FORMATION OF Mg-Al LAYERED DOUBLE HYDROXIDE MODIFIED BY ORGANIC ACID ANIONS AND ITS APPLICATION TO WASTEWATER TREATMENT

摘要

Development of scavengers to remove heavy metal ions and organic pollutants from wastewaters has been attempted by coupling Mg-Al layered double hydroxide (Mg-Al LDH) with organic acid anions having functional groups in their structure, such as edta and 2,6-naphthalene-di-sulfonate ion (2,6-NDS2-).These organic-modified Mg-Al LDHs were synthesized by adding a solution of magnesium and aluminum nitrates to alkaline solution containing the organic acid anion. The solid product was confirmed to be Mg-Al LDH with Al/(Mg+Al) mole ratio of about 0.25 and to have intercalated organic acid anions in the interlayers. The edta-intercalated Mg-Al LDH was found to remove rapidly Cd2+ from an aqueous solution. The 2,6-NDS-intercalated Mg-Al LDH could uptake organic pollutant exampled by bisphenol A. This organic sulfonate-modified Mg-Al LDH was regenerated by extraction of the uptaken bisphenol A with ethanol, and confirmed to have a high potentiality for the repeated use.