Maya Blue, a pigment used by the Mayas in Yucatan, is remarkably stable: the color is not destroyed by hot concentrated mineral acids or by heating to about 250 degrees C. The principal constituent is the colorless mineral attapulgite. It is proposed that the pigment is an adsorption complex of attapulgite and natural indigo; a synthetic equivalent may be prepared from attapulgite and either in...

Remediating soils with heavy metals contamination is a significant challenge. This study investigated the co-remediation effect when paired soil amendment mixtures were used to treat soil contaminated by Pb, Cd, and Zn. The three mixed amendments are: 1) micro particle hydroxyapatite (mHAP) and humic acid 2) nano particle hydroxyapatite (nHAP) and humic acid 3) sepiolite and humic acid. Co-reme...