Abstract
A novel adsorbent named magnetic humic acid/chitosan composite (M-HA/Cs) was synthesized by decorating humic acid/chitosan composites with Fe
3
O
4
nanoparticles. The adsorption capacity of M-HA/Cs was 1.5 times that of MCs. The effects of solution pH, initial concentration of Pb(II) ions and adsorption temperature on Pb(II) removal were examined in a batch system and further optimized using Box-Behnken analysis. The recommended optimum conditions are initial Pb(II) concentration of 139.90 mg/L, initial pH of 4.98, and temperature of 43.97 ºC. The adsorption processes could be well described by pseudo-second-order and Elovich models. Isotherm studies reveal that the adsorption process follows Sips and Temkin models. The thermodynamic study indicats that the adsorption process is spontaneous and exothermic. The potential mechanism of Pb(II) on M-HA/Cs at pH 5 may be surface electrostatic attraction, coordination and hydrogen bonding.