Nitrilotriacetic Acid, NTA

Organic chelant compounds, such as the sodium salts of ethylenedi-aminetetraacetic acid (EDTA) and nitrilotriacetic acid (NTA) are commonly used in BW deposit control treatments, often in combination with phosphates. 

Nitrilotriacetic acid (NTA) and especially its trisodium, monohydrate salt, N(CHC00Na)3,H20. NTA is primarily manufactured by Monsanto Chemical Company, Inc. and Hampshire Chemical. Anhydrous NTA has a MW of 257. It is generally supplied for incorporation into formulations as 40% NTA (42.8% NTA Na3 H20), (Hampene 150). Its chelating activity at a pH level of 11 is 156 mg CaC03 per gram of chelant. That is, 10 ppm of chelant will sequester 1.56 ppm of calcium hardness. 

Magnesium carbonate 4 M ammonium chloride plus 0.4 M trisodium salt of nitrilotriacetic acid (NTA) 2.9... 

Nitrilotriacetic acid, NTA and citrate data of Sillen and Martell (1964). 

One way in which cobalt dispersion can be increased is the addition of an organic compound to the cobalt nitrate prior to calcination. Previous work in this area is summarized in Table 1.1. The data are complex, but there are a number of factors that affect the nature of the catalyst prepared. One of these is the cobalt loading. Preparation of catalysts containing low levels of cobalt tends to lead to high concentrations of cobalt-support compounds. For example, Mochizuki et al. [37] used x-ray photoelectron spectroscopy (XPS) and temperature-programmed reduction (TPR) to identify cobalt silicate-like species in their 5% Co/Si02 catalysts modified with nitrilotriacetic acid (NTA). The nature of the support also has... 

FIGURE 1.1 Structures of organic compounds referred to in the text (a) sucrose (also known as saccharose), (b) dimethyl sulfoxide (DMSO), (c) dimethylformamide (DMF), (d) sorbitol, (e) mannitol, (f) nitrilotriacetic acid (NTA), (g) citric acid, (h) N,N,N, N -fran,s-1,2-diaminocyclohexane-tetraacetic acid (CyTA), (i) saccharic acid, (j) glutamic acid. 

The category of builders consists predominantly of several types of materials -specific precipitating alkaline materials such as sodium carbonate and sodium silicate complexing agents like sodium triphosphate or nitrilotriacetic acid (NTA) and ion exchangers, such as water-soluble polycarboxylic acids and zeolites (e.g., zeolite A). 

Experimental studies of CE mechanisms with SWV are scarce. Santos et al. [65] studied two experimental systems, i.e., the reduction of Cd + ion in the presence of nitrilotriacetic acid (NTA) and aspartic acid (ASP). For the first experimental system, the preceding chemical reaction is described by the scheme ... 

Another aminopolycarboxylic acid, closely related to IMDA and forming strong complexes with the lanthanide ions, is nitrilotriacetic acid (NTA). The hy-... 

It was reported that the 0-0 distance in the peroxide is 1.458 A, and that this value agreed well with values of 1.464, 1.463, and 1.469 A in the triclinic diaquo, difluoro, and nitrilotriacetic acid (NTA) complexes, respectively. The Ti-Operoxo distance (1.833 A) was compared with the values 1.834 and 1.856 A, 1.846 and 1.861 A, and 1.889 and 1.892 A, respectively, and the Ti-Owater apical distances of 2.018 A with the Ti-0 (F) values of 2.022 and 2.055 A in the triclinic diaquo, 1.853 and 1.887 A in the difluoro and 1.819 and 2.065 A in the NTA complexes. It was concluded that while the 0-0 bond distance of the peroxo group was practically the same in all the structures, there was a small but significant variation in the Ti-Operoxo and apical distances. There was progressive increase in the Ti-Operoxo bond lengths down the respective series, and a corresponding decrease in the apical bond lengths. ... 

The electrochemical flow sensor for in situ monitoring of total cadmium concentration in the presence of EDTA and nitrilotriacetic acid (NTA) ligands has been described [379]. 

In the condensed chelate systems, many kinds of chelating agents were used, such as ethylenediamiiie-/V,/V,/V, /V -tetraacetic acid (EDTA), nitrilotriacetic acid (NTA), /-aspartic acid (AA), trimethylenediamine (TMD), /V,/V-dimethylethylenedi-amine (DMED), diethylenetriamine (DETA), triethylenetetraamine (TETA), and t ris(2-aminoethyl)amine (TAEA) (6). The chelating agents used are listed in Table 3.2.1. 

Nitrilotriacetic acid (NTA) [N(CH2COOH)3] is a complexant for many metal ions (see Sec. 2.9.1.2 for information on this compound). The sodium or potassium salts of NTA have been used to complex Cd for CD of CdSe from selenosulphate solutions [10,87]. The rate of film growth depends on many factors, as discussed in Chapter 3 experimental details for CdSe deposition from this solution are given in Chapter 2. However, growth times are generally longer than for... 

The most common and best known chelant is ethylenediaminetetraacetic acid (EDTA). The related compounds diethylenetriaminepentaacetic acid (DTPA) and nitrilotriacetic acid (NTA) are also well known (Figure 10.2). EDTA is a powerful chelant that complexes strongly with most metal ions to form six-coordinate complexes. It has therefore become the first choice in most applications. Indeed, a search of the bathroom cabinet will spot EDTA on the ingredient list of many personal care formulations. DTPA is also a powerful chelant, but tends to be used more often in industrial settings. NTA has only four binding sites and is used more often where hardness ions require control, such as in cleaning, for example, hard surface cleaners, dishwashing, and the dairy industry. 

Ulrich et al. (1994) reported that the kbio values necessary to explain the mass balance of nitrilotriacetic acid (NTA) present in a Swiss lake at 1 to 10 nM ranged from 0.02 to 0.05 d 1. In another study, Bartholomew et al. (1983) tested an estuarine water for NTA biodegradation as a function NTA concentration, and they found Vmsx between 0.3 and 3 nmol-L-1 h 1 and KiMM between 300 and 600 nM. Are the results of these two investigations consistent Identify any assumptions you must make. 

Illustrative Example 21.1 Assessing the Behavior of Nitrilotriacetic Acid (NTA) in a Lake Time Variability and Response... 

Illustrative Example 21.2 How Certain Is the Degradation Rate of Nitrilotriacetic Acid (NTA) in Greifensee (Advanced Topic)... 

In Illustrative Examples 21.1 and 21.2 we have studied the fate of nitrilotriacetic acid (NTA) in Greifensee, especially its in situ degradation rate. Now we want to refine our analysis using the two-box model developed in Illustrative Example 21.5. 

The 1978 Guidelines for Canadian Drinking Water Quality included phenols (for organoleptic reasons), biocides, and THMs. Nitrilotriacetic acid (NTA) was included because of its use as a constituent ofdaundry detergents, most of which are disposed into surface waters. Studies with rodents have shown that very large doses of NTA can result in an increased incidence of urinary tract tumors. THMs were included because of their production during the process of chlorine disinfection. 

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