Browsing by Author "Yurekli, Y"

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    ZnAl-LDH/wood-based antifouling membranes for high-flux and efficient oil/water separation
    Wu, K; Xu, JC; Jiang, YH; Jiang, Y; Yurekli, Y; Yue, XJ; Dai, YT; Zhang, T; Yang, DY; Qiu, FX
    An efficient and antifouling cutting-edge membrane was fabricated via growing hierarchical ZnAl-layered double hydroxides (LDHs) nanosheets on the wood template for enhanced separation of immiscible oil/water mixtures and emulsions. The retained vertical channels within the wood substrate facilitated impressive liquid flux, while the LDHs layer coated on the wood surface establishes a robust hydration layer that effectively repels oil droplets. The synergistic effect of these two elements enables efficient separation of immiscible oil/water mixtures and emulsions. The ZnAl-LDHs/wood membrane demonstrates a remarkable reduction in oil adhesion, achieving exceptional antifouling performance. This innovative membrane was adept at efficiently separating oil/water mixtures, exhibiting an impressive flux of 1.87 x 106 L.m-2.h-1 with a separation efficiency of 99 %. Furthermore, it successfully processes surfactant-free emulsions at a rate of 8279 L.m-2.h-1 (99.4 % efficiency) and surfactant-stabilized emulsions at 6850 L.m-2.h-1 (98.8 % efficiency). The current work combines natural wooden channel structures and hydration layers formed by superhydrophilic LDHs nanosheets, providing new novel insights and support for the development of highly efficient membranes with antifouling properties for oil/ water separation.
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    Process intensification through enzymatic decomposition of urea with simultaneous recovery of ammonia
    Yurekli, Y; Zhang, T; Qiu, FX
    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 NH 4 + -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/m 2 .h.bar) was significantly improved to 335 L/ m 2 .h.bar, but the addition of polyethyleneimine and urease in subsequent modifications reduced the permeability to 152 L/m 2 .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.
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    Bionic root inspired CNT/regenerated cellulose aerogel membrane/Cu nanowires for enhancing physiological comfort
    Chen, YF; Zhang, RQ; Qiu, FX; Zhang, T; Yang, DY; Yurekli, Y
    Traditional thermal management and humidity management systems consume a large amount of energy and thus aggravate the energy crisis. Here, CNT/regenerated cellulose aerogel membrane/copper nanowires (CRCAMCNWs) with thermal and humidity management were successfully fabricated using layer-by-layer assembly. This composite takes advantage of high infrared reflectivity of the copper (Cu) nanowires and the high solar absorptivity of CNTs. Under simulated sunlight exposure, the surface temperature of CRCAMCNWs was 11.4 degrees C higher than the regenerated cellulose aerogel membrane, indicating that CRCAMCNWs have excellent thermal management properties. The excellent sweat transport properties of CRCAMCNWs are demonstrated by the fact that water can penetrate from the Cu side to the inside within 3.5 s. For insensible sweat, the water vapor transmission rate of CRCAMCNWs is 0.708 mg cm(-2) h(-1), which transfer insensible sweat from the inner side of to the outer side for enhanced wearer comfort. Moreover, CRCAMCNWs exhibit excellent antibacterial properties due to the presence of Cu nanowires. This work not only provides a recycling strategy to fabricate bionic-root inspired wearable materials by using sugarcane bagasse as raw material but also demonstrates intriguing applications in enhancing physiological comfort thanks to its low energy consumption and environmental friendliness.
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    A cellulose-based membrane with temperature regulation and water transportation for thermal management applications
    Chen, YN; Zhang, T; Li, YQ; Yurekli, Y; Qiu, FX; Yang, DY
    Thermal management materials are widely employed in the construction and textile industries due to their non energy input and the ability to precisely adjust the temperature. However, the application of thermal management technique toward sustainable agriculture is still challenging due to the complex environment. Herein, a coupled insulation system with highly asymmetric thermal conductivity and unidirectional water penetration is developed by using the integration of thermal management and water diodes technologies. The hierarchical membrane shows asymmetric thermal conductivity of carbonized cellulose layer (CCL, 0.64 W m-1 K-1) and Al2O3/cellulose layer (ACL, 0.16 W m-1 K-1), and good moisture permeability owing to the anisotropic wettability of the material and hierarchical structure design. Thermal management performance revealed that compared with PET and cellulose membrane, the membrane temperature increased by 4.1 & DEG;C and 1.3 & DEG;C, respectively, resulting in a decrease in greenhouse heat dissipation. Besides, benefitting from the efficient photothermal conversion performance of carbonized cellulose, the outside can rapidly warm up to 42 & DEG;C under 120 W/m2 sun radiation, providing a suitable growth temperature for crops. Meanwhile, unidirectional water penetration achieved in the 60 s not only enables the membrane to maintain long-term and effective insulation, but also ensures the demand of crops for water during drought conditions. Furthermore, the anti-flaming property broadens the range of applications, reducing damage in an emergency such as a fire. The demonstrated membrane can potentially replace the commercial plastic-based greenhouse materials, and the gradient and bilayer design open a new avenue for sustainable thermal management application.
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    Facile construction of Janus MXene/cellulose/ZnO membrane with EMI shielding property for on-demand personal thermal management
    Zhao, BC; Li, CZ; Chen, YF; Tian, Q; Yurekli, Y; Qiu, FX; 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 mu m in wavelength) of the MXene side are over 90% and 0.7, respectively. Remarkable temperature differences on both sides (7 degrees C increment on MXene side and 5 degrees 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 degrees) 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 degrees C was attained within a 1 min of low voltage (2 V) applying. The effectiveness of the electromagnetic shielding (similar to 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.
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    Large-scale fabrication NZVI rod arrays on cotton fiber surfaces for efficient selenium adsorption
    Zhang, T; Yu, HQ; Dai, YT; Yang, DY; Yurekli, Y; Qiu, FX
    Aiming to solve the worldwide challenge of selenium pollution and selenium deficiency in partial districts, a simple and effective in situ growth process combined with seed growth method was used to load nanoscale zero-valent iron (NZVI) on the surface of cotton fiber (NZVI/C) for efficient selenium adsorption. The SEM results indicated that the FeOOH rods are perpendicular to the fiber and rooted in its surface to construct the stable structure. The obtained NZVI/C composites have high chemical reactivity and exhibit efficient extraction effect on selenium and the test results are recorded by ICP. More importantly, by adjusting the temperature, time, pH, dosage, and other conditions during the adsorption process, the separation performance of the NZVI/C composites can be further enhanced. The adsorption process of NZVI/C composites was endothermic reaction, and surface adsorption dominates the whole adsorption process. Moreover, this method realizes the controllable preparation of the ordered NZVI rod arrays on the cotton fiber, which can effectively solve the agglomeration problem of NZVI, and it is expected to be promoted to various fiber materials for easy, cheap, and large-scale production.
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    Filtration and removal performances of membrane adsorbers
    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 (adsorptionidesorption)(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/m(2) 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. (C) 2017 Elsevier B.V. All rights reserved.
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    Layer-by-layer self-assembly of multifunctional enzymatic UF membranes
    Yurekli, Y
    In order to eliminate membrane fouling and to ensure enzymatic hydrolysis of urea, multifunctional biocatalytic membranes were prepared by using urease (URE) and trypsin (TRY) enzymes on the sulfonated polysulfone (SPSf) ultrafiltration membrane via layer-by-layer (LbL) self-assembly method. The membrane architecture consisted of multilayer assembly with TRY and URE enzymes as the outer layer and inner sandwiched layer, respectively. Polyethyleneimine (PEI) and alginate (ALG) were used as cationic and anionic polyelectrolytes. Sulfonation and PEI deposition were successfully accomplished as confirmed by attenuated total reflectance Fourier transform infrared spectroscopy, differential scanning calorimetry (DSC) and scanning electron microscopy analysis, contact angle measurements, staining with toluidine blue and Congo red dyes and dead-end filtration experiments. A characteristic value of SPSf membrane with a high water permeability (1000 L/m(2).h.bar) and 95% bovine serum albumin (BSA) rejection was observed. In static conditions, URE activities of SPSf2-PEI-URE membrane were not affected by BSA fouling, while TRY immobilizations with increased concentrations (SPSf2-PEI-URE-PEI-ALG-TRY) significantly lowered the activity of URE. In dynamic conditions, each deposited layer exhibited individual resistance to flow that can be considered as irreversible fouling and caused 90% of flux decline for the SPSf2-PEI-URE-PEI-ALG-TRY membrane assembly. The recovery of the initial flux for the multilayered membrane at the end of six fouling and washing cycles was observed 85%. Moreover, at the end of 5 cycles, 78% of the URE initial activity of the multilayered membrane was preserved. (c) 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 137, 48750.
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    Determination of adsorption characteristics of synthetic NaX nanoparticles
    Yurekli, Y
    Zeolite nanoparticles were synthesized by means of a hydrothermal method and the sorption performances were tested in batch experiments using single and binary components of Pb2+, Ni(2+)and Cu2+ synthetic solutions. Fast adsorption was observed and the majority of sorption occurred within the first 5 min for each case of metal cations. Percentage metal removal increased with the adsorbent dosage and it was adversely affected by the initial metal concentrations. XRD, FTIR-ATR and XPS analyses revealed that the removal of metal ions occurred mainly on the basis of ion-exchange. Equilibrium sorption data were best described by Sips isotherm model and the maximum attainable metal amount on the NaX were estimated as 1.23, 1.76 and 2.20 mmol/g for the Pb2+, Ni2+, and Cu2+ cations, respectively. A single step desorption process conducted in NaCl solution seemed to be practically applicable for regeneration and after three adsorption/desorption cycles, 79, 76 and 48% of initial sorption capacity of NaX were preserved for lead, nickel and copper ions, respectively. Single isotherm parameters used for the prediction of binary equilibrium data were satisfactory. Binary sorption experiments for Pb2+-Ni2+, Pb2+-Cu2+ and Ni2+-Cu2+ couples reflected that the presence of secondary ions decreased the uptake of the primary one. Lead exhibited greater inhibition of the sorption of nickel and copper, demonstrating the stronger affinity of NaX for Pb2+. Extended Freundlich model best described all the three binary metal systems. Adsorption experiments carried out in real wastewater demonstrated that NaX nanoparticle has a high affinity for all the cations except copper.
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    Removal of heavy metals in wastewater by using zeolite nano-particles impregnated polysulfone membranes
    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, (C) 2016 Elsevier B.V. All rights reserved.