Synthesis of novel low‐cost porous gangue microsphere/geopolymer composites and their adsorption properties for dyes

Abstract

A novel porous coal gangue microsphere/geopolymer (CG/KGP) composite was firstly synthesized by adding gangue microspheres into geopolymer matrix. Effects of precalcined temperature of CG microspheres on the microstructure and specific surface area of the porous CG/KGP particles were systematically investigated. Adsorption properties of the CG/KGP composites were also reported. Results showed that the CG/KGP composites contained mainly amorphous phase and many functional groups were on the particle surface. The precalcined CG microspheres were dispersed homogenously and bonded well with the KGP matrix. The CG900/KGP samples showed better adsorption properties than the pure KGP. As for the dosage of 4 g/L (starting concentration, 100 mg/L), adsorption capacity achieved the highest value of 24.6 mg/g and the removal efficiency reached 98%. Adsorption of MB onto CG900/KGP particles followed the pseudo‐second‐order kinetic model. The novel porous CG/KGP composite has potential application in wastewater filtration and adsorption treatment.

Geopolymer foams: An overview of recent advancements

“…The use of spheres promotes higher (30.1 mg/g) [149] dye uptake in the 1st adsorption cycle in comparison with the use of cylindrical discs ((15.4 mg/g) [87] and (17.3 mg/g) [169]). The methylene blue uptake shown by the geopolymer spheres (30.1 mg/g) is superior to several other geopolymer powders: 0.7 mg/g [170], 2.7 mg/g [171], 3.0 mg/g [172], 14.8 mg/g [173,174], 19.7 mg/g [175], 24.6 mg/g [176], 25.6 mg/g [177]; it was slightly inferior to others [137,178], and roughly 1.7 times lower than that reported by Liu et al [144]. However, the bulk-type samples (spheres and membranes) can be easily retrieved and regenerated multiple times, leading to cumulative uptakes several times superior to those obtained with powdered geopolymers.…”

Effects of flake-shape and content of nano-mullite on mechanical properties and fracture process of corundum composite ceramics

“…Relative density is used to characterize densification of the samples. Theoretical densities of mullite ceramics [23][24][25] and alumina ceramics [28,29] are 2.8 g/ cm 3 and 3.6 g/cm 3 , respectively. Figure 5 shows relative densities of the samples with different contents of mullite after sintering at different temperatures.…”

“…Coal gangue has become the largest industrial solid waste in production and storage, which is currently used as roadbed material. Cheng et al [1,2], Yang et al [3] and others used chemical treatment to convert coal gangue into adsorbent and ceramic materials. In this way, the utilization value of coal gangue has been greatly increased.…”

Geopolymers and Alkali-Activated Materials for Wastewater Treatment Applications and Valorization of Industrial Side Streams

“…Oxidative degradation or photodegradation after adsorption have been specified by authors as primary mechanisms of organic pollutants' removal. Although conventional GPs have been reported for these purposes [86,89,104,126,139], they would rather have had low adsorption/degradation characteristics. Hybrid or composite materials were proposed to improve the removal efficiency of organic pollutants.…”