Adsorption of phosphorus from slaughterhouse wastewater by carboxymethyl konjac glucomannan loaded with lanthanum

Phosphorus removal was an important measure in the control of eutrophication of water environment. In this study, a novel phosphorus removal adsorbent of lanthanum-loaded carboxymethyl konjac glucomannan microspheres (CMKGM-La) was successfully prepared by the method of electrostatic spraying and sol-gel, and was characterized by SEM, XPS and EDX. Batch experiments were performed to evaluate the adsorption capacity at different conditions: pH, temperature, initial concentration, adsorbent dosage and contact time. The results showed that the adsorption kinetics data correlated well with the pseudo-second-order kinetic model and the adsorption isotherm was well described by the Langmuir isotherm model with the maximum capacity of 16.06 mg·g-1 for CMKGM-La microspheres at pH of 4 and 318.15 K. The adsorption of phosphorus was a spontaneous, entropy-increasing and endothermic process. The possible adsorption mechanism of phosphorus on the CMKGM-La microspheres consisted of the coordination reaction of La (III) with phosphorus and electrostatic attraction between protonated hydroxyl and phosphorus. The presence of co-existing ions (such as NH4+, Cl-, SO42-, SiO32- and CO32-) had no significant effect on phosphorus removal. These results suggested that the adsorbent of CMKGM-La microspheres was a promising adsorbent for the removal of phosphorus from slaughterhouse wastewater.