One-pot removal of pharmaceuticals and toxic heavy metals from water using xerogel-immobilized quartz/banana peels-activated carbon

Here, we report the efficient one-pot removal of heavy metal ions and pharmaceuticals using xerogel, activated carbon and gravel. The simplest xerogel from tetramethyl orthosilicate showed ∼ twice the adsorption capacity of activated carbon derived from banana peels at 600 °C and far greater (x 35) than quartz pellets of diameter ∼300 μm. Functional groups present in both xerogel and activated carbon greatly enhanced the adsorption process. The combination of the three adsorbents resulted in the removal of > 95% of heavy metal ions and pharmaceuticals from water. The data fitted well in linear equations of Langmuir and Freundlich adsorption isotherms, and pseudo-first-order and pseudo-second-order kinetics, an indication for physisorption, chemisorption, adsorption and desorption processes during pollutant capture by the adsorbents.