Effect of long-term operation on membrane surface characteristics and performance in membrane distillation

2017 ◽  
Vol 543 ◽  
pp. 143-150 ◽  
Author(s):  
A.L. McGaughey ◽  
R.D. Gustafson ◽  
A.E. Childress
Keyword(s):  
Membrane Surface ◽  
Surface Characteristics ◽  
Membrane Distillation ◽  
Term Operation ◽  
And Performance

Detection method for stability of microcontroller accessories based on biosensor

2021 ◽  
pp. 1-14
Author(s):  
Yan Ren ◽  
Jiayong Liu
Keyword(s):  
Process Design ◽  
Detection Method ◽  
Detection Accuracy ◽  
Stability Testing ◽  
Term Operation ◽  
Existing Problems ◽  
Testing Method ◽  
And Performance ◽  
The Stability

In order to solve the problem of poor accuracy of traditional microcontroller attachment stability testing method, a microcontroller attachment stability testing method based on biosensor was designed to solve the existing problems. The reliability test index of the microcontroller is established, then the interference of the microcontroller accessory is detected and responded, and the interference detection signal of the microcontroller accessory is selected. The process design of stability detection of microcontroller accessories based on biosensor is completed. The experimental results show that the stability detection method based on biosensor designed in this paper can ensure the stability detection accuracy of microcontroller accessories above 80%, which is more accurate than traditional methods. It can be used to evaluate the stability, reliability and performance of microcontroller accessories in long-term operation.

Influence of humic acid on the long-term performance of direct contact membrane distillation

2018 ◽  
Vol 30 (1) ◽  
pp. 109-120 ◽  
Author(s):  
Dong-Wan Cho ◽  
Gihoon Kwon ◽  
Jeongmin Han ◽  
Hocheol Song
Keyword(s):  
Humic Acid ◽  
Membrane Fouling ◽  
Coalbed Methane ◽  
Direct Contact ◽  
Membrane Surface ◽  
Membrane Distillation ◽  
Permeate Flux ◽  
Direct Contact Membrane Distillation ◽  
High Level

In this study, the influence of humic acid on the treatment of coalbed methane water by direct contact membrane distillation was examined with bench-scale test unit. During short-term distillation (1000 min), high level of humic acid above 50 ppm resulted in significant decrease in permeate flux, while low level of humic acid (∼2 ppm) had little influence on the flux. For the long-term distillation (5000 min), the flux decline began at 3400 min in the presence of 5 ppm humic acid and 5 mM Ca2+, and decreased to ∼40% of initial flux at 5000 min. The spectroscopic analysis of the membrane used revealed that the surface was covered by hydrophilic layers mainly composed of calcite. The membrane fouling effect of humic acid became more significant in the presence of Ca2+ due to more facile calcite formation on the membrane surface. It was demonstrated that humic acid enhanced CaCO3 deposition on the membrane surfaces, thereby expediting the scaling phenomenon.

scholarly journals Development of A Novel Corrugated Polyvinylidene difluoride Membrane via Improved Imprinting Technique for Membrane Distillation

Polymers ◽  
2019 ◽  
Vol 11 (5) ◽  
pp. 865 ◽  
Author(s):  
Normi Izati Mat Nawi ◽  
Muhammad Roil Bilad ◽  
Nurazrina Zolkhiflee ◽  
Nik Abdul Hadi Nordin ◽  
Woei Jye Lau ◽  
...  
Keyword(s):  
Surface Area ◽  
Membrane Surface ◽  
Water Flux ◽  
Cross Flow ◽  
Membrane Distillation ◽  
Effective Surface Area ◽  
Effective Surface ◽  
Widespread Application ◽  
Polyvinylidene Difluoride ◽  
Term Operation

Membrane distillation (MD) is an attractive technology for desalination, mainly because its performance that is almost independent of feed solute concentration as opposed to the reverse osmosis process. However, its widespread application is still limited by the low water flux, low wetting resistance and high scaling vulnerability. This study focuses on addressing those limitations by developing a novel corrugated polyvinylidene difluoride (PVDF) membrane via an improved imprinting technique for MD. Corrugations on the membrane surface are designed to offer an effective surface area and at the same time act as a turbulence promoter to induce hydrodynamic by reducing temperature polarization. Results show that imprinting of spacer could help to induce surface corrugation. Pore defect could be minimized by employing a dual layer membrane. In short term run experiment, the corrugated membrane shows a flux of 23.1 Lm−2h−1 and a salt rejection of >99%, higher than the referenced flat membrane (flux of 18.0 Lm−2h−1 and similar rejection). The flux advantage can be ascribed by the larger effective surface area of the membrane coupled with larger pore size. The flux advantage could be maintained in the long-term operation of 50 h at a value of 8.6 Lm−2h−1. However, the flux performance slightly deteriorates over time mainly due to wetting and scaling. An attempt to overcome this limitation should be a focus of the future study, especially by exploring the role of cross-flow velocity in combination with the corrugated surface in inducing local mixing and enhancing system performance.

scholarly journals 3D-Printed Absorbers for Solar-Driven Interfacial Water Evaporation: A Mini-Review

2021 ◽  
Vol 3 (1) ◽  
pp. 0210103
Author(s):  
Leonard Tijing ◽  
John Ryan Dizon ◽  
Gil Cruz Jr.
Keyword(s):  
Water Evaporation ◽  
Interfacial Water ◽  
Water Production ◽  
New Developments ◽  
Term Operation ◽  
Solar Absorbers ◽  
Challenges And Opportunities ◽  
3D Printed ◽  
And Performance

Solar-driven interfacial water evaporation (SWE) is considered as a promising sustainable solution for clean water production especially for remote and off-grid communities. Various approaches have been developed in the last decade to improve the evaporation and thermal efficiency of the system, and to make it more robust for long-term operation. In recent years, 3D printing has emerged as an attractive method to fabricate simple and complex absorber geometries for SWE. In this mini-review, we present the new developments of 3D-printed solar absorbers including the various designs, fabrication strategies, challenges and opportunities. This study hopes to provide more insights into the use of additive manufacturing for improving the absorber design and performance of SWE.

scholarly journals Review of New Approaches for Fouling Mitigation in Membrane Separation Processes in Water Treatment Applications

Separations ◽  
2021 ◽  
Vol 9 (1) ◽  
pp. 1
Author(s):  
Mervette El Batouti ◽  
Nouf F. Alharby ◽  
Mahmoud M. Elewa
Keyword(s):  
Membrane Fouling ◽  
New Technologies ◽  
Membrane Separation ◽  
Control Strategies ◽  
Membrane Surface ◽  
Membrane Distillation ◽  
Separation Processes ◽  
Term Operation ◽  
Fouling Control ◽  
Inorganic Matter

This review investigates antifouling agents used in the process of membrane separation (MS), in reverse osmosis (RO), ultrafiltration (UF), nanofiltration (NF), microfiltration (MF), membrane distillation (MD), and membrane bioreactors (MBR), and clarifies the fouling mechanism. Membrane fouling is an incomplete substance formed on the membrane surface, which will quickly reduce the permeation flux and damage the membrane. Foulant is colloidal matter: organic matter (humic acid, protein, carbohydrate, nano/microplastics), inorganic matter (clay such as potassium montmorillonite, silica salt, metal oxide, etc.), and biological matter (viruses, bacteria and microorganisms adhering to the surface of the membrane in the case of nutrients) The stability and performance of the tested nanometric membranes, as well as the mitigation of pollution assisted by electricity and the cleaning and repair of membranes, are reported. Physical, chemical, physico-chemical, and biological methods for cleaning membranes. Biologically induced biofilm dispersion effectively controls fouling. Dynamic changes in membrane foulants during long-term operation are critical to the development and implementation of fouling control methods. Membrane fouling control strategies show that improving membrane performance is not only the end goal, but new ideas and new technologies for membrane cleaning and repair need to be explored and developed in order to develop future applications.

scholarly journals SMP Production in an Anaerobic Submerged Membrane Bioreactor (AnMBR) at Different Organic Loading Rates

Membranes ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 317
Author(s):  
Sandra C. Medina ◽  
Nataly Zamora-Vacca ◽  
Hector J. Luna ◽  
Nicolas Ratkovich ◽  
Manuel Rodríguez Susa
Keyword(s):  
Membrane Fouling ◽  
Energy Demand ◽  
Membrane Surface ◽  
Oxygen Demand ◽  
Domestic Wastewater ◽  
Term Operation ◽  
Submerged Membrane Bioreactor ◽  
Anaerobic Membrane Bioreactors ◽  
Microbial Products

Anaerobic membrane bioreactors (AnMBRs) have demonstrated an excellent capability to treat domestic wastewater. However, biofouling reduces membrane permeability, increasing operational costs and overall energy demand. Soluble microbial products (SMPs) that build up on the membrane surface play a significant role in the biofouling. In this study, the production of SMPs in a 32 L submerged AnMBR operated at three different organic loads (3.0, 4.1 and 1.2 kg chemical oxygen demand (COD)/m3d for phases 1, 2 and 3, respectively) during long-term operation of the reactor (144, 83 and 94 days) were evaluated. The samples were taken from both the permeate and the sludge at three different heights (0.14, 0.44 and 0.75 m). Higher production of SMPs was obtained in phase 2, which was proportional to the membrane fouling. There were no statistically significant differences (p > 0.05) in the SMPs extracted from sludge at different heights among the three phases. In the permeate of phases 1, 2 and 3, the membrane allowed the removal of 56%, 70% and 64% of the SMP concentration in the sludge. SMPs were characterized by molecular weight (MW). A bimodal behavior was obtained, where fractions prevailed with an MW < 1 kDa, associated with SMPs as utilization-associated products (UAPs) caused fouling by the pore-blocking mechanism. The chemical analysis found that, in the SMPs, the unknown COD predominated over the known COD, such as carbohydrates and proteins. These results suggest that further studies in SMP characterization should focus on the unknown COD fraction to understand the membrane fouling in AnMBR systems better.

OPERATIONAL CONDITIONS OF FUNCTIONAL DURABILITY AND PERFORMANCE OF ROAD TRANSPORT ENTERPRISES

2018 ◽  
Vol 73 ◽  
pp. 39-48
Author(s):  
Joanna Krupska ◽  
Adam Mytlewski
Keyword(s):  
Operating Systems ◽  
Road Transport ◽  
Transport Processes ◽  
The Other ◽  
Operational Conditions ◽  
Term Operation ◽  
And Performance ◽  
The One

Durability and efficiency are important conditions for long-term operation ofroad transport companies. In the operating aspect, the first parameter determines the quality of the manufacturing capacity and the ability to provide repetitive transport processes. The second parameter affects the long-term ability to use resources and the subsequent results of operations. The conducted study on stability and efficiency of the operating systems of road companies indicates the existence of, on the one hand, a large variation of approaches, and on the other, a clear dominance of intense and efficient behaviour in combination with ensuring the repetitiveness of processes.

Fouling and long-term durability of an integrated forward osmosis and membrane distillation system

2015 ◽  
Vol 72 (11) ◽  
pp. 2000-2005 ◽  
Author(s):  
T. Husnain ◽  
B. Mi ◽  
R. Riffat
Keyword(s):  
Membrane Fouling ◽  
Tap Water ◽  
Membrane Surface ◽  
Wastewater Reuse ◽  
Forward Osmosis ◽  
Cross Flow ◽  
Domestic Wastewater ◽  
Membrane Distillation ◽  
Hydrophobic Membrane

An integrated forward osmosis (FO) and membrane distillation (MD) system has great potential for sustainable wastewater reuse. However, the fouling and long-term durability of the system remains largely unknown. This study investigates the fouling behaviour and efficiency of cleaning procedures of FO and MD membranes used for treating domestic wastewater. Results showed that a significant decline in flux of both FO and MD membranes were observed during treatment of wastewater with organic foulants. However, shear force generated by the increased cross-flow physically removed the loosely attached foulants from the FO membrane surface and resulted in 86–88% recovery of flux by cleaning with tap water. For the MD membrane, almost no flux recovery was achieved due to adsorption of organic foulants on the hydrophobic membrane surface, thus indicating significant irreversible fouling/wetting, which may not be effectively cleaned even with chemical reagents. Long-term (10 d) tests showed consistent performance of the FO membrane by rejecting the contaminants. However, organic foulants reduced the hydrophobicity of the MD membrane, caused wetting problems and allowed contaminants to pass through. The results demonstrate that combination of the FO and MD processes can effectively reduce irreversible membrane fouling and solve the wetting problem of the MD membrane.

scholarly journals Long-term operation and performance of cryogenic sapphire oscillators

2006 ◽  
Vol 53 (12) ◽  
pp. 2386-2393 ◽  
Author(s):  
Michael Tobar ◽  
Eugene Ivanov ◽  
Clayton Locke ◽  
Paul Stanwix ◽  
John Hartnett ◽  
...  
Keyword(s):  
Term Operation ◽  
And Performance
Sign in / Sign up

Export Citation Format

Share Document