Adsorption Rate and Adsorption Behavior of Cu²⁺ in Wastewater by Blast Furnace Slag

The industrial solid waste blast furnace slag shows a good adsorption capacity for heavy metal ions in wastewater. To understand the adsorption effect of blast furnace slag on Cu²⁺, based on the influence of the consumption of industrial solid waste blast furnace slag, pH value, adsorption time and temperature on the adsorption rate of Cu²⁺ in wastewater, four factors and three levels orthogonal designed experiments were selected. The optimum reaction conditions for Cu²⁺ adsorption were obtained, and the adsorption isotherm model and adsorption kinetics were used to study the adsorption behavior of Cu²⁺ on blast furnace slag. Results show that the adsorption sites, large specific surface area and developed pore structure on the surface of blast furnace slag can promote the adsorption of Cu²⁺. The removal rate can reach 99.93% when the slag consumption is 0.5 g, the pH value is 9, the adsorption time is 360 min, and the temperature is 65℃. The residual mass concentration of Cu²⁺ in the adsorbed solution is less than 1 mg/L, which meets the national emission standard. The adsorption isotherm model of blast furnace slag for Cu²⁺ is more in line with Langmuir adsorption isotherm model. The adsorption of Cu²⁺ by blast furnace slag is more in accordance with pseudo-second-order kinetic equation.