Magnetic recovery of modified activated carbon powder used for removal of endocrine disruptors present in water

This paper was aimed at studying sustainable solutions for the treatment of water polluted by octylphenols and nonylphenols that are xenoextrogen compounds affecting human health and dangerous for the aquatic environment. We studied the removal of 4-octylphenol and 4-n-nonylphenol with concentrations of the order of 5–10 mg/l on a laboratory scale. A mixing time of 10 min with 0.1 g/l of magnetic-activated carbons (MACs) was enough to obtain 95±5% adsorption of both 4-octylphenol and 4-n-nonylphenol. The adsorption of the surfactants IGEPAL® CO-630 and TRITONTM X-100, which are precursors of branched 4-nonylphenol and the carcinogenic 4-tert-octylphenol, respectively, was also studied using the same technique. For concentrations between 2 and 10 mg/l of these alkylphenols ethoxylated, after 10min mixing with 0.5 g/l of MACs, a 95±5% adsorption was obtained. A 97±1% removal of MACs was achieved after 10 min of continuous-flow magnetic filtration (14.5 l/min). The filter used was made of SUS440C magnetic steel spheres. Sm–Co permanent magnets provided a uniform flux density field of about 500 mT.