Amorphous calcium silicate as a chemisorbent for phosphate

Southam, Daniel; Lewis, Trevor; McFarlane, Andrew J.; Johnston, James H.

doi:10.1016/j.cap.2003.11.047

Cited by 38 publications

(29 citation statements)

References 2 publications

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“…Previous research [24] has shown that nano-structured calcium silicate effectively and efficiently chemisorbs orthophosphate in all forms from aqueous solution, showing probable conformity to a Freundlich isotherm. Phosphate was found to chemisorb at several orders of magnitude above other common environmental anions, such as nitrate and chloride.…”

Section: Introductionmentioning

confidence: 78%

“…Isothermal studies were used to extend the loading studies previously described [24] and to provide information about the mechanism of sorption. As two chemical quantities were monitored during the reaction two sets of kinetics are presented: firstly with respect to the loss of phosphate from the solution and secondly with respect to hydrogen ion concentration as determined from pH.…”

Section: Kineticsmentioning

confidence: 99%

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Calcium–phosphorus interactions at a nano-structured silicate surface

Southam

Lewis

McFarlane

et al. 2008

Journal of Colloid and Interface Science

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Nano-structured calcium silicate (NCS), a highly porous material synthesized by controlled precipitation from geothermal fluids or sodium silicate solution, was developed as filler for use in paper manufacture. NCS has been shown to chemisorb orthophosphate from an aqueous solution probably obeying a Freundlich isotherm with high selectivity compared to other common environmental anions. Microanalysis of the products of chemisorption indicated there was significant change from the porous and nano-structured morphology of pristine NCS to fibrous and crystalline morphologies and non-porous detritus. X-ray diffraction analysis of the crystalline products showed it to be brushite, CaHPO42H2O, while the largely X-ray amorphous component was a mixture of calcium phosphates. A two-step mechanism was proposed for the chemisorption of phosphate from an aqueous solution by NCS. The first step, which was highly dependent on pH, was thought to be desorption of hydroxide ions from the NCS surface. This was kinetically favoured at lower initial pH, where the predominant form of phosphate present was H2PO(-)4, and led to decreased phosphorus uptake with increasing pH. The second step was thought to be a continuing chemisorption process after stabilization of the pH-value. The formation of brushite as the primary chemisorption product was found to be consistent with the proposed mechanism.

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Section: Introductionmentioning

confidence: 78%

Section: Kineticsmentioning

confidence: 99%

Calcium–phosphorus interactions at a nano-structured silicate surface

Southam

Lewis

McFarlane

et al. 2008

Journal of Colloid and Interface Science

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“…There are diverse applications, such as in fertilizers, detergents, pigment formulation, water treatment, and mineral processing. The P discharged into surface waters stimulates the growth of aquatic microand macro-organisms in nuisance quantities, which can cause eutrophication when occurring in excess in stagnant water bodies (Southam et al 2004). Therefore, the removal of P from wastewater is necessary for the control of eutrophication in lakes and similar stagnant water bodies ( } Ozacar 2003;Ou et al 2007).…”

Section: Introductionmentioning

confidence: 99%

Evaluation of phosphorus adsorption capacity of sesame straw biochar on aqueous solution: influence of activation methods and pyrolysis temperatures

Park

Kim

et al. 2015

Environ Geochem Health

127

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The phosphorus (P) adsorption characteristic of sesame straw biochar prepared with different activation agents and pyrolysis temperatures was evaluated. Between 0.109 and 0.300 mg L(-1) in the form of inorganic phosphate was released from raw sesame straw biochar in the first 1 h. The release of phosphate was significantly enhanced from 62.6 to 168.2 mg g(-1) as the pyrolysis temperature increased. Therefore, sesame straw biochar cannot be used as an adsorbent for P removal without change in the physicochemical characteristics. To increase the P adsorption of biochar in aqueous solution, various activation agents and pyrolysis temperatures were applied. The amount of P adsorbed from aqueous solution by biochar activated using different activation agents appeared in the order ZnCl2 (9.675 mg g(-1)) > MgO (8.669 mg g(-1)) ⋙ 0.1N-HCl > 0.1N-H2SO4 > K2SO4 ≥ KOH ≥ 0.1N-H3PO4, showing ZnCl2 to be the optimum activation agent. Higher P was adsorbed by the biochar activated using ZnCl2 under different pyrolysis temperatures in the order 600 °C > 500 °C > 400 °C > 300 °C. Finally, the amount of adsorbed P by activated biochar at different ratios of biochar to ZnCl2 appeared in the order 1:3 ≒ 1:1 > 3:1. As a result, the optimum ratio of biochar to ZnCl2 and pyrolysis temperature were found to be 1:1 and 600 °C for P adsorption, respectively. The maximum P adsorption capacity by activated biochar using ZnCl2 (15,460 mg kg(-1)) was higher than that of typical biochar, as determined by the Langmuir adsorption isotherm. Therefore, the ZnCl2 activation of sesame straw biochar was suitable for the preparation of activated biochar for P adsorption.

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“…Successful results have been obtained by using powdered aluminum oxide [10][11][12], slag [13], fly ash [14,15], half-burnt dolomite [16], tamarind nut shell activated carbon [17,18], activated red mud [19,20], aluminum [21], amorphous calcium silicate [22], iron oxide [23], rem nut [24] and oyster shells [25].…”

Section: Introductionmentioning

confidence: 99%

Thermodynamic and kinetic investigations of PO3−4 adsorption on blast furnace slag

Oğuz

2005

Journal of Colloid and Interface Science

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Amorphous calcium silicate as a chemisorbent for phosphate

Cited by 38 publications

References 2 publications

Calcium–phosphorus interactions at a nano-structured silicate surface

Calcium–phosphorus interactions at a nano-structured silicate surface

Evaluation of phosphorus adsorption capacity of sesame straw biochar on aqueous solution: influence of activation methods and pyrolysis temperatures

Thermodynamic and kinetic investigations of PO3−4 adsorption on blast furnace slag

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