Treatment of Wastewaters with Zirconium Phosphate Based Materials: A Review on Efficient Systems for the Removal of Heavy Metal and Dye Water Pollutants.

Monica Pica

doi:10.3390/molecules26082392

Abstract

Layered zirconium phosphate (ZrP) is a versatile material with phosphate (POH ) groups able to exchange inorganic and organic cations or to intercalate basic molecules. The present review deals with the use of this material as a sorbent for heavy metal cations or dye molecules in wastewater treatments. The possibility to combine ZrP with polymers or other inorganic materials, in order to have suitable systems for real and large scale applications, was investigated, as well as the combination with photocatalytic materials to obtain hetrogeneous photocatalysts for the capture and photodegradation of organic dye molecules.

Highlights

The progress of society led, on one hand, to a significant improvement in the quality of people’s life, but, on the other hand, to the significant anthropogenic pollution of soil, water and air due to the intensive exploitation of natural resources
Several examples of sorbents based on polymer composites, consisting of zirconium phosphate (ZrP) particles dispersed in a polymer matrix, are reported in the literature
The results showed that the D001 column produced clean water with a mass of ≈1500 times over the adsorbent mass, while the ZrP@mesoporous polystyrene (MPS) column was able to generate clean water with a mass of 7200 times over the adsorbent mass in each run

Summary

Introduction

The progress of society led, on one hand, to a significant improvement in the quality of people’s life, but, on the other hand, to the significant anthropogenic pollution of soil, water and air due to the intensive exploitation of natural resources. Water treatments for the removal of dyes and heavy metals include biological processes (in aerobic or anaerobic conditions), chemical processes (such as ozonation, coagulation and precipitation, ion exchange, electro-coagulation) and physical processes (flotation, reverse osmosis, adsorption) [2] Among these processes, adsorption is considered one of the most effective and competitive and is widely used in industrial applications. Layered zirconium(IV) phosphates are a well known class of inorganic materials, whose intercalation and ion exchange properties are widely investigated [31] Their chemical and thermal stability, the availability of several synthetic procedures, the possibility to tune its properties by changing the synthetic approach, the possibility to bind functional groups on the layer surface and their ability to uptake cations, both inorganic and organic, and basic molecules stimulated the interest in this class of compounds as potential and unconventional materials for the removal of heavy metals and dye from water. On the basis of these considerations, it seemed of interest for the scientific community to gather/collect the recent studies on water treatment by using zirconium phosphates for pollutants’ removal, heavy metal cations and dyes

Structure of Zirconium Phosphate

Removal of Heavy Metals

ZrP–Polymer Composites

Other ZrP Based Materials

Removal of Dyes

Findings

Conclusions