The formation of Fe colloids and layered double hydroxides as sequestration agents in the natural remediation of mine drainage

The increasing need to treat wastewater from mine effluents has drawn attention passive treatment systems. Colloids are common in waters and highly reactive, so their formation, characteristics, behavior, the critical factors that affect them be understood for designing efficient An investigation was conducted at abandoned Ainai drainage, Japan, where aeration is utilized remove Fe, As, Zn circumneutral during rainy dry seasons of 2016 2018 respectively, based on observations physiochemical elemental concentrations dissolved colloidal fractions, transmission electron microscopy, synthetic experiments. In this Fe-rich Fe2+ oxidized Fe3+, resulting formation Fe colloids incorporate As formation. Colloid increases turbidity, and, season, increased interaction enhances aggregation higher flow rates lead greater mobilization colloids. Zn-bearing rare drainage because low. However, Zn-Fe layered double hydroxide (LDH) identified confirmed by geochemical modelling LDH formed isomorphous substitution into an Fe2+–Fe3+–CO32–LDH, pH than 7.5, thereby achieving natural remediation drainage.