Discussion of silica speciation, fouling, control and maximum reduction

Ning, Robert Y.

doi:10.1016/s0011-9164(02)00973-6

Cited by 121 publications

(76 citation statements)

References 9 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…This is a weak polyprotic acid with pKa values of 9.9, 11.8 and 12 (Ning 2002). Orthosilicic acid only remains monomer at 25ºC when the concentration is less than 2 mM.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Silica removal in industrial effluents with high silica content and low hardness

Latour

Miranda

Blanco

2014

Environ Sci Pollut Res

View full text Add to dashboard Cite

High silica content of paper mill effluents is limiting their regeneration and reuse after membrane treatments such as reverse osmosis (RO). Silica removal during softening processes is a common treatment; however, the effluent from the paper mill studied has a low hardness content which makes necessary the addition of magnesium compounds to increase silica removal. Two soluble magnesium compounds (MgCl2·6H2O and MgSO4·7H2O) were tested at five dosages (250-1500 mg/L) and different initial pHs.High removal rates (80-90%) were obtained with both products at the highest pH tested (11.5). With these removal efficiencies, it is possible to work at high RO recoveries (75-85%) without silica scaling. Although pH regulation significantly increased the conductivity of the waters (at pH 11.5 from 2.1 mS/cm to 3.7-4.0 mS/cm), this could be partially solved by using Ca(OH)2 instead of NaOH as pH regulator (final conductivity around 3.0 mS/cm). Maximum chemical oxygen demand (COD) removal obtained with caustic soda was lower than with lime (15% vs. 30%). Additionally, the combined use of a polyaluminum coagulant during the softening process was studied; the coagulant, however, did not significantly improve silica removal, obtaining a maximum increase of only 10%.

show abstract

“…This is a weak polyprotic acid with pKa values of 9.9, 11.8 and 12 (Ning 2002). Orthosilicic acid only remains monomer at 25ºC when the concentration is less than 2 mM.…”

Section: Introductionmentioning

confidence: 99%

“…The rate of silicic acid polymerization is strongly pH-dependent. The reaction is very fast in neutral and slightly alkaline solutions, and extremely slow at low pH values of 2-3 (Ning 2002). More complex colloids can also be formed by its combination with organic and inorganic compounds.…”

Section: Introductionmentioning

confidence: 99%

Silica removal in industrial effluents with high silica content and low hardness

Latour

Miranda

Blanco

2014

Environ Sci Pollut Res

View full text Add to dashboard Cite

show abstract

“…As pH was always kept under 7.5, hydrolyzation did not represent an important problem in the performance of the trials although the silica content increased significantly from December thereafter ( Figure 2). While aluminium content was always below 0.6 mg·L -1 , iron concentrations began to increase over 0.5 mg·L -1 from mid-December onwards as well (Figure 2), being susceptible to form insoluble precipitates of Fe(OH) 3 [46,47], as it was specially observed in S-UF B .…”

Section: Quality Of the Tertiary Treated Watermentioning

confidence: 85%

Evaluation of MF and UF as pretreatments prior to RO applied to reclaim municipal wastewater for freshwater substitution in a paper mill: A practical experience

Ordóñez

Hermosilla

Pío³

et al. 2011

Chemical Engineering Journal

View full text Add to dashboard Cite

“…Other samples of Marcellus wastewater in open literature [6] show silica concentrations between 10 and 40 mg/L; in the Permian it is generally between 50 and 150 mg/L. With silica solubility between 100 and 150 mg/L at room temperature [15], it may be problematic in the Permian, but appears less likely to be so in the Marcellus.…”

Section: Produced Water Samplesmentioning

confidence: 99%

Treating produced water from hydraulic fracturing: Composition effects on scale formation and desalination system selection

Thiel

Lienhard

2014

Desalination

View full text Add to dashboard Cite

Produced water from unconventional gas and oil extraction may be hypersaline with uncommon combinations of dissolved ions. The aim of this analysis is to aid in the selection of produced water treatment technology by identifying the temperature, pH, and recovery ratio under which mineral solid formation from these produced waters is likely to occur. Eight samples of produced water from the Permian Basin and the Marcellus shale are discussed, with an average TDS of about 177 g/L but significant variability. Crystallization potential is quantified by the saturation index, and activity coefficients are calculated using the Pitzer model. The method is applied to estimate solid formation in the treatment of two design case samples: a 183 g/L sample representing the Permian Basin water and a 145 g/L sample representing the Marcellus. Without pretreatment, the most likely solids to form, defined by highest saturation index, are: CaCO 3 , FeCO 3 , MgCO 3 , MnCO 3 , SrCO 3 , BaSO 4 , CaSO 4 , MgSO 4 and SrSO 4 . Some options for mitigating the formation of these scales are discussed. With appropriate pretreatment, it is estimated that recovery ratios of as high as 40-50% are achievable before NaCl, a major constituent, is likely to limit further concentration without significant crystallization.

show abstract

Discussion of silica speciation, fouling, control and maximum reduction

Cited by 121 publications

References 9 publications

Silica removal in industrial effluents with high silica content and low hardness

Silica removal in industrial effluents with high silica content and low hardness

Evaluation of MF and UF as pretreatments prior to RO applied to reclaim municipal wastewater for freshwater substitution in a paper mill: A practical experience

Treating produced water from hydraulic fracturing: Composition effects on scale formation and desalination system selection

Contact Info

Product

Resources

About