Removal of Nitrophenols by Modified Attapulgite

This thesis concerns with the use of Iraqi Clay (attapulgite) for the removal of hazardous organic water pollutants, namely o-nitrophenol, m-nitrophenol and p-nitrophenol from their aqueous solutions. Attapulgite was modified by surfactant (hexadecyltrimethylammonium bromide (HDTMA)). Attapulgite and its modified form (A-HDTMA), were purified, sampled and characterized by X-ray diffraction (XRD), FTIR spectroscopy, scanning electron microscope (SEM) and energy dispersive X-ray spectroscopy (EDS) technique. Batch experiments were carried out at pre determined equilibration time, solution pH, adsorbent dosage, ionic strength, initial nitrophenols concentration and temperature. The results show that the maximum adsorption capacity for o-nitrophenol, m-nitrophenol and p-nitrophenol of the two clays are in the order: p-nitrophenol > o-nitrophenol > m-nitrophenol. Adsorption of nitrophenols was strongly affected by pH and best adsorption is achieved at pH 7.2. The maximum nitrophenols adsorption capacities increased from 1.438, 1.242 and 1.072 mg.g-1 of p-nitrophenol, o-nitrophenol and m-nitrophenol, respectively on raw attapulgite clay to 3.226, 3.076 and 2.988 mg g-1 for A-HDTMA.