scholarly journals CNTs Intercalated LDH Composite Membrane for Water Purification with High Permeance

Nanomaterials ◽  
2021 ◽  
Vol 12 (1) ◽  
pp. 59
Author(s):  
Qian Li ◽  
Peng Song ◽  
Yuye Yang ◽  
Yan Li ◽  
Naixin Wang ◽  
...  
Keyword(s):  
Composite Membrane ◽  
Water Purification ◽  
Weight Ratio ◽  
Water Molecules ◽  
Separation Performance ◽  
Preparation Conditions ◽  
The Stability ◽  
Double Hydroxide ◽  
Separation Performances

The pursuit of improved water purification technology has motivated extensive research on novel membrane materials to be carried out. In this paper, one-dimensional carboxylated carbon nanotubes (CNTs) were intercalated into the interlayer space of layered double hydroxide (LDH) to form a composite membrane for water purification. The CNTs/LDH laminates were deposited on the surface of the hydrolyzed polyacrylonitrile (PAN) ultrafiltration membrane through a vacuum-assisted assembly strategy. Based on the characterization of the morphology and structure of the CNTs/LDH composite membrane, it was found that the intercalation of CNT created more mass transfer channels for water molecules. Moreover, the permeance of the CNTs/LDH membrane was improved by more than 50% due to the low friction and rapid flow of water molecules in the CNT tubes. Additionally, the influence of preparation conditions on the separation performance was investigated using Evans blue (EB). Optimized fabrication conditions were given (the concentration of CoAl-LDH was 0.1 g/L and the weight ratio of CNTs was 2 wt.%). Next, the separation performances of the prepared CNTs/LDH composite membrane were evaluated using both single and mixed dye solutions. The results showed that the composite membrane obtained possessed a retention of 98% with a permeance of 2600 kg/(m2·h·MPa) for EB, which was improved by 36% compared with the pristine LDH composite membrane. Moreover, the stability of the CNTs/LDH composite membrane was investigated in 100 h with no obvious permeance drop (less than 13%), which exhibited its great potential in water purification.

Vacuum-assisted assembly of iron cage intercalated layered double hydroxide composite membrane for water purification

2020 ◽  
Vol 603 ◽  
pp. 118032 ◽  
Author(s):  
Naixin Wang ◽  
Qian Li ◽  
Xiaoting Li ◽  
Wenhai Zhang ◽  
Shulan Ji ◽  
...  
Keyword(s):  
Layered Double Hydroxide ◽  
Composite Membrane ◽  
Water Purification ◽  
Iron Cage ◽  
Double Hydroxide

Preparation of Conductive PPy/Cellulose Composite Fabric by Using Admicellar Polymerization

2010 ◽  
Vol 113-116 ◽  
pp. 2030-2034 ◽  
Author(s):  
Hui Ting Yang ◽  
Li Juan Wang
Keyword(s):  
Storage Time ◽  
Weight Ratio ◽  
Polymerization Temperature ◽  
Conductive Composite ◽  
Admicellar Polymerization ◽  
Conductive Composites ◽  
Preparation Conditions ◽  
Cellulose Composites ◽  
The Stability ◽  
Cellulose Composite

Conductive PPy/cellulose composites were prepared with flax substrate by using admicellar polymerization. In admicellar polymerization, thinner PPy layer would be formed by a surfactant template. The stability of conductive composites prepared under various conditions was analyzed and surface morphology of the composite was analyzed by SEM. The effects of different preparation conditions on the conductivity of the composite were studied in detail. The optimum preparation conditions were as follows: pyrrole concentration 0.3 mol•L-1 , FeCl3 concentration 0.3 mol•L-1, adsorption time 150 min, PVA to pyrrole weight ratio 2%, polymerization temperature 0°C, polymerization time 9h. The surface resistivity of conductive composite fabric almost linearly increased with the prolongation of storage time. The stability of the conductive composite is the best when PVA/ pyrrole is 2%.

Optimization of the PDMS/biochar nanocomposite membranes using the response surface methodology

2018 ◽  
Vol 25 (5) ◽  
pp. 947-956 ◽  
Author(s):  
Yongqiang Lan ◽  
Ning Yan ◽  
Weihong Wang
Keyword(s):  
Pyrolysis Temperature ◽  
Weight Ratio ◽  
Composite Membranes ◽  
Separation Performance ◽  
Regression Equations ◽  
Nanocomposite Membranes ◽  
Water Separation ◽  
Preparation Conditions ◽  
Silane Coupling ◽  
Loading Amount

AbstractTo improve the separation performance of the polydimethylsiloxane (PDMS)/bark biochar (BB) nanocomposite membranes used for alcohol/water separation, the preparation conditions of these composite membranes were analyzed and optimized. In this study, we investigated the following preparation parameters: the BB pyrolysis temperature, the weight ratio of the silane coupling agent (KH-550) to bark biochar (BB), and the BB loading amount. The regression equations were established between these three preparation parameters and the final pervaporation (PV) performance characteristics of the composite membranes. The membranes performed the best under the following optimal preparation conditions: a BB pyrolysis temperature of 407°C; a silane coupling reagent/BB weight ratio of 0.86, and a BB loading amount of 3.36 wt%. According to the results of the regression analysis, a maximum permeation flux of 221.2 g·m−2·h−1 and a maximum selective factor of 21.3 was obtained when the feed temperature for the 5 wt% alcohol solution was set at 40°C.

scholarly journals Ceramic-Based Composite Membrane with a Porous Network Surface Featuring a Highly Stable Flux for Drinking Water Purification

Membranes ◽  
2019 ◽  
Vol 9 (1) ◽  
pp. 5 ◽  
Author(s):  
Li Zhu ◽  
Kadalipura Puttaswamy Rakesh ◽  
Man Xu ◽  
Yingchao Dong
Keyword(s):  
Drinking Water ◽  
Composite Membrane ◽  
Water Purification ◽  
Operation Time ◽  
Ceramic Membranes ◽  
Separation Performance ◽  
High Flux ◽  
Porous Network ◽  
Drinking Water Purification

Highly efficient drinking water purification is still an important challenge for membrane techniques where high flux, high rejection, and low fouling are highly emphasized. In the present work, a porous network surface with carbon nanotubes (CNTs) was in situ constructed on hierarchically-structured mullite ceramic membranes. Interestingly, such a composite structure was demonstrated to effectively remove bacteria from drinking water with a highly stable long-term flux. After membrane structure characterizations, separation performance, such as flux and rejection, was assessed by the purification of bacteria-contaminated drinking water. The results confirmed that the mullite-CNT composite membrane claimed a complete removal of two model bacteria (100% rejection of Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus)), driven by a trans-membrane pressure of 0.1 MPa, where a surface sieving mechanism was dominant. A highly stable long-term flux for the 24 h filtration process was achieved, which can be attributed to the porous membrane surface with a special randomly-oriented CNTs network structure, featuring very high three-dimensional open porosity, allowing water to rapidly transport. The bacteria were only trapped on the CNTs network surface via surface filtration, without pore plugging, endowing the mullite-CNT membrane with unprecedentedly low fouling propensity to keep high flux with long-term operation time.

Mesoporous titania-embedded polyacrylonitrile composite nanofibrous membrane for particulate matter filtration

2019 ◽  
pp. 089270571985992
Author(s):  
P Reena ◽  
N Gobi ◽  
P Chitralekha ◽  
D Thenmuhil ◽  
V Kamaraj
Keyword(s):  
Particulate Matter ◽  
Composite Membrane ◽  
Weight Ratio ◽  
Composite Membranes ◽  
Areal Density ◽  
Mesoporous Titania ◽  
High Porosity ◽  
Homogenous Distribution

In the present work, mesoporous titania (MT)-embedded polyacrylonitrile (PAN) nanofibrous membranes have been developed and studied for their efficiency in particulate matter (PM) filtration. Using Box–Behnken method, 15 nanofibrous composite membranes were obtained through electrospinning by choosing three different process variables, such as MT (weight ratio), areal density (g m−2), and spinning time (h). The characterization of resulted nanofibrous composite membranes revealed that the homogenous distribution of MT (2.9 nm) within the PAN delivers high porosity as well as air permeability. Further, filtration efficiency (FE) was also analyzed for PM from 0.3 µm to 3 µm. PM filtration studies suggested that the nanofibrous composite membrane developed from 15% MT, spin time of 2 h, and areal density of 80 g m−2 possesses overall efficiency of 96.4%, without pressure drop for the composite. The results suggest that the role of MT was found to be significant in achieving successful filtration of PM. In addition to successful FE, the desirability value of the developed composite was also calculated statistically and the optimized composite membrane was identified.

scholarly journals Synthesis, Characterization, and Stability Evaluation of β-Carotene Encapsulated in Starch-Chitosan/Tripolyphosphate Matrices

2020 ◽  
Vol 20 (4) ◽  
pp. 929 ◽  
Author(s):  
Agnes Dyah Novitasari Lestari ◽  
Dwi Siswanta ◽  
Ronny Martien ◽  
Mudasir Mudasir
Keyword(s):  
Storage Stability ◽  
Weight Ratio ◽  
Xrd Analysis ◽  
Sem Images ◽  
Film Forming ◽  
Encapsulation Process ◽  
The Stability ◽  
Addition Level ◽  
Β Carotene

This study aims to investigate the synthesis and characterization of β-carotene encapsulated in the blending matrices of starch (native and hydrolyzed starch)-chitosan/TPP (tripolyphosphate) by examining the effects of starch-to-chitosan weight ratio, β-carotene addition level, and TPP addition level on the encapsulation efficiency (EE) and loading capacity (LC); and to evaluate their storage stability. The encapsulation was done by the dropwise addition of ethanolic β-carotene dispersion into the blending matrices. The results of XRD analysis show that the encapsulation process significantly decreases the crystallinity of the starches, chitosan, and β-carotene. Scanning electron microscope (SEM) images reveal that the encapsulation products form irregular lumps. The EE and LC tend to increase with the increase in polymer fraction of matrices and β-carotene addition level, and with the decrease in TPP addition level. The addition of chitosan and the replacement of native starch by hydrolyzed starch tend to increase storage stability of β-carotene encapsulated in the starch matrix because chitosan can act as a good film-forming and antioxidant, while hydrolyzed starch contains amylose amylopectin with a short chain which is better in film-forming ability. These results promote the use of the hydrolyzed starch-chitosan/TPP as a matrix to enhance the stability β-carotene via encapsulations.

Synthesis and Characterization of Mg-Al Layered Double Hydroxide

2012 ◽  
Vol 454 ◽  
pp. 101-104 ◽  
Author(s):  
Wan Zhong Yin ◽  
Qi Tan ◽  
Lei Liu ◽  
Xiao Li Li
Keyword(s):  
Layered Double Hydroxide ◽  
Milling Time ◽  
Raw Materials ◽  
Weight Ratio ◽  
Hydroxyl Groups ◽  
Wet Milling ◽  
Ft Ir ◽  
Double Hydroxide ◽  
Partical Size

Mg-Al layered double hydroxide was synthesized by the method of mechanochemistry /crystallization at the dry milling time of 6 h, wet milling time of 2 h, milling speed of 250 r/min, and ball to powder weight ratio of 50 to 1 using brucite, Al(OH)3 and Na2CO3 as the raw materials. Characterizations of the materials were achieved by XRD, TEM, FT-IR and TG-DSC. The results showed that well crystallized Mg-Al LDH with average partical size of 40 nm were synthesized under this condition. Mg-Al LDH was formed with CO32- freely intercalated between the hydroxide host layers. The material generally decomposed via two distinct stages. The first stage at 229.5 °C was attributed to the loss of interlayer water, and the second stage at 407.8°C was due to the loss of hydroxyl groups from the brucite-like layer, as well as of the carbonate irons.

TEM characterization of Au/Polysilicon interactions

1990 ◽  
Vol 48 (4) ◽  
pp. 650-651
Author(s):  
N. David Theodore ◽  
Leslie H. Allen ◽  
C. Barry Carter ◽  
James W. Mayer
Keyword(s):  
Solid Phase ◽  
Single Crystal Silicon ◽  
Chemical Vapor ◽  
Electrical Contacts ◽  
Silicon Substrates ◽  
Crystal Silicon ◽  
Transmission Electron ◽  
Polysilicon Films ◽  
The Stability

Metal/polysilicon investigations contribute to an understanding of issues relevant to the stability of electrical contacts in semiconductor devices. These investigations also contribute to an understanding of Si lateral solid-phase epitactic growth. Metals such as Au, Al and Ag form eutectics with Si. reactions in these metal/polysilicon systems lead to the formation of large-grain silicon. Of these systems, the Al/polysilicon system has been most extensively studied. In this study, the behavior upon thermal annealing of Au/polysilicon bilayers is investigated using cross-section transmission electron microscopy (XTEM). The unique feature of this system is that silicon grain-growth occurs at particularly low temperatures ∽300°C).Gold/polysilicon bilayers were fabricated on thermally oxidized single-crystal silicon substrates. Lowpressure chemical vapor deposition (LPCVD) at 620°C was used to obtain 100 to 400 nm polysilicon films. The surface of the polysilicon was cleaned with a buffered hydrofluoric acid solution. Gold was then thermally evaporated onto the samples.

Rheological characterization of tack and viscoelasticity of compositions of crepe coating used in the Yankee dryer

TAPPI Journal ◽  
2019 ◽  
Vol 18 (11) ◽  
pp. 641-649
Author(s):  
JOSHUA OMAMBALA ◽  
CARL MCINTYRE
Keyword(s):  
Normal Force ◽  
Weight Ratio ◽  
Good Combination ◽  
Rheological Characterization ◽  
Nonlinear Viscoelastic ◽  
Coating Composition ◽  
Linear And Nonlinear ◽  
Work Done ◽  
Tissue Production

The vast majority of tissue production uses creping to achieve the required set of properties on the base sheet. The Yankee coating helps to develop the desired crepe that in turn determines properties such as bulk and softness. The adhesion of the sheet to the Yankee surface is a very important characteristic to consider in achieving the desired crepe. The coating mix usually consists of the adhesive, modifier, and release. A good combination of these components is essential to achieving the desired properties of the tissue or towel, which often are determined by trials on the machine that can be time consuming and lead to costly rejects. In this paper, five compositions of an industrial Yankee coating adhesive, modifier, and release were examined rheologically. The weight ratio of the adhesive was kept constant at 30% in all five compositions and the modifier and release ratios were varied. The normal force and work done by the different compositions have been shown at various temperatures simulating that of the Yankee surface, and the oscillatory test was carried out to explain the linear and nonlinear viscoelastic characteristic of the optimal coating composition.

Physical - Chemical Issues of Cephalosporin Intercalated Nanoparticles for Life - Threatening Infections Treatment

2001 ◽  
Vol 71 (3) ◽  
pp. 342-349
Author(s):  
Lucian Eva ◽  
Letitia Doina Duceac ◽  
Liviu Stafie ◽  
Constantin Marcu ◽  
Geta Mitrea ◽  
...  
Keyword(s):  
Chemical Characterization ◽  
Advanced Characterization ◽  
Generation Cephalosporin ◽  
Fourth Generation ◽  
Exchange Method ◽  
Physico Chemical ◽  
Life Threatening ◽  
Double Hydroxide ◽  
Double Hydroxides

The fourth generation cephalosporin antibacterial agent, cefepime, was loaded into layered double hydroxides for enhancing antibiotic efficiency, reducing side effects, as well as achieving the sustained release property. The intercalation of antibiotic into the inter-gallery of ZnAl-layered double hydroxide (LDH) was carried out using ion exchange method, by this constituting a nano-sized organic-inorganic hybrid material for a controlled release novel formulation. Although cefepime is a broad spectrum antibiotic, it has various adverse effects and a significant degradation rate. Thus, the preparation and physico-chemical characterization of nanomaterials able to intercalate this drug is an important study for medical and pharmaceutical field. The antibiotic inclusion into LDHs nanostructure was confirmed by advanced characterization techniques and the release profile of cefepime was analysed with the respect to pH of the simulated media.

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