Simultaneous Removal and Recovery of Metal Ions and Dyes from Wastewater through Montmorillonite Clay Mineral

Abstract

The main objective of this work was to evaluate the potential of Montmorillonite nanoclay (Mt), readily and inexpensively available, for the simultaneous adsorption (and removal) of two classes of pollutants: metal ions and dyes. The attention was focused on two “model” pollutants: Ce(III) and crystal violet (CV). The choice is due to the fact that they are widespread in wastewaters of various origins. These characteristics, together with their effect on human health, make them ideal for studies on water remediation. Moreover, when separated from wastewater, they can be recycled individually in industrial production with no or simple treatment. Clay/pollutant hybrids were prepared under different pH conditions and characterized through the construction of the adsorption isotherms and powder X-ray diffraction. The adsorption behavior of the two contaminants was revealed to be significantly different: the Langmuir model reproduces the adsorption isotherm of Ce(III) better, thus indicating that the clay offers a unique adsorption site to the metal ions, while the Freundlich model proved to be the most reliable for the uptake of CV which implies heterogeneity of adsorption sites. Moreover, metal ions do not adsorb at all under acidic conditions, whereas the dye is able to adsorb under all the investigated conditions. The possibility to modulate the adsorption features by simply changing the pH conditions was successfully employed to develop an efficient protocol for the removal and separation of the different components from aqueous solutions mimicking wastewaters.

Acid Dye Removal from Aqueous Solution by Using Neodymium(III) Oxide Nanoadsorbents

“…Therefore, wastewaters containing this type of dyes were highlighted as one of the most important threatening factors in environmental and public health [2,5]. Different studies have reported that there are several methods for removing dyes from textile wastewaters, including the application of photodecomposition [6], electrolysis [7,8], adsorption [9][10][11][12][13][14][15][16][17][18], oxidation [19], biodegradation [20], combined sonochemical and adsorption [21], coagulation-flocculation [22,23], etc.…”

Poly (N-vinyl Imidazole)/Nitrogen-Doped Graphene Quantum Dot Hydrogel Adsorbent With Remarkable Capability for Metal Ion Removal From Aqueous Systems

“…The carbon-based nanomaterials such as activated carbon, carbon nanotubes (CNTs), montmorillonite and graphene may be successfully used as efficient, cost-effective and environmentally friendly adsorbents with excellent adsorption capacity for the removal of various toxic substrates from wastewater such as heavy metals, azo dyes, etc. [13]. For example, CNTimpregnated chitosan hydrogel beads have been developed for the removal of congo red with high maximum adsorption capacity [14].…”

Synthesize of Poly (Acrylamide-Co-Itaconic/TiO2) Nanocomposite for Ce(III) Sorption from Monazite Leachate

“…Various soils [13], montmorillonite nanoclay [14], HKUST-1 framework [15] and chert rocks [16] were used as sorbents for Ce(III) from aqueous solutions.…”