Carbon ions from

Calcium phosphate precipitation may also be involved in the fixation of phosphate fertilizer in soils. Studies of the uptake of phosphate on calcium carbonate surfaces at low phosphate concentrations typical of those in soils, reveal that the threshold concentration for the precipitation of the calcium phosphate phases from solution is considerably increased in the pH range 8.5 -9.0 (3). It was concluded that the presence of carbonate ion from the calcite inhibits the nucleation of calcium phosphate phases under these conditions. A recent study of the seeded crystal growth of calcite from metastable supersaturated solutions of calcium carbonate, has shown that the presence of orthophosphate ion at a concentration as low as 10-6 mol L" and a pH of 8.5 has a remarkable inhibiting influence on the rate of crystallization (4). A seeded growth study of the influence of carbonate on hydroxyapatite crystallization has also shown an appreciable inhibiting influence of carbonate ion.(5). 

An argument in favor of direct precipitation of the muds stems from the study of Broecker and Takahashi (1966). They show a decrease in the removal rate of carbonate ion with decreasing supersaturation of the water on the Great Bahama Bank. This correlation would not necessarily occur if the source of the needles were algae. The more recent work of Morse et al. (1984) also shows this trend. There are, however, two problems with this conclusion. The first is that Morse et al. (1984) found a continued strong removal of carbonate ion from the water in the inner part of the bank where whitings are not observed and clear water is present. The second is that nutrient availability is likely to decrease with increasing age of... 

The equilibrium limitations of these two reforming reactions are overcome by continuous removal of hydrogen and carbon monoxide which are directly oxidized electrochemically at the anodic electrode. There, these components react with carbonate ions from the electrolyte to produce carbon dioxide, water and electrons according to the following stoichiometric relationships ... 

Recarbonation will transform the 15.0 mg/L as CaC03 of carbonate ions from the limit of technology to 15.0 mg/L as CaC03 of bicarbonate ions. From the order of removal, these carbonate ions will be coming solely from the removal of the raw calcium bicarbonate. The carbonate ions coming from the use of soda ash to form calcium carbonate will not be accounted for in this limit of technology consideration, since by the time they are formed, the water is already saturated with the carbonate coming from the removal of the raw calcium bicarbonate. 

Accordingly, students often round off the mass ratio 46 60 generously to a quantity number ratio of ions to 2 3, which has a very different meaning. Advanced high school students are often not able to derive at the actual ion number ratio of 2 1 of sodium ions and carbonate ions from the mass ratio. 

The same carbonic gas with light carbon will, on encountering surrounding micrite carbonates, the isotope composition of which is characterized by a predominance of C, produce a sort of leaching effect on the latter. We thus will have in solution bicarbonate of organic derivation together with carbonate ions from the dissolved initial... 

Figure 1. ATR-FTIR difference spectra of a) aqueous bicarbonate and b) carbonate ions from solutions of 1.0 M NajCOj at pH 11.2 and 7.9, respectively. Subtracted spectra were of NaCl at the same concentration and pH. Spectra taken from Su and Suarez (75).

Fig. 9, upper-left quadrant C3 - three-fold axis) (Nakamoto, 1997). The lowering of the symmetiy of the carbonate ion from Dsh to either C2 or Cs, which means loss of the equivalence of the three C-O bonds in the CQ32- and, therefore, loss of the three-fold rotational axis, leads to the sep>aration (sphtting) of the doubly degenerate vibrations (Fig. 9, bottom-right quadrant). 

The anions that are involved in secondary inorganic chemical analysis are, in general, carbonate, chloride, iodide, nitrate(V), sulfate(IV) and sulfate(VI). Students may be familiar with the carbonate ion from lower secondary science the reactions of the remaining anions have been introduced in the tests for gases or ionic precipitation (iodide). Silver nitrate(V) solution, barium chloride/nitrate(V) solution, lead(II) nitrate(V) solution and dilute acids are generally used to test for anions. 

Methane is a stable molecule and can typically be activated only at HT, e.g., above 650 °C in the steam reforming process. Recently, however. Spinner and Mustain (2012, 2013) have reported that methane could conceivably be activated in a room temperature carbonate fuel cell based on an AEM, and a novel catalyst that could produce the carbonate ion from O2 and CO2 at the cathode (Figure 15.33). The carbonate ion diffuses through the AEM and partially oxidizes methane at a NiO—Z1O2 composite anode catalyst to produce oxygenates such as formaldehyde and methanol with syngas. Such LT methane activation, if feasible, could allow the selective production of platform chemicals, rather than syngas, directly from natural gas. 

Fuel cells (FCs) are electrochemical devices able to convert the chemical energy of reactions directly into electric energy [1]. The electrochemical conversion is possible in molten carbonate fuel cells (MCFCs) thanks to a ceramic matrix consisting of LiAl02 filled with a combination of molten alkali metal carbonates, which acts as an electrolyte and allows the transfer of carbonate ions from the cathode to the anode [2]. The electrochemical reactions occurring in MCFCs are as follows ... 

The net ionic equation tells us that nickel ions from one solution combine with the carbonate ions from the other solution to form solid nickel carbonate. The sodium ions and nitrate ions that were in the separate solutions remain as ions in the combined solution. 

Three ion combinations yield molecular products that are not the products you would expect. Two of the expected products are carbonic and sulfurous acids. If hydrogen ions from one reactant react with carbonate ions from another, carbonic acid, H2CO3, should form ... 

The high pH required can be provided by the basic carbonate ion from soda ash ... 

As MCFC operates at high temperatures, the carbonate salts melt and conduct carbonate ions from cathode to anode. From Fig. 1.16. it can be seen that both oxygen and carbon dioxide must be supplied at the cathode. The carbon dioxide gets converted into COs ions which help in the conduction process. At the anode, the... 

The carbonate fuel cell principle of operation is based on transfer of the oxygen in the form of carbonate ions from the cathode to the anode. In many ways, this is similar to Solid Oxide Fuel Cell (SOFC) technology, with the main differences being that the medium of the ionic transfer is a molten carbonate immobilized in a ceramic matrix. Various eutectic mixtures of lithium, potassium, and sodium carbonates have been used as electrolyte with the most prevalent ones being 38Li/62K or 60Li/40Na carbonate mixtures. 

Shultin, A. A., 1959. Effect of the field of the crystal lattice on the vibration of nitrate (or carbonate) ions, from data on the infrared spectra for sodium nitrate and calcite. Dokl. Akad. Nauk SSSR 125 767. 

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