Total phosphate

The routes by which mineral phosphates are processed into finished fertilizers are outlined in Eigure 7. World and U.S. trends in the types of products produced are shown in Eigures 8 and 9, respectively. Most notable in both instances is the large, steady increase in the importance of monoammonium and diammonium phosphates as finished phosphate fertilizers at the expense of ordinary superphosphate, and to some extent at the expense of triple superphosphate. In the United States, about 65% of the total phosphate appHed is now in the form of granular ammonium phosphates, and additional amounts of ammonium phosphates are appHed as integral parts of granulated mixtures and fluid fertilizers. 

The relation between free phosphoric acid content and total phosphate content in a processing bath, whether based on iron, manganese or zinc, is very important this relation is generally referred to as the acid ratio. An excess of free acid will retard the dissociation of the primary and secondary phosphates and hinder the deposition of the tertiary phosphate coating sometimes excessive loss of metal takes place and the coating is loose and powdery. When the free acid content is too low, dissociation of phosphates (equations 15.2, 15.3 and 15.4) takes place in the solution as well as at the metal/solution interface and leads to precipitation of insoluble phosphates as sludge. The free acid content is usually determined by titrating with sodium... 

The ordination of 23 taxa or groups of taxa in relation to the environmental predictors was examined by means of multivariate analyses. Nutrients (nitrates, total phosphate, and ammonia), conductivity, total suspended solids and water flow were retained by the redundancy analysis (RDA) (Fig. 4). The first RDA axis (RDA1 16.6% of the variance) showed a strong correlation between nutrients and suspended solids and (negatively) water flow. Large centric diatoms and Scenedesmus sp.pl. best defined this situation, which was characteristic of the meandering zone, mostly in autumn. Other taxa (Coelastrum microporum,... 

For the extraction of total phosphate a weighed aliquot of sediment (0.3-0.5g), together with 3 0.1g of potassium persulphate (Analar) and 5.00ml of concentrated sulphuric acid, was added to the bomb, which was then heated in an oven at 135 5°C for 2h. The contents of the bomb were then transferred quantitatively into a 500ml calibrated flask. After dilution to volume with distilled water, the extract (containing 1% v/v of sulphuric acid) was analysed for total phosphate by the automated procedure outlined below. 

Experiments examining the influence of calcium and phosphate on the reductive dissolution of manganese oxides by hydroquinone have, in fact, shown inhibition by adsorbed ions (33). As the total phosphate in solution is increased, the rate of Mn + release diminished in proportion to the phosphate surface coverage. 

Figure 8 shows effect of recirculation ratio and space velocity. Horizontal line shows total PO4 as P in the influent and vertical line does total phosphate in the effluent. Black circles were data obtained from the experiments in case that recirculation ratio was 0 and space velocity 38 1/h. White circles were obtained, in case that recirculation was 2 and space velocity 13 1/h. Solid line and dotdash line shows theoretical values calculated from eq.(8), to agree well with experimental results. Increasing in recirculation ratio and decreasing in space velocity was recognized to improve phosphate removal efficiency. 

Provided only polyphosphates are present it is possible to determine titrimetrically (1) the end-group content of mixtures (2) the content of groups within the chain, after hydrolysis and by estimating the total phosphate content (3) the monophosphate content after precipitation with silver nitrate (347). These methods are likewise of no use in presence of meta- and cross-linked phosphates. 

Aqueous solutions were prepared from water distilled twice from quartz glass. To maintain pH s < 6, HC1 was used for pH 7 to 8, NaH2P04-Na0H, total phosphate 2 X 10 3M for pH 9.2, 10 3M... 

The isoionic point of RNase-A determined as the pH of a concentrated salt-free solution is 9.60 (268). Estimates of the isoelectric point in buffers not containing phosphate all give values above 9, Anderson and Alberty (269) reporting 9.45. In phosphate buffers specific anion binding dramatically reduces the measured isoelectric point to an extent dependent on the total phosphate concentration. Values below 6 have been measured (270). 

The logarithmic form lends itself to graphical presentation. For example, in a system containing a number of acid-base systems of known total concentrations, the concentration of each individual species is a unique function of the master variable log [H ], which may be represented in a logarithmic diagram. In Figure 1, for a system with total phosphate... 

This program formulation will tend to be dosed continuously to achieve a total phosphate reserve in the recirculating cooling water based on calcium hardness (as ppm CaCC>3), as shown here. 

If significant phosphate is present, it is possible that a stabilized phosphate program has been used and the O-P ratios have not been maintained correctly, or the total phosphate reserve has been too high (check the makeup for phosphate content), or the reserve phosphate specific dispersant has been maintained at too low a level in relation to the calcium hardness. 

Aspila, K. I., Agemian, H., and Chau, A. S. (1976). A semi-automated method for the determination of inorganic, organic and total phosphate in sediments. Analyst 101,187-197. 

How many moles of NaH2P04 and Na2HP04 should be used to prepare 250 mL of a solution with a total phosphate concentration of 0.10 M and pH = 7.00 ... 

Ames BN (1965) Assay of inorganic phosphate, total phosphate and phosphates. In Neufeld EF, Ginsburg V (eds) Methods in Enzymology 8, Academic Press, New York, p 115... 

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