Green additives to enhance silica dissolution during water treatment

Demadis, Konstantinos D.; Mavredaki, Eleftheria

doi:10.1007/s10311-005-0015-0

Cited by 51 publications

(35 citation statements)

References 8 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Among the water-, or steam-formed deposits colloidal silica (SiO 2 nH 2 O, n is variable and dependents on hydration), a very persistent precipitate, is thought to be of the toughest to combat, as it can cause serious materials failure and operational shut-downs, Figure 1 [9]. Control of silica polycondensation, in principle, can be achieved by use of chemical additives [10] or capital-intensive water desilicification [11][12][13][14][15]. Unfortunately, traditional scale control methods (inhibition and crystal modification) applied to crystalline mineral salt precipitates [16], do not apply to silica because of its amorphous state [17].…”

Section: Introductionmentioning

confidence: 99%

Profound “turn-off” effects of anionic polymers on the inhibitory activity of cationic polyallylamine in the prevention of silica scale

Spinthaki¹,

Stathoulopoulou²,

Demadis

2015

Int. J. Corros. Scale Inhib.

View full text Add to dashboard Cite

Colloidal/amorphous silica (SiO 2 nH 2 O, n is variable) is considered as the most undesirable inorganic precipitate that forms during various processes in silica-supersaturated industrial waters. In this paper we present how certain polymeric chemical additives can prevent silicic acid polymerization to form colloidal silica, which may lead to deposition onto industrial equipment. More specifically, stabilization of silicic acid is accomplished by using a cationic polymer, polyallylamine hydrochloride (PALAM), in supersaturated silica solutions (starting silica concentration in the form of silicate 500 ppm, or 8.3 mM sodium orthosilicate, Na 2 SiO 3 ·5H 2 O, expressed as SiO 2 ) at pH = 7. PALAM is a linear homopolymer that carries one amine side functional group every two carbon atoms, so it becomes protonated at circumneutral pH, rendering the molecule cationic. Its blends with anionic polymers such as carboxymethylinulin (CMI), poly(acrylamide-co-acrylic acid) (PAM-co-AA) and phosphonomethylated chitosan (PCH) are also studied for their silica scale inhibition efficiency.

show abstract

Section: Introductionmentioning

confidence: 99%

Profound “turn-off” effects of anionic polymers on the inhibitory activity of cationic polyallylamine in the prevention of silica scale

Spinthaki¹,

Stathoulopoulou²,

Demadis

2015

Int. J. Corros. Scale Inhib.

View full text Add to dashboard Cite

show abstract

“…They consist of a complex, heterogeneous mixture of various polyfunctional organic molecules that presents a wide range of molecular weights [3]. They can adsorb onto mineral surfaces, modifying the physicochemical properties of the mineral, i.e., their reactivity and surface characteristics [4][5][6][7]. Therefore, understanding the sorption behaviour of humic substances onto mineral surfaces is of particular interest, since the fate and transport, i.e., both mobilisation and retardation, of inorganic contaminants in aquatic environments are strongly correlated to the presence of humic substances in solution and of humic substances adsorbed onto mineral surfaces [8,9].…”

Section: Introductionmentioning

confidence: 99%

Humic acid sorption onto a quartz sand surface: A kinetic study and insight into fractionation

Pitois

Abrahamsen

Ivanov

et al. 2008

Journal of Colloid and Interface Science

View full text Add to dashboard Cite

“…This increase in these environments depends of the water acidity level and the acid's availability to form new chemical bonds. The other reaction is an ionic reaction that occurs with organic compounds to oxidize the organic matter in the paleolake, as noted by Turker (1991) and Demadis & Mavredki (2005) in water treatment tanks. The dissolution was further increased by the temperature increment during the Holocene.…”

Section: Dissolutionmentioning

confidence: 96%

Taphonomic signatures and paleoecology of Holocene diatom assemblages in the Llano Grande Basin, northwestern Andean Cordillera, Colombia

Sierra-Arango¹,

Souza²,

Ruiz³

2014

Rev. bras. paleontol.

View full text Add to dashboard Cite

-This paper presents the results of a taphonomic study of Holocene diatoms in the Llano Grande Basin, Páramo de Frontino, which is located 3,460 m above sea level in the northwestern Andean Cordillera (6º29'N/76º6'W), Colombia. Samples measuring 1 cm 3 from 57 levels distributed over a core depth of 8.5 m (LLG3) were randomly collected from sediment representing a paleolake that developed on the Llano Grande Basin. The density of diatoms and the number of fragmented and dissolved valves were estimated from 10 μL of each sample. A high variability in the density and preservation of the diatom assemblages was verifi ed along the core, which is related to temperature variation, macroinvertebrates grazing, volcanic ash infl ux, and water-level fl uctuations over the 11.000 C 14 years BP. Fragmentation was higher than dissolution, which indicates the predominance of lotic environments and grazing. The substantial decrease in the diatoms on specifi c level is interpreted as a result of the limitation of silica, decreased water levels, intense herbivory, dry environment or dissolution. In these cases, it is impossible to recognize most of the periphytic diatoms due to the high degree of fragmentation of the frustules. The authors conclude that the high degree of variation of the taphonomic damage in the diatoms of Páramo de Frontino represents different environmental events along the Holocene. Therefore, in the early Holocene, input from ash and high temperatures favored reproduction, which resulted in the high density of diatoms. In the last 4,000 years, the water level in the lake has decreased, and probably the predation on diatoms has increased as evidenced by the increasing of fragmentation of the state 3.Key words: taphonomy, diatom paleoecology, peats, Holocene.RESUMO -Este trabalho apresenta os resultados do estudo tafonômico das diatomáceas holocênicas da Bacia Llano Grande, Páramo de Frontino, localizado a 3.460 m acima do nível do mar, noroeste da Cordilheira dos Andes (6°29'N/76°6'O), Colômbia. Foram coletadas aleatoriamente amostras de 1 cm 3 de sedimentos, distribuídas em 57 níveis ao longo dos 8,5 m do testemunho LLG3, as quais representam um paleolago que se desenvolveu na bacia. A densidade das diatomáceas e o número de valvas fragmentadas e dissolvidas foram estimados a partir de 10 uL de cada amostra. A alta variabilidade na densidade e preservação das assembleias de diatomáceas no testemunho está relacionada com variação de temperatura, consumo por macroinvertebrados, aporte de cinzas vulcânicas e fl utuações no nível de água ao longo dos 11.000 anos AP (C 14 ). A fragmentação foi superior à dissolução, o que indica predominância de ambientes lóticos e consumo por herbívoros. O decréscimo substancial das diatomáceas em nível específi co é interpretado como resultado da limitação de sílica, diminuição dos níveis de água, intensa herbivoria, ambiente seco ou dissolução. Nestes casos, é impossível reconhecer a maioria das diatomáceas perifíticas devido ao grau de fragmentação das frústulas...

show abstract

Green additives to enhance silica dissolution during water treatment

Cited by 51 publications

References 8 publications

Profound “turn-off” effects of anionic polymers on the inhibitory activity of cationic polyallylamine in the prevention of silica scale

Profound “turn-off” effects of anionic polymers on the inhibitory activity of cationic polyallylamine in the prevention of silica scale

Humic acid sorption onto a quartz sand surface: A kinetic study and insight into fractionation

Taphonomic signatures and paleoecology of Holocene diatom assemblages in the Llano Grande Basin, northwestern Andean Cordillera, Colombia

Contact Info

Product

Resources

About