Determination of cake thickness and porosity during cross-flow ultrafiltration on a plane ceramic membrane surface using an electrochemical method

2002 ◽  
Vol 210 (2) ◽  
pp. 245-258 ◽  
Author(s):  
C Gaucher ◽  
P Jaouen ◽  
J Comiti ◽  
P Legentilhomme
Keyword(s):  
Electrochemical Method ◽  
Ceramic Membrane ◽  
Membrane Surface ◽  
Cross Flow ◽  
Cake Thickness

Rapid novel test for the determination of biofouling potential on reverse osmosis membranes

2016 ◽  
Vol 73 (12) ◽  
pp. 2978-2985 ◽  
Author(s):  
Cervinia V. Manalo ◽  
Masaki Ohno ◽  
Tetsuji Okuda ◽  
Satoshi Nakai ◽  
Wataru Nishijima
Keyword(s):  
Reverse Osmosis ◽  
Fluorescence Intensity ◽  
Biofilm Formation ◽  
Membrane Surface ◽  
Cross Flow ◽  
Direct Analysis ◽  
Novel Method ◽  
Ro Membrane ◽  
Flow Experiments

Abstract A novel method was proposed to determine biofouling potential by direct analysis of a reverse osmosis (RO) membrane through fluorescence intensity analysis of biofilm formed on the membrane surface, thereby incorporating fouling tendencies of both feedwater and membrane. Evaluation of the biofouling potential on the RO membrane was done by accelerated biofilm formation through soaking of membranes in high biofouling potential waters obtained by adding microorganisms and glucose in test waters. The biofilm formed on the soaked membrane was quantified by fluorescence intensity microplate analysis. The soaking method's capability in detecting biofilm formation was confirmed when percentage coverage obtained through fluorescence microscopy and intensity values exhibited a linear correlation (R2 = 0.96). Continuous cross-flow experiments confirmed the ability and reliability of the soaking method in giving biofouling potential on RO membranes when a good correlation (R2 = 0.87) between intensity values of biofilms formed on the membrane during soaking and filtration conditions was obtained. Applicability of the test developed was shown when three commercially available polyamide (PA) RO membranes were assessed for biofouling potential. This new method can also be applied for the determination of biofouling potential in water with more than 3.6 mg L−1 easily degradable organic carbon.

Effect of Process Factors on Pervaporation Dehydration of Isopropanol

2017 ◽  
Vol 68 (6) ◽  
pp. 1302-1305
Author(s):  
Ali A. A. Al Janabi ◽  
Oana Cristina Parvulescu ◽  
Bogdan Trica ◽  
Tanase Dobre
Keyword(s):  
Ceramic Membrane ◽  
Membrane Surface ◽  
Water System ◽  
Surface Model ◽  
Feed Water ◽  
Mixture Flow ◽  
Water Separation ◽  
Membrane Area ◽  
Operation Temperature ◽  
Process Factors

The paper aimed at studying the performances of pervaporation separation of isopropanol-water system using a Pervatech ceramic membrane at various values of feed mixture flow rate (F=1000 kg/hr), feed water mass fraction (xF=0.1-0.2), operation temperature (t=60-90 �C), permeate pressure (pP=1000-9000 Pa) and water separation degree (sW=0.9, 0.95). Membrane total flux and separation factor were predicted applying a second order response surface model with 3 factors, i.e., xF, t and pP. An algorithm for estimating the membrane surface area was presented. Membrane area increased with sW and xF and its lowest values (A=13 m2 for xF=0.1 and A=24 m2 for xF=0.2) were attained for t=60 �C and pP=9000 Pa. These findings could be applied for optimizing the process of isopropanol dehydration by pervaporation.

Low-pressure membrane filtration with unconventional coagulation regimes

2005 ◽  
Vol 5 (5) ◽  
pp. 1-8 ◽  
Author(s):  
K.Y. Choi ◽  
B.A. Dempsey
Keyword(s):  
Activated Carbon ◽  
Membrane Filtration ◽  
Membrane Surface ◽  
Cross Flow ◽  
Chemical Cleaning ◽  
Sand Filters ◽  
Charge Neutralization ◽  
Floc Size ◽  
Filtration System ◽  
Pre Treatment

The objective of the research was to evaluate in-line coagulation to improve performance during ultrafiltration (UF). In-line coagulation means use of coagulants without removal of coagulated solids prior to UF. Performance was evaluated by removal of contaminants (water quality) and by resistance to filtration and recovery of flux after hydraulic or chemical cleaning (water production). We hypothesized that coagulation conditions inappropriate for conventional treatment, in particular under-dosing conditions that produce particles that neither settle nor are removed in rapid sand filters, would be effective for in-line coagulation prior to UF. A variety of pre-treatment processes for UF have been investigated including coagulation, powdered activated carbon (PAC) or granular activated carbon (GAC), adsorption on iron oxides or other pre-formed settleable solid phases, or ozonation. Coagulation pre-treatment is often used for removal of fouling substances prior to NF or RO. It has been reported that effective conventional coagulation conditions produced larger particles and this reduced fouling during membrane filtration by reducing adsorption in membrane pores, increasing cake porosity, and increasing transport of foulants away from the membrane surface. However, aggregates produced under sweep floc conditions were more compressible than for charge neutralization conditions, resulting in compaction when the membrane filtration system was pressurized. It was known that the coagulated suspension under either charge-neutralization or sweep floc condition showed similar steady-state flux under the cross-flow microfiltration mode. Another report on the concept of critical floc size suggested that flocs need to reach a certain critical size before MF, otherwise membranes can be irreversibly clogged by the coagulant solids. The authors were motivated to study the effect of various coagulation conditions on the performance of a membrane filtration system.

Effect of Fluidized Bed on Permeate Flux in Ceramic Membrane Cross-Flow Microfiltration

1995 ◽  
Vol 60 (12) ◽  
pp. 2074-2084
Author(s):  
Petr Mikulášek
Keyword(s):  
Fluidized Bed ◽  
Ceramic Membrane ◽  
Cross Flow ◽  
Experimental System ◽  
Experimental Results ◽  
Spherical Particles ◽  
Permeate Flux ◽  
Model Fluid ◽  
Optimum Porosity ◽  
Tubular Membranes

The microfiltration of a model fluid on an α-alumina microfiltration tubular membrane in the presence of a fluidized bed has been examined. Following the description of the basic characteristic of alumina tubular membranes, model dispersion and spherical particles used, some comments on the experimental system and experimental results for different microfiltration systems are presented. From the analysis of experimental results it may be concluded that the use of turbulence-promoting agents resulted in a significant increase of permeate flux through the membrane. It was found out that the optimum porosity of fluidized bed for which the maximum values of permeate flux were reached is approximately 0.8.

scholarly journals Determination of platelet antigens and glycoproteins in the human fetus

Blood ◽  
1986 ◽  
Vol 68 (2) ◽  
pp. 488-492 ◽  
Author(s):  
Y Gruel ◽  
B Boizard ◽  
F Daffos ◽  
F Forestier ◽  
J Caen ◽  
...  
Keyword(s):  
Monoclonal Antibodies ◽  
Human Fetus ◽  
Antenatal Diagnosis ◽  
Polyclonal Antibodies ◽  
Umbilical Vein ◽  
Membrane Surface ◽  
Platelet Suspension ◽  
Direct Puncture ◽  
Normal Human

Abstract The autosomal recessive transmission of Glanzmann's thrombasthenia (GT) and Bernard-Soulier syndrome (BSS), together with requests of families who already had children with these diseases, prompted us to investigate the feasibility of their antenatal diagnosis. The preliminary step leading to the early detection of GT or BSS was to characterize, in the normal human fetus, the platelet antigens and glycoproteins (GPs) and to define their normal amounts on the membrane surface. Blood samples from 32 fetuses between 18 to 26 weeks of gestation were collected by direct puncture of the umbilical vein using an ultrasound-guided needle. Polyclonal antibodies from human origin directed against PLA1, Leka antigens, and the GPIIb IIIa complex (IgGL), or murine monoclonal antibodies specific for GPIb (AN51, 6D1), GPIIIa (AP-3), or GPIIb IIIa (AP-2) were studied using platelet suspension immunofluorescence tests. The binding of each antibody was quantified using a cytofluorograph (Ortho 50H). PLA1 and Leka antigens were expressed in normal amounts on fetal platelets as early as 16 weeks of intrauterine life. The GPIIb IIIa complex quantified by polyclonal or monoclonal antibodies was in the same range in fetuses (IgGL = 427 +/- 23 AUF, AP-2 = 459.5 +/- 8.5; AP-3 = 536 +/- 14) and in adults (IgGL = 420 +/- 30; AP-2 = 498 +/- 11; AP-3 = 515 +/- 13). The platelet binding of antibodies that recognized GPIb was higher in fetuses (AN51 = 491.5 +/- 14; 6D1 = 479 +/- 15) than in adults (AN51 = 426.5 +/- 9; 6D1 = 449 +/- 8.7). These results suggest that immunological techniques can be applied as early as 18 weeks of gestation for the antenatal diagnosis of GT and BSS.

The macrophage capacity for phagocytosis

1992 ◽  
Vol 101 (4) ◽  
pp. 907-913 ◽  
Author(s):  
G.J. Cannon ◽  
J.A. Swanson
Keyword(s):  
Surface Area ◽  
Membrane Surface ◽  
Fc Receptors ◽  
Phagocytic Capacity ◽  
Membrane Surface Area ◽  
Murine Bone Marrow ◽  
Latex Beads ◽  
Endocytic Compartments ◽  
Frustrated Phagocytosis

Murine bone marrow-derived macrophages, which measure 13.8 +/− 2.3 microns diameter in suspension, can ingest IgG-opsonized latex beads greater than 20 microns diameter. A precise assay has allowed the determination of the phagocytic capacity, and of physiological parameters that limit that capacity. Ingestion of beads larger than 15 microns diameter required IgG-opsonization, and took 30 minutes to reach completion. Despite the dependence on Fc-receptors for phagocytosis of larger beads, cells reached their limit before all cell surface Fc-receptors were occupied. The maximal membrane surface area after frustrated phagocytosis of opsonized coverslips was similar to the membrane surface area required to engulf particles at the limiting diameter, indicating that the capacity was independent of particle shape. Vacuolation of the lysosomal compartment with sucrose, which expanded endocytic compartments, lowered the phagocytic capacity. This decrease was reversed when sucrose vacuoles were collapsed by incubation of cells with invertase. These experiments indicate that the phagocytic capacity is limited by the amount of available membrane, rather than by the availability of Fc-receptors. The capacity was also reduced by depolymerization of cytoplasmic microtubules with nocodazole. Nocodazole did not affect the area of maximal cell spreading during frustrated phagocytosis, but did alter the shape of the spread cells. Thus, microtubules may coordinate cytoplasm for engulfment of the largest particles.

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