Composition, structure and potential applications of schwertmannite.

Source	Composition		Structural/E-K parameters			Conditions						Adsorptions	Ref.
	Fe/S	SO42− %	Morphology	S BET [m2 g−1]	pHzpc	Pollutanta	C 0 [mM]	S/L [g L−1]	pHb	T [°C]	T [h]	Q e [mmol g−1] or Qm [mg g−1]
AMD or AMLs	1.3–16	32–19.4	Large spheroids	72 (ml 77)	—	—	—	—	—	—	—	—	20
	5.37	16	—	173	2	—	—	—	—	—	—	—	45
	4.35	15.0	Sphericity	80 ± 8	—	As	Trace	—	—	—	—	—	81
	4.60	—	Spherical/elliptical	—	—	—	—	—	—	—	—	—	15
	5.30	—	Spheroidal	14.7	—	AsIII	0.067–1.33	5–100	—	2–25	2	Q e: 0.0126	104
Chemical oxidation	3.81	—	—	—	—	—	—	—	—	—	—	—	20
	5	—	—	4–14	—	AsIII	0–60	68.0	9.0	—	60	Q m: 280.0	32
						AsV			3.0			Q m: 246.0
	4.71	16.3	Smooth rounded	5.3	—	AsIII	0.13–1.33	10	2.6	—	120	Q m: 14.16	38
	—	—	40 nm	—	—	—	—	—	—	—	—	—	35
	4.32	16.2	Spheroids	—	—	—	—	—	—	—	—	—	78
	—	—	Closely packed	—	—	—	—	—	—	—	—	—	43
	—	—	Dendritic	—	—	—	—	—	—	—	—	—	43
	—	—	Aggregates	130.9	7.1	SbV	0–0.49	0.3	7.0 ± 0.2	5 ± 1	24	Q m: ca. 90	34
	4.75	—	Spheroidal	—	—	—	—	—	—	—	—	—	63
	4.71	—	Spheroidal	10	—	—	—	—	—	—	—	—	64
	4.17	—	Sphere shape	48.18	—	—	—	—	—	—	—	—	89
	4.67–5.04	—	Spheroids, hedge-hog	2.06–16.30	—	AsIII	(3.33–13.3) × 10−4	0.25	7.0	30	24	—	31
	5.30	—	Spheroidal	50.4	—	Nitro-Ph	—	—	—	—	—	—	33
Fast hydrolysis	4.04–4.82	15.1–16.1	—	—	—	—	—	—	—	—	—	—	1
	—	—	—	165	4.2	CrVI	—	—	4.2	—	5	Q m: 178.6 mg g−1	60
	4.57	—	Hedge-hog like	325.52	3.05	—	—	—	—	—	—	—	62
	—	—	—	206.1	—	AsV	(10–35)	0.3	5.0	5 ± 1	24	Q m: (104.2)	82
	5.30	5.31	—	—	—	AsV	—	1.0	3–4	5	24	Q m: 114	6
	—	—	Hedge like	—	3.7	AsIII	(0.2–0.6)	0.25–2	3–11	25	4	Q m: 1.011	61
	4.57	—	Hedgehog-like	325.52	—	AsV	1.33	1	3	5	5	Qm: 182.86	89
						AsIII			7	25		Qm: 217.85
	—	24 ± 1	Agglomeration	5.6 ± 1.2	—	—	—	—	—	—	—	—	52
	—	—	—	199.43	—	SbII	0.181	0.5/1/2/4	7.0 ± 0.2	25 ± 1	48	Qm: 84.03	92
						SbV	0.189					Qm: 78.60
Slow dialysis	—	13.5	—	154	—	AsV	0–100.5	1	3.95 ± 0.04	5	24	Qm: 82.4	26
	6.15	—	Hedge-hog	—	—	—	—	—	—	—	—	—	20
	—	12.3	—	—	—	—	—	—	—	—	—	—	45
	—	—	—	—	—	—	—	—	—	—	—	—	46
	5.30	15.4	Uneven surfaces	210.0	—	AsIII	0.13–1.33	10	2.6	—	120	Qm: 20.08	38
	7.84	9.79	—	171	—	As	0.5–4	1	4.5–4.6	25 ± 1	72	Qm: 196 mmol/molFe	102
						Cr	0.15–2		4.5			Qm: 115 mmol/molFe
						Mo	0.2–2.5		4.5			Qm: 88 mmol/molFe
	—	—	Aggregate	—	—	—	—	—	—	—	—	—	35
	—	—	Irregular-shaped	199.43	—	AsV	0.02–0.27	0.5	7.0	25 ± 1	24	Qm: 31.7	82
			Cylindrical-shaped	189.27								Qm: 22.3
			Spherical-shaped	32.52								Qm: 3.6
	5.13	—	—	—	—	HAsO42-	0–20	1	7.00 ± 0.28	25	24	Qm: 76.6	103
						CrO42-						Qm: 37.6
						SeO42-						Qm: 24.7
	—	—	Macropore/network	14.81	—	HA	—	—	—	—	—	Qe: 15.1	53
						CrVI						Qe: 4.2
Biological ferrooxidation	6.4	12.5	Fibrous aggregates	14.7	—	AsIII	0.13–1.33	10	3.1	—	120	Qm: 103.39	38
	4.7	14.9	Spheroidal	14.7	—	AsIII	2.0	10	3.0	25	132	Q e: 3.746	90
	—	—	—	—	—	CrIV	10	0.1	2–8	—	—	Q m: 35.30	83
	—	—	Spherical, net like	—	—	CuII	0.31–3.15	—	8.0	—	24	Q m: 10.35–50.14	84
						CrVI	0.39–3.85		5.0			Q m: 30.46–38.82
	—	—	Needle, whiskers	—	—	—	—	—	—	—	—	—	40
	5.16	—	Net-work like	33.52	—	As	—	—	—	—	—	—	41
	—	—	—	—	—	As	—	—	—	—	—	—	42
	—	—	Spherical	5.14	—	AsIII	0.013	0.25	7.50	28	4	Q e: 1.004	44
	—	—		110.06–78.82	—							Q e: 3.72–2.928	44
	—	—	Sea urchin, flower	34.55	—	HA	—	—	—	—	—	Q e: 12.3	53
						CrVI						Q e: 5.5
	6.3	—	—	14.7		—	—	—	—	—	—	—	24
	4.65	—	Spheric	92.92	—	BPA	—	—	—	—	—	—	51

^aThe relative atomic masses of As (74.92 ≈ 75), Cr (51.996 ≈ 52), Cu (63.546 ≈ 64), Sb (121.75 ≈ 122), and Se (78.96 ≈ 79), respectively.

^bThe optional pH for adsorption is chosen as a defined value rather than a value range, if provided.