Abstract
Blast Furnace Slag (BFS) is a by-product of the iron ore processing industry with potential to be used in different industrial applications. In this research, BFS was used to examine its ability for dye removal from wastewater. The efficiency of two types of BFS samples for removal of cationic methylene blue (MB) and acidic methyl orange (MO) dyes was investigated and results found that the optimal conditions for treatment of wastewater were 80 g/L of adsorbent dose and 1 h of treatment time for both dyes. BFS was found to be more effective for removal of the acidic MO dye than the cationic MB dye. Under shorter residence times, the results showed reverse trends with BFS samples removing higher concentrations of MB than MO. The BFS chemistry had additional impacts on the efficiency of dye removal. Higher basicity of BFS had lower dye removal ability for adsorption of acidic dye when applied at smaller concentrations, while for cationic dye when applied at higher concentrations. The results showed that BFS has potential role for pre-treatment of industrial wastewater contaminated with dyes and may contribute to reduced use of more expensive adsorbents, such as activated carbons.
Highlights
Blast Furnace Slag (BFS) is a by-product of the blast furnace ironmaking process produced in significant amounts of around 175–225 Mt per year worldwide [1,2]
Higher basicity of BFS is associated with lower dye removal ability for adsorption of acidic dye when applied at smaller concentrations, while for cationic dye when applied at higher concentrations
This study investigated the dye removal ability of BFS considering the chemical composition of the slag, its basicity and the type of dye
Summary
Blast Furnace Slag (BFS) is a by-product of the blast furnace ironmaking process produced in significant amounts of around 175–225 Mt per year worldwide [1,2]. The chemical composition of BFS varies with the grade of iron ore and the fluxes used in smelting [4], while its structural phase is influenced by the slag cooling rate [7]. The dyeing mechanism involves adsorption of the dye onto the fibre surface and diffusion of the dye into the internal parts of the fibre [12]. Many industries, such as textile, paper, leather, food and cosmetic, use dyes to colour their products [13]. There are more than 100,000 commercial dyes on the market, mainly synthetic, produced at a rate of more than 700 kt/year [11]. Sustainability 2021, 13, 1970 complex molecular structure that, when discharged in the wastewater, makes them stable with slow biodegradation rates [12,13]
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