Effect of acid on morphology of calcite during acid enhanced defluoridation

Nath, S. K.; Bordoloi, Shreemoyee; Dutta, Robin K.

doi:10.1016/j.jfluchem.2010.10.007

Cited by 23 publications

(5 citation statements)

References 39 publications

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“…A sharp weight loss was observed after 600 °C. These observations are in good agreement with those reported in the literature. − For the oil-aged sample, a rapid weight loss was observed when the temperature increased from room temperature to around 100 °C. The weight loss in this region can be attributed to desorption of water molecules from the surface.…”

Section: Resultssupporting

confidence: 92%

Experimental Investigation of Wettability Alteration of Oil-Wet Carbonates by a Non-ionic Surfactant

et al. 2018

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Wettability alteration toward a more water-wet state was found to be a promising approach for oil recovery improvement in oil-wet and naturally fractured carbonate reservoirs. This approach has been extensively studied in the literature using low-salinity/smart water and surfactant injection separately. However, application of surfactants in enhanced oil recovery is limited by their compatibility with the conditions of the reservoirs. In this study, polyethoxylated non-ionic surfactants with different ethylene oxide units were combined with low-salinity brine for a more efficient and cost-effective process. The compatibility of the surfactant solutions highly improved by reducing the salinity in the range of 200–2 g/L. Interfacial tension (IFT) measurements revealed that IFT decreased with increasing salinity. Contact angle measurements of calcite surfaces showed that wettability can be altered from a strong oil-wet state to a water-wet state after treatment with solutions of non-ionic surfactants over a wide range of salinities (∼2–110 g/L). ζ potential, Fourier transform infrared spectroscopy, and thermogravimetric analysis revealed that the non-ionic surfactant could partially displace carboxylate compounds from the surface and adsorb by forming a hydrogen bond with the hydroxyl group on the calcite surface. The formation of hydrogen bonds between ethoxy groups of the surfactant and hydroxyl or carboxylic groups on the solid surface can result in the replacement of organic compounds on the calcite surface. The organic compounds could form a new layer on the layer of adsorbed surfactant molecules via hydrophobic interactions. In addition, adsorption of the hydrophobic part of the non-ionic surfactant on the hydrophobic calcite surface and the formation of a surfactant double layer could partially contribute to the wettability alteration process.

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Section: Resultssupporting

confidence: 92%

Experimental Investigation of Wettability Alteration of Oil-Wet Carbonates by a Non-ionic Surfactant

et al. 2018

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“…Recently, it was shown that the defluoridation with limestone may be increased by an acid activation. Of particular interest is the paper using oxalic acid in this activation leading to the formation of calcium oxalate [36,37]. The addition of oxalic acid improves the fluoride removal by crushed limestone.…”

Section: Introductionmentioning

confidence: 99%

Tamarind (Tamarindus indica) fruit shell carbon: A calcium-rich promising adsorbent for fluoride removal from groundwater

Sivasankar¹,

Rajkumar²,

Murugesh³

et al. 2012

Journal of Hazardous Materials

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“…In most chemical treatments, phosphorus can be removed by precipitation with a metal salt, e.g., iron, aluminum and calcium salts [11]. In wastewater with high fluoride content, the most commonly adopted method is precipitation under calcium fluoride form (CaF 2 ), using different calcium salts (CaCl 2 , Ca(NO 3 ) 2 •4H 2 O, and hydrated lime Ca(OH) 2 ) as precipitants [12][13][14].…”

Section: Introductionmentioning

confidence: 99%

Zero-Liquid Discharge Treatment of Wastewater from a Fertilizer Factory

et al. 2020

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This article describes the improvement of wastewater treatment in a fertilizer plant located in Central Italy (municipality of Vasto). In this facility, water is used for the removal of dust and fluorinated gases from the air. The resulting wastewater contains fluorides and phosphates in hazardous forms. Its treatment ordinarily does not result in a Zero-Liquid Discharge (ZLD) process. To achieve this purpose, several reagents were tested, focusing on the correlation linking pH, type of reagent and the effect on the separation of fluorides and phosphates from the wastewater. It was eventually found, and explained with a model, that hydrated lime at pH = 12 was so effective as a precipitating agent that phosphate and fluoride separation reached a value of 99.9%, thus allowing for reuse of the water in the plant process. Furthermore, phosphates and fluorides precipitated in a non-hazardous form, so that the material could also be recycled. In synthesis, wastewater treatment of the fertilizer plant was upgraded so that it became a ZLD process coupled with the recovery and recycling of fluorides and phosphates.

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Effect of acid on morphology of calcite during acid enhanced defluoridation

Cited by 23 publications

References 39 publications

Experimental Investigation of Wettability Alteration of Oil-Wet Carbonates by a Non-ionic Surfactant

Experimental Investigation of Wettability Alteration of Oil-Wet Carbonates by a Non-ionic Surfactant

Tamarind (Tamarindus indica) fruit shell carbon: A calcium-rich promising adsorbent for fluoride removal from groundwater

Zero-Liquid Discharge Treatment of Wastewater from a Fertilizer Factory

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