scholarly journals MECHANISM OF FORMING NANODISPERSE COPPER SILICATE POWDER DURING ANODIC POLZRIZATION OF COPPER ELECTRODE IN POTASSIUM SILICATE SOLUTION

2018 ◽  
Vol 6 (432) ◽  
pp. 130-137
Author(s):  
M.M Dospaev ◽  
◽  
A. Bayeshov ◽  
A.S. Zhumakanova ◽  
D.M. Dospaev ◽  
...  
Keyword(s):  
Silicate Solution ◽  
Copper Electrode ◽  
Potassium Silicate ◽  
Potassium Silicate Solution ◽  
Copper Silicate

Activating effect of potassium silicate solution in low portland cement binder

2022 ◽  
Vol 319 ◽  
pp. 126091
Author(s):  
Linlin Zhao ◽  
Xianwei Ma ◽  
Shuaiqi Song ◽  
Peibo You ◽  
Hairong Wu
Keyword(s):  
Portland Cement ◽  
Silicate Solution ◽  
Potassium Silicate ◽  
Potassium Silicate Solution ◽  
Cement Binder

Synthesis of Silica-Potassium-Nitrogen from Carbamide and Potassium Silicate by CO2 Precipitator

2019 ◽  
Vol 966 ◽  
pp. 77-82
Author(s):  
Ketut Sumada ◽  
Srie Muljani ◽  
Caecilia Pujiastuti
Keyword(s):  
Ir Spectra ◽  
Potassium Hydroxide ◽  
Potassium Hydroxide Solution ◽  
Silicate Solution ◽  
Potassium Silicate ◽  
Precipitation Method ◽  
Precipitation Process ◽  
X Ray ◽  
Hydroxide Solution ◽  
Potassium Silicate Solution

Potassium silicate is well known as a fertilizer and source of silica for plants growth. This study aims to infiltrate nitrogen from carbamide (urea) into potassium silicate solution to produced silica potassium nitrogen (Si-K-N) matrix by precipitation method using CO2 as precipitator. Potassium silicate in the range of 3-8% SiO2 was obtained by extracting silica from geothermal sludge using potassium hydroxide solution. Carbamide is added to the potassium silicate solution allowed by mixing and flowing of CO2 gas in reactor glass. The result of IR spectra indicated the presence of N-H groups, potassium and silica in the gel matrix produced from precipitation process while no N-H group appears in the gel matrix produced from precipitation in the absence of carbamide. X-ray fluorescence showed the composition of the product Si-K-N in the range of 40 to 50 %SiO2 and in the range of 50 to 60 %K2O.

scholarly journals Reactivity and Microstructure of Metakaolin Based Geopolymers: Effect of Fly Ash and Liquid/Solid Contents

Materials ◽  
2019 ◽  
Vol 12 (21) ◽  
pp. 3485 ◽  
Author(s):  
Vogt ◽  
Ukrainczyk ◽  
Ballschmiede ◽  
Koenders
Keyword(s):  
Mechanical Properties ◽  
Fly Ash ◽  
Isothermal Calorimetry ◽  
Bound Water ◽  
Silicate Solution ◽  
X Ray Diffraction ◽  
Solid Ratio ◽  
Potassium Silicate Solution ◽  
Dissolution Tests ◽  
Strength Tests

Geopolymers are inorganic binders based on mixtures of an aluminosilicate powder with an alkali-silicate solution. Properties of geopolymers are strongly determined by the type of reactive solid, the liquid/solid ratio of paste and, amongst others, the Si/Al ratio of the formed geopolymer network. In this study, fly ash blended metakaolin based geopolymers with varying liquid/solid ratios (l/s), activated by potassium silicate solution, are investigated. Reactivity of metakaolin and fly ash was investigated by powder X-ray diffraction (XRD) and dissolution tests. Reactivity, mechanical properties and microstructure of hardened pastes were analyzed by setting and compressive strength tests, mercury intrusion porosimetry (MIP), capillary water absorption tests, thermogravimetric analysis-differential scanning calorimeter (TGA-DSC), isothermal calorimetry and scanning electron microscopy with energy dispersive spectroscopy (SEM-EDS). The results show that substitution of metakaolin by fly ash as well as variation of l/s brings advantages up to a certain degree, but also has a considerable influence on the pore size distribution, mechanical properties, Si/Al ratio of the geopolymer network and the content of bound water.

CO2 Reduction to Propanol by Copper Foams: A Pre- and Post-Catalysis Study

2020 ◽  
Author(s):  
Jennifer A. Rudd ◽  
Ewa Kazimierska ◽  
Louise B. Hamdy ◽  
Odin Bain ◽  
Sunyhik Ahn ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Photoelectron Spectroscopy ◽  
Carbon Capture ◽  
Surface Composition ◽  
Co2 Reduction ◽  
Structural Rearrangement ◽  
Copper Electrode ◽  
Ex Situ ◽  
X Ray ◽  
Copper Electrodes

The utilization of carbon dioxide is a major incentive for the growing field of carbon capture. Carbon dioxide could be an abundant building block to generate higher value products. Herein, we describe the use of porous copper electrodes to catalyze the reduction of carbon dioxide into higher value products such as ethylene, ethanol and, notably, propanol. For <i>n</i>-propanol production, faradaic efficiencies reach 4.93% at -0.83 V <i>vs</i> RHE, with a geometric partial current density of -1.85 mA/cm<sup>2</sup>. We have documented the performance of the catalyst in both pristine and urea-modified foams pre- and post-electrolysis. Before electrolysis, the copper electrode consisted of a mixture of cuboctahedra and dendrites. After 35-minute electrolysis, the cuboctahedra and dendrites have undergone structural rearrangement. Changes in the interaction of urea with the catalyst surface have also been observed. These transformations were characterized <i>ex-situ</i> using scanning electron microscopy, X-ray diffraction, and X-ray photoelectron spectroscopy. We found that alterations in the morphology, crystallinity, and surface composition of the catalyst led to the deactivation of the copper foams.

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