The use of Moringa oleifera seeds and their fractionated proteins for Microcystis aeruginosa and microcystin‐LR removal from water

Abstract

The aim of this study was to evaluate the coagulation, flocculation, and dissolved air flotation (C/F/DAF) process using four types of coagulants based on Moringa oleifera (MO) seeds for the removal parameters of colour, turbidity, UV 254 nm, dissolved organic carbon (DOC), chlorophyll‐a, and microcystin‐LR. Tests were performed using water contaminated with Microcystis aeruginosa in a concentration of 104 cells mL−1. The coagulants analyzed were fractionated proteins (albumin and globulin), proteins extracted from saline solution, and the integral powder of MO seeds. The results obtained presented the same optimum dosage for globulin and albumin removal (1.5 mg L−1), in which globulin reached removal percentages of 83.87 and 80.88 % for chlorophyll‐a and microcystin‐LR, respectively, and in which albumin reached removal percentages of 79.44 and 48.14 % for chlorophyll‐a and microcystin‐LR, respectively. The optimal dosage of proteins extracted from the saline solution was 8.0 mg · L−1, which achieved removal percentages of 74.80 and 73.52 % for chlorophyll‐a and microcystin‐LR, respectively. For the DOC, removal was only observed after the use of fractionated proteins, which emphasizes the need for methods based on the use of active purified agents of MO seeds involved in flocculation. Therefore, it is concluded that globulin, as a coagulant, is the most suitable for the present study, since it improves the C/F/DAF process efficiency in Microcystis aeruginosa and microcystin‐LR reduction in addition to removing other analyzed parameters.