Nanoporous polyanilines as sorbents for dyes and heavy metals abatement from water

Every year, from 300 to 500 millions of tons of solvents, heavy metals, toxic sewage sludges and others industrial waste are released in water [1]. Pollutants ad/absorption on a solid support represents one of the most employed approach for waste abatement. To date, activated carbon is the most used support thanks to its high surface area, high porosity and low selectivity. The main disadvantage of this material is the necessity to activate and regenerate it through thermic treatment at high temperature or using solvents, causing additional costs. In this regard, the necessity to develop innovative materials is crucial. The present study is focused on the “green” synthesis and characterization [2] of porous polyanilines (PANI), characterized by specific features that make them useful for the removal of two classes of wastewater pollutants: organic dyes (methylene blue and acid green) and heavy metals (Pb+2, Cd+2 and Cr+6). The role of the doping agent was investigated, such as the reaction parameters. H2SO4-doped PANI showed the best performances and the material porosity and pH conditions resulted to be the most important parameters influencing its activity. After a 4-run recycling, it retained its high activity thus opening the way to the use of this material as substitute for the presently employed activated carbon. References 1. http://www.unesco.it/it/News/Detail/510 2. C. Della Pina, M. A. De Gregorio, P. Dellavedova, E. Falletta, Materials 13 (2020) 2161(1-10).