Elucidation of flux decline phenomenon in ultrafiltration of polydisperse silica solution

The public drinking water supply of southern Germany is characterized by a rather decentralized network. Due to the hydrogeological setting in these parts of Germany many of the small water works with an average capacity of 50 m3/h have to treat raw water extracted from karstic or cliffy aquifers. These raw waters tend to be contaminated with particles and pathogens acquired during snowmelt or after strong rainfalls. In the last decade ultrafiltration has become the technology of choice for the removal of the aforementioned contaminants. Flux decline caused by unanticipated membrane fouling is the main limitation for the application of ultrafiltration membranes. This paper describes how membrane fouling phenomena can be predicted by using a statistical approach based on data from large scale filtration systems in combination with field and lab experiments on raw water quality and membrane performance. The data defines water quality and respective fouling phenomena both in technical scale filtration plants and in lab experiments of eleven different raw waters. The method described here is more economically feasible for small water works when compared to typical pilot experiments that are used for high capacity water works.

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Potential Pitfalls in Membrane Fouling Evaluation: Merits of Data Representation as Resistance Instead of Flux Decline in Membrane Filtration

Membranes ◽

10.3390/membranes11070460 ◽

2021 ◽

Vol 11 (7) ◽

pp. 460

Author(s):

Bastiaan Blankert ◽

Bart Van der Bruggen ◽

Amy E. Childress ◽

Noreddine Ghaffour ◽

Johannes S. Vrouwenvelder

Keyword(s):

Membrane Fouling ◽

Membrane Filtration ◽

Data Representation ◽

Strong Impact ◽

Experimental Conditions ◽

Permeable Membrane ◽

Dead End ◽

Flux Decline ◽

The Difference ◽

Filtration Flux

The manner in which membrane-fouling experiments are conducted and how fouling performance data are represented have a strong impact on both how the data are interpreted and on the conclusions that may be drawn. We provide a couple of examples to prove that it is possible to obtain misleading conclusions from commonly used representations of fouling data. Although the illustrative example revolves around dead-end ultrafiltration, the underlying principles are applicable to a wider range of membrane processes. When choosing the experimental conditions and how to represent fouling data, there are three main factors that should be considered: (I) the foulant mass is principally related to the filtered volume; (II) the filtration flux can exacerbate fouling effects (e.g., concentration polarization and cake compression); and (III) the practice of normalization, as in dividing by an initial value, disregards the difference in driving force and divides the fouling effect by different numbers. Thus, a bias may occur that favors the experimental condition with the lower filtration flux and the less-permeable membrane. It is recommended to: (I) avoid relative fouling performance indicators, such as relative flux decline (J/J0); (II) use resistance vs. specific volume; and (III) use flux-controlled experiments for fouling performance evaluation.

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Evaluating Fertilizer-Drawn Forward Osmosis Performance in Treating Anaerobic Palm Oil Mill Effluent

Membranes ◽

10.3390/membranes11080566 ◽

2021 ◽

Vol 11 (8) ◽

pp. 566

Author(s):

Ruwaida Abdul Wahid ◽

Wei Lun Ang ◽

Abdul Wahab Mohammad ◽

Daniel James Johnson ◽

Nidal Hilal

Keyword(s):

Palm Oil ◽

Pure Water ◽

Water Flux ◽

Forward Osmosis ◽

Salt Flux ◽

Palm Oil Mill Effluent ◽

Performance Ratio ◽

Water Recovery ◽

Flux Decline ◽

Palm Oil Mill

Fertilizer-drawn forward osmosis (FDFO) is a potential alternative to recover and reuse water and nutrients from agricultural wastewater, such as palm oil mill effluent that consists of 95% water and is rich in nutrients. This study investigated the potential of commercial fertilizers as draw solution (DS) in FDFO to treat anaerobic palm oil mill effluent (An-POME). The process parameters affecting FO were studied and optimized, which were then applied to fertilizer selection based on FO performance and fouling propensity. Six commonly used fertilizers were screened and assessed in terms of pure water flux (Jw) and reverse salt flux (JS). Ammonium sulfate ((NH4)2SO4), mono-ammonium phosphate (MAP), and potassium chloride (KCl) were further evaluated with An-POME. MAP showed the best performance against An-POME, with a high average water flux, low flux decline, the highest performance ratio (PR), and highest water recovery of 5.9% for a 4-h operation. In a 24-h fouling run, the average flux decline and water recovered were 84% and 15%, respectively. Both hydraulic flushing and osmotic backwashing cleaning were able to effectively restore the water flux. The results demonstrated that FDFO using commercial fertilizers has the potential for the treatment of An-POME for water recovery. Nevertheless, further investigation is needed to address challenges such as JS and the dilution factor of DS for direct use of fertigation.

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Pyrite (FeS2)-supported ultrafiltration system for removal of mercury (II) from water

Emergent Materials ◽

10.1007/s42247-021-00282-7 ◽

2021 ◽

Author(s):

Dong Suk Han ◽

Kawsher M. D. Solayman ◽

Ho Kyong Shon ◽

Ahmed Abdel-Wahab

Keyword(s):

Membrane Filter ◽

Pyrite Surface ◽

Ph Change ◽

Filtration Process ◽

Sem Images ◽

Flux Decline ◽

Cake Layer ◽

Water Effects ◽

Almost All ◽

Over Time

AbstractThis study investigated the Hg(II) removal efficiencies of the reactive adsorbent membrane (RAM) hybrid filtration process, a removal process that produces stable final residuals. The reaction mechanism between Hg(II) and pyrite and the rejection of the solids over time were characterized with respect to flux decline, pH change, and Hg and Fe concentration in permeate water. Effects of the presence of anions (Cl−, SO42−, NO3−) or humic acid (HA) on the rejection of the Hg(II)-contacted pyrite were studied. The presence of both HA and Hg(II) increased the rate of flux decline due to the formation of irreversible gel-like compact cake layers as shown in the experimental data and modeling related to the flux decline and the SEM images. Stability experiments of the final residuals retained on the membrane using a thiosulfate solution (Na2S2O3) show that the Hg(II)-laden solids were very stable due to little or no detection of Hg(II) in the permeate water. Experiment on the possibility of continuously removing Hg(II) by reusing the Hg/pyrite-laden membrane shows that almost all Hg(II) was adsorbed onto the pyrite surface regardless of the presence of salts or HA, and the Hg(II)-contacted pyrite residuals were completely rejected by the DE/UF system. Therefore, a membrane filter containing pyrite-Hg(II) could provide another reactive cake layer capable of further removal of Hg(II) without post-chemical treatment for reuse.

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Evaluation of the effects of additives on the properties of starch-based bioplastic film

SN Applied Sciences ◽

10.1007/s42452-021-04433-7 ◽

2021 ◽

Vol 3 (4) ◽

Author(s):

Olugbenga O. Oluwasina ◽

Bolaji P. Akinyele ◽

Sunday J. Olusegun ◽

Olayinka O. Oluwasina ◽

Nelcy D. S. Mohallem

Keyword(s):

Tensile Strength ◽

Food Packaging ◽

Surface Topology ◽

Root Mean Square Roughness ◽

Starch Solution ◽

Dialdehyde Starch ◽

Force Microscopy ◽

Silica Solution ◽

The One ◽

Bioplastic Film

AbstractThe adverse environmental effects of petroleum-based packaging plastics have necessitated the need for eco-friendly bioplastics. Most bioplastics are starch-based and are not without drawbacks, hence there is the need for their properties to be improved. In this study, the effect of varying concentrations of dialdehyde starch and silica solutions on the physical, mechanical, biodegradable, surface topology, and thermal properties of the bioplastic films was examined. The additive concentrations were varied from 60 to 100%. The bioplastic films produced with dialdehyde starch solution recorded better moisture content (6.62–11.85%), bioplastic film solubility (4.23–7.90%), and tensile strength (1.63–3.06 MPa), against (11.24–14.26%), (7.77–19.27%) and (0.53–0.73 MPa) respectively for bioplastic films produced with silica solution. The atomic force microscopy analysis; root-mean-square roughness, kurtosis, and skewness revealed better miscibility and compatibility between the starch matrix and the dialdehyde solution than between the starch matrix and the silica solution. Bioplastic with added dialdehyde starch solution has better tensile strength and long biodegradability than that with silica solution. The research has demonstrated that bioplastic film produced with starch and dialdehyde starch solution has better properties than the one produced with starch and silica solution. The properties evaluation results of the bioplastic films thus demonstrated their aptness for food packaging applications. Graphic abstract

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Flux decline due to gypsum precipitation on RO membranes

Desalination ◽

10.1016/0011-9164(92)80033-6 ◽

1992 ◽

Vol 86 (2) ◽

pp. 187-222 ◽

Cited By ~ 45

Author(s):

M. Brusilovsky ◽

J. Borden ◽

D. Hasson

Keyword(s):

Gypsum Precipitation ◽

Flux Decline

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Membrane fouling mechanisms and permeate flux decline model in soy sauce microfiltration

Journal of Food Process Engineering ◽

10.1111/jfpe.12599 ◽

2017 ◽

Vol 41 (1) ◽

pp. e12599 ◽

Cited By ~ 7

Author(s):

Ye Sun ◽

Zhen Qin ◽

Liming Zhao ◽

Qiming Chen ◽

Qingyun Hou ◽

...

Keyword(s):

Membrane Fouling ◽

Soy Sauce ◽

Permeate Flux ◽

Flux Decline

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The Prediction of Flux Decline and Blinding in Cellular Ceramic Microfiltration Membranes

Separation Science and Technology ◽

10.1080/01496399508010361 ◽

1995 ◽

Vol 30 (7-9) ◽

pp. 1529-1553 ◽

Cited By ~ 1

Author(s):

N. M. Jackson ◽

G. A. Davies ◽

D. J. Bell

Keyword(s):

Flux Decline ◽

Microfiltration Membranes ◽

Cellular Ceramic

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Influence of bulk concentration on the organisation of molecules at a membrane surface and flux decline during reverse osmosis of an anionic surfactant

Journal of Membrane Science ◽

10.1016/j.memsci.2015.10.012 ◽

2016 ◽

Vol 499 ◽

pp. 257-268 ◽

Cited By ~ 14

Author(s):

Zhaohuan Mai ◽

Vincent Butin ◽

Mohammed Rakib ◽

Haochen Zhu ◽

Murielle Rabiller-Baudry ◽

...

Keyword(s):

Reverse Osmosis ◽

Anionic Surfactant ◽

Membrane Surface ◽

Bulk Concentration ◽

Flux Decline

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Application of forward osmosis in reusing the brackish concentrate produced in reverse osmosis plants with secondary treated wastewater as feed solution: a case study

Journal of Water Reuse and Desalination ◽

10.2166/wrd.2016.097 ◽

2016 ◽

Vol 6 (4) ◽

pp. 533-543 ◽

Cited By ~ 1

Author(s):

W. D. Wang ◽

M. Esparra ◽

H. Liu ◽

Y. F. Xie

Keyword(s):

Reverse Osmosis ◽

Membrane Fouling ◽

Water Flux ◽

Forward Osmosis ◽

Pump Energy ◽

Feed Solution ◽

Disinfection Byproducts ◽

Treated Wastewater ◽

Membrane Flux ◽

Flux Decline

This study evaluated the feasibility of forward osmosis (FO) in diluting and reusing the concentrate produced in a reverse osmosis (RO) plant in James City County, VA. Secondary treated wastewater (STW) was used as the feed solution. Findings indicated that pH had slight effects on the water flux of the FO membrane. As the concentration of total dissolved solids (TDS) in the concentrate was diluted from 12.5 to 1.0 g/L or the temperature in the STW decreased from 23 to 10 °C, the membrane flux decreased from 2.2 to 0.59 and 0.81 L/(m2 h), respectively. The FO membrane showed a good performance in the rejection of organic pollutants, with only a small part of the protein-like substances and disinfection byproducts permeating to the diluted concentrate. During an 89-hour continuous operation, water flux decline due to membrane fouling was not observed. Controlling the TDS in the second-stage FO effluent at 1.5 g/L, approximately 8.3% of the pump energy input could be saved. The consumption of groundwater was reduced from 22.7 × 103 to 10.6 × 103 m3/d. FO was proved to be an effective method in both diluting the discharged concentrate and reducing the energy consumption of RO.

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