Sol–gel synthesis of a humic acid-silica gel composite material as low-cost adsorbent for thorium and uranium removal

Prasetyo, Erik; Toyoda, Kazuhiro

doi:10.1007/s10967-016-4861-y

Cited by 13 publications

(6 citation statements)

References 42 publications

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“…Silica has been identified as an ideal support for this method, due to its strong hydrophilicity, acknowledged biocompatibility, as well as tunable size, shape, porosity and surface chemistry [21,24]. The immobilization of HA onto silica appears as a valid approach to exploit the large reactive potential of these moieties for several technological solutions spanning separation chromatography [25], water remediation [9,[26][27][28] and antioxidant products [14,15].…”

Section: Introductionmentioning

confidence: 99%

“…Two different strategies have been usually explored to combine HA with a silica support. The physical entrapment of humic molecules into silica matrices provides a simple but effective route to obtain HA-SiO 2 composites with a high sorption capacity towards heavy metals cations [26] as well as organic hydrophobic contaminants [27]. Alternatively, chemical immobilization has been exploited to bind humic acids onto the silica surface [28][29][30][31].…”

Section: Introductionmentioning

confidence: 99%

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Tuning Functional Behavior of Humic Acids through Interactions with Stöber Silica Nanoparticles

et al. 2020

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Humic acids (HA) exhibit fascinating multifunctional features, yet degradation phenomena as well as poor stability in aqueous environments strongly limit their use. Inorganic nanoparticles are emerging as a powerful interface for the development of robust HA bio-hybrid materials with enhanced chemical stability and tunable properties. Hybrid organic-inorganic SiO 2 /HA nanostructures were synthesized via an in-situ sol-gel route, exploiting both physical entrapment and chemical coupling. The latter was achieved through amide bond formation between carboxyl groups of HA and the amino group of 3-aminopropyltriethoxysilane (APTS), as confirmed by Fourier-Transform Infrared (FTIR) and Nuclear Magnetic Resonance (NMR) spectroscopy. Monodisperse hybrid nanoparticles about 90 nm in diameter were obtained in both cases, yet Electron Paramagnetic Resonance (EPR) spectroscopy highlighted the different supramolecular organization of HA. The altered HA conformation was reflected in different antioxidant properties of the conjugated nanoparticles that, however, resulted in being higher than for pure HA. Our findings proved the key role of both components in defining the morphology of the final system, as well as the efficacy of the ceramic component in templating the HA supramolecular organization and consequently tuning their functional features, thus defining a green strategy for bio-waste valorization.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Tuning Functional Behavior of Humic Acids through Interactions with Stöber Silica Nanoparticles

et al. 2020

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“…50 Additionally, despite the unity, which is considered a completely reversible case, the value of R L tended toward zero (the completely ideal irreversible case). 51 Another model, Freundlich isotherm, is used to describe the adsorption on a solid surface. This model describes heterogeneous surface adsorption.…”

Section: Initial Concentrations Effect and Models Of Sorption Isothermmentioning

confidence: 99%

Synthesis and Characterization of a Nanosilica-Cysteine Composite for Arsenic(III) Ion Removal

Alnasra,

Khalili

2023

ACSi

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This article describes the synthesis of a nanosilica-cysteine composite (SiO2-Cys) and its application as a sorbent and carrier for arsenic(III) using different media. Attenuated total reflectance-Fourier-transform infrared spectroscopy, scanning and transmission electron microscopy, X-ray diffraction, and thermogravimetric analysis were applied to characterize SiO2-Cys. Using the batch technique, the sorption of As(III) ions by SiO2-Cys was studied, and the effects of pH, sorbent dosage, temperature, initial concentration, and contact time were all taken into consideration. According to kinetic studies, the pseudo-second-order equation adequately described the sorption of the As(III) ion. The spontaneity of the sorption process on SiO2-Cys is suggested by the negative values of Gibbs free energy (ΔG°). Positive values of enthalpy (ΔH°) indicate an endothermic adsorption process and positive values of entropy (ΔS°) for the adsorption of As(III) ions mean that adsorption is associated with increasing randomness. The Langmuir model, which has a maximum sorption capacity for SiO2-Cys of (66.67 mg/g) at 25 °C, provided a better fit to the sorption isotherm.

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“…Several studies on the synthesis of alkali-silica-humic acid have been carried out but have not involved gelation method. Most products are obtained through the process of mixing some raw materials to produce a solid fertilizer (Roger et al, 1971) or as suport for immobilization of humic acid to silica gel (Sandor et al, 2016;Alexander et al, 2016;Prasety et al, 2016). The gelation is that cluster grow by condensation of polymer aggregation of particulate until the clusters collide, then links form between the clusters to produce a single giant cluster that is called a gel (Brinker, 1990;Muljani et al, 2014).…”

Section: Introductionmentioning

confidence: 99%

Synthesis of Matrix Si-K-HAs Gel from Geothermal Sludge and Peat

Muljani

Wahyudi

Suprihatin

et al. 2018

Reaktor

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The synthesis of matrix silica-potassium-humic acid gel (Si-K-HAs) has been performed successfully by gradual extraction and acidification method. The extraction was carried out in two stages: 1) extraction of humic substances from peat prepared by potassium hydroxide to produce potassium humate (K-HAS) solution, 2) extraction silica from geothermal sludge using K-HAs solution to produce Si-K-HAs solution. Acidification of Si-K-HAs solution prepared by citric acid (1-3N) to produce matrix gel of Si-K-HAs. The Si-K-HAs matrix gel products are characterized by Fourier Transform InfraRed (FTIR), X-ray fluroscence (XRF), and Brunauer–Emmett–Teller (BET) analysis. The acidification process was carried out in neutral to acid (pH 3-7) conditions and the results showed that at neutral pH no Si-K-HAs gel formed. IR spectra confirmed the presence of humic acid in the gel product, whereas XRF analysis confirmed the presence of potassium (K) and silica (SiO2) in the gel product. The molar ratio of SiO2:K2O in the product is 0.9 - 0.3 in the pH range of 3-5. Si-K-HAs powder can be used as soil fertilizer especially for soils that lack silica, humic, and potassium nutrients or for future application development. Keywords: gradual extraction; geothermal sludge; matrix gel; humic substance

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Sol–gel synthesis of a humic acid-silica gel composite material as low-cost adsorbent for thorium and uranium removal

Cited by 13 publications

References 42 publications

Tuning Functional Behavior of Humic Acids through Interactions with Stöber Silica Nanoparticles

Tuning Functional Behavior of Humic Acids through Interactions with Stöber Silica Nanoparticles

Synthesis and Characterization of a Nanosilica-Cysteine Composite for Arsenic(III) Ion Removal

Synthesis of Matrix Si-K-HAs Gel from Geothermal Sludge and Peat

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