Adsorption experiments
The adsorption experiments of Cd2+ and Zn2+ were performed
according to the batch method. The conical flasks containing 0.002 g
adsorbent and 20.00mL metal solution with the initial pH value
5.0±0.1 were placed on a constant temperature bath oscillator to
vibrate at room temperature (25±1 ◦C). After a period of time, the
MNHAPwere separated from the solutions using a permanent magnet
and the initial and final metal concentrations were determined
by a Perkin-Elmer Analyst 700 AAS.