Membrane fouling mechanisms by BSA in aqueous-organic solvent mixtures

Melike Begum Tanis-Kanbur,Navin Raj Tamilselvam,Jia Wei Chew 한국공업화학회 2022 Journal of Industrial and Engineering Chemistry Vol.108 No.-

To exploit the benefits of membrane-based separation for the pharmaceutical and chemical industries,the understanding of membrane fouling in organic solvents is crucial. Specifically for the separation ofbiocatalysts in the manufacture of pharmaceuticals, this study investigated membrane fouling by bovineserum albumin (BSA) in 10% v/v isopropanol (IPA), 10% v/v dimethyl sulfoxide (DMSO), 30% v/v IPA, and30% v/v DMSO, benchmarked against that in water. The presence of either IPA or DMSO worsened fouling,with the latter comparatively worse. To understand the fouling mechanisms, Field Emission ScanningElectron Microscopy (FESEM) images were taken to assess external fouling, Evapoporometry (EP) wasused to measure the pore-size distributions of the fouled membranes to examine internal fouling, a foulingmodel was applied to extract the fouling parameters, and the interfacial interaction energies werederived. Results indicate that the worst fouling in 30% v/v DMSO was due to both significant externalfouling and internal fouling, whereas the second-worst fouling by 30% v/v IPA was caused predominantlyby internal fouling. The magnitudes of the total DLVO- and XDLVO-based interaction energies were foundto be poorly related to the relative flux declines. This study provides valuable insights into membranefouling in different solvent environments.

Proposing a new fouling index in a membrane bioreactor (MBR) based on mechanistic fouling model

Kim, M.J.,Kang, O.Y.,Rao, B.S.,Kim, J.R.,Hwang, H.J.,Kim, M.H.,Yoo, C.K. Balaban Publishers 2011 Desalination and water treatment Vol.33 No.1

<P> Membrane fouling is the most serious problem in membrane bioreactor (MBR) process, which is restricting the widespread application of MBRs in wastewater treatment processes. In recent years, several studies on the precise diagnosis and prediction of the membrane fouling have been carried out to obtain an efficient operation of MBRs. The aims of this study are 1) to predict the membrane fouling and to determine the chemical cleaning interval of membrane using traditional mechanistic fouling model; and 2) to propose the new fouling index based on the usually obtained traditional technique. As the traditional fouling technique use an exponential fouling model, however, this method has some shortcomings, such as inadequate comprehension of the fouling mechanism and steady state assumption. Therefore, in this study, the coefficient (κ) of the exponential fouling model is proposed as a new fouling index to overcome the inadequate understanding of the fouling mechanism and steady state assumption in traditional technique. To propose the coefficient (κ) as the new fouling index, least-square (LS) method and recursive least-square (RLS) methods are applied in the exponential fouling model. The coefficient (κ) shows the similar tendency with the permeability which is another kind of fouling index. It is verified that the coefficient has been validated as the new index for diagnosis of the fouling progress as well as the prediction of membrane fouling. </P>

TiO2 나노입자/UV 결합 침지형 중공사막 시스템에서 자연유기물의 파울링거동

박승수,서형준,김정환 한국막학회 2011 멤브레인 Vol.21 No.1

자연유기물을 처리하는 침지형 중공사막 정밀여과 시스템에서 TiO2 나노입자와 UV를 이용한 광촉매 반응을 적용 시 공기폭기, TiO2 농도, 용액의 pH 그리고 Ca+2의 존재가 자연유기물에 의한 파울링에 미치는 혼합영향을 관찰하였다. 실험결과, TiO2 나노입자 없이 단순 UV의 조사만으로 자연유기물에 의한 파울링은 약 40% 정도 감소시킬 수 있었다. 또한 UV의 조사 없이 TiO2 나노입자의 교반만으로 약 25%의 파울링 감소효과를 나타내었다. 공기폭기가 광촉매 반응에 미치는 영향을 확인해 본 결과 공기폭기를 적용해 주지 않은 경우와 비교했을시 공기폭기로 인한 자연유기물의 제거효율은 약 12% 정도 향상되었다. 이는 공기폭기로 인한 분리막 표면으로부터 자연유기물의 물리적인 역수송 보다는 산소공급으로 인해 광촉매 반응이 더욱 향상된 것으로 판단된다. 공기폭기 유량, TiO2 농도, 용액의 pH 영향정도를 관찰한 결과 공기폭기가 자연유기물 파울링 감소에 미치는 영향이 가장 낮은 것으로 나타났다. 반면, 용액의 pH 경우 낮은 pH (= 4.5)에서 파울링 감소에 미치는 영향이 가장 높은 것으로 관찰되었다. 또한 TiO2 나노입자 농도가 증가할 수록 파울링 감소효과도 증가하였으며 용액의 pH를 낮출수록 파울링 감소는 증가하였다. 이는 낮은 pH에서 서로 반대전하를 지닌 자연유기물과 TiO2 나노 입자간의 정전기적인 인력이 증가하여 TiO2 나노입자 표면에서 자연유기물의 광촉매분해능이 향상된 것으로 사료된다. 또한 자연유기물 중 Ca+2의 첨가는 상대적으로 높은 pH (= 10)에서 자연유기물과 TiO2 나노입자 사이 가교현상을 촉진시켜 Ca+2이 첨가되지 않은 경우와 비교시 높은 파울링 감소효과와 자연유기물의 분해효과를 달성시킬 수 있었다. In this study, combined effect of airflow rate, TiO2 concentration, solution pH and Ca+2 addition on HA (humic acid) fouling in submerged, photocatalytic hollow-fiber microfiltraiton was investigated systematically. Results showed that UV irradiation alone without TiO2 nanoparticles could reduce HA fouling by 40% higher than the fouling obtained without UV irradiation. Compared to the HA fouling without UV irradiation and TiO2 nanoparticles, the HA fouling reduction was about 25% higher only after the addition of TiO2 nanoparticles. Both adsorptive and hydrophilic properties of TiO2 nanoparticles for the HA can be involved in mitigating membrane fouling. It was also found that the aeration itself had lowest effect on fouling mitigation while the HA fouling was affected significantly by solution pH. Transient behavior of zeta potential at different solution pHs suggested that electrostatic interactions between HA and TiO2 nanoparticles should improve photocatalytic efficiency on HA fouling. TiO2 concentration was observed to be more important factor than airflow rate to reduce HA fouling, implying that surface reactivity on TiO2 naoparticles should be important fouling mitigation mechanisms in submerged, photocatalyic microfiltraiton. This was further supported by investigating the effect of Ca+2 addition on fouling mitigation. At higher pH (= 10), addition of Ca+2 can play an important role in bridging between HA and TiO2 nanoparticles and increasing surface reactivity on nanoparticles, thereby reducing membrane fouling.

Insights into the roles of recently developed coagulants as pretreatment to remove effluent organic matter for membrane fouling mitigation

Ly, Quang Viet,Nghiem, Long D.,Cho, Jinwoo,Hur, Jin Elsevier 2018 Journal of membrane science Vol.564 No.-

<P><B>Abstract</B></P> <P>Membrane fouling by dissolved organic matter (EfOM) in secondary treated effluent is a problematic and inevitable issue during wastewater reclamation using low pressure membrane filtration. This study evaluates the performance of coagulation/flocculation (C/F) using two recently developed coagulants (namely TiCl<SUB>4</SUB> and ZrCl<SUB>4</SUB>) in comparison to conventional alum (i.e. Al<SUB>2</SUB>(SO<SUB>4</SUB>)<SUB>3</SUB>) as pretreatment to remove EfOM for subsequent ultrafiltration (UF) membrane fouling mitigation. At the optimal dosage, TiCl<SUB>4</SUB>-based C/F pretreatment showed the greatest performance in membrane fouling mitigation, followed by ZrCl<SUB>4</SUB> and then alum. The underlying mechanisms were well explained by classical fouling models and the extended Derjaguin-Landau-Verwey-Overbeek (xDLVO) theory, highlighting a dominant role of standard blocking in the fouling potential of the C/F treated EfOM. The interfacial free energy of cohesion and adhesion showed that C/F pretreatment using TiCl<SUB>4</SUB> and ZrCl<SUB>4</SUB> as coagulant can lower the binding affinity between EfOM molecules and between EfOM molecules and membrane surface, ultimately reduce membrane fouling. The results of size exclusion chromatography (SEC) and fluorescence excitation emission matrix- parallel factor analysis (EEM-PARAFAC) also supported the classical fouling mechanisms, providing additional insights into the potential roles of chemical interactions in the preferential removal of certain organic substances by C/F pretreatment and the chemical composition of subsequent membrane foulants. Protein-like components were highly associated with reversible fouling after the C/F, while the reversibility of humic-like substances was enhanced upon C/F pretreatment. After C/F pretreatment, small sized EfOM molecules became the dominant fraction responsible for UF membrane fouling.</P> <P><B>Highlights</B></P> <P> <UL> <LI> TiCl<SUB>4</SUB>, ZrCl<SUB>4</SUB> coagulants to pretreat EfOM prior to UF was studied for the first time. </LI> <LI> Fouling mechanisms were explained using classical models and xDLVO theory. </LI> <LI> Contribution of small MW organic fractions to membrane fouling increased after C/F. </LI> <LI> Contribution of HS-like fraction to fouling reversibility increased after C/F. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

UV radiation pretreatment for reverse osmosis (RO) process in ultrapure water (UPW) production

Jin, Yongxun,Lee, Hyunkyung,Zhan, Min,Hong, Seungkwan Elsevier 2018 Desalination Vol.439 No.-

<P><B>Abstract</B></P> <P>In ultrapure water (UPW) production, ultraviolet (UV) radiation is an effective process for reducing microorganisms and organic matter. An increasing trend of reusing the spent UPW further encourages the adoption of UV at the upstream of reverse osmosis (RO) to mitigate membrane fouling and to enhance water quality. In this study, UV technology, both low and medium pressure lamps, was assessed for RO pretreatment in UPW production. The fouling potential of problematic pollutants (e.g., silica and IPA) was evaluated pre and post UV treatment based on fouling index under constant flux mode. We found that the rejection rate of IPA was enhanced up to 80% and thus reduced the organic fouling potential in RO. On the contrary, for inorganic nano-particle such as silica, a significant increase in fouling potential after UV exposure was observed. Zeta and small angle X-ray scattering analysis implied that this fouling potential transition was derived from silica particle agglomeration under UV radiation. The RO fouling tests corroborated findings from fouling index measurements, showing severe flux decline after UV radiation. This research provides new insight for UPW production design by revealing the influence of UV on inorganic and organic pollutants during the reclamation of spent UPW.</P> <P><B>Highlights</B></P> <P> <UL> <LI> UV radiation was evaluated as pretreatment for RO in reclamation of spent UPW. </LI> <LI> Fouling in RO was simulated by fouling index newly developed for UPW process. </LI> <LI> UV treatment effectively degraded low-molecular weight organic matter (IPA). </LI> <LI> UV dose is a dominant factor which controls the rise of silica fouling. </LI> <LI> Increased silica fouling was manifested by aggregation under UV exposure. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

다양한 코팅 표면을 갖는 열교환기의 표면에 흡착하는 fouling에 대한 수치해석 - 우유를 대상으로 -

최원 ( Won Choi ),이정재 ( Jeongjae Lee ),전수진 ( Soojin Jun ) 한국농공학회 2011 한국농공학회 학술대회초록집 Vol.2011 No.-

Milk-fouling phenomena of plate heat exchangers (PHEs) result in an increase of energy consumption, extra maintenance, higher labor costs, and a decrease of production capacity. In addition, they can cause the growth of unwanted microorganisms on the corrugated surfaces of PHEs. It is important to understand fouling kinetics on PHE surfaces and the preventive strategy. This research was aimed to develop the transient 3-D model to describe fouling phenomena and estimate the amount of surface fouling using computational fluid dynamics (CFD) based on the hydrodynamic and thermodynamic performances of the PHEs and surface characteristics. Lower flow rates create lower shear forces acting on the fouling. It was found that there is a linear relationship between the amounts of fouling and Reynolds numbers. Therefore, the pre-exponential factors related to milk fouling kinetics were determined by mass flow rate of milk empirically associated with different coating materials (conventionally uncoated stainless steel (SS-316) and stainless steel surfaces with Lectrofluor-641 and graded Ni-P-Polytetrafluoroethylene (Ni-P-PTFE)). The constant heat flux delivered from hot water to skim milk was used as a boundary condition. It was the first time to simulate the fouling pattern and temperature distribution of the PHEs in which all the realistic corrugation profiles have been successfully imported to the CFD codes using AutoCAD software. The amount of fouling on the plate coated with Lectrofluor-641 showed an approximate 90% decrease compared to the control plate. However, there was no significant difference of milk deposits between Lectrofluor-641 and graded Ni-P-PTFE coated surfaces. Consistency was observed between the measurement and model prediction for fouling masses with a maximum prediction error of 7%.

Organic fouling characterization of a CTA-based spiral-wound forward osmosis (SWFO) membrane used in wastewater reuse and seawater desalination

Im, Sung-Ju,Rho, Hojung,Jeong, Sanghyun,Jang, Am Elsevier 2018 Chemical engineering journal Vol.336 No.-

<P><B>Abstract</B></P> <P>This research explores initial organic membrane fouling of element-scale spiral-wound forward osmosis (SWFO) operated at a wastewater plant using real secondary wastewater effluent (SWWE) as feed solution (FS) and synthetic seawater as draw solution (DS). The SWFO was operated long-term and the average water flux reduced from 6.0 to 3.2 L/m<SUP>2</SUP>·h. After the operation, membrane samples were taken from three locations in the SWFO element (i.e., inlet, middle, and outlet) to study the structural effects of organic membrane fouling. The membrane foulants were extracted in sodium hydroxide and deionized water to characterize irreversible and reversible organic foulants, respectively. Organic matter (OM) contained in the FS was dominated by hydrophilic (HPI) aromatic proteins (molecular weights (MWs) of 30,000 Da) and soluble microbial byproducts (which are associated with humic substances and have MWs of 920–2000 Da). The highest organic content (2.67 mg-C/cm<SUP>2</SUP>) was found in the inlet of the SWFO element and, interestingly, was mostly irreversible. In the inlet, humic- or fulvic-like organics and aromatic proteins were dominant, while higher protein-like organics were detected in the middle and the outlet of the element. The organic fouling behavior of the SWFO membrane can be explained as follows: HPI OM formed the initial, irreversible fouling on the membrane surface, after which the hydrophobic (HPO) OM, which is reversible, attached to the initially formed HPI fouling layer by electric interaction dominantly. Therefore, HPI organic foulants should be controlled to reduce irreversible fouling and subsequently guarantee the sustainable operation of SWFO in the SWWE treatment.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Organic fouling experiment was performed using CTA based SWFO element. </LI> <LI> SWFO element was operated at a WWTP using real secondary wastewater effluent. </LI> <LI> Fouling characteristics in inlet, middle and outlet of the element were compared. </LI> <LI> HPI OM formed initial fouling layer while HPO/TPI OM made secondary fouling layer. </LI> <LI> Irreversible HPI OM was dominant on the fouled membrane surface in SWFO element. </LI> </UL> </P>

Variation in organic matter characteristics and mitigation of ultrafiltration membrane fouling by chlorine and UV/chlorine pre-oxidation in secondary effluent treatment

Zhihua Sun,Lei Gao,Dong Wang,Lingjie Liu,Chensheng Qiu,Shaopo Wang 대한환경공학회 2024 Environmental Engineering Research Vol.29 No.5

Evaluation of fouling potential and power density in pressure retarded osmosis (PRO) by fouling index

Choi, Y.,Vigneswaran, S.,Lee, S. Elsevier 2016 Desalination Vol.389 No.-

Pressure retarded osmosis (PRO) is an osmotically-driven membrane process to utilize salinity gradient power (SGP), which is renewable energy originated from the different salt concentration between seawater and fresh water. However, PRO suffers from membrane fouling, leading to decreased water permeability and energy density. Although prediction of fouling is important for its mitigation and control, little information is available on fouling potential in PRO process. Accordingly, this study aims at the investigation of fouling propensity of PRO membranes under different conditions. Feed solutions that have different fouling potential were used in a laboratory-scale PRO system. Silt density index (SDI) and modified fouling index (MFI) were applied as indicators for assessing PRO membrane fouling. Results showed that the power density of PRO decreases with an increase of the fouling potential of the feed waters. MFI was proposed to be a fouling index for PRO because it showed a better correlation with the power density than SDI and turbidity. When MFI value is lower than 1400s/L<SUP>2</SUP>, the efficiency is higher than 70%, indicating that 30% loss in energy recovery compared to the case with D.I. water. This suggests that pretreatment requirements for PRO may be determined based on MFI results.

Effects of COD/N ratio on soluble microbial products in effluent from sequencing batch reactors and subsequent membrane fouling

Ly, Quang Viet,Nghiem, Long D.,Sibag, Mark,Maqbool, Tahir,Hur, Jin Elsevier 2018 Water research Vol.134 No.-

<P><B>Abstract</B></P> <P>The relative ratios of chemical oxygen demand (COD) to nitrogen (N) in wastewater are known to have profound effects on the characteristics of soluble microbial products (SMP) from activated sludge. In this study, the changes in the SMP characteristics upon different COD/N ratios and the subsequent effects on ultrafiltration (UF) membrane fouling potentials were examined in sequencing batch reactors (SBR) using excitation emission matrix-parallel factor analysis (EEM-PARAFAC) and size exclusion chromatography (SEC). Three unique fluorescent components were identified from the SMP samples in the bioreactors operated at the COD/N ratios of 100/10 (N rich), 100/5 (N medium), and 100/2 (N deficient). The tryptophan-like component (C1) was the most depleted at the N medium condition. Fulvic-like (C2) and humic-like (C3) components were more abundant with N rich wastewater. Greater abundances of large size biopolymer (BP) and low molecular weight neutrals (LMWN) were found under the N deficient and N rich conditions, respectively. SMPs from various COD/N exhibited a greater degree on membrane fouling following the order of 100/2 > 100/10 > 100/5. C1 and C2 had close associations with reversible and irreversible fouling, respectively, while the reversible fouling potential of C3 depended on the COD/N ratios. No significant impact of COD/N ratio was observed on the relative contributions of SMP size fractions to either reversible or irreversible fouling potential. However, the COD/N ratios likely altered the BP foulants' composition with greater contribution of proteinaceous substances to reversible fouling under the N deficient condition than at other N richer conditions. The opposite trend was observed for irreversible fouling. Our results provided further insight into changes in different SMP constitutes and their membrane fouling in response to microbial activities under different COD/N ratios.</P> <P><B>Highlights</B></P> <P> <UL> <LI> EEM-PARAFAC and SEC evidenced the changes in SMP composition at varying COD/N. </LI> <LI> Humic-like substances are more abundant with N enrichment. </LI> <LI> SMP's membrane fouling characteristics are highly dependent on COD/N ratios. </LI> <LI> Humic-like FDOM make more contribution to reversible fouling at lower COD/N. </LI> <LI> It provides insight into COD/N-dependent SMP and the effects on fouling behavior. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>