The role of dissolved aluminum in silica chemistry for membrane processes

Gabelich, Christopher J.; Chen, Wei R.; Yun, Tae I.; Coffey, Bradley M.; Suffet, I. H.

doi:10.1016/j.desal.2005.02.009

Cited by 70 publications

(39 citation statements)

References 5 publications

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“…Previous research conducted at MWDSC using Colorado River water has identified aluminum hydroxide, aluminum silicate, and aluminum phosphate-based fouling during reverse osmosis (RO) treatment ( Figure 1) [1,6]. Each of these foulants was presumably caused by excessive aluminum introduced into the RO feed water by the use of aluminum sulfate (alum) coagulation upstream, which imparts up to 200 µg/L of total aluminum at the filter effluent.…”

Section: Previous Researchmentioning

confidence: 99%

“…Previous research conducted by the Metropolitan Water District of Southern California (MWDSC) identified aluminum silicate-based, aluminum hydroxide-based, and aluminum phosphate-based fouling during reverse osmosis (RO) treatment [1]. Each of these foulants presumably resulted from excessive aluminum introduced into the RO feed water by the use of aluminum sulfate (alum) during the upstream coagulation process.…”

Section: Introductionmentioning

confidence: 99%

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Control of residual aluminum from conventional treatment to improve reverse osmosis performance

Gabelich¹,

Ishida

Gerringer³

et al. 2006

Desalination

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Soluble aluminum (Al 3+ ) may react with both ambient silica and antiscalant components to form colloidal foulants during reverse osmosis (RO) treatment. Whereas conventional treatment (coagulation/filtration/sedimentation/dual-media filtration) was being used prior to RO, aluminum sulfate (alum) and polyaluminum chloride (PACl) coagulants were evaluated at ambient pH (pH 7.8 to 7.9) and suppressed pH (pH 6.7) in an effort to lower the total aluminum to below 50 µg/L-a level previously observed to prevent RO membrane fouling. Additional tests were conducted with 5 mg/L citric acid added to the RO influent to chelate the soluble aluminum fraction. All tests were conducted with 1.5 to 2.5 mg/L chloramines present. Testing of a RO process fed with optimized alum-or PACl-coagulated water showed that PACl outperformed alum regardless of pH. Alum coagulation at ambient pH resulted in 184 to 273 µg/L total aluminum passing through the filtration process. Only by lowering the mean influent water pH to 6.7 was the mean soluble aluminum residual (45 µg/L) for alum coagulation reduced to below the 50 µg/L aluminum goal. Regardless of pH, for alum-coagulated waters, the higher aluminum carryover resulted in severe RO membrane fouling within 500 hours of operation. Only when a chelating agent (citric acid) was added to the RO feed was the loss in productivity and selectivity arrested. However, PACl consistently met the 50-µg/L goal for both total and soluble aluminum for all pH levels tested, which resulted in more stable membrane performance over time. Further research on the compatibility of PACl and polyamide membranes in the presence of chloramines is needed as data from this project suggest PACl coagulation may facilitate membrane oxidation.

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Section: Previous Researchmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Control of residual aluminum from conventional treatment to improve reverse osmosis performance

Gabelich¹,

Ishida

Gerringer³

et al. 2006

Desalination

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“…Além disso, o equilíbrio mineral e o pH da solução são responsáveis por regular a concentração e o tipo das espécies iônicas geradas [9], o que pode influenciar no tipo de aluminosilicato a ser formado. Por exemplo, uma solução aquosa contendo ~ 10 -7 mol/L de Al e ~ 10 -4 mol/L de Si (na forma de H 4 SiO 4 ) é considerada supersaturada em relação ao mineral caulinita [11]. Nestas condições, a precipitação de caulinita é termodinamicamente favorecida.…”

Section: Resultsunclassified

Resistência à corrosão de pós metálicos em concretos refratários contendo elevado teor de carbono

2006

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“…In the presence of multivalent metal ions, however, the formation of metal silicates is possible at pH values close to the pKa of silicic acid (9.8) [23]. The ROC used in these experiments contained sufficient quantities of calcium, magnesium and aluminium for silicate scale formation to occur at alkaline pH values [7]. The presence of calcium and magnesium have also been found to accelerate polymerization of silicic acid at acidic pH values, but the mechanism for this is not clearly understood [9].…”

Section: Effect Of Phmentioning

confidence: 99%

“…Although it is possible to estimate silica scaling potential of a test water based on the pure water solubility limits [6], the scaling potential of the water can be expected to be higher than this prediction if even small quantities of trivalent metal ions are present [7] or if the ionic strength is high [8], and lower than this prediction under conditions where the polymerization reactions responsible for the formation of amorphous silica are slow, e.g., at low pH [8].…”

Section: Introductionmentioning

confidence: 99%

Silica scale mitigation for high recovery reverse osmosis of groundwater for a mining process

Sartipy

Milne

Taylor³

et al. 2014

Desalination

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Abstract:The feasibility of silica removal in RO treatment of groundwater from a Western Australian mining and processing operation to prevent scaling and enhance water recovery was investigated. This study has shown that it is possible to decrease the silica concentration in RO concentrate to levels that would allow an overall water recovery of 90% to 95% using 10 g/L of regenerable activated alumina adsorbent. Regeneration of the adsorbent using 2% NaOH was found to be effective for at least three regeneration cycles. A preliminary costing of the high water recovery RO process using silica removal by adsorption indicated product water (permeate) costs of $5.6/kL and savings due to a reduction in brine volume from the current 40% of feed volume to 5-10% of feed volume. It also allows better utilization of a scarce groundwater resource, allowing the production of up to 1.6 times more low salt water from a given volume of groundwater. These results warrant larger scale investigation of silica removal and adsorbent regeneration for high recovery RO processing for mining operations, and application of silica removal to RO treatment of other silica laden waters such as coal seam gas produced water.

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The role of dissolved aluminum in silica chemistry for membrane processes

Cited by 70 publications

References 5 publications

Control of residual aluminum from conventional treatment to improve reverse osmosis performance

Control of residual aluminum from conventional treatment to improve reverse osmosis performance

Resistência à corrosão de pós metálicos em concretos refratários contendo elevado teor de carbono

Silica scale mitigation for high recovery reverse osmosis of groundwater for a mining process

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