Towards overcoming TOC increase in wastewater treated with Moringa oleifera seed extract

Moringa oleifera seed extract was purified for treating textile wastewater effluents. Whereas the classical problem of these kinds of coagulants is the increase of TOC, purified M. oleifera seed extract was efficient in the removal of several anionic dyes and did not present this drawback. Specifically, Moringa purified coagulant was able to remove Acid Red 88, an azo dye, with a maximum coagulant capacity of ca. 1.2 mg mg−1. The dye–coagulant system was adequately studied under the perspective of the Response Surface Methodology and an optimum combination of 17 mg L−1 of coagulant concentration and 78 mg L−1 of initial dye content was established. This system was modeled according to Langmuir hypothesis and gave an average correlation factor (r2) of 0.89. M. oleifera coagulant, after purification, did not increase the TOC concentration in the treated water and the final levels of such parameter were comparable to those obtained with alum or other coagulants, such as tannin-derived ones.

► Purification with IEX. ► Dye removal. Optimization by RSM. ► Max q = 1.26 mg mg−1.