Nitrogen-Riched Functional Cellulose Enhanced the Removal of Pb(II) from Water

Since lead is a non-biodegradable and neurotoxic heavy metal, efficient removal of Pb(II) from water is of great significance. Herein, a new type of functional cellulose with enriched thiourea groups (Thiourea-PC) was synthesized using the leaves of plumeria frangipani, a common agricultural solid waste, as the starting materials and applied for the efficient removal of lead ions from water. The properties of the cellulose-based adsorbent have been carefully analyzed and evaluated using FT-IR, SEM, XPS, and elemental analysis techniques. The results showed that the maximum adsorption capacity of Thiourea-PC was 173.92 mg/g under the optimal conditions. The adsorption mechanism was attributed to the complex reaction between Pb(II) and mercaptan/nitrogen-containing groups, and the adsorption process conformed to Langmuir isothermal adsorption model and Pseudo-second-order kinetic model. It is worth noting that after five cycles of adsorption–desorption, the removal rate of Pb(II) by Thiourea-pc was still high, reaching more than 97%, and it had been successfully applied to the simulated adsorption of actual water samples with excellent selectivity. Adsorbent precursors come from a wide range of sources, are economical and effective, and the resource utilization of biomass waste can be realized through sustainable synthesis.