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

Table 5

Maximum sorption capacities of previously reported various adsorbents for Cr(VI) ions.

Adsorbent	Maximum capacity (mg/g)	Solution pH	Temperature (°C)	Reference
Iron oxide nanoparticles	45.0	1	25	Burks et al., [89]
Fe3O4 nanoparticles	26.5	2	25	Liang et al., [90]
Activated Iron bamboo biochar	25.7	2	25	He et al., [50]
Fe^3+/Fe^2+ black cumin seeds	15.75	5	25	This study
Magnetite-pine composite	13.9	2	25	Pholosi et al., [91]
Banana waste	10.0	2	28	Sharma et al., [92]
Starch-based iron oxide	9.0	2	25	Singh et al., [93]
Activated carbon mango	7.80	2	35	Rai et al., [94]
Activated bamboo biochar	5.4	2	25	He et al., [50]
Peapod	4.3	2	28	Sharma et al., [92]
Carbon nanotubes	2.5	9	50	Mubarak et al., [95]