Chemical cleaning reagent of sodium hypochlorite eroding polyvinylidene fluoride ultrafiltration membranes: Aging pathway, performance decay and molecular mechanism

2021 ◽  
Vol 625 ◽  
pp. 119141
Author(s):  
Liumo Ren ◽  
Shuili Yu ◽  
Haijun Yang ◽  
Lei Li ◽  
Luyang Cai ◽  
...  
Keyword(s):  
Molecular Mechanism ◽  
Sodium Hypochlorite ◽  
Polyvinylidene Fluoride ◽  
Chemical Cleaning ◽  
Ultrafiltration Membranes

Formation of halogenated by-products during chemical cleaning of humic acid-fouled UF membrane by sodium hypochlorite solution

2018 ◽  
Vol 332 ◽  
pp. 76-84 ◽  
Author(s):  
Zongping Wang ◽  
Jiaqi Ding ◽  
Pengchao Xie ◽  
Yiqun Chen ◽  
Ying Wan ◽  
...  
Keyword(s):  
Humic Acid ◽  
Sodium Hypochlorite ◽  
Sodium Hypochlorite Solution ◽  
Chemical Cleaning ◽  
Hypochlorite Solution ◽  
By Products

scholarly journals Chemical Cleaning of Ultrafiltration Membrane Fouled by Humic Substances: Comparison between Hydrogen Peroxide and Sodium Hypochlorite

2019 ◽  
Vol 16 (14) ◽  
pp. 2568 ◽  
Author(s):  
Kai Li ◽  
Shu Li ◽  
Tinglin Huang ◽  
Chongzhe Dong ◽  
Jiawei Li ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Humic Substances ◽  
Sodium Hypochlorite ◽  
Alkaline Condition ◽  
Chemical Cleaning ◽  
H2o2 Treatment ◽  
Cleaning Agent ◽  
Cleaning Agents ◽  
Cleaning Efficacy ◽  
By Products

Chemical cleaning is indispensable for the sustainable operation of ultrafiltration (UF) system in water and wastewater treatment. Sodium hypochlorite (NaClO) is an established cleaning agent for membranes subject to organic and microbial fouling, but concerns have been raised about the generation of toxic halogenated by-products during NaClO cleaning. Hydrogen peroxide (H2O2) is a potential “green” cleaning agent that can avoid the formation of halogenated by-products. In this work, cleaning efficacy of H2O2 and NaClO for UF membrane fouled by humic substances (HS) was evaluated under a wide pH range, and change of HS’s properties due to reaction with cleaning agents was examined. The cleaning efficacy of H2O2 was lower than that of NaClO at pH 3–9, but it increased to a level (91.4%) comparable with that of NaClO at pH 11. The extents of changes in properties and fouling potential of HS due to reacting with cleaning agents were consistent with their cleaning efficacy. H2O2 treatment at pH 11 significantly increased negative charge of HS molecules, decomposed high-MW molecules, and reduced its fouling potential. Therefore, considering treatment/disposal of cleaning waste and cleaning efficacy, H2O2 cleaning under strong alkaline condition can be a good choice for HS-fouled membrane.

scholarly journals Improving chemical cleaning of fouled membranes in a drinking water treatment plant

2019 ◽  
Vol 19 (8) ◽  
pp. 2330-2337
Author(s):  
Susumu Hasegawa ◽  
Yasuhiro Tanaka ◽  
Naokazu Wake ◽  
Ryosuke Takagi ◽  
Hideto Matsuyama
Keyword(s):  
Drinking Water ◽  
Water Treatment ◽  
Humic Substances ◽  
Sodium Hypochlorite ◽  
Membrane Fouling ◽  
Treatment Plant ◽  
Drinking Water Treatment ◽  
Water Treatment Plant ◽  
Chemical Cleaning ◽  
Water Treatment Plants

Abstract Recently, membrane filtration systems have become increasingly common in drinking water treatment plants. In this industry, preventing membrane fouling is of utmost importance. Many studies on the relationship between raw water components and membrane fouling have been performed in laboratory conditions. However, very few studies have analyzed the components of foulants on the fouled membrane as operated in actual drinking water treatment plants. By analyzing these components in plant-conditions, membrane fouling will be more effectively prevented. In this study, we analyzed the components of foulants extracted with 0.1 N NaOH from a fouled membrane operated in a drinking water treatment plant in Japan. Our analysis revealed that the main foulants were humic substances. In order to dissolve the accumulated humic substances, additional chemical cleaning was attempted with 500 ppm sodium hypochlorite. As a result, it was found that humic substances were dissolved and filtration resistance significantly decreased. Additionally, the removal of inorganic foulants was also greater after chemical cleaning with 500 ppm sodium hypochlorite, as inorganic foulants trapped within humic substances were released to the membrane surface as hydroxides by the additional sodium hypochlorite cleaning and were dissolved by the periodic citric acid cleaning.

scholarly journals Ageing of polyvinylidene fluoride hollow fiber membranes in sodium hypochlorite solutions

2016 ◽  
Vol 505 ◽  
pp. 174-184 ◽  
Author(s):  
J. Ravereau ◽  
A. Fabre ◽  
A. Brehant ◽  
R. Bonnard ◽  
C. Sollogoub ◽  
...  
Keyword(s):  
Sodium Hypochlorite ◽  
Hollow Fiber ◽  
Polyvinylidene Fluoride ◽  
Hollow Fiber Membranes ◽  
Fiber Membranes

Novel Nanoparticles Incorporated Polyvinylidene Fluoride Ultrafiltration Membrane

2013 ◽  
Vol 746 ◽  
pp. 390-393
Author(s):  
Qiong Zhi Gao ◽  
Hong Qiang Li ◽  
Xing Rong Zeng
Keyword(s):  
Polyvinylidene Fluoride ◽  
Phase Inversion ◽  
Water Flux ◽  
Silver Ions ◽  
Inversion Method ◽  
Hybrid Films ◽  
Ultrafiltration Membranes ◽  
Pvdf Membrane ◽  
Basic Performance ◽  
Phase Inversion Method

In this study, polyvinylidene fluoride (PVDF) composite ultrafiltration membranes were prepared by a phase inversion method, N,N-dimethylacetamide (DMAc) was used as solvent and polyvinylpyrrolidone (PVP) was used as dispersant, nanoTiO2 and AgNO3 were used as addictive materials. With different doping content of nanoTiO2 and silver ions, those hybrid films have different functions and structure. The basic performance and photocatalytic properties of those ultrafiltration membranes were studied in detail. The experiment results show that adding nanosized TiO2 particles will make the porosity of PVDF membrane increase, adding silver ion with low content can not improve water flux and porosity of membranes, however, nanoTiO2 and silver ions doping together can effectively improve the photocatalytic degradation rate.

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