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The concentration dissociation constants p K c of the α and β D-glucose anomers were measured at pH 12–14 by the 13C NMR method. The p K c values for L ⇔ H−1L + H equilibria at 25°C and an ionic strength of 1.0 mol/l (NaCl) were p K = 12.31 ± 0.03 and p K = 12.03 ± 0.01. Dissociation was found to shift all the spectrum lines downfield. The most probable hydroxyl group responsible for the dissociation of β-D-glucose was determined. [ABSTRACT FROM AUTHOR]

Abstract: The 13C NMR technique is used for the measurement of the first dissociation constant of sucrose (HL) in highly alkaline solutions. In 1.0M NaCl/NaOH medium and for 25°C, the concentration dissociation constant (pK 1) was 13.1±0.3; and, for 60 °C, pK 1 =12.30±0.05. The β-d-fructofuranosyl ring was found to be responsible for dissociation. The NMR data reveal no clear evidence of the second dissociation step below pH 14, either at 25 °C or at 60 °C. In the solutions with 4–10 moldm−3 NaOH content the 13C NMR technique indicated the chemical shift changes, treated as the second dissociation step of sucrose and a sodium complex formation. A very rough estimation, for variable ionic strength, gives the value: pK 2 ∼15.8±0.8. The anionic species L− and NaH−1L− have been registered by electrospray ionization time-of-flight mass spectrometry (ESI-ToF MS) for 0.01 M sucrose solutions with initial pH 13. [Copyright &y& Elsevier]

7Li, 23Na, 39K and 133Cs NMR spectrometric comparative study of 0.05 M alkali metal chloride hydrolysis in aqueous solutions 3.4 M Me4NCl/Me4NOH at 25 °C is performed. It is found that chemical shifts of all nuclei involved are sensitive to variations of ionic strength and pH. Stability constants for Li+, Na+, K+ and Cs+ lg K(M+OH⇔MOH) are found to be −0.04 (0.05), −0.93 (0.04), −0.7 (0.2) and −0.8 (0.1), respectively. The stability of CsOH is estimated to be the same as that of NaOH and KOH within an experimental error. No evidence of chloro-complexes formation was found. [Copyright &y& Elsevier]

The low conductivity landfill barrier layers protect the groundwater and soil by limiting the water flow through the bottom layers of the landfill material. Many materials used in hydraulic barrier layers also have sorption properties which could be used to reduce environmental risks. The adsorption of lead, chromium, copper, and arsenic to peat was studied with a batch-type test and a column test for compacted peat, both without pH adjustment in acidic conditions. Peat adsorbed all the metals well, 40000mg/kg of lead, 13000mg/kg of chromium, and 8400mg/kg of copper in the column test. Arsenic was only tested in a batch-type test, and in that peat adsorbed 60mg/kg of arsenic. The column test showed heavy metals to be adsorbed on the surface layers of the compacted peat sample, on the first centimeter of the sample. The adsorption was much greater in the column test than in the batch-type test, partly due to the different pH conditions and the buffer capacity of the peat in the column test. The liquid/solid ratio of the column experiment represented a time period of approximately 40 years in a landfill, under Finnish climate conditions. The hydraulic conductivity of the peat decreased as it was compressed, but it already met the hydraulic conductivity limits set by European Union legislation for the hydraulic barrier layer (1x10(-9)m/s at a pressure of 150kPa for a 5-m layer), with a pressure of 50kPa. The results show that peat would be an excellent material to construct compacted, low hydraulic conductivity layers with adsorption properties in, e.g. industrial waste landfills.

A sequential inductively coupled plasma atomic emission spectrometer (ICP-AES) was used to determine Al content in Al-tetrabromophthalate (Al-TBP). Four emission lines of Al (I) at 309.271, 396.152, 308.215 and 394.401 nm were compared. The microwave mineralisation was carried out by using a two-step digestion procedure and HNO(3)-H(2)SO(4). The thermal analysis of Al-TBP and tetrabromophthalic anhydride (TBPA) was performed in the air atmosphere. Statistical tests applied (t-test, F-test) showed no significant differences between the Al results obtained by ICP-AES and thermal method of analysis.