The Influence of Salinity on the Removal of Ni and Zn by Sorption onto Iron Oxide- and Manganese Oxide-Coated Sand

Abstract

The influence of salinity on the single and binary sorption of Ni and Zn onto iron oxide- and manganese oxide-coated sand (IOCS and MOCS) was investigated at pH = 5. The single sorption experimental data were fitted to Freundlich, Langmuir, Dubinin–Radushkevich, and Sips models, and a nonlinear sorption isotherm was observed (NF = 0.309–0.567). The higher Brunauer–Emmett–Teller (BET) surface area (ABET) and cation exchange capacity (CEC) of MOCS contributed to the higher maximum sorption capacities (qmL) of Ni and Zn than that of IOCS. The Ni sorption capacities in the single sorption were higher than that in the binary sorption, while the Zn sorption capacities in the single sorption were less than that in the binary sorption. The single and binary sorptions onto both IOCS and MOCS were affected by the salinity, as indicated by the decrease in sorption capacities. Satisfactory predictions were shown by the binary sorption model fitting including P-factor, ideal adsorbed solution theory (IAST)–Freundlich, IAST–Langmuir, and IAST–Sips; among these, the P-factor model showed the best fitting results in predicting the influence of salinity of Ni and Zn in the binary sorption system onto IOCS and MOCS. IOCS and MOCS offer a sustainable reactive media in a permeable reactive barrier (PRB) for removing Ni and Zn in the presence of salinity.

Modeling the sorption of Ni(II) and Zn(II) by Mn oxide–coated sand: Equilibrium and kinetic approaches

“…This is consistent with the results of Choi et al. (2020), where sorption of both Zn and Ni by a MOCS was decreased in the presence of the other, but Zn sorption was dominant. Similarly, Gou et al.…”

“…This suggests that Ni and Zn competed for sorption sites at the MOCS surface, and that Zn sorption was dominant. This is consistent with the results of Choi et al (2020), where sorption of both Zn and Ni by a MOCS was decreased in the presence of the other, but Zn sorption was dominant. Similarly, Gou et al (2018) reported that Zn sorption by an Al oxide was unaffected by the presence of Ni, whereas Ni sorption decreased in the presence of Zn.…”

“…In general, the sorbed concentrations of Zn were greater than Ni at pH 5.5 and 7.0; however, no difference (α = .05) was observed at pH 4.0. Previous studies demonstrated that Mn oxides have a greater affinity for Zn than Ni (Choi et al, 2020;Kanungo et al, 2004;Trivedi et al, 2004); however, results presented here indicate that the preference of MOCS for either solute is pH dependent. Best-fit MDI and GFI isotherms for Ni and Zn are included in Figure 1, with optimized parameter values given in Table 1.…”

Influence of Salinity on the Removal of Ni and Zn by Phosphate-Intercalated Nano Montmorillonite (PINM)

“…Several literatures have reported similar results (adsorption capacities of Ni > that of Zn) for adsorbents such as Na-montmorillonite [18]. The adsorption affinity of Ni and Zn decreased with the increase salinity (30% ) owing to competition between the added metals and cations in background solution by the limited cation exchange sites [45][46][47]. Table 3 summarizes the comparison of Ni and Zn sorption capacities of Langmuir model for various adsorbents found in literature.…”

Recycling of Waste Toner Powder as Adsorbent to Remove Aqueous Heavy Metals

“…The adsorption method has become preferred for removing heavy metals from wastewater because of its high effectiveness, simplicity and flexibility in plant design, operation and environmental considerations. Numerous adsorbents have been used to remove heavy metals such as activated carbon, alumina, zeolites, iron oxides and manganese oxide [23][24][25][26]; agricultural waste such as coffee grounds, walnut shells, sawdust and rice husk ash [27][28][29]; industrial waste such as fly ash or bottom ash from power plants, and red sludge and steel slag [30][31][32][33].…”