An All-Green Strategy to Convert Waste to New Material by a Solvent-Free Method for Heavy Metal Adsorption

Zeolite has been widely used as an adsorption material to reduce water and air pollution. In place of the conventional hydrothermal method, zeolite in this study was synthesized by the solvent-free method to reduce the large water solvent used and limit wastewater pollutants. In addition, fly ash was used as raw material for zeolite due to its high proportion of Si and Al. It was determined by several structural and morphological characterization tequniques that the synthesized zeolite was of the analcime type with porosity comparable to those of other known zeolite adsorbents. Several experiments with Pb2+ and Cu2+ solutions under different contact times, initial ion concentrations and temperatures were conducted to investigate the adsorption behaviors of analcime zeolite toward those heavy metals. This investigation illustrates a waste-to-value approach and a green process to produce material that reduces the impact of heavy metal pollutants on environment, thus promoting a sustainable and circular economy.