Синтез пролонгованих добрив шляхом адсорбції елементів живлення цеолітом з комунальних стоків

Abstract

The purpose of this study is to develop, based on experimental data, recommendations on the optimum conditions for the deposition of ammoniacal nitrogen from ion exchange regenerator for its further use as ammonium fertilizer. In these studies, ion-exchange material natural zeolite of the Sokirnitsky deposit until a breakthrough was reached, after which the ion-exchange material was regenerated by pumping 30 g/l NaCl through it. The maximum saturation of ion-exchange material was determined by increasing the electrical conductivity of the solution at the exit from the column. The analyses were done at various molar ratios of magnesium and phosphate ions and at various pH values. The obtained data was compared to the initial concentrations in the model solution of the corresponding ions to determine the deposition efficiency. It was established that the maximum efficiency of ammonium nitrogen removal at its initial concentration in the regenerate 470 mg/l is achieved at approx. 8,5 pH level with Mg2+ : NH4 +: PO43– = 1,5 : 1 : 1,5 correlations. Based on the results of the best options, deposition of real concentrates of ion exchange was carried out. The degree of NH4+-N ion deposition for concentrate extracted from zeolite was 93,91%, that means, that results almost not differ from the values of samples concentrates. Moisture level was set during mineral fertilizersdrying. Based on the values of the moisture we determined content of the precipitate, which is close to the number of water molecules to the formula of fertilizer MgNH4PO4× 4,5H2O. The comparative thermal analysis of chemical precipitation products and pure struvite was performed. The optimal conditions were identified to experience the maximum efficiency of simultaneous removal of ammonium nitrogen and phosphate ions from wastewater, forming MgNH4PO4 · 4,5 ÷ 6H2O. Recommendations on the use of the obtained product as a fertilizer were elaborated.