Chemical cleaning of reverse osmosis membrane fouled by wastewater

Madaeni, S.S.; Samieirad, S.

doi:10.1016/j.desal.2010.03.002

Cited by 157 publications

(84 citation statements)

References 22 publications

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“…Among these reagents, caustic formulations have been shown to exert a considerable impact on membrane performance immediately after chemical cleaning [9,10,13,14]. This phenomenon has been recently explained by conformational rearrangements of polymeric chains in the membrane active skin layer (membrane swelling) as a response to the deprotonation of the membranes functional groups in a high pH environment [9].…”

Section: Introductionmentioning

confidence: 99%

Effects of caustic cleaning on pore size of nanofiltration membranes and their rejection of trace organic chemicals

Simon

McDonald

Khan

et al. 2013

Journal of Membrane Science

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The aim of this study was to assess the impact of caustic cleaning on the rejection of three different trace organic chemical (TrOC) groups (i.e. neutral hydrophilic, neutral hydrophobic and negatively charged) by two nanofiltration (NF) membranes -namely NF270 and NF90. Chemical cleaning was simulated by exposing virgin membrane samples to commercial caustic cleaning formulations as well as sodium hydroxide solutions containing analytical grade additives such as sodium dodecyl sulfate or ethylenediaminetetraacetic acid. The membrane average pore size before and after exposure to a commercially available caustic cleaning formulation was determined based on the pore transport model. The results show that caustic chemical cleaning could cause an increase in the membrane pore size, leading to an increase in permeability and decrease in rejection of conductivity. The impact of caustic cleaning on the pore size and solute rejection was a function of the membrane active skin layer and the chemistry of the cleaning formulation. Caustic cleaning led to a small increase in pore size of the NF270 membrane and resulted in a notable increase in the permeability and salt passage. By contrast, the impact on the NF90 membrane was negligible. The influence of caustic cleaning on TrOC rejection was dependent on physical characteristics of each TrOC including their molecular size, charge, and hydrophobicity. The rejection of neutral and hydrophobic TrOC by the NF270 membrane decreased significantly after exposure to caustic cleaning formulation. However, because the rejection of negatively charged TrOC is governed mostly by electrostatic interaction, their rejection was not significantly affected by caustic cleaning.

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Section: Introductionmentioning

confidence: 99%

Effects of caustic cleaning on pore size of nanofiltration membranes and their rejection of trace organic chemicals

Simon

McDonald

Khan

et al. 2013

Journal of Membrane Science

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“…The impact of chemical cleaning on the membrane integrity depends on the cleaning concentration, cleaning solution composition, time of exposure, cleaning methodology and temperature. Increasing the cleaning solution temperature during the cleaning process is particularly attractive as it accelerates transport processes, chemical reactions and the solubility of various foulants [17]. Apart from chemical interactions with the membrane, high cleaning temperature may also further enhance the modification of the membrane properties [18].…”

Section: Introductionmentioning

confidence: 99%

Impact of chemical cleaning on the nanofiltration of pharmaceutically active compounds (PhACs): The role of cleaning temperature

Simon

Price

Nghiem

2013

Journal of the Taiwan Institute of Chemical Engineers

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This study investigated the impact of chemical cleaning on the physicochemical properties of a nanofiltration membrane and its subsequent separation efficiency of inorganic salts and two pharmaceutically active compounds (PhACs), sulfamethoxazole and carbamazepine. Chemical cleaning was simulated by immersing virgin membrane samples in aqueous citric acid, sodium hydroxide (NaOH), ethylenediaminetetraacetic-acid (EDTA) and sodium dodecyl sulphate (SDS) at various temperatures for 18 h. The cleaning temperature did not exert any discernible impact on the surface charge of the NF270 membrane selected in this study. However, high cleaning temperatures were shown to either amplify or reduce the impact of chemical cleaning on several other membrane properties (including hydrophobicity, surface roughness and permeability) as well as the rejection of both inorganic salts and PhACs. The influence of chemical cleaning on the membrane surface roughness was enhanced at elevated cleaning temperatures. Similarly, at a high cleaning temperature, caustic and acidic cleaning caused a more significant increase in the membrane surface hydrophobicity than that at an ambient temperature. An increase in the cleaning temperature could also slightly amplify the decrease in the membrane permeability due to acidic cleaning. When a caustic cleaning solution (pH 11.5) was used, the membrane permeability only varied slightly with the temperature. Results obtained from Fourier transform infrared spectroscopy (FTIR) analysis suggest that chemical cleaning even at a high temperature did not permanently alter the chemical composition of the membrane active or support layer. Indeed, the effects of chemical cleaning at a high temperature on the physicochemical properties of the membrane could be attributed to the conformational changes of the membrane polymeric matrix. Chemical cleaning using citric acid, SDS or EDTA at a high temperature resulted in a considerable increase in the rejection of salts and PhACs in their neutral form. On the other hand, caustic cleaning at an elevated temperature had no discernible impact on the rejection of inorganic salts and neutral PhACs. This is because caustic cleaning and an elevated cleaning temperature cause opposing effects on the rejection of these solutes. Chemical cleaning at all temperatures investigated in this study did not affect the removal of negatively charged sulfamethoxazole.

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“…The strong base of NaOH can serve as hydrolysis, saponification, and solubilization agent of organic foulants [28]. The presence of hydroxyl ions enhances the disaggregation of the fouling layer by increasing the pH and the ionic strength as well as the solubility of the organic compounds [19].…”

Section: Alkaline Phmentioning

confidence: 99%

“…the iron ions by forming a bidentate mononuclear complex more easily removable from the membrane surface [19]. Figure 9 shows the membrane rejection change and the cleaning effectivity after alkaline cleaning using NaOH pH 12.…”

Section: Alkaline Phmentioning

confidence: 99%

“…Previous researches reported that chemical membrane cleaning can already provide almost 100% recovery of membrane flux so it is able to extend membrane lifespan [1,[16][17][18][19][20][21]. The cleaning agents that are usually used are ethylene diamine tetraacetic acid (EDTA) [17,21], alkali solutions like sodium hydroxide (NaOH) [16,18], acid solutions like hydrogen chloride (HCl) [18] and citric acid [16].…”

Section: Introductionmentioning

confidence: 99%

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Case Study of a Small Scale Reverse Osmosis System for Treatment of Mixed Brackish Water and STP Effluent

Widiasa

Jayanti

2017

J. Eng. Technol. Sci.

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Abstract.A case study on utilizing reverse osmosis (RO) technology to fulfill fresh water needs at a mall and a hotel has been done on Bali Island, Indonesia. A mix of brackish water and sewage treatment plant (STP) effluent was used as feed water in the RO system. The system used 36 membrane elements (CSM RE 8040 BLN) arranged into two stages: 8 pressure vessels (PVs) in the first stage and 4 PVs in the second stage, each loaded with 3 membranes. The objectives of this research were to assess the cleaning effectivity in the plant, to evaluate the cleaning of 1 membrane element using a CIP system, and to assess the use of the membrane for filtration in the pre-treatment system. SEM and FTIR analysis indicated that the foulants on the membrane surface were dominated by organic foulants and inorganic deposits. To clean the discarded membrane the proposed method used NaOH solution (pH 12 and pH 13) and citric acid (pH 2 and pH 3). All membranes displayed a dramatic decline in rejection of about 80%. Based on the rejection tests of SO 4 2-, Cl -, turbidity reduction approached 100%. It can be concluded that an RO membrane that has undergone selectivity decline can be re-used as a filtration membrane in the pre-treatment system.

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Chemical cleaning of reverse osmosis membrane fouled by wastewater

Cited by 157 publications

References 22 publications

Effects of caustic cleaning on pore size of nanofiltration membranes and their rejection of trace organic chemicals

Effects of caustic cleaning on pore size of nanofiltration membranes and their rejection of trace organic chemicals

Impact of chemical cleaning on the nanofiltration of pharmaceutically active compounds (PhACs): The role of cleaning temperature

Case Study of a Small Scale Reverse Osmosis System for Treatment of Mixed Brackish Water and STP Effluent

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