Abstract The effects of gas composition on gliding arc (glidarc) electrical discharge reactors with pure water have been studied. The glidarc reactors utilized AC electrical discharges with two different electrode configurations. In one case a set of two stainless steel electrodes connected to a single power supply was placed in the gas phase over the liquid surface (power=250–300 W, maximum voltage=12 kV). The second experimental arrangement utilized a reactor with a set of three stainless steel electrodes supplied by two identical high-voltage transformers, where the electrodes were placed over the water surface or with the water sprayed directly in the plasma formed between the electrodes (power=500–600 W, maximum voltage=12 kV). The variation of pH and conductivity and the formation of hydrogen peroxide, ozone, nitrate, and hydrogen were measured. The effects of the type of gas, including pure oxygen, pure nitrogen, and dry air, were determined.

Formation of Reactive Species in Gliding Ark Discharge with Liquid Watet

Mechanisms of interfacial bond in steel and polypropylene fiber reinforced geopolymer composites

Geopolymer for use in heavy metals adsorption, and advanced oxidative processes: A critical review

Advances in alkali-activation of clay minerals

Recycling of seashell waste in concrete: A review

Potential of using granite waste as raw material for geopolymer synthesis

Geopolymers are alternative materials to portland cement, obtained by alkaline activation of aluminosilicates. They exhibit excellent properties and a wide range of potential applications in the field of civil engineering. Several natural aluminosilicates and industrial by-products can be used for geopolymer synthesis, but a lot of starting materials have the disadvantage of poor reactivity and low strength development. This paper presents a comprehensive review of the main methods used to alter the reactivity of aluminosilicate materials for geopolymer synthesis, as reported recently in the literature. The methods consist of mechanical, thermal, physical separation and chemical activation, of which mechanical activation is the most commonly employed technique. The reactivity of the activated aluminosilicate materials is mainly related to the activation method and the treatment parameters. Chemical activation by alkaline fusion is a promising method allowing preparation of one-part geopolymer materials, an alternative class of geopolymeric binders. However, the resulting alkaline-fused geopolymer products are vulnerable to attack by excessive alkalis.

Enhancing the reactivity of aluminosilicate materials toward geopolymer synthesis

Synthesis of geopolymer composites from a mixture of volcanic scoria and metakaolin

The gel composition and mechanical properties of alkali-activated oyster shell-volcanic ash were investigated at different NaOH concentrations (8, 12, and 15M) and curing temperatures (60°C and 80°C) in wet and dry conditions. XRD, FTIR, SEM-EDS, and TGA-DSC were used for microstructural characterization of the binder. The gel composition of the system was found to be influenced by NaOH concentration and was not affected when curing temperature was varied from 60°C to 80°C. The main phase was N,C–A–S–H for all alkali-activated oyster shell-volcanic ash, with C–S–H as secondary phase for some samples and contains high percentage of iron. The splitting at υ3 = 1400–1494 cm−1 on FTIR spectra corresponded to the elimination of the degeneracy due to the distortion of CO32− group. The high degree of splitting indicated that this carbonate group is linked to Ca2+. The compressive strength was influenced by curing temperature and the formation of a secondary phase. The compressive strength in dry condition increased roughly between 28 and 180 d for some samples, while in wet condition, the partial dissolution of Si–O–Si bonds of some silicate phases resulted in a reduction of strength.

Gel Composition and Strength Properties of Alkali‐Activated Oyster Shell‐Volcanic Ash: Effect of Synthesis Conditions

A comparative study of two methods to produce geopolymer composites from volcanic scoria and the role of structural water contained in the volcanic scoria on its reactivity

L.N. Tchadjié

Papers

Potential of using granite waste as raw material for geopolymer synthesis

Enhancing the reactivity of aluminosilicate materials toward geopolymer synthesis

Synthesis of geopolymer composites from a mixture of volcanic scoria and metakaolin

Gel Composition and Strength Properties of Alkali‐Activated Oyster Shell‐Volcanic Ash: Effect of Synthesis Conditions

A comparative study of two methods to produce geopolymer composites from volcanic scoria and the role of structural water contained in the volcanic scoria on its reactivity