hydrophilicity of the membranes was evaluated by contact angle, porosity and water uptake studies. The permeability of the membranes was determined by pure water flux (PWF). Membranes were also subjected to antifouling studies using bovine serum albumin (BSA) as the standard protein for rejection studies. The membranes showed greater permeability and antifouling property with the addition of BiOCl-AC. A unique cross flow ultrafiltration method was used to study the oil rejection results of both diesel fuel and crude oil. The experimental results of oil in water separation by the membrane M-3, showed 80% rejection for diesel fuel and 90.74% rejection for crude oil

Bio-inspired, fouling resistant, tannic acid functionalized halloysite nanotube reinforced polysulfone loose nanofiltration hollow fiber membranes for efficient dye and salt separation

Superficial functionalization of the hollow fiber membrane with progressive nanomaterials exhibits increased hydrophilicity, outstanding selectivity, and permeability. In the present study, a simple and novel loose nanofiltration (NF) membranes were prepared by the addition of tannic acid functionalized halloysite nanotubes (THNTs) in polysulfone (PSf) membrane matrix via phase inversion method. The successful modification of halloysite (HNTs) was confirmed by FT-IR, zeta potential measurement, TGA, TEM and EDX analysis. The membrane permeation studies were carried out with a sequence of salts (NaCl and Na2SO4) and dyes (reactive black 5 and reactive orange 16). The resulted membranes exhibited increased hydrophilicity, porosity, water uptake, antifouling performance, along with higher dye rejection (>99% for reactive black 5 and >90% of reactive orange 16) and low salt rejection (2.5% of NaCl and 7.5% of Na2SO4) properties. The nanocomposite membrane also exhibited the highest pure water flux of 92 L/m2 h compared to the pristine membrane of 18 L/m2 h made it a worthy candidate for the wastewater purification

Design and performance study of hybrid photocatalytic reactor-PVDF/MWCNT nanocomposite membrane system for treatment of petroleum refinery wastewater

This study focuses on the design and performance of a hybrid system consisting of a photocatalytic reactor and a membrane permeation cell. Initially, an ultraviolet lamp was installed in the photocatalytic reactor to decompose the organic pollutants in the presence of 200 ppm titanium-dioxide (TiO2). Individual hydrocarbon pollutants were identified by gas chromatography–mass spectrometry (GC–MS) analysis of wastewater samples. Polyvinylidene fluoride (PVDF)/multi-walled carbon nanotube (MWCNT) nanocomposite membranes were fabricated to enhance the rejection, flux and fouling resistance for full filtration of pollutants from photocatalytic reactor such as decomposed refinery wastewater and TiO2 photocatalyst. The nanocomposite membranes were characterized by Fourier transform infrared (FTIR), scanning electron microscopy (SEM) and atomic force microscopy (AFM). The TiO2 cross-over during permeation was detected by using an atomic adsorption spectrometer, which proved that TiO2 rejection was more than 99% for oxidized MWCNT nanocomposite membranes. Furthermore, GC–MS analysis was concluded over 90% decomposition which occurred by photocatalytic reaction and practically all pollutants were removed by ultrafiltration permeation cell. The nanocomposite membrane with 1.0 wt.% of oxidized MWCNTs incorporated in PVDF matrix was found to be the best nanocomposite membrane among all of the fabricated membranes for the filtration purposes, due to the over 99% rejection and excellent anti-fouling property

Novel hybrid photocatalytic reactor-UF nanocomposite membrane system for bilge water degradation and separation

This study focuses on the design and performance of a hybrid system consisting of a photocatalytic reactor and ultrafiltration permeation cell. Initially, an ultraviolet (UV) lamp was installed in the photocatalytic reactor to decompose the bilge organic pollutants in the presence of 200 ppm titanium-dioxide (TiO2). Individual hydrocarbon compounds of bilge water samples were identified by gas chromatography-mass spectrometry (GC-MS) analysis. Two types of membrane, which are a pure polyvinylidene fluoride (PVDF) membrane and PVDF/modified halloysite nanotube clay (M-HNTs) nanocomposite membrane were fabricated aiming to enhance the rejection, flux and fouling resistance for full filtration of pollutants from the photocatalytic reactor. The membranes were characterized by Fourier transform infrared (FTIR), field emission scanning electron microscopy (FESEM) and atomic force microscopy (AFM). Furthermore, GC-MS analysis showed that, over 90% bilge decomposition occurred by a photocatalytic reaction. The TiO2 cross-over during permeation was detected by using an atomic absorption spectrophotometer (AAS), which proved that, TiO2 rejection was more than 99% for the nanocomposite membrane. A UV- vis spectrophotometer confirmed over 99% rejection of decomposed bilge hydrocarbons via the nanocomposite membrane with 1.0 wt% of M-HNTs incorporated in the PVDF matrix

Fabrication of novel PPSU/ZSM-5 ultrafiltration hollow fiber membranes for separation of proteins and hazardous reactive dyes

Polyphenylsulfone (PPSU) based asymmetric hollow fiber membranes were prepared by the addition of different percentages of ZSM-5 particles by diffusion induced phase separation method. Polyvinylpyrrolidone (PVP) was used as a pore forming agent. The fabricated membranes were characterized by Field Emission scanning electron microscopy (FESEM), Energy Dispersive Spectroscopy (EDS), contact angle, water permeability, water uptake and by porosity measurements. Membranes filtration study was performed using different proteins namely bovine serum albumin (BSA), egg albumin (EA) and hazardous dyes like Reactive black 5 (RB-5), Reactive orange 16 (RO-16) in aqueous solutions. It was found that, addition of ZSM-5 in membrane matrix showed better dye removal capacity because of its hydrophilic and adsorptive nature. The membrane (PZ-3) with higher loading of additive exhibited rejection percentages of 100% for BSA, 95.23% for EA proteins and with reactive dyes 90.81% for RB-5 and 82.84% for RO-16 as compared to the pristine HF membrane

An investigation of temperature effects on the properties and CO2 absorption performance of porous PVDF/montmorillonite mixed matrix membranes

Although alterations of polyvinylidene fluoride (PVDF) membrane performance and properties in contactor applications are more severe at high temperature, to date, detailed information on the relationship between performance and properties with temperature is available. Hence, this study was undertaken to improve thermal stability of PVDF membranes by montmorillonite (MMT) incorporation. The fabricated membranes were operated in a closed contactor loop with water temperature of either 27 °C or 80 °C, followed by measuring CO2 absorption flux before and after 2 days exposure. Higher partial pore wetting at elevated temperature resulted in performance reduction of 31% and 13% for plain PVDF and 5 wt% MMT-filled PVDF membrane (MMM hollow fiber), respectively. To determine the reasons, the membranes were immersed in water of 80 °C for 7 days and analyzed by analytical characterization methods after drying. It was revealed from FESEM images that large pores on the membrane surfaces became larger while the small pores became smaller, leading porous membrane surfaces to deform to semi-dense layers with small number of large pores. Furthermore, strong reductions in membrane gas permeance, porosity, contact angle and wetting resistance were detected after 7-day immersion. Therefore, changes in the absorbent-induced membrane properties were found to be the reasons of the flux reduction at high operation temperatures. The alterations were, however, less pronounced for PVDF-filled MMT membrane than the original PVDF indicating thermal stability enhancement effect of the embedded clay particles. The results suggest that the impregnation of polymeric membranes by hydrophobic inorganic particles can be an effective method to stabilize the performance and properties of PVDF hollow fibers at harsh contactor operating conditions

Novel green hybrid processes for oily water photooxidation and purification from merchant ship

Two hybrid photooxidation systems consisting of two different reactors; photocatalytic reactor-ultrafiltration (PR-UF) and photocatalytic membrane reactor (PMR) have been investigated and compared for photolysis and separation of oily water. In both, oily water was irradiated by ultraviolet (UV) light. In PR, UV irradiation was made on the TiO2 photocatalyst suspended in oily water, followed by ultrafiltration (UF) to remove TiO2 particles and hydrocarbon residues. On the other hand, TiO2 was immobilized on the halloysite nanotube (HNT) and embedded in the UF membrane in PMR. In both systems, hydrocarbon concentration, chemical oxygen demand (COD), total dissolved solid (TDS), and hydrocarbon concentration were measured at each step of photooxydation and filtration. In UF, membrane flux, reduction in solute concentration, flux decline and flux recovery by backwashing were investigated. The experimental results showed that the reduction in TOC by PR-UF was ~10% higher than PMR. On the other hand, reduction in hydrocarbon concentration, COD and TDS was higher for PMR. The TiO2 concentration in UF permeate was 8 ppm and 0.2 ppm, respectively, for PR-UF and PMR

Membrane technology enhancement in oil-water separation. A review

Membrane separation processes have become an emerging technology for the treatment of oily wastewater due to high oil removal efficiency and relatively facile operational process. This review will highlight the recent development of advanced membrane technology such as surface modification, addition of inorganic particles in polymer membrane and the development of ceramic membranes. Additionally, the effect of operating parameters on the membrane performance is discussed in detail. Future outlooks in oil-water membrane separation are also discussed to further broaden the research and development related to this technology

Membrane technology enhancement in oil-water separation. A review

Membrane separation processes have become an emerging technology for the treatment of oily wastewater due to high oil removal efficiency and relatively facile operational process. This review will highlight the recent development of advanced membrane technology such as surface modification, addition of inorganic particles in polymer membrane and the development of ceramic membranes. Additionally, the effect of operating parameters on the membrane performance is discussed in detail. Future outlooks in oil-water membrane separation are also discussed to further broaden the research and development related to this technology