Synthesis of Zeolites from Coal Fly Ash for Removal of Harmful Gaseous Pollutants: A Review

Xiaoyu Ren,Xuecheng Wu,Chenghang Zheng,Xiang Gao,Haitao Zhao,Weihong Wu,Hao Song,Ruiyang Qu,Shaojun Liu

doi:10.4209/aaqr.2019.12.0651

Abstract

ABSTRACT SOx, NOx, COx, volatile organic compounds (VOCs), and Hg vapor directly and indirectly harm the atmospheric environment and human health by contributing to the formation of photochemical smog, acid rain, and haze and posing risks of potential toxicity (e.g., carcinogenicity). Therefore, effectively controlling and reducing the pollution caused by these chemicals is critical, and to that end, several methods have been developed, among which adsorption is one of the most common and effective techniques. As adsorption materials, zeolites show great potential in reducing air pollution. Moreover, coal fly ash (CFA)-based zeolite synthesis enables the simultaneous treatment of air and solid waste pollution. In this study, the progress of recent years in research on zeolite synthesis by CFA is reviewed, and the challenges besetting this method are discussed. In addition, we examine the application of CFA-based zeolites in removing or minimizing harmful gases. As we enter an era of utilizing disposed waste, developing efficient and low-cost materials for the removal of harmful gases may require improving the synthesis of high-purity, high-performance fly ash zeolite materials.

Highlights

Coal is the second largest fuel in the global energy mix, and it accounted for 27% of the global energy consumption in 2018 (Fig. 1(a)) (BP, 2019)
Coal fly ash (CFA)-based zeolite synthesis enables the simultaneous treatment of air and solid waste pollution
As we enter an era of utilizing disposed waste, developing efficient and low-cost materials for the removal of harmful gases may require improving the synthesis of high-purity, high-performance fly ash zeolite materials

Summary

Introduction

Coal is the second largest fuel in the global energy mix, and it accounted for 27% of the global energy consumption in 2018 (Fig. 1(a)) (BP, 2019). Izidoro et al (2012) discussed the synthesis of zeolites from five kinds of Brazilian CFA using the hydrothermal method and discovered that zeolite made from CFA containing more than 70% SiO2 and Al2O3 has a high ion exchange capacity. Wang et al (2008) discussed the effects of NaOH concentration on the dissolution of silica in CFA and synthesized different types of zeolites through the twostep method.

Results

Conclusion