Evaluation of the coagulation properties of magnesium hydroxide for removal combined contamination of reactive dyes and microfibers

Microfibers are a new type of pollutants that are widely distributed in water bodies. And the simultaneous removal of pollutants in water is popular research in the field of water treatment. In this study, magnesium hydroxide was used as coagulant to investigate the performance and mechanism of coagulation and removal of dyes (reactive orange) and microfibers (MFs). The presence of dyestuff in the composite system promoted the removal of microfibers, and the maximum removal efficiency of both could reach 95.55% and 95.35%. The coagulation mechanism was explored by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), and zeta potential. The removal of reactive orange and microfibers relied on electrical neutralization, sweep flocculation, and adsorption mechanisms. Turbidity can enhance the removal efficiency of both. Boosting the rotational speed can increase the removal efficiency of microfibers. This study provides an important theoretical support for an in-depth understanding of the characteristics and mechanisms of coagulation for the removal of complex pollutants from printing and dyeing wastewater.

Automated summary

Microfibers are a type of pollutants widely found in water bodies. In this study, magnesium hydroxide was used as a coagulant to investigate its performance and mechanism in removing dyes and microfibers. The presence of dyes in the system enhanced the removal of microfibers. The removal mechanisms involved electrical neutralization, sweep flocculation, and adsorption. Higher turbidity and rotational speed improved the removal efficiency. This study provides important theoretical support for understanding the coagulation characteristics and mechanisms in removing complex pollutants in printing and dyeing wastewater.