Fabrication of magnetic carboxyl-functionalized attapulgite/calcium alginate beads for lead ion removal from aqueous solutions

In the present study, we synthesized an effective Pb(II) adsorbent from magnetic carboxyl-functionalized attapulgite (McAPT) and sodium alginate (Alg) by simple mechanical agitation at room temperature. The novel McAPT@Alg composite was systematically characterized using a number of instrumental techniques, and the effects of adsorbent dosage, initial concentration of Pb(II), adsorption time, pH, and temperature on the adsorption capacity were investigated by performing batch experiments. The obtained results demonstrated that adsorption equilibrium could be reached within 1.5 h, with the maximum adsorption capacity being 471.20 mg g−1 while the temperature was 297.2 K. The experimental data were suitable for application to the Langmuir isotherm model, and the adsorption kinetics agreed with the pseudo-second-order model. More importantly, a Pb(II) removal efficiency of >70% could be achieved after 6× adsorbent recycling, which demonstrated the excellent potential of McAPT@Alg for removing Pb(II) from contaminated water.