Modified activated carbon with silver–copper mixed oxides nanoparticles for removal of heavy metals from water

Abstract

Gravitational filtration column experiments were carried out using granular activated carbon impregnated with metallic compounds for the removal of heavy metals from water. The material produced was characterised by textural characterisation: specific surface area Brunauer–Emmett–Teller, area of micropores (method t), volume and diameter of micropores (Horvath–Kawazoe method) and mesopores (Barret, Joyner and Halenda method); structural characterisation by X-ray diffraction; morphological characterisation by scanning electron microscopy and transmission electron microscopy. The removal of the metals was analysed by atomic absorption spectrometry. Activated carbon (AC) and activated carbon modified with silver and copper metal compounds (ACAgCu) columns were monitored by physical–chemical parameters and efficiency of heavy metals removal. The removal of Pb from water ranged between 93 and 96%, reaching values in accordance with the acceptable standard for both AC and ACAgCu, with a residual of 9 µg L−1 and 5 µg L−1, respectively, at the end of the filtration. For Fe contaminant, the filtration column with ACAgCu was the best with a final residual of 0.18 mg L−1 and average removal of 74%. For AC, the residual was 0.42 mg L−1 with an average removal of 38%. Zn removal was low for AC and ACAgCu, with a final residual of 7.4 mg L−1 (mean removal of 39%) and 8.5 mg L−1 (mean removal of 19%), respectively.