Experimental and Modeling Assessment of Sulfate and Arsenic Removal from Mining Wastewater by Nanofiltration

2017 ◽  
Vol 16 (1) ◽  
Author(s):  
Sachin V. Jadhav ◽  
Piia Häyrynen ◽  
Kumudini V. Marathe ◽  
Virendra K. Rathod ◽  
Riitta L. Keiski ◽  
...  
Keyword(s):  
Arsenic Removal ◽  
Membrane Surface ◽  
Membrane Resistance ◽  
Water Recovery ◽  
Permeate Flux ◽  
Experimental Conditions ◽  
Gel Layer ◽  
Mining Wastewater ◽  
A Minor ◽  
The Given

Abstract The application of nanofiltration membranes to remove sulfate and arsenic from wastewaters was investigated. The influence of operating parameters on the rejection and permeate flux was determined. The nanofiltration experiments carried out with NF90 and NF270 membranes showed a high rejection of sulfate (~90 %) and arsenic (~97 %) under the given set of experimental conditions. Better permeate flux values were obtained by NF270 membrane with a minor drop in rejections, but it proved to be better in water recovery. In FESEM analysis, the sulfate deposition on the membrane surface confirmed its well-known precipitation in desalination types of equipment. The experimental results were successfully predicted by using theoretical framework available in the literature. The simulation was carried out by using Levenberg–Marquardt with Gauss–Newton algorithm in MATLAB and the prime important parameters, viz. membrane resistance $({R_m})$ , permeability coefficient ${{\rm{P}}_{\rm{m}}}$ , and mass transfer coefficient (k) were established separately for each membrane. The gel layer thickness was determined to better understand the hydrodynamics over the membrane surface and it validated the assumption of negligible fouling.

Ultrafiltration of silica sols

1989 ◽  
Vol 54 (1) ◽  
pp. 91-101 ◽  
Author(s):  
Milan Stakić ◽  
Slobodan Milonjić ◽  
Vladeta Pavasović ◽  
Zoja Ilić
Keyword(s):  
Particle Size ◽  
Silica Particle ◽  
Specific Resistance ◽  
Membrane Surface ◽  
Membrane Resistance ◽  
Experimental Conditions ◽  
Surface Unit ◽  
Silica Sols ◽  
Filtration Flux ◽  
Batch Cell

Ultrafiltration of three laboratory made silica and two commercial silica sols was studied using Amicon YC membrane in a 200 ml capacity batch-cell. The effect of silica particle size, stirring conditions, pressure, pH and silica contents on ultrafiltration was investigated. The results obtained indicate that the smaller particles have, disregarding the stirring conditions, lower filtration flux. The differences observed in filtration flux are more pronounced in the conditions without stirring. The obtained value of the membrane resistance is independent of the conditions investigated (stirring, pressure, pH, silica contents and particle size). The values of the resistance of polarized solids, specific resistance, and the mass of gel per membrane surface unit were calculated for all experimental conditions.

scholarly journals Long-Running Comparison of Feed-Water Scaling in Membrane Distillation

Membranes ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 173
Author(s):  
Mohammad Rezaei ◽  
Albraa Alsaati ◽  
David M. Warsinger ◽  
Florian Hell ◽  
Wolfgang M. Samhaber
Keyword(s):  
Tap Water ◽  
Saturation Index ◽  
Membrane Surface ◽  
Membrane Distillation ◽  
Salt Crystallization ◽  
Feed Water ◽  
Water Recovery ◽  
Permeate Flux ◽  
Salt Scaling ◽  
Precipitous Decline

Membrane distillation (MD) has shown promise for concentrating a wide variety of brines, but the knowledge is limited on how different brines impact salt scaling, flux decline, and subsequent wetting. Furthermore, past studies have lacked critical details and analysis to enable a physical understanding, including the length of experiments, the inclusion of salt kinetics, impact of antiscalants, and variability between feed-water types. To address this gap, we examined the system performance, water recovery, scale formation, and saturation index of a lab-scale vacuum membrane distillation (VMD) in long-running test runs approaching 200 h. The tests provided a comparison of a variety of relevant feed solutions, including a synthetic seawater reverse osmosis brine with a salinity of 8.0 g/L, tap water, and NaCl, and included an antiscalant. Saturation modeling indicated that calcite and aragonite were the main foulants contributing to permeate flux reduction. The longer operation times than typical studies revealed several insights. First, scaling could reduce permeate flux dramatically, seen here as 49% for the synthetic brine, when reaching a high recovery ratio of 91%. Second, salt crystallization on the membrane surface could have a long-delayed but subsequently significant impact, as the permeate flux experienced a precipitous decline only after 72 h of continuous operation. Several scaling-resistant impacts were observed as well. Although use of an antiscalant did not reduce the decrease in flux, it extended membrane operational time before surface foulants caused membrane wetting. Additionally, numerous calcium, magnesium, and carbonate salts, as well as silica, reached very high saturation indices (>1). Despite this, scaling without wetting was often observed, and scaling was consistently reversible and easily washed. Under heavy scaling conditions, many areas lacked deposits, which enabled continued operation; existing MD performance models lack this effect by assuming uniform layers. This work implies that longer times are needed for MD fouling experiments, and provides further scaling-resistant evidence for MD.

Formation and prevention of hardly removable particle layers in inside-out capillary membranes operating in dead-end mode

2003 ◽  
Vol 3 (5-6) ◽  
pp. 117-124 ◽  
Author(s):  
S. Panglisch
Keyword(s):  
Boundary Conditions ◽  
Membrane Surface ◽  
Cross Flow ◽  
Membrane Resistance ◽  
Permeate Flux ◽  
Dead End ◽  
Capillary Membrane ◽  
Theoretical Predictions ◽  
Capillary Membranes ◽  
Geometrical Boundary

Although numerous ultra- and microfiltration dead-end plants with capillary membranes are already operative, some phenomena are still unexplained. Therefore, the fundamental processes taking place inside a capillary membrane were observed. Initially, the flow field depending on axial and radial position inside the capillary was determined. Then, particle transport and deposition were theoretically studied by determination of particle trajectories considering influences of particle concentration and walleffects on hydrodynamics, DLVO-forces, buoyancy, gravitation, diffusion and interparticular forces. Following these calculations, incoming particles with a diameter smaller than the so-called “limiting diameter”, which depends on operational and geometrical boundary conditions, due to depositions are widely and evenly distributed. Larger particles do not deposit until they are at a certain distance from the water inlet. The larger the particle size, the longer the distance. If the particle is larger than the so-called “corkforming diameter” then the particles are transported to the dead-end of the capillary which may cause a clogging of the capillary. This “corkforming diameter” depends on operational as well on geometrical boundary conditions. These theoretical predictions are confirmed by experimental results from investigations with spherical latex and non-spherical walnut particles. To avoid this clogging, the deposition of the particles should be evenly distributed, which means that the “corkforming diameter” should be as large as possible. That goal could be achieved by operating the membrane plant with short and/or wide capillaries. However, a small permeate flux, a small membrane resistance and/or a small membrane surface potential succeed as well. Another possibility could be to operate the capillaries with a very small cross flow.

scholarly journals Reliable Sea Water Ro Operation with High Water Recovery and No-Chlorine/No-Sbs Dosing in Arabian Gulf, Saudi Arabia

Membranes ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 141 ◽  
Author(s):  
Hiroki Miyakawa ◽  
Mohammed Maghram Al Shaiae ◽  
Troy N. Green ◽  
Yohito Ito ◽  
Yuichi Sugawara ◽  
...  
Keyword(s):  
Membrane Fouling ◽  
Sea Water ◽  
Surface Condition ◽  
Membrane Surface ◽  
Formation Rate ◽  
Arabian Gulf ◽  
High Water ◽  
Water Recovery ◽  
Permeate Flux ◽  
Autopsy Study

For providing advanced desalination the combination of the improvement of water recovery ratio in the reverse osmosis (RO) process and the No-Chlorine/No-Sodium Bisulfite (SBS) Dosing process was studied. In order to prevent membrane fouling even in high recovery water operations, an advanced two-stage design was implemented to (1) control the permeate flux through the RO membrane module, (2) optimize the system to reduce contaminant build-up and (3) eliminate the use of chlorine and SBS, which can accelerate membrane fouling. The system was evaluated by monitoring the biofouling and the microorganisms proliferation on the membrane surface based on membrane biofilm formation rate (mBFR). The pilot plant was operated in the condition of a water recovery rate of 55%. As a result, the system was operated for longer than four months without membrane cleaning (clean in place; CIP) and the possibility of operation for seven months without CIP was confirmed by the extrapolation of the pressure values. In addition, the mBFR is a reliable tool for water quality assessment, based on a comparison between the fouling tendency estimated from the mBFR and the actual membrane surface condition from autopsy study and the effectiveness No-Chlorine/No-SBS Dosing process was verified from mBFR of pretreated seawater.

scholarly journals Recovery of Methyl Green from Aqueous Solution using NF Membrane

2017 ◽  
Vol 12 (1) ◽  
Author(s):  
P. Sharma ◽  
M. M. Bora ◽  
S. Hazarika ◽  
S. Borthakur ◽  
C. Tamuli ◽  
...  
Keyword(s):  
Membrane Fouling ◽  
Transport Model ◽  
Membrane Surface ◽  
Water Flux ◽  
Applied Pressure ◽  
Membrane Resistance ◽  
Methyl Green ◽  
Permeate Flux ◽  
Pore Flow ◽  
Polyamide Membrane

Recovery of a cationic synthetic dye, methyl green by nanofiltration (NF 270–400) membrane from commercial source (Filmtec, USA) was used for this study. The effect of membrane characteristics, applied pressure gradient ( ΔP ) and aqueous phase concentration of dye on the rejection, membrane fouling and water flux was studied over a range of pressure and concentration of 2 to 5 bar and 0.01 mmole L–1 to 0.05 mmole L–1 respectively. The solution flux increases with pressure in the pressure range studied indicate the effect of concentration polarization is not significant in this range. The cation shield effects of the dye on the negatively charged polyamide membrane perhaps result in decrease of permeate flux with concentration. The permeation phenomenon has been analyzed on the basis of pore flow transport model and the data analysis revealed that adsorption of dye on the membrane surface and intrinsic membrane resistance control the permeate flux.

scholarly journals Desalination of brackish groundwater by direct contact membrane distillation

2010 ◽  
Vol 61 (8) ◽  
pp. 2013-2020 ◽  
Author(s):  
D. Y. Hou ◽  
J. Wang ◽  
D. Qu ◽  
Z. K. Luan ◽  
C. W. Zhao ◽  
...  
Keyword(s):  
Direct Contact ◽  
Polyvinylidene Fluoride ◽  
Membrane Surface ◽  
Negative Influence ◽  
Membrane Distillation ◽  
Rapid Decline ◽  
Water Recovery ◽  
Permeate Flux ◽  
Feed Concentration ◽  
Direct Contact Membrane Distillation

The direct contact membrane distillation (DCMD) applied for desalination of brackish groundwater with self-made polyvinylidene fluoride (PVDF) membranes was presented in the paper. The PVDF membrane exhibited high rejection of non-volatile inorganic salt solutes and a maximum permeate flux 24.5 kg m−2 h−1 was obtained with feed temperature at 70°C. The DCMD experimental results indicated that the feed concentration had no significant influence on the permeate flux and the rejection of solute. When natural groundwater was used directly as the feed, the precipitation of CaCO3 would be formed and clog the hollow fibre inlets with gradual concentration of the feed, which resulted in a rapid decline of the module efficiency. The negative influence of scaling could be eliminated by acidification of the feed. Finally, a 250 h DCMD continuous desalination experiment of acidified groundwater with the concentration factor at constant 4.0 was carried out. The permeate flux kept stable and the permeate conductivity was less than 7.0 μS cm−1 during this process. Furthermore, there was no deposit observed on the membrane surface. All of these demonstrated that DCMD could be efficiently used for production of high-quality potable water from brackish groundwater with water recovery as high as 75%.

Arsenic removal by MF membrane with chemical sludge adsorption and NF membrane equipped with vibratory shear enhanced process

2003 ◽  
Vol 3 (5-6) ◽  
pp. 303-310 ◽  
Author(s):  
S.-H. Yi ◽  
S. Ahmed ◽  
Y. Watanabe ◽  
K. Watari
Keyword(s):  
Arsenic Removal ◽  
Membrane Surface ◽  
Membrane Process ◽  
Low Concentrations ◽  
Strong Shear ◽  
Low Levels ◽  
Removal Processes ◽  
Removal Of Arsenic ◽  
Concentration Polarization Layer ◽  
Chemical Sludge

Conventional arsenic removal processes have difficulty removing low concentrations of arsenic ion from water. Therefore, it is very hard to comply with stringent low levels of arsenic, such as below 10 μg/L. So, we have developed two arsenic removal processes which are able to comply with more stringent arsenic regulations. They are the MF membrane process combined with chemical sludge adsorption and NF membrane process equipped with the vibratory shear enhanced process (VSEP). In this paper, we examine the performance of these new processes for the removal of arsenic ion of a low concentration from water. We found that chemical sludge produced in the conventional rapid sand filtration plants can effectively remove As (V) ions of H2AsO4- and HAsO42- through anion exchange reaction. The removal efficiency of MF membrane process combined with chemical sludge adsorption increased to about 36%, compared to MF membrane alone. The strong shear force on the NF membrane surface produced by vibration on the VSEP causes the concentration polarization layer to thin through increased back transport velocity of particles. So, it can remove even dissolved constituents effectively. Therefore, As (V) ions such as H2AsO4- and HAsO42- can be removed. The concentration of As (V) ions decreased from 50 μg/L to below 10 μg/L and condensation factor in recirculating water increased up to 7 times by using NF membrane equipped with VSEP.

scholarly journals From Stress to Shape: Equilibrium of Cloister and Cross Vaults

2021 ◽  
Vol 11 (9) ◽  
pp. 3846
Author(s):  
Andrea Montanino ◽  
Carlo Olivieri ◽  
Giulio Zuccaro ◽  
Maurizio Angelillo
Keyword(s):  
Error Function ◽  
Membrane Surface ◽  
Equilibrium Analysis ◽  
Test Cases ◽  
Order Partial Differential Equation ◽  
Negative Semidefinite ◽  
Historical Heritage ◽  
Masonry Vaults ◽  
Membrane Shape ◽  
The Given

The assessment of the equilibrium and the safety of masonry vaults is of high relevance for the conservation and restoration of historical heritage. In the literature many approaches have been proposed for this tasks, starting from the 17th century. In this work we focus on the Membrane Equilibrium Analysis, developed under the Heyman’s theory of Limit Analysis. Within this theory, the equilibrium of a vault is assessed if it is possible to find at least one membrane surface, between the volume of the vaults, being in equilibrium under the given loads through a purely compressive stress field. The equilibrium of membranes is described by a second order partial differential equation, which is definitely elliptic only when a negative semidefinite stress is assigned, and the shape is the unknown of the problem. The proposed algorithm aims at finding membrane shapes, entirely comprised between the geometry of the vault, in equilibrium with admissible stress fields, through the minimization of an error function with respect to shape parameters of the stress potential, and then, with respect to the boundary values of the membrane shape. The application to two test cases shows the viability of this tool for the assessment of the equilibrium of existing masonry vaults.

scholarly journals Hydrophylicity Enhancement of Modified Cellulose Acetate Membrane to Improve the Membrane Performance in Produced Water Treatment

2018 ◽  
Vol 156 ◽  
pp. 08003 ◽  
Author(s):  
Tutuk Djoko Kusworo ◽  
Danny Soetrisnanto ◽  
Cynthia Santoso ◽  
Tyas Dwi Payanti ◽  
Dani Puji Utomo
Keyword(s):  
Water Treatment ◽  
Produced Water ◽  
Uv Light ◽  
Light Exposure ◽  
Membrane Surface ◽  
Asymmetric Structure ◽  
Dense Layer ◽  
Cellulose Acetate Membrane ◽  
Permeate Flux ◽  
Produced Water Treatment

Produced water is a wastewater generated from petroleum industry with high concentration of pollutants such as Total Dissolved Solid, Organic content, and Oil and grease. Membrane technology has been currently applied for produced water treatment due to its efficiency, compact, mild and clean process. The main problem of produced water using membrane is fouling on the membrane surface which causes on low permeate productivity. This paper is majority focused on the improvement of anti-fouling performance through several modifications to increase CA membrane hydrophilicity. The membrane was prepared by formulating the dope solution consists of 18 wt-% CA polymer, acetone, and PEG additive (3 wt-%, 5 wt-%, and 7 wt-%). The membranes are casted using NIPS method and being irradiated under UV light exposure. The SEM images show that parepared membrane has asymmetric structure consist of dense layer, intermediete layer, and finger-like support layer. The filtration test shows that PEG addition increase the membrane hydrophilicity and the permeate flux increases. UV light exposure on the membrane improves the membrane stability and hydrophilicity. The imrpovement of membrane anti-fouling performance is essential to achieve the higher productivity without lowering its pollutants rejection.

scholarly journals Data-driven Modelling of Microfiltration Process with Embedded Static Mixer for Steepwater from Corn Starch Industry

2017 ◽  
Author(s):  
Laslo Šereš ◽  
Ljubica Dokić ◽  
Bojana Ikonić ◽  
Dragana Šoronja-Simović ◽  
Miljana Djordjević ◽  
...  
Keyword(s):  
Corn Starch ◽  
Desirability Function ◽  
Specific Energy Consumption ◽  
Cross Flow ◽  
Operating Conditions ◽  
Transmembrane Pressure ◽  
Static Mixer ◽  
Permeate Flux ◽  
Experimental Conditions ◽  
Starch Industry

Cross-flow microfiltration using ceramic tubular membrane was applied for treatment of steepwater from corn starch industry. Experiments are conducted according to the faced centered central composite design at three different transmembrane pressures (1, 2 and 3 bar) and cross-flow velocities (100, 150 and 200 L/h) with and without the usage of Kenics static mixer. For examination of the influence of the selected operating conditions at which usage of the static mixer is justified, a response surface methodology and desirability function approach were used. Obtained results showed improvement in the average permeate flux by using Kenics static mixer for 211 % to 269 % depending on experimental conditions when compared to the system without the static mixer. As a result of optimization, the best results considering flux improvement as well as reduction of specific energy consumption were obtained at low transmembrane pressure and lower feed cross-flow rates.

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