Adsorption of heavy metals from mine wastewater using amino-acid modified Montmorillonite

Figures & data

Table

Cations	Formulae = Mass/Molar mass	Concentration (Conc.)
Lead (Pb^2+)	335.38mg/207.20 g/mol	1.6190 mmol
Nickle (Ni^2+)	79.93mg/58.69 g/mol	1.3619 mmol
Copper (Cu^2+)	108.48mg/63.55 g/mol	1.7070 mmol
	Total Conc.	4.6879 mmol

Table

Name of Heavy Metal	Grams required (250 ml)	Grams required (500 ml)	Actual Readings of grams weighed
Lead (Cu^2+)	1.3400 g	2.6800 g	2.6805 g
Nickle (Ni^2+)	0.4737 g	0.9474 g	0.9474 g
Copper (Pb^2+)	0.7285 g	1.4560 g	1.4565 g

Figure 1. The mineralogical composition of the Montmorillonite Clay.

Table 1. XRF results for the raw Montmorillonite sample

Compo-und Name	SiO2	Al2O3	MgO	CaO	Na2O	Fe2O3	K2O	TiO2	Cl	P2O5	SO3	BaO
Conc. (%) for K0	72.30	19.27	0.29	2.86	0.13	3.20	1.30	0.39	0.02	0.07	0.08	0.04

Figure 2. XRD patterns of the raw and purified Montmorillonite.

Table 2. XRF results of both Raw and Na-Activated and purified clay

Compound Name	SiO2	Al2O3	MgO	Cao	Na2O	Fe2O3	K2O	TiO2	Cl	P2O5
Conc. (%) for Ca-Mont (K0)	72.30	19.27	0.29	2.86	0.13	3.20	1.30	0.39	0.02	0.07
Conc. (%) for Na-Mont (K1)	65.03	18.28	5.17	3.72	3.49	2.97	0.79	0.30	-	0.05

Figure 3. XRD results for Na-Mont and AA-Monts.

Table 3. Characterization data of both the raw, sodium activated and the amino-acid intercalated clay materials at different pH

No.	Substance	d001(nm)	BET surface area (m^2/g)	2 theta (degree)	θ [^o]	Expansion [Ǻ]
	Ca-Mont 1.504 60.000 Na-Mont 1.280 77.400			5.879 6.900	2.940 3.450	--
1.	Cys–Mont@ pH 4.0	1.560	91.580	5.660	2.830	0.280
2.	Cys–Mont@ pH 6.0	1.560	41.290	5.660	2.830	0.280
3.	Lys–Mont@ pH 6.0	1.438	51.610	6.140	3.070	0.158
4.	Lys–Mont@ pH 11.0	1.424	42.250	6.200	3.100	0.144
5.	Gly-Mont @ pH 7.0	1.560	86.660	5.660	2.830	0.280
6.	Gly-Mont @ pH 5.0	1.560	88.310	5.659	2.830	0.280

Figure 4. Schematic orientations for the intercalation of Amino Acids on clay minerals.

Figure 5. SEM image of Ca-Mont @ 2um before the purification process.

Figure 6. SEM image of Na-Mont @ 2um.

Figure 7. SEM images of AA-Mont clay in 2um and 1um respectively.

Figure 8. FTIR wave spectrum for Ca-Mont and Lys-Mont.

Figure 9. Total Heavy Metal removal efficiency for the Amino Acid modified Montmorillonites (AA-Monts) at adsorbent dosage (25 mg—400 mg), pH(6), Shaker speed (180 rmp) and temp. (25°C).

Figure 10. Adsorption of Cu²⁺, Ni²⁺, and Pb²⁺ by Cys-Mont at adsorbent dose range (20 mg-400 mg) pH(6), Shaker speed (180 rmp) and temp. (25°C).

Figure 11. Adsorption of Cu²⁺, Ni²⁺, and Pb²⁺ by Gly-Mont at adsorbent dose range (20 mg-400 mg) pH(6), Shaker speed (180 rmp) and temp. (25°C).

Figure 12. Adsorption of Cu²⁺, Ni²⁺, and Pb²⁺ by Lys-Mont at adsorbent dose range (20 mg-400 mg) pH(6), Shaker speed (180 rmp) and temp. (25°C).

Figure 13. Adsorption capacity (Qt) with increasing initial concentration for the Amino acid-modified Montmorillonite Cys-Mont at adsorbent dose range (25 mg), pH (6), Shaker speed (180 rmp) and temp. (25°C).

Figure 14. Adsorption capacity (Qt) with increasing initial concentration for the Amino acid-modified Montmorillonite Gly-Mont (25 mg), pH (6), Shaker speed (180 rmp) and temp. (25°C).

Figure 15. Adsorption capacity (Qt) with increasing initial concentration for the Amino acid-modified Montmorillonite Lys-Mont.