Lead Ion Sorption by Perlite and Reuse of the Exhausted Material in the Construction Field

Andrea Petrella,Danilo Spasiano,Nicoletta De Vietro,Pinalysa Cosma,Vito Rizzi,Marco Race

doi:10.3390/app8101882

Abstract

This paper deals with the possibility of using perlite as a lead ion sorbent from industrial wastewater. Dynamic (laboratory column) operations were carried-out using beads, which were percolated by metals in a 2–10 mg·L−1 concentration range. To this purpose, lead ion solutions were eluted in columns loaded with different amounts of sorbent (2–4 g) within a 1–2 mm bead size range, at 0.15–0.4 L·h−1 flow-rates. Tests were performed to complete sorbent exhaustion (column breakthrough). The highest retention was obtained at 0.3 L·h−1, with 4 g of perlite and 10 mg·L−1 of influent, lead ion concentration. Film diffusion control was the kinetic step of the process in the Nerst stationary film at the solid/liquid interface. At the end of the sorption, perlite beads were used as lightweight aggregates in the construction field (i.e., for the preparation of cement mortars). Specifically, conglomerates showing different weights and consequently different thermal insulating and mechanical properties were obtained, with potential applications in plaster or panels.

Highlights

Anthropogenic activity causes the direct and indirect discharge of billions of contaminants of different natures and origins [1,2,3,4,5], which need specific treatment for their removal [6,7,8,9]
At the end of the sorption, perlite beads were used as lightweight aggregates in the construction field
Cheap and eco-friendly sorbents [17,18,19] have been used to remove Potential toxic metals (PTMs) from wastewater. These sorbents may be considered an alternative to conventional activated carbon—which has a high cost of production and regeneration [20,21]—or ion exchange resins, which are expensive and pH-dependent [22]. The use of these cheap materials allows for “once-through operations” (i.e., PTM-laden, or exhausted, sorbents can be put into a cement conglomerate as aggregate) [17,23,24,25,26], overcoming the expensive regeneration procedures and problems related to the large, hazardous sludge production that is typical of traditional sorbents

Summary

Introduction

Anthropogenic activity causes the direct and indirect discharge of billions of contaminants of different natures and origins [1,2,3,4,5], which need specific treatment for their removal [6,7,8,9]. Cheap and eco-friendly sorbents [17,18,19] have been used to remove PTMs from wastewater. These sorbents may be considered an alternative to conventional activated carbon—which has a high cost of production and regeneration [20,21]—or ion exchange resins, which are expensive and pH-dependent [22]. The use of these cheap materials allows for “once-through operations” (i.e., PTM-laden, or exhausted, sorbents can be put into a cement conglomerate as aggregate) [17,23,24,25,26], overcoming the expensive regeneration procedures and problems related to the large, hazardous sludge production that is typical of traditional sorbents

Methods

Results

Conclusion