Influence of floc structure on membrane permeability in the coagulation-MF process

2005 ◽  
Vol 51 (6-7) ◽  
pp. 143-150 ◽  
Author(s):  
M.-H. Cho ◽  
C.-H. Lee ◽  
S. Lee
Keyword(s):  
Fractal Dimension ◽  
Membrane Permeability ◽  
Hybrid System ◽  
Concentration Ratio ◽  
Particle Concentration ◽  
Specific Resistance ◽  
Suspended Particle ◽  
Ion Concentration ◽  
Operating Parameters ◽  
Floc Structure

The relation between floc structure and membrane permeability was studied in a coagulation-MF hybrid process. The floc structure changed with operating parameters in the coagulation process and was quantified with fractal dimension (dF). The concentration ratio between suspended colloids and injected coagulant had an essential effect on dF of coagulated flocs. Larger flocs with low fractal dimension were produced for ALT (aluminum ion concentration dosed/suspended particle concentration) between 0.4 and 0.8. Flocs maintained stable characteristics at the coagulation period of over 20 minutes. Membrane permeability was improved with coagulated flocs of lower fractal dimension, which tend to have higher porosity and aggregate relatively loosely. These more porous flocs reduce specific resistance of coagulated flocs. The relation between membrane filterability and fractal dimension of flocs was explored in a submerged MF hybrid system as well as in a batch unstirred cell filtration.

scholarly journals Microbial Flocculants as an Alternative to Synthetic Polymers for Wastewater Treatment: A Review

Symmetry ◽  
2018 ◽  
Vol 10 (11) ◽  
pp. 556 ◽  
Author(s):  
Faouzi Ben Rebah ◽  
Wissem Mnif ◽  
Saifeldin M. Siddeeg
Keyword(s):  
Heavy Metals ◽  
Wastewater Treatment ◽  
Suspended Solids ◽  
Specific Resistance ◽  
Oxygen Demand ◽  
Synthetic Polymers ◽  
Operating Parameters ◽  
Flocculating Activity ◽  
Microbial Strains ◽  
Active Substances

Microorganisms such as bacteria, fungi, and microalgae have been used to produce bioflocculants with various structures. These polymers are active substances that are biodegradable, environmentally harmless, and have flocculation characteristics. Most of the developed microbial bioflocculants displayed significant flocculating activity (FA > 70–90%) depending on the strain used and on the operating parameters. These biopolymers have been investigated and successfully used for wastewater depollution in the laboratory. In various cases, selected efficient microbial flocculants could reduce significantly suspended solids (SS), turbidity, chemical oxygen demand (COD), total nitrogen (Nt), dye, and heavy metals, with removal percentages exceeding 90% depending on the bioflocculating materials and on the wastewater characteristics. Moreover, bioflocculants showed acceptable results for sludge conditioning (accepted levels of dry solids, specific resistance to filtration, moisture, etc.) compared to chemicals. This paper explores various bioflocculants produced by numerous microbial strains. Their production procedures and flocculating performance will be included. Furthermore, their efficiency in the depollution of wastewater will be discussed.

Effect of slurry concentration on erosion wear behavior of AISI 5117 steel and high-chromium white cast iron

2018 ◽  
Vol 70 (4) ◽  
pp. 628-638 ◽  
Author(s):  
Mohammed Ahmed Al-Bukhaiti ◽  
Ahmed Abouel Kasem Mohamad ◽  
Karam Mosa Emara ◽  
Shemy M. Ahmed
Keyword(s):  
Fractal Dimension ◽  
Cast Iron ◽  
Erosion Rate ◽  
Particle Concentration ◽  
White Cast Iron ◽  
Slurry Erosion ◽  
Content Type ◽  
High Chromium ◽  
Slurry Concentration ◽  
The Impact

Purpose This paper aims to investigate the influence of slurry concentration on the erosion behavior of AISI 5117 steel and high-chromium white cast iron by using a whirling-arm rig. In this study, the slurry erosion mechanism with particle concentration has been studied. Design/methodology/approach The tests were carried out with particle concentrations in the range of 1-7 Wt.%, and the impact velocity of slurry stream was 15 m/s. Silica sand with a nominal size range of 500-710 µm was used as an erodent. The study revealed that the failure mode was independent of concentration. Findings The results showed that the erosion rate decreases with the increase in particle concentration and the variation in the reduction depends on the material. It was found that the variation of fractal dimension calculated from slope of linearized power spectral density of eroded surface image for different concentrations can be used to characterize the slurry erosion intensity in a similar manner to the erosion rate. It was also found that the variation of fractal dimension versus concentration of sand has a general trend that does not depend on magnification factor. Originality/value Using the gravitational measurement and image analysis, the variation of the wear with slurry concentration has been analyzed to investigate the implicated mechanisms of erosion during the process.

scholarly journals Investigating Methylene Blue Adsorption and Photocatalytic Activity of ZnO/CNC Nanohybrids

2020 ◽  
Vol 2020 ◽  
pp. 1-10
Author(s):  
Vu Nang An ◽  
Tran T. T. Van ◽  
Ha T. C. Nhan ◽  
Le Van Hieu
Keyword(s):  
Methylene Blue ◽  
Photocatalytic Activity ◽  
Concentration Ratio ◽  
Low Cost ◽  
Nitrogen Adsorption ◽  
Ion Concentration ◽  
Strong Absorption Band ◽  
Pure Cellulose ◽  
Nypa Fruticans ◽  
Bet Analysis

Nanohybrids of zinc oxide/cellulose nanocrystals (ZnO/CNCs) were successfully prepared by using a low cost and green method for adsorption and photocatalytic degradation of methylene blue (MB). CNCs have been derived through the hydrolysis reaction by citric/hydrochloric acid from the pure cellulose isolated from Vietnamese Nypa fruticans trunk. The influence of the Zn2+ ion concentration on the morphology, microstructure, and thermal properties as well as the photocatalytic activity of the ZnO/CNC nanohybrids was investigated in detail. Analyses of FTIR spectra, XRD, and SEM indicated that the ZnO nanocrystals with the size of 50 nm formed and loaded on the surface of CNC. Based on the DRS spectra and the nitrogen adsorption–desorption isotherms (BET) analysis, the absorption of ultraviolet light with a strong absorption band around 400 nm was found for all the ZnO/CNC nanohybrids, and the values of specific surface areas (SBET) of materials can be controlled by changing the concentration ratio of Zn2+ ion and CNC. The TGA analysis demonstrated that the ZnO loading samples (ZnO/CNC) had the thermal degradation onset temperature higher than that of neat CNC. The effect of MB removal showed the results which were contributed not only by the adsorption ability of CNC but also by the photocatalytic activity of ZnO. The photocatalytic efficiency significantly depended on the content of ZnO loading. The maximum degradation of MB was about 95% in 150 min for the ZnO/CNC-1.0 sample in which the concentration ratio of zinc-precursor Zn(NO3)2·6H2O and CNC was 1.0.

Lithium/sodium ion concentration ratio measurements in blood serum with lithium and sodium ion selective liquid membrane electrodes

1987 ◽  
Vol 59 (13) ◽  
pp. 1600-1603 ◽  
Author(s):  
Erich. Metzger ◽  
Rene. Dohner ◽  
Wilhelm. Simon ◽  
Dieter J. Vonderschmitt ◽  
Kurt. Gautschi
Keyword(s):  
Blood Serum ◽  
Concentration Ratio ◽  
Liquid Membrane ◽  
Sodium Ion ◽  
Ion Concentration ◽  
Membrane Electrodes

scholarly journals THE ELECTRIC CAPACITY OF SUSPENSIONS WITH SPECIAL REFERENCE TO BLOOD

1925 ◽  
Vol 9 (2) ◽  
pp. 137-152 ◽  
Author(s):  
Hugo Fricke
Keyword(s):  
Specific Resistance ◽  
Suspended Particle ◽  
Specific Capacity ◽  
Major Axis ◽  
Electrolytic Cell ◽  
Substitution Method ◽  
Static Capacity ◽  
Electric Capacity ◽  
Polarization Capacity ◽  
Made In

1. The specific capacity of a suspension is that capacity which) combined in parallel with a certain resistance, electrically balances 1 cm. cube of the suspension. 2. The following formula holds for the specific capacity of a suspension of spheroids, each of which is composed of a well conducting interior surrounded by a thin membrane of a comparatively high resistance: See PDF for Equation C, specific capacity of suspension; Co, static capacity of one sq. cm. of membrane; r, r1 specific resistances respectively of suspension and of suspending liquid; 2 q major axis of spheroid, α constant tabulated in Table I. 3. The following formula holds practically for any suspension whatever the form of the suspended particle. See PDF for Equation C = C100 being the specific capacity of a suspension with a concentration of 100 per cent. Formulæ (1a) and (1b) hold only for the case, when the frequency is so low, that the impedance of the static capacity of the membrane around a single particle is high as compared with the resistance of the interior of the particle. The formulae hold also for a suspension of homogeneous particles, when polarization takes place at the surface of each particle, provided the polarization resistance is low as compared with the impedance of the polarization capacity. 4. A description is given of a method for measuring the capacity of a suspension at frequencies between 800 and 4½ million cycles. By means of a specially designed bridge, a substitution method is employed, by which in the last analysis the suspension is compared with the suspending liquid which is so diluted as to have the same specific resistance as the suspension, consecutive measurements being made in the same electrolytic cell. 5. Formula (1b) is verified by measurements of the capacity of suspensions of varying volume concentrations of the red corpuscles of a dog. 6. By means of the above measurements, the value of Co is calculated by equation (1a). 7. It is found that Co is independent of the frequency up to 4½ million cycles and that it is also independent of the suspending liquid. These results furnish considerable evidence of the validity of the theory, that Co represents the static capacity of a corpuscle membrane. 8. On this assumption and using a probable value for the dielectric constant of the membrane, the thickness of the membrane is calculated to be 3.3·10–7 cm.

Dynamic removal of uranium by chitosan: influence of operating parameters

1996 ◽  
Vol 34 (10) ◽  
pp. 169-177 ◽  
Author(s):  
Marielle Jansson-Charrier ◽  
Eric Guibal ◽  
Jean Roussy ◽  
Robert Surjous ◽  
Pierre Le Cloirec
Keyword(s):  
Metal Ion ◽  
Fixed Bed ◽  
Ion Concentration ◽  
Operating Parameters ◽  
Hydrodynamic Behaviour ◽  
Fixed Bed Reactors ◽  
Effective Sorbent ◽  
Predominant Effect ◽  
Main Operating ◽  
Abandoned Mine Site

New wastewater treatments involving biosorption processes are being developed. This work focuses on the dynamic removal of uranium using chitosan in fixed-bed reactors and investigates the main operating parameters: particle size, column size, flow velocity and metal ion concentration. The results confirm the predominant effect of diffusion on the control rate. The optimization of the process should take into account both sorption performances and hydrodynamic behaviour. The process is successfully applied to the treatment of leachates at an abandoned mine site. This study shows that chitosan is an effective sorbent for the treatment and recovery of uranium from dilute effluents.

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