Preliminary evaluation of polymeric Fe‐ and Al‐modified clays as adsorbents for heavy metal removal in water treatment

Abstract

This paper assesses the potential of modified montmorillonite clays as low-cost adsorbents/ion-exchangers for the removal of trace level heavy metals (Cd, Cu, Ni, Pb and Zn) from potable water. Modification of the montmorillonites resulted in the exchange of the interlayer calcium ions for the polymeric species. One unmodified montmorillonite and three polymeric Fe- and Al-modified montmorillonites have been evaluated with respect to their selectivity and uptake performance. All of the clays are selective for Pb and Cu adsorption from aqueous solutions at the mildly acidic pH range in which the experiments were performed (pH 5.5–6). Polymeric iron- and polymeric Al/Fe-modified clays had comparatively great affinities for all the metals studied, whilst the original and polymeric Al modified clays had relatively lower affinities. Only the uptake of Pb and Cu could be correlated with physical properties such as clay surface area. The metal selectivity could be correlated to the type of intercalated polymeric Fe and Al species of the modified clays

Synthesis and characterization of ZnS-montmorillonite nanocomposites and their application for degrading eosin B

“…It was reported that MMT had strong ability to adsorb organic compounds from aqueous solutions [43,44], and ZnS could be used as a semiconductor-type photocatalyst for the photoreductive degradation of water pollutants. To demonstrate the potential applicability of the present ZnS-MMT composite in photoreductive area, the catalytic activity of the prepared ZnS-MMT composites was determined via degrading eosin B in aqueous solution as a test reaction under UV irradiation.…”

Adsorption of Zn(II) from aqueous solution by using different adsorbents

“…Pretreatment of adsorbent is also commonly used to increase the adsorption capacity of these materials. Several researches have been made significant contributions in this area, utilizing a number of materials including fly ash [24,25], sugar beat pulp [26], clay [27,28], chitosan [29], coconut coirpitch carbon [30], biomass [31,32], zeolites [33,34], rice bran, soybeans and cotton seed hulls [35], sunflower stalks [36], calcined phosphate [37], low-grade phosphate [16], red mud [38,39], tea leaves [40], natural zeolite [41], almond shells, olive stones and peach [42], sediments of rivers [43], peanut hull [44], bentonite [45], saw dust [46,47], baggage fly ash [48], banana and orange peels [49], carrot residue [50], etc.…”

Removal of heavy metals by using adsorption on alumina or chitosan

“…Metal oxides can quantitatively adsorb heavy metals from their aqueous solutions and are thus employed in metal preconcentration [1,2,3] and metal removal [4].…”