Removal of Alizarin Violet 3R (anthraquinonic dye) from aqueous solutions by natural coagulants

In this paper the ability of two natural products in removing dyes has been tested. After a preliminary screening for dye removal capacity, a tannin-based coagulant called ACQUAPOL C-1 and a vegetal protein extract derived from Moringa oleifera seed have been fully studied. The influence of several parameters such as pH, temperature or initial dye concentration (IDC) have been tested and the behavior of both coagulants has been compared. pH results to be an interesting variable and dye removal decreases as pH increases. This effect is higher in ACQUAPOL C-1 than in M. oleifera seed extract. Temperature seems not to be so affecting parameter, while IDC appears to be a very important variable in q(c), capacity, which is higher as IDC increases. Langmuir isotherm model fits very well in both cases of ACQUAPOL C-1 and M. oleifera seed extract dye removal. (C) 2009 Elsevier B.V. All rights reserved.