In Situ Growth of Layered Double Hydroxides on Sawdust for Pb(II) Adsorption

Abstract

In this paper, waste wood (sawdust) was modified with layered double hydroxides (LDHs) to improve its adsorption capacity for Pb(II). The LDHs grew easily and evenly on the sawdust in situ through a hydrothermal method. Then, the functional groups and favorable crystal structures of sawdust/LDHs composites were demonstrated by FTIR and XRD. The results showed that the adsorption capacity of sawdust/LDHs composites for Pb(II) increased by 83.61% compared to sawdust, and the optimum conditions for adsorption were at pH 6 for 180 min with an adsorbent dosage of 3 g/L. Moreover, the behavior of Pb(II) adsorption preferably followed pseudo‐second‐order, Langmuir and Freundlich models, with all the R2 values exceeding 0.97. It was indicated that Pb(II) adsorption occurred on the monolayer and heterogeneous surfaces through chemical bonding and electrostatic interaction. Due to their low cost and high adsorption capacity, the plant‐based composites have great potential in the treatment of lead‐containing wastewater.