Coupling effects of feed solution pH and ionic strength on the rejection of boron by NF/RO membranes

Tu, Kha L.; Nghiem, Long D.; Chivas, Allan R.

doi:10.1016/j.cej.2011.01.101

Cited by 139 publications

(53 citation statements)

References 29 publications

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“…The resistance of clean RO membranes (Table 4) is much higher than that of clean NF membranes, and this is consistent with the more closed polymeric structure of the former (Tu et al, 2011). This makes permeate flux through RO membranes very low, about 7 to 12 times lower than the permeate flux through NF membranes.…”

Section: Evaluation Of Different Nf and Ro Membranessupporting

confidence: 61%

Nanofiltration and Reverse Osmosis Applied to Gold Mining Effluent Treatment and Reuse

Andrade

Aguiar

Pires

et al. 2017

Braz. J. Chem. Eng.

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-Gold mining and ore processing are activities of great economic importance. However, they are related to generation of extremely polluted effluents containing high concentrations of heavy metals and low pH. This study aims to evaluate the optimal conditions for gold mining effluent treatment by crossflow membrane filtration regarding the following variables: nanofiltration (NF) and reverse osmosis (RO) membrane types, feed pH and permeate recovery rate. It was observed that retention efficiencies of NF90 were similar to those of RO membranes though permeate fluxes obtained were 7-fold higher. The optimum pH value was found to be 5.0, which resulted in higher permeate flux and lower fouling formation. At a recovery rate above 40% there was a significant decrease in permeate quality, so this was chosen as the maximum recovery rate for the proposed system. We conclude that NF is a suitable treatment for gold mining effluent at an estimated cost of US$ 0.83/m³.

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Section: Evaluation Of Different Nf and Ro Membranessupporting

confidence: 61%

Nanofiltration and Reverse Osmosis Applied to Gold Mining Effluent Treatment and Reuse

Andrade

Aguiar

Pires

et al. 2017

Braz. J. Chem. Eng.

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“…Boron rejection by commercial RO membranes is relatively low because the boric acid molecule is small in size (its Stokes radius is approximately double that of the water molecule) and neutrally charged. The transformation from boric acid to borate species explains the increase in boron rejection as the pH increased (Tu et al, 2011). On the other hand, being a hydrated and charged species at all pH values, the sodium ion can be efficiently removed by a RO membrane regardless of operating condition changes (Tu et al, 2011).…”

Section: The Rejection Of Boron and Sodiummentioning

confidence: 96%

“…A detailed description of this system is available elsewhere (Tu et al, 2011). The cross-flow membrane cell has an active surface area of 40 cm 2 (10 cm × 4 cm) with a channel height of 2 mm.…”

Section: Cross-flow Membrane Filtration System and Experimental Protocolmentioning

confidence: 99%

Chemical cleaning effects on properties and separation efficiency of an RO membrane

Tu¹,

Chivas²,

Nghiem³

2015

Membr. Water Treat.

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This study aims to investigate the impacts of chemical cleaning on the performance of a reverse osmosis membrane. Chemicals used for simulating membrane cleaning include a surfactant (sodium dodecyl sulfate, SDS), a chelating agent (ethylenediaminetetraacetic acid, EDTA), and two proprietary cleaning formulations namely MC3 and MC11. The impact of sequential exposure to multiple membrane cleaning solutions was also examined. Water permeability and the rejection of boron and sodium were investigated under various water fluxes, temperatures and feedwater pH. Changes in the membrane performance were systematically explained based on the changes in the charge density, hydrophobicity and chemical structure of the membrane surface. The experimental results show that membrane cleaning can significantly alter the hydrophobicity and water permeability of the membrane; however, its impacts on the rejections of boron and sodium are marginal. Although the presence of surfactant or chelating agent may cause decreases in the rejection, solution pH is the key factor responsible for the loss of membrane separation and changes in the surface properties. The impact of solution pH on the water permeability can be reversed by applying a subsequent cleaning with the opposite pH condition. Nevertheless, the impacts of solution pH on boron and sodium rejections are irreversible in most cases. Abstract. This study aims to investigate the impacts of chemical cleaning on the performance of a reverse osmosis membrane. Chemicals used for simulating membrane cleaning include a surfactant (sodium dodecyl sulfate, SDS), a chelating agent (ethylenediaminetetraacetic acid, EDTA), and two proprietary cleaning formulations namely MC3 and MC11. The impact of sequential exposure to multiple membrane cleaning solutions was also examined. Water permeability and the rejection of boron and sodium were investigated under various water fluxes, temperatures and feedwater pH. Changes in the membrane performance were systematically explained based on the changes in the charge density, hydrophobicity and chemical structure of the membrane surface. The experimental results show that membrane cleaning can significantly alter the hydrophobicity and water permeability of the membrane; however, its impacts on the rejections of boron and sodium are marginal. Although the presence of surfactant or chelating agent may cause decreases in the rejection, solution pH is the key factor responsible for the loss of membrane separation and changes in the surface properties. The impact of solution pH on the water permeability can be reversed by applying a subsequent cleaning with the opposite pH condition. Nevertheless, the impacts of solution pH on boron and sodium rejections are irreversible in most cases.

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“…The linear regression coefficients for all calibration curves were greater than 0.99 for all elements. Prior to each batch of analyses, the ICP-MS was tuned by a multielement tuning solution that contained 10 g/L of Li, Y, Ce, Tl, and Co. Each analysis was conducted in triplicate and the variation was less than 5% [32].…”

Section: Cation Analysismentioning

confidence: 99%

Treatment of RO brine from CSG produced water by spiral-wound air gap membrane distillation — A pilot study

Duong

Chivas

Nelemans³

et al. 2015

Desalination

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208

112

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Brine management is a major bottleneck for coal seam gas (CSG) production in Australia. This study investigated the concentration of CSG reverse osmosis (RO) brine using a pilot membrane distillation (MD). The system was equipped with a novel spiral-wound air gap membrane distillation (AGMD) module. By operating the pilot MD system at low feed temperature and a small temperature gradient, a stable distillate production rate could be maintained. The resulting low permeate flux can be offset by a high packing density of the spiral-wound membrane module. Here, using a module with diameter, height, and total membrane surface area of 0.4 m, 0.5 m, and 7.2 m2, respectively, the pilot MD system sustainably achieved 80% water recovery and produced 10 L/h of distillate from CSG RO brine. Overall, 95% water recovery could be obtained from CSG produced water for beneficial uses by a combination of RO and AGMD without any observable membrane scaling. A preliminary thermal energy demand analysis suggests that if installed in New South Wales (Australia), 1 ha of flat-plate solar thermal collector arrays could provide sufficient thermal energy to treat 472 m3/day (2970 bbl/day) of CSG produced water using the proposed RO/AGMD treatment train. o An overall water recovery of 95% was achieved over a sustained period.o The precipitation of Si and Ca may lead to scaling in long term operation.o One ha of land can provide solar thermal for treating 118 m 3 /d of CSG RO brine.Abstract: Brine management is a major bottleneck for coal seam gas (CSG) production in Australia. This study investigated the concentration of CSG reverse osmosis (RO) brine using a pilot membrane distillation (MD). The system was equipped with a novel spiral-wound air gap membrane distillation (AGMD) module. By operating the pilot MD system at low feed temperature and a small temperature gradient, a stable distillate production rate could be maintained. The resulting low permeate flux can be offset by a high packing density of the spiralwound membrane module. Here, using a module with diameter, height, and total membrane surface area of 0.4 m, 0.5 m, and 7.2 m 2 , respectively, the pilot MD system sustainably achieved 80% water recovery and produced 10 L/h of distillate from CSG RO brine. Overall, 95% water recovery could be obtained from CSG produced water for beneficial uses by a combination of RO and AGMD without any observable membrane scaling. A preliminary thermal energy demand analysis suggests that if installed in New South Wales (Australia), one hectare of flat-plate solar thermal collector arrays could provide sufficient thermal energy to treat 472 m 3 /day (2970 bbl/day) of CSG produced water using the proposed RO/AGMD treatment train.

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Coupling effects of feed solution pH and ionic strength on the rejection of boron by NF/RO membranes

Cited by 139 publications

References 29 publications

Nanofiltration and Reverse Osmosis Applied to Gold Mining Effluent Treatment and Reuse

Nanofiltration and Reverse Osmosis Applied to Gold Mining Effluent Treatment and Reuse

Chemical cleaning effects on properties and separation efficiency of an RO membrane

Treatment of RO brine from CSG produced water by spiral-wound air gap membrane distillation — A pilot study

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