Alkali-Activated Material Based on Red Clay and Silica Gel Waste

Abstract The search for alternative alumosilicates source for production of alkali activated materials (AAM) is intensively researched. Wide spread of natural materials such as clays and waste materials are one of potential alternatives. In this research AAM was made from local waste brick made of red clay and calcined low-carbonate illite clay precursor and its properties evaluated. Waste silica gel containing amorphous silica from fertilizer production plant was proposed as additional raw material. 6 M and 7 M NaOH alkali activation solutions were used to obtain AAM. Raw materials were characterized by X-ray diffraction, laser particle size analyser, DTA/TG. Raw illite clay was calcined at a temperature of 700 to 800 °C. Waste brick was ground similar as raw clay and powder was obtained. Replacement of red clay with silica gel from 2–50 wt.% in mixture composition was evaluated. Results indicate that the most effective activator was 6 M NaOH solution and AAM with strength up to 13 MPa was obtained. Ground brick had the highest strength results and compressive strength of AAM reached 25 MPa. Silica gel in small quantities had little effect of AAM strength while significant strength reduction was observed with the increase silica gel content. The efflorescence was observed for samples with silica gel.

Download Full-text

Synthesis of Zeolite-A and Zeolite-Y Using Silica Gel Waste as Silica Source and Modifying with Fe

International Journal of Engineering & Technology ◽

10.14419/ijet.v7i4.38.27878 ◽

2018 ◽

Vol 7 (4.38) ◽

pp. 1376

Author(s):

Pornnipa Khaosomboon ◽

Kulyakorn Khuanmar ◽

Panomchai Weerayutsil

Keyword(s):

Surface Area ◽

Silica Gel ◽

Zeolite Y ◽

Physical Adsorption ◽

Lower Surface ◽

Zeolite A ◽

Silica Source ◽

Bet Specific Surface Area ◽

Silica Gel Waste ◽

Modified Zeolites

The purpose of this research was to synthesize zeolite-A (Ze-A) and zeolite-Y (Ze-Y) using silica sources from silica gel waste, and also improving adsorption capacity with Fe which was trapped in the synthesized zeolites: Ze-Fe-A and Ze-Fe-Y. All synthesized zeolites were tested with lead solution of 40 mg/L at pH 5. For BET specific surface area, the parent Ze-A and Ze-Y presented surface area of 27.02 and 211.42 m2/g, respectively, whereas Ze-Fe-A and Ze-Fe-Y presented a lower surface area of 10.90 and 28.22 m2/g, respectively. SEM and TEM image demonstrated the cubic and polygon shapes for Ze-A and Ze-Y, respectively, while their modification with Fe presented more round shape. Additionally, both modified zeolites with Fe presented higher adsorption efficiency than their parents. Although the modified zeolites gave lower surface area, the efficiency removal of lead showed higher capacity than zeolite without Fe. It could be concluded that the adsorption mechanism of modified zeolites did not only rely on physical adsorption, but also on chemical adsorption.

Download Full-text

The Effect of Various Hydroxide and Salt Additives on the Reduction of Fluoride Ion Mobility in Industrial Waste

Sustainability ◽

10.3390/su13031554 ◽

2021 ◽

Vol 13 (3) ◽

pp. 1554

Author(s):

Tadas Dambrauskas ◽

Kestutis Baltakys ◽

Agne Grineviciene ◽

Valdas Rudelis

Keyword(s):

Liquid Medium ◽

Silica Gel ◽

Ion Mobility ◽

Fluoride Removal ◽

Dynamic Conditions ◽

Treatment Conditions ◽

Medium Flow ◽

Silica Gel Waste ◽

Fluorine Ions ◽

Static Conditions

In this work, the influence of various hydroxide and salt additives on the removal of F− ions from silica gel waste, which is obtained during the production of AlF3, was examined. The leaching of the mentioned ions from silica gel waste to the liquid medium was achieved by the application of different techniques: (1) leaching under static conditions; (2) leaching under dynamic conditions by the use of continuous liquid medium flow; and (3) leaching in cycles under dynamic conditions. It was determined that the efficiency of the fluoride removal from this waste depends on the w/s ratio, the leaching conditions, and the additives used. It was proven that it is possible to reduce the concentration of fluorine ions from 10% to <5% by changing the treatment conditions and by adding alkaline compounds. The silica gel obtained after the leaching is a promising silicon dioxide source.

Download Full-text

The Prospective Approach for the Reduction of Fluoride Ions Mobility in Industrial Waste by Creating Products of Commercial Value

Sustainability ◽

10.3390/su11030634 ◽

2019 ◽

Vol 11 (3) ◽

pp. 634 ◽

Cited By ~ 1

Author(s):

Valdas Rudelis ◽

Tadas Dambrauskas ◽

Agne Grineviciene ◽

Kestutis Baltakys

Keyword(s):

Liquid Medium ◽

Silica Gel ◽

Reaction Temperature ◽

Industrial Waste ◽

Adsorption Properties ◽

Raw Material ◽

Fluoride Ions ◽

Dynamic Conditions ◽

Stable Compound ◽

Silica Gel Waste

In this work, we present the possibility to reduce the amount of fluoride ions in silica gelwaste by using different techniques or to immobilize these ions by creating products ofcommercial value. The leaching of fluoride ions from silica gel waste to the liquid medium wasdone under static and dynamic conditions. It was determined that the removal of fluoride ionsfrom this compound depends on various factors, such as dissociation, solubility, the w/s ratio,reaction temperature, leaching conditions, the adsorption properties of silica gel waste, and others.The obtained results showed that, by applying different techniques, the quantity of fluoride ionscan be reduced by 60%, while obtained water was neutralized by calcium hydroxide.Additionally, it was determined that silica gel waste is a promising raw material for thehydrothermal synthesis of a stable compound containing fluoride ions – cuspidine.

Download Full-text