Adsorption of heavy metals using activated carbon produced from municipal organic solid waste

Adsorption of cadmium (Cd²⁺) and lead (Pb²⁺) was investigated using activated carbon (AC) produced from municipal organic solid waste (MOSW). The produced AC was characterized using Scanning Electron Microscopy, X-ray Diffraction, Fourier Transform Infrared spectroscopy, and Brunauer–Emmett–Teller. The results showed that an AC with a surface area of 790 m²/g was produced at carbonization temperature and time of 700°C and 2 h, respectively, and activation with phosphoric acid concentration of 30%. The effect of operational factors, namely, pH 3–7, contact time (0–480 min), metal concentration (25–300 mg/L), and adsorbent dosage (25–300 mg per 50 mL of metal solution) on the adsorption process was investigated. The results showed that optimum adsorption of Cd²⁺ and Pb²⁺ were obtained at pH of 5, contact time of 180 min, metal concentration of 100 mg/L, and adsorbent dose of 200 mg per 50 mL of metal solution. At optimum operational conditions, removal efficiencies of 78 and 94% for Cd²⁺ and Pb²⁺, respectively, were achieved. The isotherms also showed that the maximum adsorption capacity of Cd₂₊ and Pb²⁺ were 61 and 90 mg/g, respectively, at equilibrium time of 120 min and pH value of 5.