To develop a novel, low-cost adsorbent with natural material and industrial waste as raw materials, nanoscale manganese residue-derived FeS@starch-derived carbon (MR-FeS@SC) composite was prepared by the carbonization of starch-manganese residue gel. Manganese residue-derived FeS (MR-FeS) and starch-derived carbon (SC) were also prepared as contrasts for comparative studies. The MR-FeS@SC nanocomposite exhibited relatively large specific surface area and micropore volume, appropriate pore size, abundant functional groups, strong interaction between the functional groups of SC and MR-FeS, and the immobilization and uniform distribution of MR-FeS nanoparticles onto SC support material, which contributed to better adsorption properties for the removal of Safranine T (ST) from the aqueous solution compared with those of MR-FeS and SC. The adsorption could be conducted at a wide range of pH and temperature to achieve a satisfy removal efficiency of ST with MR-FeS@SC nanocomposite as adsorbent. The adsorption kinetics well followed the pseudo-second-order model, and the dominant mechanism was chemisorption. The adsorption behavior was well described by the Langmuir isotherm model. Due to the strong interaction between MR-FeS nanoparticles and SC support, MR-FeS@SC nanocomposite exhibited better reusability and stability even after fifteen cycles. This study provides a facile method of preparing effective and stable adsorbents for the treatment of dye wastewater.
Keywords: FeS nanoparticles; adsorption; carbon; manganese residue; stable adsorbent; starch.