| Aluminophosphate molecular sieves (APO-5) and heteroatoms aluminophosphate molecular sievesand (MeAPO-5) were synthesized hydrothermally. And also loading the APO-5with metal ions was carried out. It was investigated the influence of raw materials, calcination temperatures and adding sequence on the characteristic of molecular sieves; The influence of loading metal salts, loading amounts of metal atoms and calcination temperature on the characteristics of molecular sieves was studied as well.The materials were characterized using XRD, SEM, and BET to investigate the phase, morphology, and pore size distribution of molecular sieves. And the experiments on adsorbing of ammonia-nitrogen were carried out using all the materials obtained above to select one kind of molecular sieves as the main object of next ammonia-nitrogen adsorption process. The optimum technical condition of the ammonia-nitrogen adsorbing process were determined by investigating the influence of pH value, dosage of adsorbent and retention time on the adsorption behavior. According to results, it was concluded that the optimum synthesis condition of MAPO-5was as follows:aluminum isopropoxide as aluminum source, magnesium hydrate as magnesium source and600℃as the calcination temperature. As well the optimum loading condition was as follows:APO-5synthesized with aluminum isopropoxide as support, cobalt nitrate as loading salt, mass fraction0.5%,700℃as calcination temperature. When treated the wastewater whose iniatal ammonia-nitrogen concentration was20ppm with40g·L-1as the dosage of adsorbents obtained via the technology condition, the ammonia-nitrogen removal rate of adsorbents was more than90%in10min, and it was more than98%in60min. And the effluent ammonia-nitrogen concentration was lower than lppm. The regeneration experiments of adsorbents with acid, alkali, salt treatment showed a worse result, so the regeneration methods needed to be researched. |
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