مهسا استادي

The membrane filtration system integrates with the activated sludge process in membrane bioreactor technology. One of the main issues with this system is the rapid membrane fouling by micro-contaminants in the feed and sludge. Changing the surface properties is known as an effective method to reduce fouling. This study introduced a hierarchical nanocomposite polymeric membrane with a micro/nano structure using a patterned knife and the spray induced phase inversion (s- NIPs) method. CuO nanoparticles were sprayed on the membrane’s surface to create nano hierarchical structure, and thus, the membrane with a dual hierarchical structure was fabricated. Field emission microscopy (FESEM), X-ray diffraction (XRD), atomic force microscopy (AFM), dynamic contact angle and porosity were eva‎luated to determine the structural and surface characteristics of the membranes. Pure water flux (PWF), protein rejection, chemical oxygen demand (COD), extraction of extracellular polymeric substances (EPS) and confocal microscope images were also studied to eva‎luate membrane performance in membrane bioreactor. The fouling resistance of the membranes was investigated using activated sludge filtration. The results showed that the presence of nanoparticles on the surface of the hierarchical nanocomposite membrane caused super hydrophilicity so that the contact angle from 90 ° for the reference membrane reached about 0 °. The presence of nanoparticles increased the surface roughness, and the average roughness increased from 3.8 nm for the reference membrane to 11.3 nm. Hierarchical nanocomposite membranes with micro/nano structure showed 924 l / m2.h of pure water flux, flux recovery of 94%, 95.7% protein rejection and chemical oxygen removal efficiency of 97.78%. In addition, shear stresses caused by the presence of surface patterns and antibacterial properties of CuO nanoparticles significantly improved membrane performance in reducing fouling/biofouling. The total reversible and irreversible fouling for the hierarchical nanocomposite membrane with micro/nano structure reached 53.8%, 47.8% and 6%, respectively, while these values were 47.6%, 8% and 39.6% for the reference membrane. Confocal microscopy images and the extraction results of extracellular polymeric substances confirmed the ability of hierarchical nanocomposite membranes with micro/nano structure to reduce fouling/biofouling. To eva‎luate the membrane performance in membrane bioreactors, membrane performance at different concentrations (12000-6000 mg / l) of suspended solids was assessed. The results showed that by increasing the concentration of suspended solids up to 12000 mg / l, the flux decreased (140 l/m2.h), but the percentage of chemical oxygen removal (3.55% decrease) did not change significantly. The outstanding performance of the fabricated membrane promises its good performance on an industrial scale.

بيوراكتور غشايي , غشاي پليمري شياردار با ساختار سلسله مراتبي ميكرو/نانو , گرفتگي غشا , غشاي پليمري فوق آبدوست , خاصيت ضدباكتريايي نانوذرات اكسيد مس

Membrane Bioreactor , Patterned Polymeric Membrane with micro/nano hierarchical structure , Membrane Fouling , Superhydrophilic Polymeric Membrane , Antibacterial Properties of CuO nanoparticles

Mahsa Ostadi

Dr. Toraj Mohammadi