A facile method for the production of high-surface-area mesoporous silica gels from geothermal sludge

Muljani, Srie; Setyawan, Heru; Wibawa, Gede; Altway, Ali

doi:10.1016/j.apt.2014.05.012

Cited by 28 publications

(27 citation statements)

References 12 publications

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“…This high-temperature melt process is, however, very costly both in equipment and as regards the amounts of energy required and leads moreover to not inconsiderable emissions, such as dust, nitrogen oxides, and sulfur oxides (US 5238668 A). The alkali extraction and acid precipitation method, low energy method, has also been successfully used to produce silicate solution (Muljani et al, 2014), but this method is less precise when solid silicate product is desired. The hydrothermal reaction of quartz sand with aqueous potassium hydroxide obtained potassium silicate solutions which have SiO2: K2 O molar ratios of less than 2.75:1.…”

Section: Introductionmentioning

confidence: 99%

Potassium Silicate Foliar Fertilizer Grade from Geothermal Sludge and Pyrophyllite

Muljani

Wahyudi

Sumada

2016

MATEC Web of Conferences

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Potassium silicate fertilizer grade were successfully produced by direct fusion of silica (SiO2) and potasium (KOH and K2CO3) in furnaces at temperatures up to melting point of mixture. The geothermal sludge (98% SiO2) and the pyrophyllite (95% SiO2) were used as silica sources. The purposes of the study was to synthesise potassium silicate fertilizer grade having solids concentrations in the range of 31-37% K2O, and silica in the range of 48-54% SiO2. The weight ratio of silicon dioxide/potasium solid being 1:1 to 5:1. Silica from geothermal sludge is amorphous, whereas pyrophylite is crystalline phase. The results showed that the amount of raw materials needed to get the appropriate molar ratio of potassium silicate fertilizer grade are different, as well as the fusion temperature of the furnace. Potassium silicate prepared from potassium hydroxide and geothermal sludge produced a low molar ratio (2.5: 1 to 3: 1). The potassium required quite small (4:1 in weight ratio), and on a fusion temperature of about 900 °C. Meanwhile, the potassium silicate prepared from pyrophyllite produced a high molar ratio (1.4 -9.4) and on a fusion temperature of about 1350 °C, so that potassium needed large enough to meet the required molar ratio for the fertilizer grade. The product potassium silicate solid is amorphous with a little trace of crystalline.Keywords: geothermal sludge, pyrophyllite, fusion reaction, potassium silicate solid, fertilizer INTRODUCTIONPotassium or sodium water glasses are generally produced on an industrial scale by melting together quartz sand and sodium/potassium carbonate in suitable furnaces at temperatures in the range of 1400° to 1500° C with the splitting-off of carbon dioxide. This high-temperature melt process is, however, very costly both in equipment and as regards the amounts of energy required and leads moreover to not inconsiderable emissions, such as dust, nitrogen oxides, and sulfur oxides (US 5238668 A). The alkali extraction and acid precipitation method, low energy method, has also been successfully used to produce silicate solution (Muljani et al, 2014), but this method is less precise when solid silicate product is desired. The hydrothermal reaction of quartz sand with aqueous potassium hydroxide obtained potassium silicate solutions which have SiO2: K2 O molar ratios of less than 2.75:1. However, in this case, hydrothermal reaction must go through a two-stage process: stage quartz reaction with KOH solution at a temperature of 300 C and quartz reaction stage at a temperature up to melting point (over 1100 °C).SiO2 structural differences between amorphous and crystalline silica can lead to differences in dissolution behavior. But the physical properties of amorphous silica remains elusive in comparison to crystalline silica based on the more comprehensive quartz dissolution studies. There are also known hydrothermal processes for the production of aqueous potassium silicate solutions that are described in a number of patent applications. Gunnarsson, et al (2010) report...

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Section: Introductionmentioning

confidence: 99%

Potassium Silicate Foliar Fertilizer Grade from Geothermal Sludge and Pyrophyllite

Muljani

Wahyudi

Sumada

2016

MATEC Web of Conferences

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“…Next, the silica gel was aged for 18 hours and washed by demineralized water until the salt resulted from the titration procces was not present. The pure silica gel was subsequently heated to degradate the water in an oven for 24 hours [4].…”

Section: Synthesis Of Silica Powdermentioning

confidence: 99%

The Effects of the Addition of Silica Mol Fraction (x = 1.5; 2; 2.5) as a Solid Electrolyte on Ion Conductivity of NASICON (Na_1-xZr₂Si_xP_3-xO₁₂) Using Solid-State Method

Pratiwi

Purwaningsih

Widyastuti

et al. 2017

IOP Conf. Ser.: Mater. Sci. Eng.

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Abstract.Energy is a very important in modern life and need innovations to develop it. One innovation is the application of energyfor storage devices, such as batteries, capacitors, fuel cells, etc. For 30 years, the application of the NASICON (Na 1+x Zr 2 Si x P 3-x O 12 ) into the NASICON gas sensor material was successfully prepared by using solid-state method. The raw materials such as SiO 2 , Na 2 CO 3 , ZrO 2 , and NaH 2 PO 4 with a little methanol were mixed in Ballmill equipment. The silica powder was made by the extraction of bagasse ash by using solgel method. The x-ray diffraction patternshowedthat the result of silica extraction was amorphous and the NASICON structure wassynthesizedto bemonoclinic. The scanning electron microscopy results indicated that silica had non-uniform surface morphology and the NASICON had good surface morphology only on the form of Na 3 Zr 2 Si 2 PO 12 . The ionic conductivty of NASICON wasshown on LCR Nyquist plot of the three compositions. The highest NASICON conductivity was found inthe composition of x = 2.0, i.e. 1.142x10 -8 S/m.

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“…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). The present study developed a gelation process to form a combined gel matrix of silica, potassium, and HAs.…”

Section: Introductionmentioning

confidence: 99%

“…Silica from geothermal sludge is amorphous structure (Muljani et al, 2014) and is known that amorphous silica soluble in alkaline but insoluble at low pH (Iller, 1978). Meanwhile, HAs are materials that are insoluble under acidic conditions (at pH < 2) but soluble at higher pH values, and humin is the humic susbstances fraction that is insoluble in water at any pH (Stevenson, 1994).…”

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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A facile method for the production of high-surface-area mesoporous silica gels from geothermal sludge

Cited by 28 publications

References 12 publications

Potassium Silicate Foliar Fertilizer Grade from Geothermal Sludge and Pyrophyllite

Potassium Silicate Foliar Fertilizer Grade from Geothermal Sludge and Pyrophyllite

The Effects of the Addition of Silica Mol Fraction (x = 1.5; 2; 2.5) as a Solid Electrolyte on Ion Conductivity of NASICON (Na_1-xZr₂Si_xP_3-xO₁₂) Using Solid-State Method

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

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A facile method for the production of high-surface-area mesoporous silica gels from geothermal sludge

Cited by 28 publications

References 12 publications

Potassium Silicate Foliar Fertilizer Grade from Geothermal Sludge and Pyrophyllite

Potassium Silicate Foliar Fertilizer Grade from Geothermal Sludge and Pyrophyllite

The Effects of the Addition of Silica Mol Fraction (x = 1.5; 2; 2.5) as a Solid Electrolyte on Ion Conductivity of NASICON (Na1-xZr2SixP3-xO12) Using Solid-State Method

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

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The Effects of the Addition of Silica Mol Fraction (x = 1.5; 2; 2.5) as a Solid Electrolyte on Ion Conductivity of NASICON (Na_1-xZr₂Si_xP_3-xO₁₂) Using Solid-State Method