Effective membrane backwash with carbon dioxide under severe fouling and operation conditions

Alpatová, Alla; Qamar, Adnan; Al-Ghamdi, Mohanned A.; Lee, Jung-Gil; Ghaffour, Noreddine

doi:10.1016/j.memsci.2020.118290

Cited by 28 publications

(8 citation statements)

References 65 publications

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“…The voids found within membrane surfaces can be anticipated to be CO 2 nucleation vicinities, thus lowering the free interfacial energy essential for CO 2 nucleation. Moreover, the fouling layer evolved onto the membrane surface may also serve as a substrate for CO 2 nucleation [ 21 ]. The dissolved CO 2 molecules would, in all probability, travel into the apertures inside the scale layer, prompting the nucleation, progression, and extrication of CO 2 molecules.…”

Section: Resultsmentioning

confidence: 99%

CO2 as an Alternative to Traditional Antiscalants in Pressure-Driven Membrane Processes: An Experimental Study of Lab-Scale Operation and Cleaning Strategies

Shahid

Choi

2022

Membranes

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Scaling, or inorganic fouling, is a major factor limiting the performance of membrane-based water treatment processes in long-term operation. Over the past few decades, extensive studies have been conducted to control the scale growth found in membrane processes and to develop sustainable and greener processes. This study details the role of CO2 in scale inhibition in membrane processes. The core concept of CO2 utilization is to reduce the influent pH and to minimize the risk of scale formation from magnesium or calcium salts. Three reverse osmosis (RO) units were operated with a control (U1), CO2 (U2), and a commercial antiscalant, MDC-220 (U3). The performances of all the units were compared in terms of change in transmembrane pressure (TMP). The overall efficiency trend was found as U1 > U3 > U2. The membrane surfaces were analyzed using Scanning Electron Microscopy (SEM) and Energy Dispersive Spectroscopy (EDS) for the morphological and elemental compositions, respectively. The surface analysis signified a significant increase in surface smoothness after scale deposition. The noticeable reduction in surface roughness can be described as a result of ionic deposition in the valley region. A sludge-like scale layer was found on the surface of the control membrane (U1) which could not be removed, even after an hour of chemical cleaning. After 20–30 min of cleaning, the U2 membrane was successfully restored to its original state. In brief, this study highlights the sustainable membrane process developed via CO2 utilization for scale inhibition, and the appropriate cleaning approaches.

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Section: Resultsmentioning

confidence: 99%

CO2 as an Alternative to Traditional Antiscalants in Pressure-Driven Membrane Processes: An Experimental Study of Lab-Scale Operation and Cleaning Strategies

Shahid

Choi

2022

Membranes

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“…At higher applied pressure, organic or inorganic particles are forced to pass through the membrane structure. Thus, under this condition, it is anticipated that pore-blocking could occur which leads to a greater accumulation of bacteria and other foulants on the membrane surface 45 , 46 . Moreover, the bacterial attachment would also be greater as the normal shear stress (equivalent to static pressure 47 ) is increased, resulting in higher biofilm thickness, as evident in the OCT scans.…”

Section: Resultsmentioning

confidence: 99%

Novel hole-pillar spacer design for improved hydrodynamics and biofouling mitigation in membrane filtration

Qamar

Kerdi

Ali

et al. 2021

Sci Rep

Self Cite

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Feed spacers are the critical components of any spiral-wound filtration module, dictating the filtration performance. Three spacer designs, namely a non-woven commercial spacer (varying filament cross-section), a symmetric pillar spacer, and a novel hole-pillar spacer (constant filament diameter) were studied using Direct Numerical Simulations (DNS), 3-D printed and subsequently experimentally tested in a lab-scale ultrafiltration set-up with high biofouling potential feed water at various feed pressures. Independent of the applied pressure, the novel hole-pillar spacer showed initially the lowest feed channel pressure drop, the lowest shear stress, and the highest permeate flux compared to the commercial and pillar spacers. Furthermore, less biofilm thickness development on membrane surface was visualized by Optical Coherent Tomography (OCT) imaging for the proposed hole-pillar spacer. At higher feed pressure, a thicker biofilm developed on membrane surface for all spacer designs explaining the stronger decrease in permeate flux at high pressure. The findings systematically demonstrated the role of various spacer designs and applied pressure on the performance of pre-treatment process, while identifying specific shear stress distribution guidelines for engineering a new spacer design in different filtration techniques.

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“…The voids present on the surface of membrane can be assumed as CO 2 nucleation localities, thus decreasing the free interfacial energy needed for the CO 2 nucleation. Likewise, the fouling layers developed onto the surface of membrane may also assist as a substrate for CO 2 nucleation [ 29 ]. The dissolved CO 2 molecules potentially move into the nooks inside the fouling layer triggering nucleation, development, and extrication of CO 2 .…”

Section: Resultsmentioning

confidence: 99%

Sustainable Membrane-Based Wastewater Reclamation Employing CO2 to Impede an Ionic Precipitation and Consequent Scale Progression onto the Membrane Surfaces

Shahid

Choi

2021

Membranes

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CO2 capture and utilization (CCU) is a promising approach in controlling the global discharge of greenhouse gases (GHG). This study details the experimental investigation of CO2 utilization in membrane-based water treatment systems for lowering the potential of ionic precipitation on membrane surface and subsequent scale development. The CO2 utilization in feed water reduces the water pH that enables the dissociation of salts in their respective ions, which leave the system as a concentrate. This study compares the efficiency of CO2 and other antifouling agents (CA-1, CA-2, and CA-3) for fouling control in four different membrane-based wastewater reclamation operations. These systems include Schemes 1, 2, 3, and 4, which were operated with CA-1, CA-2, CA-3, and CO2 as antiscalants, respectively. The flux profile and percent salt rejection achieved in Scheme 4 confirmed the higher efficiency of CO2 utilization compared with other antifouling agents. This proficient role of CO2 in fouling inhibition is further endorsed by the surface analysis of used membranes. The SEM, EDS, and XRD examination confirmed the higher suitability of CO2 utilization in controlling scale deposition compared with other antiscalants. The cost estimation also supported the CO2 utilization for environmental friendly and safe operation.

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Effective membrane backwash with carbon dioxide under severe fouling and operation conditions

Cited by 28 publications

References 65 publications

CO2 as an Alternative to Traditional Antiscalants in Pressure-Driven Membrane Processes: An Experimental Study of Lab-Scale Operation and Cleaning Strategies

CO2 as an Alternative to Traditional Antiscalants in Pressure-Driven Membrane Processes: An Experimental Study of Lab-Scale Operation and Cleaning Strategies

Novel hole-pillar spacer design for improved hydrodynamics and biofouling mitigation in membrane filtration

Sustainable Membrane-Based Wastewater Reclamation Employing CO2 to Impede an Ionic Precipitation and Consequent Scale Progression onto the Membrane Surfaces

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