scholarly journals Effect of chitosan on membrane formation and processability of bamboo dissolving pulp based ultrafiltration membrane

BioResources ◽  
2021 ◽  
Vol 16 (3) ◽  
pp. 4752-4768
Author(s):  
Hongmei Yuan ◽  
Jianfei Wu ◽  
Junkang Lin ◽  
Liulian Huang ◽  
Lihui Chen ◽  
...  
Keyword(s):  
Phase Transformation ◽  
Weight Ratio ◽  
Rejection Rate ◽  
Ultrafiltration Membrane ◽  
Dissolving Pulp ◽  
Processing Temperature ◽  
Ultrafiltration Membranes ◽  
Membrane Formation ◽  
Optimal Processing

Bamboo dissolving pulp (BP)/chitosan (CS) blend solutions were obtained by adding different weight ratios of BP and CS particles to N-methyl-morpholine-N-oxide (NMMO) solvent. The processing and membrane-forming performances of the blend solutions were studied using a rotating rheometer. The BP/CS blend solutions’ optimal processing temperature was 50 to 70 °C. When the CS weight ratio was 9.09 wt%, the viscosity of the solution decreased, which was conducive to the processing of the membrane. The BP/CS blend ultrafiltration membranes were prepared by phase transformation of the blend solutions. The results showed that the rejection rate of the BP/CS blend ultrafiltration membrane with physically added CS particles was greatly improved compared with that of the regenerated BP ultrafiltration membrane.

Hydrophilic ultrafiltration membranes with surface-bound eosin Y for an integrated synthesis-separation system of aqueous RAFT photopolymerization

2020 ◽  
Vol 8 (19) ◽  
pp. 9825-9831
Author(s):  
Yujie Zhao ◽  
Senlin Shao ◽  
Jiangbin Xia ◽  
Ya Huang ◽  
Yu Chi Zhang ◽  
...  
Keyword(s):  
Membrane Separation ◽  
Raft Polymerization ◽  
Ultrafiltration Membrane ◽  
Separation Process ◽  
Eosin Y ◽  
Separation System ◽  
Ultrafiltration Membranes

The photocatalyst-based ultrafiltration membrane fitted integrated synthesis–separation system holds the promises to bridge the gap between the precision of PET-RAFT polymerization and the efficiency of membrane separation process.

ULTRAFILTRATION MEMBRANE FORMATION OF PES-C, PES AND PPESK POLYMERS WITH DIFFERENT SOLVENTS

2009 ◽  
Vol 27 (02) ◽  
pp. 165 ◽  
Author(s):  
Wei-na Sun ◽  
Cui-xian Chen ◽  
Ji-ding Li ◽  
Yang-zheng Lin
Keyword(s):  
Ultrafiltration Membrane ◽  
Membrane Formation

scholarly journals Preparation and Characterization of Matrix Hybrid Membranes Polyvinylidene Fluoride/Polyvinylpyrrolidone/Silica Gel/Zinc Oxide for Cr(VI) Removal from Water

2020 ◽  
Vol 44 (5) ◽  
pp. 311-318
Author(s):  
Mustapha Chabane ◽  
Chikh Melkaoui ◽  
Benamar Dahmani ◽  
Sihem Zahia Belalia
Keyword(s):  
Zinc Oxide ◽  
Silica Gel ◽  
Water Permeability ◽  
Polyvinylidene Fluoride ◽  
Membrane Filtration ◽  
Weight Ratio ◽  
Rejection Rate ◽  
Precipitation Method ◽  
Hybrid Membranes

Matrix hybrid membranes, based on polyvinylidene fluoride (PVDF), poly (N-vinylpyrrolidone) (PVP), silica gel (SG) and zinc oxide (ZnO) were synthesized by phase inversion via immersion precipitation method. The characterization of membrane samples was performed using Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), optical microscopy, contact angle, porosity, mean pore size and water permeability measurements. The FTIR analysis showed the appearance of new bands attributed to the functional groups of SG and ZnO. The XRD analysis confirmed a modification in the structure of membranes. The prepared membranes were used for the removal of hexavalent chromium (Cr(VI)) from aqueous solution. Membrane filtration experiments show that the water permeability and Cr(VI) rejection ratios increase with increasing the weight ratio ZnO (%)/SG (%). The maximum values of the Cr(VI) rejection rate and water permeability were respectively 85% and 685 L/m2hbar for weight ratios (0.75% of ZnO/0.25% of SG).

High rejection performance ultrafiltration membrane with ultrathin dense layer fabricated by the movement and dissolution of metal–organic frameworks

2020 ◽  
Vol 44 (32) ◽  
pp. 13745-13754
Author(s):  
Qi Wang ◽  
Shaohu Zhang ◽  
Xiwei Ji ◽  
Fen Ran
Keyword(s):  
Water Pollution ◽  
Metal Organic Frameworks ◽  
Ultrafiltration Membrane ◽  
Dense Layer ◽  
Ultrafiltration Membranes ◽  
Metal Organic ◽  
High Rejection

Ultrafiltration membranes have potential to solve the problems of water pollution and shortage.

PEMBUATAN MEMBRAN ULTRAFILTRASI DARI POLIMER SELULOSA ASETAT DENGAN METODE INVERSI FASA

Konversi ◽  
2018 ◽  
Vol 6 (1) ◽  
pp. 11 ◽  
Author(s):  
Agus Mirwan ◽  
Vera Indriyani ◽  
Yunita Novianty
Keyword(s):  
Water Treatment ◽  
Membrane Separation ◽  
Drinking Water Treatment ◽  
Ultrafiltration Membrane ◽  
Ultrafiltration Membranes ◽  
Membrane Pore ◽  
Running Water ◽  
Water Treatment Process ◽  
Rejection Coefficient ◽  
Pass Through

Abstrak- Pengolahan air bersih dengan teknologi membran merupakan proses pengolahan air dengan kualitas yang sangat baik dan sesuai untuk pengolahan air minum di negara-negara berkembang karena membran memiliki banyak sekali keunggulan. Salah satu jenis operasi pemisahan membran adalah dengan membran ultrafiltrasi. Ultrafiltrasi merupakan proses penyaringan partikel-partikel dalam rentang ukuran koloid, yaitu larutan dan molekul besar ditahan dipermukaan membran dan zat terlarut dengan ukuran sangat kecil dapat melewati membran. Tujuan dari penelitian ini adalah untuk menentukan komposisi % berat dimetilformamida pada pembuatan membran ultrafiltrasi yang terbaik. Membran ultrafiltrasi ini dibuat dengan memvariasikan konsentrasi aditif dimetilformamida yang berfungsi untuk penentuan ukuran pori membran dan konsentrasi aseton. Pencampuran bahan dilakukan dengan pengadukan selama ± 6 jam, hasil cetakan film polimer dikoagulasi selama 1 jam dalam air es (± 4°C) kemudian dicuci dengan air mengalir dan disimpan dalam wadah yang diberi formalin. Kemudian dilakukan pengujian pada membran tersebut menggunakan air gambut dimana permeat yang dihasilkan di ukur volumenya setiap selang waktu 5 menit untuk menentukan fluks membrannya. Kemudian dilakukan analisa terhadap konsentrasi permeat  untuk menentukan koefisien rejeksi, di mana rejeksi yang diharapkan adalah > 90%. Berdasarkan hasil penelitian, membran ultrafiltrasi yang terbaik adalah membran dengan komposisi % berat dimetilformamida 20; 24 dan 28 dimana koefisien rejeksi rata-rata yang diperoleh masing-masing adalah 98,15; 92,80 dan 95,41%. Kata kunci: dimetilformamida, koefisien rejeksi, fluks Abstract-Clean water treatment with membrane technology is a water treatment process with very good quality and suitable for drinking water treatment in developing countries because the membrane has a lot of advantages. One type of membrane separation operation is with ultrafiltration membranes. Ultrafiltration is a process of filtering particles in the size range of colloids, namely liquid while large molecules detained on the surface of the membrane and the solute with very small size can pass through the membrane. The purpose of this study was to determine the best composition of %wt of dimethylformamide in the manufacture of ultrafiltration membranes. Ultrafiltration membrane is made by varying the concentration of the additive of  dimethylformamide which serves for the determination of membrane pore size and the concentration of acetone. Mixing materials done by stirring for ± 6 hours, polymer film printouts is coagulated  for 1 hour in ice water (± 4 ° C) and then washed with running water and stored in a container containing formalin. Then conducted testing on the membrane using peat water where permeate that generated is measured the volume of each interval of 5 minutes to determine the membrane flux. Then analyzing the concentration of permeate to determine the coefficient of rejection, where the expected rejection is> 90%. Based on the research results, the best ultrafiltration membrane was membrane with  composition wt% of dimethylformamide of 20; 24 and 28, where rejection coefficient average respectively was 98.15; 92.80 and 95.41%. Keywords: dimethylformamide, rejection coefficient, flux

Phase Transformation in Mechanically Alloyed and Hot-Pressed Ti-2Nb-22Si-11B and Ti-6Nb-22Si-11B Powder Mixtures

2014 ◽  
Vol 802 ◽  
pp. 9-13 ◽  
Author(s):  
Andrezza Campos Zanardo ◽  
Neide Aparecida Mariano ◽  
Luciano Braga Alkmin ◽  
Alex Matos da Silva Costa ◽  
Carlos Angelo Nunes ◽  
...  
Keyword(s):  
Phase Transformation ◽  
Hot Pressing ◽  
Energy Dispersive Spectrometry ◽  
Weight Ratio ◽  
Milling Process ◽  
X Ray Diffraction ◽  
Mechanically Alloyed ◽  
Powder Mixtures ◽  
Eds Analysis ◽  
Rotary Speed

This work aims to discuss on the phase transformation in mechanically alloyed and hot-pressed Ti-2Nb-22Si-11B and Ti-6Nb-22Si-11B powder mixtures. The milling process was conducted in a planetary ball milling using stainless steel vials (225 mL) and balls (19 mm diameter), rotary speed of 300 rpm, and a ball-to-powder weight ratio of 10:1. Hot pressing of mechanically alloyed Ti-Nb-Si-B powders was performed under vacuum at 1100°C for 1h. The as-milled and hot-pressed Ti-Nb-Si-B samples were evaluated by X-ray diffraction, scanning electron microscopy, and energy dispersive spectrometry. XRD results of milled Ti-Nb-Si-B powders indicated that the peaks of Nb and Si were reduced for longer milling times, suggesting that Nb and Si atoms were dissolved into the Ti lattice to form extended solid solutions. Iron contamination close to 6 at% was detected by EDS analysis. Hot pressing produced dense and homogeneous samples containing a small amount of Ti6Si2B.

scholarly journals Preparation and Characterization of Semi-Alicyclic Polyimide Resins and the Derived Alignment Layers for Liquid Crystal Display Technology

Polymers ◽  
2020 ◽  
Vol 12 (1) ◽  
pp. 217
Author(s):  
Hong-sheng Bi ◽  
Xin-xin Zhi ◽  
Peng-hui Wu ◽  
Yan Zhang ◽  
Lin Wu ◽  
...  
Keyword(s):  
Liquid Crystal ◽  
Liquid Crystal Display ◽  
Weight Ratio ◽  
Volume Resistivity ◽  
Solid Content ◽  
Processing Temperature ◽  
Aromatic Diamines ◽  
Good Thermal Stability ◽  
Rigid Rod ◽  
Alignment Layers

Uniform alignment of rigid-rod liquid crystal (LC) molecules under applied voltage is critical for achievement of high-quality display for thin-film transistor-driven liquid crystal display devices (TFT-LCDs). The polymeric components that can induce the alignment of randomly aligned LC molecules are called alignment layers (ALs). In the current work, a series of organo-soluble polyimide (SPI) ALs were designed and prepared from an alicyclic dianhydride, hydrogenated 3,3′,4,4′-biphenyltetracarboxylic dianhydride (HBPDA), and various aromatic diamines, including 4,4′-methylenedianiline (MDA) for SPI-1, 4,4′-aminodianiline (NDA) for SPI-2, 3,3′,5,5′-tetramethyl-4,4′-diaminodiphenylmethane (TMMDA) for SPI-3, and 3,3′-diethyl-5,5′-dimethyl-4,4′-diaminodiphenylmethane (DMDEDA) for SPI-4. The derived SPI resins were all soluble in N-methyl-2-pyrrolidone (NMP). Four SPI alignment agents with the solid content of 6 wt.% were prepared by dissolving the SPI resins in the mixed solvent of NMP and butyl cellulose (BC) (NMP/BC = 80:20, weight ratio). Liquid crystal minicells were successfully fabricated using the developed SPI varnishes as the LC molecule alignment components. The SPI ALs showed good alignment ability for the LC molecules with the pretilt angles in the range of 1.58°–1.97°. The LC minicells exhibited good optoelectronic characteristics with voltage holding ratio (VHR) values higher than 96%. The good alignment ability of the SPI ALs is mainly attributed to the good comprehensive properties of the SPI layers, including high volume resistivity, high degree of imidization at the processing temperature (230 °C), good rubbing resistance, good thermal stability with glass transition temperatures (Tgs) higher than 260 °C, and excellent optical transparency with the transmittance higher than 97% at the wavelength of 550 nm.

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