Removal of Heavy Metal Ions from Wastewater Using Food Waste Char

Abstract. Lead (Pb) and copper (Cu) are the most common pollutants found in industrial effluents that affect the ecosystem and human health. To remove Pb and Cu from aquatic systems, cost-effective and environmentally friendly adsorbents are required. Hydrothermal liquefaction (HTL) of biomass into biofuel also produces carbon material HTL-char. In this study, char prepared from HTL of food waste, and an activated version of the HTL-char, were characterized and tested for Pb and Cu removal from wastewater. Batch experiments were conducted to study the effects of activation, initial pH and initial metal concentration, on the adsorption properties. Preliminary results showed that HTL-char derived from food waste has a higher adsorption capacity for Pb than for Cu. The maximum adsorption capacity of Pb (32.9 mg Pb g-1 dry char) was obtained at pH = 3.5, T = 23.1°C, and initial solution concentration of 80 mg/L. Brunauer-Emmett-Teller (BET) surface area measurement and Fourier transform infrared spectroscopy (FTIR) indicated that the high Pb adsorption capacity of the char is due to its abundance of oxygen-containing functional groups, rather than its BET surface area (9.9 m2/g), which is relatively low compared to the activated HTL-char (50.7 m2/g) and commercial carbon (600 m2/g).