Functionalization of kaolinite for removal of phosphate from urban sewage
2021
Carbinatti, Camilla | da Conceição, Fabiano Tomazini | Moruzzi, Rodrigo Braga | Menegário, Amauri Antônio
The PO₄³⁻ widespread in urban sewages promotes eutrophication of water sources, with harmful effects to natural life and endanger human health. The removal of PO₄³⁻ from urban sewage requires treatment at tertiary level, with high costs and low efficiency in most cases. Thus, a functionalization method for surface modification of kaolinite was proposed to improve the removal of PO₄³⁻ from urban sewage. The kaolinite commercial did not remove PO₄³⁻ from aqueous solution. However, the functionalized kaolinite (FK) was efficient, with a maximum removal capacity of 8.4 ± 0.1 mg PO₄³⁻/L, within less than 1 min of reaction. The removal of PO₄³⁻ is associated with precipitation of pyromorphite, a mineral with low solubility (Kₛₚ < 10⁻⁷⁹,⁶). Finally, real urban sewage samples (raw and treated) were also tested for removal of PO₄³⁻ using FK, confirming its effectiveness. The central aspects of this development are:•Functionalized kaolinite (FK), with Pb(II), for removal of PO₄³⁻ from urban sewage was studied.•The FK was efficient for removal of up to 8.4 mg PO₄³⁻/L from aqueous solution, within a short reaction time.•The precipitation of pyromorphite was the mechanism responsible for removal of PO₄³⁻ and FK efficiency have been confirmed for real urban sewage samples.
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