LAUSR

Abstract The removal of increasing number of pollutants in water needs the search of new adsorbents, or the improvement of known adsorbents. In this paper, the adsorption capacity of aluminum phosphate AlPO4 was investigated after its chemical modification by adsorption of the surfactant sodium dodecylbenzenesulfonate (SDBS). The new adsorbent SDBS-modified AlPO4 was characterized by X-ray diffraction (XRD), Fourier Transform Infra-red (FTIR), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), and the Brunauer, Emmet and Teller (BET) method. SDBS-modified AlPO4 was applied to the removal of Ponceau S (PS) or Acid Red 112 which is suspected to be carcinogenic from aqueous solutions.The influential parameters like pH, PS concentration, contact time and temperature were studied. The results showed that the removal of PS was fast and that the equilibrium was reached in 30 min. The kinetics showed that adsorption followed a pseudo-second-order model and the adsorption at equilibrium was in agreement with the experimental values. The isothermal adsorption led to an adsorption capacity of 60.8 mg/g for SDBS-modified AlPO4. This result shows that the SDBS modification improves the adsorption efficiency of AlPO4. The adsorption models of Langmuir, Freundlich and Sips were applied. Sips model gave the best fitting. The temperature did not affect the adsorption. The regeneration of aluminum phosphate modified by SDBS was carried out by calcination leading to a material which was again modified by SDBS and then used as adsorbent of PS with an adsorption capacity of 28.13 mg/g.