Magnetite Functionalized Nigella Sativa Seeds for the Uptake of Chromium(VI) and Lead(II) Ions from Synthetic Wastewater

Table 1

Maximum sorption capacities of previously reported various adsorbents for Pb(II) ions.

Adsorbent	Maximum capacity (mg/g)	Solution pH	Temperature (°C)	Reference
Magnetic coffee waste	41.2	6	25	Edathil et al., [83]
Magnetic cane biochar	40.6	5	20	Mohan et al., [84]
Fe3O4@SiO2-IP polymer	32.6	4.8	25	Guo et al., [85]
Fe^3+/Fe^2+ black cumin seeds	39.67	5	25	This study
Plums biochar	28.8	6	25	Pap et al., [86]
Dolomite	19.7	6	45	Irani et al., [87]
Apricot biochar	12.7	6	25	Pap et al., [86]
Wood biochar	7.9	5	25	Bardestani et al., [8]
Mushroom	3.9	6	25	Kariuki et al., [88]
Rice husk biochar	2.4	5	25	Liu and Zhang [41]