Amidoxime functionalized low-cost cellulose-based adsorbent derived from waste filters for efficient metal removal

A tremendous amount of waste cigarette butts are arbitrarily discarded everywhere, which not only smears the appearance of the city, pollutes the environment, but also causes a huge waste of resources. In this study, using waste cigarette filters as cellulose resources, the amidoxime functionalized cellulose-based adsorbent was successfully prepared through a two-step reaction, with the advantage of simple fabrication, low cost and reusability. The prepared adsorbent has a high adsorption capacity of heavy metals owing to the chelation of amidoxime groups with metal ions. The adsorption process of Pb(II) and Cu(II) on the adsorbent follows the pseudo-second-order kinetic model, while for Cd(II), it follows the pseudo-first-order kinetic model. The adsorption isotherm of Cu(II) and Pb(II) is well-fitting with the Freundlich model, while the adsorption of Cd(II) is well-fitting with the Langmuir isotherm model. The amidoxime functionalized cellulose-based adsorbent exhibits high recyclable adsorption efficiency after five adsorption-desorption cycles. This study provides a feasible attempt to turn waste into treasure and solve the problem of environmental pollution.