Browsing by Subject "Microfiltration"
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Item Treatment investigation of the Erzurum City municipal wastewaters with anaerobic membrane bioreactors(2007) Kocadagistan E.; Topcu N.An anaerobic reactor coupled with a cross-flow microfiltration unit (CFMF) was applied to treat the municipal wastewater of the Erzurum City of Turkey. Although the atmospheric conditions of Erzurum are too cold (6°C average of years) to operate a big municipal wastewater treatment plant in normal operation conditions, the anaerobic membrane bioreactor system, evaluated in this study, is thought to be more useful than the conventional activated sludge wastewater treatment systems. The laboratory scale experimental unit consists of one microfiltration module of 0.2 μm pore sized and 0.003 m2 membrane surface area and an anaerobic reactor having a total working volume of 50 L. The maximum working volume of the reactor was kept at 15 L throughout the study. At 450 L/m2.h, permeate flux, COD, PO4-P and suspended solids removal efficiencies were achieved as 98.1, 81 and up to 99% respectively. Our anaerobic membrane bioreactor system displayed a good performance to remove carbonaceous and phosphorous materials. Furthermore, suspended sludge and sludge microorganism concentrations were under the detectable levels in the effluent of the system. © 2007 Elsevier B.V. All rights reserved.Item Removal of heavy metals in wastewater by using zeolite nano-particles impregnated polysulfone membranes(Elsevier B.V., 2016) Yurekli Y.In this study, the adsorption and the filtration processes were coupled by a zeolite nanoparticle impregnated polysulfone (PSf) membrane which was used to remove the lead and the nickel cations from synthetically prepared solutions. The results obtained from X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive X-ray (EDX) analysis indicated that the synthesized zeolite nanoparticles, using conventional hydrothermal method, produced a pure NaX with ultrafine and uniform particles. The performance of the hybrid membrane was determined under dynamic conditions. The results also revealed that the sorption capacity as well as the water hydraulic permeability of the membranes could both be improved by simply tuning the membrane fabricating conditions such as evaporation period of the casting film and NaX loading. The maximum sorption capacity of the hybrid membrane for the lead and nickel ions was measured as 682 and 122 mg/g respectively at the end of 60 min of filtration, under 1 bar of transmembrane pressure. The coupling process suggested that the membrane architecture could be efficiently used for treating metal solutions with low concentrations and transmembrane pressures. © 2016 Elsevier B.V.Item Filtration and removal performances of membrane adsorbers(Elsevier B.V., 2017) Yurekli Y.; Yildirim M.; Aydin L.; Savran M.Membrane adsorbers are promising candidates for the efficient and effective removal of heavy metals in waste water due to their unattainable adsorption and filtration capabilities. In the present study, zeolite nanoparticles incorporated polysulfone (PSf10) membrane was synthesized by means of non-solvent induced phase separation technique for the removal of lead and nickel ions in water. PSf10 showed a remarkable sorption capability and after repeated (adsorption/desorption)5 cycles in batch experiments, it preserved 77% and 92% of its initial sorption capacity for the lead and nickel, respectively. Addition of nanoparticles increased the pore radius of the native PSf from 10 to 19 nm, while bovine serum albumin rejection remained unchanged at 98%. Increments in the pore size and enhancement in hydrophilicity caused to increase hydraulic permeability of the native PSf from 23 to 57 L/m2 h bar. Cross-flow filtration studies revealed that the filtrate concentrations were inversely affected by the initial metal concentration and transmembrane pressure due to reaction limited region. Nonlinear rational regression model perfectly described the filtration behavior of the PSf10 within the experimental range and suggested that lower initial metal concentration and pressure with a short filtration time should be selected for the target response to be minimum. © 2017 Elsevier B.V.Item Facile construction of Janus MXene/cellulose/ZnO membrane with EMI shielding property for on-demand personal thermal management(Springer Science and Business Media B.V., 2023) Zhao B.; Li C.; Chen Y.; Tian Q.; Yurekli Y.; Qiu F.; Zhang T.To handle the increasingly harsh living space caused by extreme temperatures and floods of electromagnetic waves, wearable materials have been attracting much attention for decades due to their good versatile compatibility and precise utility. In this work, a Janus MXene/cellulose/ZnO nanorods membrane for accurate on-demand personal thermal management and electromagnetic interference shielding was fabricated via hydrothermal treatment and vacuum-assisted filtration, followed by a hydrophobization process. The ZnO nanorod side of obtained Janus membrane exhibits a high visible reflectance (96.3%) and infrared emissivity in the atmospheric window band (0.837). The corresponding visible absorption and average infrared reflectivity (5–25 μm in wavelength) of the MXene side are over 90% and 0.7, respectively. Remarkable temperature differences on both sides (7 °C increment on MXene side and 5 °C reduction on ZnO side compared to bare wooden board) were achieved in the validation test under direct sunshine, reflecting to the great optical properties and radiative thermal management performances of the obtained membrane. Moreover, the water contact angles (≥ 120°) indicated the hydrophobicity and associated stain resistance of this membrane. Active Joule heating and electromagnetic interference shielding characteristics have been successfully introduced into the Janus membrane by means of the integration of MXene. A rapid increase in temperature to 75 °C was attained within a 1 min of low voltage (2 V) applying. The effectiveness of the electromagnetic shielding (~ 30 dB) was higher than the commercial shielding materials. The results in general, provide a promising solution to protecting people from temperature extremes and electromagnetic waves interference in modern living space. © 2023, The Author(s), under exclusive licence to Springer Nature B.V.Item Process intensification through enzymatic decomposition of urea with simultaneous recovery of ammonia(Elsevier Ltd, 2024) Yurekli Y.; Zhang T.; Qiu F.Urea in the human body and in municipal wastewater discharges above safe limit can impair the human health and adversely affect the environment. Innovative technologies for sustainable urea recovery are widely recognized as a necessity. In this study, multifunctional enzymatic composite membranes comprised of zeolite nanoparticles dispersed in sulfonated polysulfone (S2PSf) ultrafiltration membranes and urease enzyme deposited by layer-by-layer self-assembly method on the rear surface and in the pores have been fabricated. The proposed architecture offers biocatalytic reaction, ion exchange, and filtration mechanisms sequentially to first degrade urea by the urease catalyzed reaction and recover the released ammonium cations by the zeolite nanoparticles (NPs) within the membrane under continuous flow mode. Zeolite (NaX) NPs were synthesized with environmentally friendly approach and then characterized in detail. The batch mode of adsorption results revealed that the NaX NPs had an uptake of 62.3 mg/g for NH4+-N. It was also found that the mixed matrix membrane (MMM) was more effective than the powdered NaX under similar batch operation. The hydraulic permeability of the MMM compared to the PSf membrane (0.3 L/m2.h.bar) was significantly improved to 335 L/m2.h.bar, but the addition of polyethyleneimine and urease in subsequent modifications reduced the permeability to 152 L/m2.h.bar. The continuous removal of ammonium cations during filtration resulted in a higher catalytic activity of the S2PSf-10Z-PEI-URE membrane compared to the batch mode under similar conditions. However, due to the short residence time in the flow-through mode, the sorption capacity of the membrane was greatly reduced. This study demonstrates a practical tool for the complete recycling of urea contained wastewater, and further development for the applications in hemodialysis and recycling of the astronaut urine during long-term space flight. © 2024 Elsevier Ltd