Preparation and photocatalytic efficiency evaluation of hydroxyapatite -titanium toward orange acid 7 dye in aqueous medium [Préparation et évaluation de l'efficacité photocatalytique du hydroxyapatite -titane vis-à-vis du colorant acide orange 7 en milieu aqueux]

In this work,the degradation of orange acid 7 (oa7) dye by heterogeneous photocatalysis using a non-stoichiometric hydroxyapatite doped with titanium was investigated. first,the developed catalyst was characterized by different analytical techniques such as xrd,ftir and tga-dta. its effectiveness in degrading oa7 dye was then studied in a batch reactor. the effect of several parameters such as concentration,ph and irradiation time on photodegradation efficiency was investigated. obtained results show that composite material hap-titanium has a significant photocatalytic activity complete discoloration of dying solution can be achieved after 16 hours of irradiation. results show that discoloration performance depends on the catalyst mass,its titanium content,the initial dye concentration and the presence of oxygen in medium. however,photodegradation is little affected by the variation of ph of treated solutions. increasing the mass of the catalyst and its percentage of titanium improves considerably the efficiency and the speed of discoloration. the optimum mass of the catalyst hap-titanium (ti 11%) is about 2 g per liter of solution. obtained results also show that discoloration yield decreases by increasing the initial concentration of dye and that the presence of oxygen in medium improves further the phodegradation phenomenon.