Mg/P molar ratio

In this paper, the reactive crystallization of MAP has been studied in a batch agitated crystallizer, in order to obtain the crystallization characteristics and the effect of Mg/P molar ratio on the properties of produced crystals and the behavior of the concentration decrease. 

Based on the results of experiment (1), crystallization experiments were done in the presence of excess MAP crystals, chwging the pH conditions as shown in Table 1, to obtain the concentration of the reactant after 24h. Also the phosphate removal efficiency was obtained under the same experimental condition, changing pH and Mg/P molar ratio. 

Effect of Mg/P molar ratio on the behavior of concentration decrease and the properties of produced crystals... 

Experiments were done, using a batch crystallizer apparatus as shown in Fig.l, varying the Mg/P molar ratio from 1-4. The experimental conditions are shown in Table 2. During the process of batch crystallization, the mixed suspension was sampled at the determined crystallization time. The samples were filtered through 0.45 fjL m membrane filter, and the concentrations in the filtrate were measured. Also sampled crystals were obtained when the concentration was observed to be constant, to be observed by SEM and be analyzed by the Xray diffractometer. The composition of crystals was analyzed after dissolution by a pH 2 HCl solution. 

It was recognized that excess of ammonium ion and suitable pH and Mg/P molar ratio were desirable as the operating conditions for selective MAP crystallization. 

Fig.4 also shows the effect of pH on the phosphate removal efficiency at two different Mg/P ratios. The highest removal efficiency was obtained in the pH range from 9 to 10. Increasing Mg/P molar ratio increased the phosphate removal efficiency. 

SEM photographs of produced crystals are shown in Photos 1,2 and 3, where the Mg/P molar ratio is varying from 1 to 4. Also Xray diffraction analysis of each crystal are shown in Figs. 5,6 and 7. At Mg/P molar ratio 1, the shape of crystals was observed to be one of typical MAP. However the crystals were ag omerat at Mg/P molar ratio 2. When Mg/P molar ratio became 4, the shape of crystals became needlelike and in addition, fine crystals were observed. These crystals were found to be MAP by Xray diffraction analysis, although the shape of the crystals was different. But the results of the composition analysis shown in Table 3, indicate the amount of ammonium ions in the case of Mg/P molar ratio 2 and 4, was higher than in the case of Mg/P molar ratio 1. The reason for the excess uptake of ammonium ion was not clear, but this phenomenon is important when considering the ammonium ion removal. 

Experiments of reactive crystallization of MAP were performed to obtain the optimal operational conditions for MAP selective crystallization, which were an excess of ammonium ions, pH 9-10, and Mg/P molar ratio 1-4. It was also found that Mg/P molar ratio affected the behavior of the concentration decrease, and changed the properties of the produced crystals. Based on the results of these experiments, MAP crystallization is proposed as an efficient method for the removal of phosphate and ammonium ions from the wastewater of the sludge treatment. 

ICP-AES analyses confirmed that the coated substance is Mg-doped calcium phosphate. ICP-AES analyses (5 analyses on 5 repetition samples) indicated the presence of 1568 45 ppm Mg in the coated substance having a Ca/P molar ratio of 1.40 0.11. ATR-FTIR data of DMEM-coated Ti coupons are shown in Fig. 3, together with those of as received grade-1 Ti and alkali-treated grade-1 Ti. 

In 1984, P. Sobota disclosed the structure of a crystalline material that was isolated from saturated solutions of MgCl CTHF) and TiCl fTHF) in THF at a Mg/Ti molar ratio of 2 that were mixed to form yellow crystals which were isolated [55]. The stoichiometry of these yellow crystals was shown to be Mg TiCl (THF) formed via the reaction below. 

No. Metal Salt (g/mmol) Tenside (g/mmol) Metal Salt/ Tenside Molar Ratio Reducing Agent Solvent (mL) T(°C) Reaction Conditions T (h) P (bar) Amount of Product Isolated (g) Metal Content(%) Water Solubility in mg Atom Metal/L Water... 

HS-II. The mean (+ SD) daily apparent absorption values were 153+77, 94+65 and 23+66 mg for 0.5, 1.7 and 2.9 g phytate intakes, respectively. There was a significant difference between all means P <0.05, by ANOVA. A plot of apparent absorption of calcium vs the dietary phytate/calcium molar ratio is shown in Figure 1. 

Miller et al., 1989 n = 6 children n = 3 n — 3 Age range 11-17 years 250 mg Ca as CCM enriched with tracer in form of chewable tablets Stable dual isotope tracers used to quantify CaAbs in urine and serum. Comparison of CCM chewable versus CCM swallowable supplements and CaCOa from data collected previously in same subjects Based on urinary excretion which correlated with serum data (r = 0.85) x SD% CaAbs from chewable CCM for molar ratio 6 2 3 (41.4 8.2%) > swallowable CCM for molar ratio 5 1 1 (39.5 10.6%) > CaCOa (26.7 7.8%) Chewable CCM > CaCOa (p =. 047) and swallowable CCM > CaCO (p =. 094)... 

Species and tissue mg Fe mg protein Fe atoms/ molecule Molar ratio P Fe... 

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