Mercury removal from wastewater using porous cellulose carrier modified with polyethyleneimine

An adsorbent for heavy metal was synthesized by introducing polyethyleneimine (PEI) into porous cellulose carriers. Evaluations of synthesis results and adsorbent properties were conducted. Elementary analysis of the adsorbent revealed extensive crosslinking of PEI with the modified matrix. Batch adsorption tests showed the ability of cell-PEI to selectively remove mercury even at acidic regions. At low concentration ranges, mercury adsorption by cell-PEI can be interpreted by the Langmuir isotherm. With this model, an adsorbent capacity and Hg-ligand stability constant of approximately 288.0 mg g−1 and 12.91 mg−1, respectively, were obtained. From adsorption rate experiments, diffusivity of Hg in the carrier was found to be approximately equal to 7.30 × 10−14 m2 s−1. Extensive crosslinking of PEI chains that restricts ligand mobility was cited as the foremost factor contributing to these observed properties.