Effects of Recycled Sponge Iron on Phosphorus Recovery from Polluted Water

The adsorbent preparation of lanthanum functionalized sponge based on CMC coating for effective phosphorous removal

Eutrophication is a severe worldwide concern caused by excessive phosphorus release. Thus, significant efforts have been made to develop phosphorus removal techniques, particularly by nanomaterial adsorption. However, because of the limitations associated with nanoparticles including easy agglomeration, and separation challenges, a novel nanocomposite adsorbent with great adsorption performance is urgently required. A sponge adsorbent (MS-CMC@La) was developed in this study to remove phosphorus using melamine sponge (MS), LaCl3, and sodium carboxymethyl cellulose (CMC). The results of SEM/EDS, FTIR, and XPS demonstrated that La was well-dispersed on MS-CMC@La. Adsorption isotherm and kinetics met with the Langmuir model (R2 = 0.981) and the pseudo-second-order kinetics (R2 = 0.989), respectively. The maximum adsorption capacity of MS-CMC@La was found to be 15.28 mg/g; the material exhibited excellent selectivity toward phosphorus in the presence of coexisting anion except of F-; the adsorption behavior was greatly impacted by pH. Furthermore, the electrostatic attraction, ligand exchange and inner-sphere coordination regulate the phosphate adsorption mechanism, with inner-sphere coordination dominating. In summary, the nano-enriched materials developed in this study are capable of facilitating the application of functionalized sponges in the field of wastewater.