Synthesis of zeolites by in-situ conversion of geopolymers and their performance of heavy metal ion removal in wastewater:A review

Toxic heavy metal ions, as one of the most common pollutants in wastewater, are harmful and widespread, which have severely threatened human health and survival. Therefore, the removal of toxic heavy metal ions from wastewater is becoming an intractable problem. In recent years, geopolymer-based zeolite functional materials have been considered as promising adsorbents for the efficient removal of toxic heavy metal ions from waste-water due to their wide range of solid raw materials, low price, and efficient adsorption properties. This review reports the general methods of zeolites by in-situ conversion of geopolymers, such as direct synthesis method, hydrothermal synthesis method, focusing on the factors that affecting the types and microstructure of zeolites synthesized in-situ by geopolymers during the preparation process. In next, the performance of the products is used for removal of heavy metal from wastewater. The different interactions between experimental parameters in the removal procedure are also highlighted. In view of the published literature, the proposed review points out a critical discussion of research gaps, so as to benefit environmental scientists, engineers and chemists interested in deploying geopolymer-based zeolite functional materials for environmental remediation purposes. Finally, the moving forward section highlighted several barriers that are likely to hinder future research and translation.

Automated summary

This article reviews the research progress of geopolymer-based zeolite functional materials in the removal of toxic heavy metal ions from wastewater. It focuses on the influence of different synthesis methods on the types and microstructure of zeolites and highlights the interactions between experimental parameters. The review is of great importance for environmental scientists, engineers, and chemists interested in using geopolymer-based zeolite functional materials for environmental remediation purposes.