Functionalization of kaolinite for removal of phosphate from urban sewage.

The PO widespread in urban sewages promotes eutrophication of water sources, with harmful effects to natural life and endanger human health. The removal of PO 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 PO from urban sewage. The kaolinite commercial did not remove PO from aqueous solution. However, the functionalized kaolinite (FK) was efficient, with a maximum removal capacity of 8.4 ± 0.1 mg PO /L, within less than 1 min of reaction. The removal of PO is associated with precipitation of pyromorphite, a mineral with low solubility ( < 10). Finally, real urban sewage samples (raw and treated) were also tested for removal of PO using FK, confirming its effectiveness. The central aspects of this development are:•Functionalized kaolinite (FK), with Pb(II), for removal of PO from urban sewage was studied.•The FK was efficient for removal of up to 8.4 mg PO /L from aqueous solution, within a short reaction time.•The precipitation of pyromorphite was the mechanism responsible for removal of PO and FK efficiency have been confirmed for real urban sewage samples.