Porous Glass Microspheres from Alkali-Activated Fiber Glass Waste.

Mokhtar Mahmoud,Hana Kaňková,Jozef Kraxner,Miroslava Hujová,Dušan Galusek,Si Chen,Enrico Bernardo

doi:10.3390/ma15031043

Abstract

Fiber glass waste (FGW) was subjected to alkali activation in an aqueous solution with different concentrations of sodium/potassium hydroxide. The activated materials were fed into a methane–oxygen flame with a temperature of around 1600 °C. X-ray diffraction analysis confirmed the formation of several hydrated compounds, which decomposed upon flame synthesis, leading to porous glass microspheres (PGMs). Pore formation was favored by using highly concentrated activating alkali solutions. The highest homogeneity and yield of PGMs corresponded to the activation with 9 M KOH aqueous solution.

Highlights

Reusing glass waste can considerably decrease the demand for new raw materials for glass production and contribute to the reduction of landfills, known to represent a multiform ecological problem [1,2].Landfilling can be significantly reduced only if waste glass is involved in the manufacturing of a new generation of original glass articles
The present paper concerns the exploitation of alkali activation for the manufacturing synthesis apparatus: glass microbeads formed by high-temperature processing are simulof highly porous glass microspheres (PGMs), following a preliminary study on Bioglass®
Glass matrix bonds including Si-O-Si, Al-O-Si, and Ca-O are attacked by the alkaline solutions during the alkali activation process, yielding hydrated compounds, which form coagulated structures, leading to condensation and crystallization [10,11]

Summary

Introduction

Reusing glass waste can considerably decrease the demand for new raw materials for glass production and contribute to the reduction of landfills, known to represent a multiform ecological problem (in terms of consumption of free land, water and air pollution, and emission of greenhouse gases) [1,2]. Landfilling can be significantly reduced only if waste glass is involved in the manufacturing of a new generation of original glass articles The sustainability of this approach (e.g., cullet from crushed container used for new containers) is complicated by the need for expensive sorting operations, aimed at separating glass from other materials, glasses of different chemical compositions, or even glasses with different colors [3]. The present paper concerns the exploitation of alkali activation for the manufacturing synthesis apparatus: glass microbeads formed by high-temperature processing are simulof highly porous glass microspheres (PGMs), following a preliminary study on Bioglass®. Slovakia) were in wt.%, data obtained by XRF analysis) was crushed and a fraction below 40 μm was dissolved in deionized water to form activating solutions of different molarity Glass waste powders dissolved in deionized water to form activating solutions of different molarity Å) and thermopowders obtained by crushing of hardened suspensions were characterized gravimetry

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Results and Discussion

X-ray diffraction ofFGW