Remediation of PO43- in Water Using Biodegradable Materials Embedded with Lanthanum Oxide Nanoparticles

Eutrophication, a process in which algae grow inordinately, adversely affects aqueous fauna. Phosphorous at levels above 0.1 mg/L is adequate to cause eutrophication. In this study, we aimed to reduce the amount of PO43- in water using biodegradable and ecofriendly sorbents. Lanthanum oxide nanoparticles were doped in agar and cellulose sponge to produce two new sorbents, agar-La and sponge-La, respectively. Both sorbents showed high efficacy in remediating up to 10 mg/L PO43- in water. Sponge-La was found to be more proficient in terms of adsorption than agar-La because it required just 1 h to achieve 80% adsorption when the initial concentration of PO43- was 10 mg/L. Sponge-La was effective at pH levels ranging from 4 to 8, with a removal rate of 80-100%. Although agar-La displayed a slow sorption process, it presented a high adsorption capacity (156 mg/g); moreover, the cake-shaped agar-La could be easily manufactured and separated from an aqueous matrix or any water-based solutions. These two sorbents could effectively remove high concentrations of PO43-, and their preparation requires a simple step. Agar-La was easier to manufacture, whereas the adsorption process using sponge-La was more rapid. In addition, both sorbents can be easily separated from the matrix after sorption.

Automated summary

In this study, two new sorbents, agar-La and sponge-La, were developed by doping lanthanum oxide nanoparticles in agar and cellulose sponge, respectively. Both sorbents showed high efficacy in removing phosphorous from water, with agar-La having a slow sorption process but high adsorption capacity, and sponge-La being more rapid in adsorption. Both sorbents can be easily separated from the matrix after sorption.