Using nanobubblized carbon dioxide for effective microextraction of heavy metals

Abstract

We pioneer the use of CO2 nanobubbles (NCHM) for adjusting the physiochemical properties of activated carbon fibers (ACF) to improve the microextraction performance of heavy metal ions. We first synthesized NCHM-loaded ACF (N-ACF) through the gas-phase using a mixture of CO2 and H2O. To explore another green alternative, F-ACF was also prepared by the impregnation of formic acid. Physiochemical analyses indicated that N-ACF experienced minimized surface area decrement (16.60 % better than F-ACF), but increased surface functional moieties (25.54 wt% better than ACF). Herein, we successfully modulated abundant but abandoned macropores into micropores by NCHM with a median size of 147 nm and the concentration of 3.08 x 10(10) particle ml(-1). The microextraction performance of Pb(II) and Cd(II) under the simulated river environment was in the order of N-ACF (Q(max) for Pb(II): 4.963 and Cd(II): 4.677) > ACF (4.632, 4.448) > F-ACF (4.447, 4.357) with revealed characteristics of monolayer adsorption, feasible, spontaneous and endothermic in nature. Ultimately, it can be postulated that NCHM could be a promising method in which case physiochemical properties of an absorbent affect the overall microextraction performance.