Study on the influence mechanism of underground mineral element Fe(II) on Cr(VI) transformation under subsurface and groundwater interaction zones

Environmental Sciences Europe

Table 4 Effect of groundwater hardness experiment

Case	Experiment conditions	C_Fe(II) (mg/L)	C_Cr(VI) (mg/L)	\(C_{{{\text{Ca}}_{2 + } }}\) (mg/L)	\(C_{{{\text{Mg}}_{2 + } }}\) (mg/L)	\(C_{{{\text{HCO}}_{3}^{ - } }}\) (mg/L)	DO
1	Blank	20	20	0	0	0	Hyperoxia
2	Blank	20	20	0	0	0	Anoxic
3	Only Ca²⁺	20	20	40	0	0	Hyperoxia
4	Only Ca²⁺	20	20	40	0	0	Anoxic
5	Only Mg²⁺	20	20	0	40	0	Hyperoxia
6	Only Mg²⁺	20	20	0	40	0	Anoxic
7	Only HCO₃⁻	20	20	0	0	60	Hyperoxia
8	Only HCO₃⁻	20	20	0	0	60	Anoxic
9	Ca²⁺, HCO₃⁻	20	20	40	0	60	Hyperoxia
10	Ca²⁺, HCO₃⁻	20	20	40	0	60	Anoxic