Influence of a polyacrylate antiscalant on gypsum nucleation and growth

Ahmed, Samia ben; Tlili, Mohamed; Amor, Mohamed Ben

doi:10.1002/crat.200800066

Cited by 32 publications

(22 citation statements)

References 30 publications

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“…According to the manufacturer, Flocon 260 contains a mixture of polycarboxylic acids. These polycarboxylic acids are good chelating agents for multivalent cations [38,39].…”

Section: Chemicals and Solution Chemistrymentioning

confidence: 99%

Gypsum scaling during forward osmosis process—a direct microscopic observation study

Shan

Tang

2014

Desalination and Water Treatment

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A B S T R A C TThis study investigated the effect of supersaturation index (SI), ionic strength, membrane orientation, and antiscalant (AS) addition on gypsum scaling during forward osmosis (FO) desalination. Scaling tests were performed in a cross-flow FO system, and the development of gypsum scalants on FO membrane was directly observed using an optical microscope integrated with the FO filtration cell. Greater surface coverage by gypsum crystals and larger crystal sizes occurred on the scaled FO membranes for feed solutions (FS) with higher SI values accompanying with more severe flux reduction. At fixed Ca 2+ and SO 2À 4 concentrations, reducing the ionic strength of the FS from 0.55 to 0.15 M resulted in longer induction time. Nevertheless, more flux loss and surface coverage by scalants occurred at longer filtration duration for 0.15 M FS due to its greater ion activities and thus higher SI. The active layer facing (AL)-draw solution membrane orientation was found to be prone to internal scaling, which is likely as a result of unfavorable internal concentration polarization of scaling precursors inside the FO membrane support layer. On contrary, the AL-FS orientation had much more stable flux behavior. The current study also demonstrated the effectiveness of AS addition and rinsing under cross-flow conditions for FO scaling control.

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“…According to the manufacturer, Flocon 260 contains a mixture of polycarboxylic acids. These polycarboxylic acids are good chelating agents for multivalent cations [38,39].…”

Section: Chemicals and Solution Chemistrymentioning

confidence: 99%

Gypsum scaling during forward osmosis process—a direct microscopic observation study

Shan

Tang

2014

Desalination and Water Treatment

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“…Ben Ahmed vd. [6] akrilik asidin farklı çalışma koşullarında kalsiyum sülfat dihidrat kristal büyüme hızına etkisini incelemiş; akrilik asit konsantrasyonunun artmasıyla nükleasyon hızının azaldığını belirlemişlerdir. Titiz-Sargut vd.…”

Section: Gi̇ri̇ş (Introduction)unclassified

MSMPR tipi kristalizörde kalsiyum sülfat dihidrat kristalizasyonunun glutamik asit varlığında incelenmesi

Polat

Titiz‐Sargut

2017

Gazi Üniversitesi Mühendislik-Mimarlık Fakültesi Dergisi

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Bu çalışmada, kalsiyum sülfat dihidrat kristalizasyonu, 65ºC sıcaklıkta, pH 2,5'da ve 0,5 saat bekleme süresinde MSMPR tipi bir kristalizörde saf ve glutamik asit varlığında incelenmiştir. Bu amaçla %20'lik CaCO3 ve H2SO4 çözeltisi kullanılarak saf ortamda ve 250 ppm, 1000 ppm ve 2500 ppm glutamik asit varlığında kristalizasyon deneyleri yürütülmüştür. Elde edilen kristal ürünün tane boyutu, filtrasyon hızı ve zeta potansiyel değişimi ölçülmüş, XRD, TG-FTIR-MS, SEM analizleri yapılmıştır. Glutamik asidin kristalizasyon ortamında bulunması durumunda üretilen kalsiyum sülfat dihidrat kristallerinin en/boy oranlarının değiştiği, filtrasyon hızının azaldığı ve ortalama tane boyutunun glutamik asit konsantrasyonunun artışına bağlı olarak 73µm'den 54µm'ye düştüğü belirlenmiştir. İncelenen koşullarda kalsiyum sülfat dihidratın kristalizasyon kinetiği McCabe'in L teorisine göre belirlenmiş ve kristal büyüme hızının tane boyutuna bağlı olduğu gösterilmiştir. Ayrıca ASL, C-R, MJ2 ve MJ3 büyüme modelleri kullanılarak kristal büyüme hızı belirlenmiştir. Yapılan hata analizleri sonucunda MJ3 modelinin sistemi en iyi karakterize eden model olduğu bulunmuştur. Sem analizleri ile de glutamik asidin kristal habiti üzerine olan etkisi gösterilmiştir.

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“…[1][2][3][4][5][6][7]. The calcium sulfate whiskers were usually prepared by hydrothermal methods, using mainly the natural gypsum with high purity or the impurity-containing gypsum as the raw materials [8][9][10][11][12].…”

Section: Introductionmentioning

confidence: 99%

Formation of calcium sulfate whiskers from CaCO3-bearing desulfurization gypsum

Hu-ping

Luo

et al. 2011

Res Chem Intermed

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Calcium sulfate whiskers can be used as the reinforcing agents in many composites, such as polymers, ceramics, cements, and papers, etc. This paper investigated the feasibility of preparing calcium sulfate whiskers using desulfurization gypsum as the raw material. The desulfurization gypsum composed mainly of CaSO 4 Á2H 2 O (93.45 wt%) and CaCO 3 (1.76 wt%) were treated with dilute H 2 SO 4 at room temperature to convert CaCO 3 to CaSO 4 ; the latter was then treated at 110-150°C to form CaSO 4 Á0.5H 2 O whiskers. The removal of the CaCO 3 impurity from the desulfurization gypsum favored the formation of CaSO 4 Á0.5H 2 O whiskers with high aspect ratios.

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Influence of a polyacrylate antiscalant on gypsum nucleation and growth

Cited by 32 publications

References 30 publications

Gypsum scaling during forward osmosis process—a direct microscopic observation study

Gypsum scaling during forward osmosis process—a direct microscopic observation study

MSMPR tipi kristalizörde kalsiyum sülfat dihidrat kristalizasyonunun glutamik asit varlığında incelenmesi

Formation of calcium sulfate whiskers from CaCO3-bearing desulfurization gypsum

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