Preparation and adsorption properties of microsphere geopolymers derived from calcium carbide slag and fly ash

In this work, using fly ash and calcium carbide slag as mixed precursors, hydrogen peroxide and sodium dodecyl sulfate as mixed foaming agents, porous microsphere geopolymer was prepared by suspension curing technology to remove Cu (II) from aqueous solution. Because the Ca (OH) 2 in calcium carbide slag effectively improves the pozzolana activity of fly ash, more C-S-H gel is produced in the geopolymerization process, and the foaming process makes the material have larger specific surface area and better adsorption properties. The results show that the specific surface area of the material is 63.46 m2·g-1, the product regeneration rate is 83.20%, the optimal adsorption conditions are pH = 5, and the adsorption capacity was 118.48 mg·g-1. At the same time, it is found that the pseudo-first-order kinetic model and the Langmuir isotherm model can be applied to adsorption kinetics and isothermal adsorption respectively. Adsorption mechanisms may include physisorption and chemisorption. The adsorption capacity of this product for Cu(II) is better than that of other similar products, which has great potential in the field of heavy metal adsorption and provides a new idea for the resourceful use of industrial by-products.