Antifouling performance of polytetrafluoroethylene and polyvinylidene fluoride ultrafiltration membranes during alkali/surfactant/polymer flooding wastewater treatment: Distinctions and mechanisms

Pilot study on the effects of operating parameters on membrane fouling during ultrafiltration of alkali/surfactant/polymer flooding wastewater: optimization and modeling

“…8 ASP ooding wastewater is generally characterized by a pH of 10.0-11.0, a high concentration of polymers and a high concentration of total dissolved solids. 9 Flooding wastewater treated by conventional treatments, such as gravity settling, 10 air otation, [11][12][13] de-emulsication, [14][15][16] coagulation 17,18 and biotechnology, [19][20][21] does not meet the standards for reuse. 22 Therefore, advanced treatment needs to be implemented.…”

Efficiencies and mechanisms of the chemical cleaning of fouled polytetrafluoroethylene (PTFE) membranes during the microfiltration of alkali/surfactant/polymer flooding oilfield wastewater

“…In recent decades, alkali/surfactant/polymer (ASP) ooding oileld wastewater is being increasingly produced during the oil recovery process. [1][2][3] This wastewater needs to be processed prior to getting discharged into the environment to avoid the risk of severe pollution caused by its organic and inorganic components. 1 Many countries that possess oilelds are seeking efficient and cost effective methods to manage this wastewater.…”

“…[7][8][9] Microltration (MF) is considered to be one of the most effective membrane applications among the membrane separation processes for oileld wastewater treatment. 2,3,10 However, the pH of the wastewater has been observed to exceed the tolerable limit of commonly used MF membranes, which signicantly shortens the membrane lifespan and increases operating costs. As an MF membrane, polytetrauoroethylene (PTFE) is considered to be the best due to its high resistance to strong acids and alkalis, high and low temperatures, and corrosion.…”

“…Thus, it is preferred for ASP ooding oileld wastewater treatment. 1,2,[10][11][12] However, one of the obstacles impeding the large-scale development of MF is membrane fouling, which accounts for the decrease in membrane permeability or a rise in membrane resistance, resulting in the increase in operation costs and cleaning frequency. 13 Although many methods have been adopted to prevent and alleviate membrane fouling, it remains inevitable during the MF process.…”

“…22 The commonly used inexpensive acids, bases, and oxidants cause some damage to normal MF membranes, while they cause little damage to the PTFE membranes. 2,21 Zhao et al 23 immersed PTFE and polyvinylidene uoride (PVDF) MF membranes in hydrochloric acid (HCl), sodium hydroxide (NaOH), hydrogen peroxide (H 2 O 2 ), and sodium hypochlorite (NaClO) solutions for 20 d, 40 d, and 60 d at 40 C. The results showed that the PTFE membranes exhibited better resistance to chemicals compared to the PVDF membranes and maintained better membrane structural integrity.…”