Adsorptive (Removal) Potential of Viable Shewanella putrefaciens against Coordination Ability of Dissolved Fulvic Acids during the Long-Term Contact with Aqueous Mn²⁺: Implication for Minerology of Mn

Figures & data

Figure 1. Short-term removal of aqueous Mn(II) by viable S. putrefaciens in absence/presence of equal concentration of fulvic acids (A) and alteration of pH in the same experimental batches (B).

Figure 2. Long-term uptake of aqueous Mn(II) by S. putrefaciens in absence/presence of equal concentration of fulvic acids (A) and drift of pH in the same experiments (B).

Table 1. Adsorptive (q, mg/g_dw) and removal (%) characteristics of viable S. putrefaciens of the density (adsorbent dose) of 0.5 and 1.0 g_dw/L at Mn²⁺ initial concentration of 200 mg/L.

Units	Contact time, days
	1	3	5	10	15	20	25	30	35	38
	S. putrefaciens (0.5 dw/L) + Mn^2+ (200 mg/L)
% removal	13	17	17	19	37	38	41	53	–	–
q, mg/gdw	54	70	71	79	148	154	164	210	–	–
	S. putrefaciens (0.5 dw/L) + Mn^2+ (200 mg/L) + fulvic acids (0.5 g/L)
% removal	10	2	3	8	2	3	0	2	–	–
q, mg/gdw	42	6	12	32	8	12	0	8	–	–
	S. putrefaciens (1.0 dw/L) + Mn^2+ (200 mg/L)
% removal	12	17	17	23	26	31	27	55	65	65
q, mg/gdw	24	35	35	46	52	63	53	110	130	130
	S. putrefaciens (1.0 dw/L) + Mn^2+ (200 mg/L) + fulvic acids (45 mg/L)
% removal	9	13	19	23	24	25	23	40	32	34
q, mg/gdw	18	27	38	46	49	51	45	80	63	67

These data are associated with Figures 2 and 4. Note: Adsorption (q, mg/g_dw) in 0.5 g_dw/L adsorbent dose experiment is overstated because an adsorbent dose is in the formulae (1) in denominator. The data are rounded to the whole numbers.

Figure 3. Kinetics of Mn(II) sorption by viable S. putrefaciens (1 g_dw/L) for 30 min in absence/presence of fulvic acids (45 mg/L) at the initial Mn(II) concentration of 200 mg/L (A) and drift of pH in the same batches (B).

Figure 4. Kinetics of Mn(II) sorption by viable S. putrefaciens (1 g_dw/L) for 38 days in absence/presence of fulvic acids (45 mg/L) at the initial Mn(II) concentration of 200 mg/L (A) and change of pH in the same experiments (B).

Figure 5. FTIR spectra of initial S. putrefaciens and contacted to aqueous Mn²⁺ in 0.1 M NaCl electrolyte for three days.

Figure 6. FTIR spectra of initial S. putrefaciens (1 g_dw/L), contacted to Mn²⁺ in absence/presence of fulvic acids (45 mg/L) for 38 days and fulvic acids used in this study (A), and of two references, Mn₃(PO₄)₂ (B) and MnCO₃ (C).

Table 2. Characteristic (400–2000 cm⁻¹) IR-vibrations in experimental samples of original S. putrefaciens (1 g_dw/L) and influenced by aqueous Mn²⁺ in absence/presence of fulvic acids (shown in Figure 4).

Characteristic vibrations (cm^−1)	Sample
	S. putrefaciens	SP+Mn^2+	SP+Mn^2++fulvic	Fulvic acids
Mn3(PO4)2↓	–	578, 565, 1120, 942, 1063,1012	503, 555, 581, 621, 953, 943, 990, 1012, 1062, 1119	–
MnCO3↓	–	726, 861, 1402, 1433, 1518	726, 861 (γ2 CO3 mode), 1402, 1451 (ν3 CO3), 1512 (γ3 CO3 (Grunenwald et al. 2014)	–
Mn(OH)2↓	–	–	1155 (Wang et al. 2009) 503 (Mn–O stretching) (Yang et al. 2011)	–
–COOH	1389, 1454	Overlapped by bands of CO3 from MnCO3		1720, 1232
PO4^3− group	1235	1236	Not visible	–
Amides	1652, 1530	1652	1654	1656
Region 400–800	508, 551, 631 (backbone vibrations polysaccharides)	Became dominant by inorganics	Became dominant by inorganic vibrations	620 (C–H), 724
Region 950–1150	stretching in phosphate; vibrations of C-OH and C-C bonds in polysaccharides and alcohols (Jiang et al. 2004)	Became dominant by inorganic vibrations	Became dominant by inorganic vibrations	1037 (C–O, polysaccharides)
C=C aromatics				1630
γ3C–O, alcoholic ether, R–O–R, C–O carbohydrate				Broad band around 1232

The data in this table are extracted from Figure 6(A). SP is short name of Shewanella putrefaciens. The references are given to support band assignments of Figure 6(A).

Table 3. C 1 s and N 1 s XPS features in four samples: uncontacted S. putrefaciens and with Mn(II) sorbed in absence/presence of fulvic acids over 38 days, and fulvic acids.

	BE (eV)	FWHM (eV)	At.%	BE (eV)	FWHM (eV)	At.%
	C 1 s (C–(C,H))			C 1 s (C–OH, C–O–C, C–N)
SP	285.0	1.20	42.71	286.4	1.25	15.64
SP + Mn(II)	285.0	1.20	34.06	286.5	1.30	17.03
SP + Mn(II)+fulvic	285.0	1.30	29.60	286.5	1.40	18.24
Fulvic acids	285.0	1.35	28.81	286.4	1.45	21.96
	C 1 s (C = O, C in amide group)			C 1 s (Carbonate COO–, –COOH)
SP	288.2	1.25	9.98	289.3	1.0	1.0
SP + Mn(II)	288.2	1.25	9.91	289.6	1.05	1.70
SP + Mn(II)+fulvic	288.3	1.25	10.29	289.6	1.60	2.41
Fulvic acids	287.9	1.10	4.67	289.1	1.25	10.69
	N 1 s (Unprotonated amine)			N 1 s (Protonated amine)
SP	400.1	1.55	8.91	402.0	1.35	0.29
SP + Mn(II)	400.1	1.35	7.39	401.5	1.60	0.51
SP + Mn(II)+fulvic	400.2	1.40	8.89	401.6	1.70	0.64
Fulvic acids	400.1	1.45	2.59	401.9	1.60	0.49

Table 4. XPS features (O 1 s, Mn 2p, Na 1 s, P 2p, Cl 2p and S 2p) in four samples: initial S. putrefaciens and with Mn(II) sorbed in absence/presence of fulvic acids over 38 days, and fulvic acids.

	BE (eV)	FWHM (eV)	At.%	BE (eV)	FWHM (eV)	At.%
	Mn 2p 3/2			Na 1 s
SP	–	–	–	1071.7	1.45	2.60
SP + Mn(II)	641.2	1.50	3.32	1071.7	1.55	0.28
SP + Mn(II)+fulvic	641.3	1.80	2.11	–	–	–
Fulvic acids	–	–	–	1071.7	1.55	0.24
	O 1 s (Mn-O)			O 1 s (Organic, PO4^3−)
SP	–	–	–	531.6	1.60	10.1
SP + Mn(II)	–	–	–	531.6	1.65	18.48
SP + Mn(II)+fulvic	529.9	1.05	0.73	531.7	1.70	20.17
Fulvic acids	–	–	–	–	–	–
	O 1 s (other vibrations organics)			P 2p 3/2 (PO4^3−)
SP	533.0	1.55	3.89	133.3	1.35	0.73
SP + Mn(II)	533.2	1.55	5.51	133.3	1.35	1.81
SP + Mn(II)+fulvic	533.2	1.50	5.14	133.3	1.35	1.78
Fulvic acids	532.4 533.5	1.90 1.60	22.14 7.96	–	–	–
	Cl 2p 3/2			S 2p 3/2 (thiol—SH and SO4^2−
SP	198.7	1.25	4.15	–	–	–
SP + Mn(II)	–	–	–	–	–	–
SP + Mn(II)+fulvic	–	–	–	–	–	–
Fulvic acids	–	–	–	164.1 168.1	1.75 1.45	0.12 0.33

Figure 7. Concentrations of dissolved protein-like substances released by viable S. putrefaciens for one month contact with aqueous Mn²⁺ in absence/presence of very high (A) and low (environmentally relevant) (B) contents of fulvic acids.

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