Excellent adsorption ability of Hg(II) by poly(o-phenylenediamine) modified mesoporous materials

ABSTRACT In this study, we used mesoporous silica materials as inorganic carrier and poly(o-phenylenediamine) with more active amino and imino groups as organic ligand to obtain functionalized adsorbent. The composite adsorbent poly(o-phenylenediamine) modified mesoporous composites (MPP) were prepared by loading poly(o-phenylenediamine) onto the surface of the aminated mesoporous material through in-situ polymerization. It was found that the maximum saturation adsorption capacity of MPP reached 225 mg/g when the solution pH, temperature, initial Hg(II) concentration, and adsorption time were 4, 298.15 K, 100 mg/L, and 240 min, respectively. When common interfering ions Zn(II), Ni(II), Cu(II), Ca(II), Mg(II) and Al(III) were present, the adsorption of Hg(II) by MPP still showed good selectivity. The adsorption of Hg(II) by MPP followed quasi-secondary kinetics and the Langmuir adsorption isotherm model, indicating that the adsorption process was chemisorption. In addition, MPP removed up to 81.35% of Hg(II) from industrial wastewater. After five cycles for adsorbent regeneration experiments, the adsorption capacity of MPP could reach 191.67 mg/g, indicating that the adsorbent has good regeneration performance and potential application value for removal of Hg(II).