Preparation of Adsorbent with Lead Removal Ability from Paper Sludge Using Sulfur-impregnation

During the manufacture of recycled paper, paper sludge is discharged as an industrial waste. The amount of sludge discharged from manufacturing plants increases annually. In this study, the organic constituents, such as cellulose, in the sludge were converted into carbonaceous heavy metal absorbents using sulfur treatment, and its removal ability of lead from aqueous solution was examined. The sludge was treated with 5 M HCl to remove inorganic content, and then immersed in 1 M K₂S solution to prepare sulfur-immersed sludge. The immersed-sludge was heated at 100-1000 °C for 1 hour in nitrogen gas to produce the sulfur-impregnated adsorbent by pyrolysis. The product obtained at 400 °C (Product-400) has a high removal ability for lead ion, which has high specific surface areas and high sulfur content. The product-400 shows the highest adsorption of lead from aqueous solution, and high selective removal for lead ions in low pH solution.