A combined electrodialysis and coal dust suppression system for acid mine drainage treatment and high mechanical hydrogel dust suppressant generation

Abstract

The acid mine drainage (AMD) and coal dust from coal mining cause erosion to the ecological environment. Herein, a combined electrodialysis (ED) and coal dust suppression system is developed to realize AMD resource utilization and coal dust suppression. In the ED, >97% removal rate of Fe³⁺, Zn²⁺, Cu²⁺, and Ni²⁺ were obtained. Metal ions coordination among acrylic acid (AA), ammonium persulfate (APS), and concentrated AMD have been utilized to prepare an interpenetrating network hydrogel dust suppressant (ED-AMD-PAA). Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM) demonstrated that metal ions of concentrated AMD coordination in polyacrylic acid (PAA) based hydrogels. The mass of ED-AMD-PAA remains relatively stable at 175 ​°C by thermogravimetric analysis. The compressive strength of the solidified coal dust by mixed ED-AMD-PAA dust suppressant reached 247.44 ​± ​34.45 ​KPa, the mass loss of coal dust consolidation was only 0.05 ​± ​0.02 ​g after the wind resistance test, and ED-AMD-PAA still preserved about 2.4 ​± ​0.17% moisture after 48 ​h. The degradation rate of ED-AMD-PAA dust suppressant in the soil reached 37.4 ​± ​1.43% on the 10^th cycle. Those results will help the engineering application of PAA in coal dust suppression and AMD resource utilization.