Evaluating adsorbent properties of drinking water treatment plant sludge-based carbons activated by K2CO3/CH3COOH: a low-cost material for metal ion remediation

Abstract

Sludge reclaimed from drinking water treatment plant was carbonized and chemically activated by K2CO3 and CH3COOH. The proposal was to evaluate its adsorbent properties as a low-cost alternative material for metal ion remediation. Morphological, physicochemical, and chemical characteristics have been presented and comprehensively discussed. Main findings revealed a surface area rich in mesopores and loaded with weakly acidic functional groups, also presenting an eroded aspect. Carbonization of the sludge’s organic content increased the concentration of nitrogenic and oxygenated functional surface groups. Chemical activation by K2CO3 and CH3COOH increased adsorption and desorption capacity, pore volume, and pore size by two, three, and over tenfolds, respectively. Uptake of cations increased by 51% and, for anions, around 27%. Association of carbonization with sequenced activation processes converted drinking water treatment plant sludge into an excellent and promising alternative adsorbent material.