Diatoms and Their Capability for Heavy Metal Removal by Cationic Exchange

Abstract

This work shows the physicochemical behavior of two different diatoms from the country of Mexico (State of Jalisco and Hidalgo) with similar compositions. These were used to eliminate toxic cations from a synthetic solution containing 5.270 mg As 3+ /L; 4.280 mg Ag + /L; 3.950 mgNi 2+ /L; 4.090 mg Cr 6+ /L; and 4.081 mg Pb 2+ /L. These diatoms were used as filters, and the quantity of cations remaining in the solution after filtering was measured. According to the most important results found, for the recovery of metals, both minerals achieved arsenic, silver, lead, and nickel recoveries up to 95%, and lower than 10% for chromium. This could be due to the absence of an environment to reduce Cr 6+ to Cr 3+ . On the other hand, it was observed that there was no selectivity during the recovery of the other cations present in the solution. According to efficiency of interchange, the mineral from Hidalgo is slightly better than the mineral from Jalisco for the removal of arsenic, lead, and silver. For nickel, and particularly Cr 6+ , the efficiency is higher for the sample from Jalisco.

Mineral Materials Coated with and Consisting of MnOx—Characteristics and Application of Filter Media for Groundwater Treatment: A Review

“…Quartz sand 2650 [44] 1520-1568 [45] 0.05-1.8 [46] 7 [47] 2650-2667 [45] Chalcedonite 2390-2500 [48] 1237-1403 [45] 6.13 [49], 7.44 [50] 6-6.5 [51] 2488-2682 [45] Diatomite 2000-2100 * [52] 200-400 * [52] 14.6 [53], 5-6.5 [54] 2244 ** [55] 1280-1780 ** [56] 22 [57], 42 [58] Glauconite 2450-2600 [59] 1380 [60] 48 [58], 58 [61], 78 [60] 2 [47] 2650-2750 [62] Zeolite 2339-2407 (clinoptilolite) [45] 2390 (clinoptilolite) [63] 800-1000 (clinoptilolite) 700-850 (chabazite) 1000-1100 (phillipsite-analcime) [64] 14 (clinoptilolite 71.8 wt. %) [57] 19.2 (clinoptilolite 45-50 wt. %) [65] 30.98 (clinoptilolite >90 wt.…”

Use of Porous no Metallic Minerals to Remove Heavy Metals, Precious Metals and Rare Earths, by Cationic Exchange

“…The other elements show an efficiency superior to 99%, not so for the Gd, since its exchange efficiency is 97.86, which corroborates that the diatomite has an exchange efficiency for these types of metals. On the other hand, the author also has to demonstrate the efficiency of cationic exchange of diatomite, getting 96.46% of efficiency for the removal of As 3+ , 95.44% for Ni 2+ , and 98.80% of Pb 2+ [13]. Likewise, the mineral species were identified by X-ray diffraction (Figure 11), observing the presence of majority mineral phases such as quartz, anorthoclase, orthoclase, albite and berlinite; as well as the presence of rare earths such as Er, La, and Eu.…”

“…On the other hand, various works on the ion exchange of metals with natural adsorbents (aluminosilicates such as zeolites, mineral clays, feldspars, and zeolites) show that these can be good candidates for the recovery of rare earths, as well as heavy and precious metals, taking into consideration some factors that affect the ion exchange such as pH, temperature, contact time, particle size, nature of the cations (size, ionic charge, shape, and concentration), anions associated with the cations in solution, solvent (water, organic solvents) and material selectivity, as well as the ion exchange rate [13][14][15][16].…”

Mixed Oxide Layered Double Hydroxide Materials: Synthesis, Characterization and Efficient Application for Mn2+ Removal from Synthetic Wastewater

“…The results indicate that the adsorption was strongly driven by van der Waals interactions at the highly covered surface, where the consideration of dispersion corrections reduces the modifier−adsorbate interatomic distances and increases the adsorption energy. Hernández-Ávila et al [19] used different minerals from the country of Mexico to eliminate toxic cations from a synthetic solution containing As 3+ (arsenic), Ag + (silver), Ni 2+ (nickel), Cr 6+ (chromium) and Pb 2+ (lead). The results indicate that the recovery of arsenic, silver, lead and nickel was up to 95% and for chromium was lower than 10%, for both minerals.…”