PubMed · 15656715
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2004. Monograph. Boron.. https://pubmed.ncbi.nlm.nih.gov/15656715/
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Boron removal from wastewaters by electrocoagulation using aluminum electrode material was investigated in this paper. Several working parameters, such as pH, current density, boron concentration and type and concentration of supporting electrolyte were studied in an attempt to achieve a higher removal capacity. The experiments were carried out by keeping the pH of solution constant and optimum pH of solution was determined 8.0 for the aluminum electrode. Although energy consumption increased with decreasing boron concentration, which conductivity of these solutions were low, boron removal efficiency was higher at 100 mg/L than that of 1000 mg/L. Current density was an important parameter affecting removal efficiency. Boron removal efficiency and energy consumption increased with increasing current density from 1.2 to 6.0 mA/cm2. The types of different supporting electrolyte were experimented in order to investigate to this parameter effect on boron removal. The highest boron removal efficiency, 97%, was found by CaCl2. Added CaCl2 increased more the conductivity of solution according to other supporting electrolytes, but decreased energy consumption. The results showed to have a high effectiveness of the electrocoagulation method in removing boron from aqueous solutions.
We report on the formation of monomolecular layers of perylene- and pyrene-alkanoic acids on boron-doped diamond (BDD) substrates. The carboxylic acid layers are bound by coordination to zirconium phosphate (ZP) functionalities on the BDD substrate surface. The resulting Zr-phosphate-carbonate (ZPC) linkages between the substrate and the adlayer are asymmetric, of the form -(OPO3(2-) Zr4+-O2C-R)+ X-. Pyrene and perylene are well-established optical probes of polarity and viscosity at interfaces. We have used electrochemical and steady-state fluorescence techniques to study the loading density and behavior of these monomolecular films, allowing comparison of BDD and indium-doped tin oxide (ITO) substrates. Electrochemical data suggest that the pyrene chromophores are positioned roughly at the same distance from the surface, regardless of the length of the anchoring alkanoic acid chain, a finding that can be explained by the pyrene lying on the substrate surface. Such a conformation is plausible given the surface coverage (5 x 10(-11) mol/cm2, ca. 0.1 monolayer) we measure for these systems.
The existence of NH bond according to the hydrogen nuclear magnetic resonance ((1)H NMR) spectra of polyindole and its derivatives, such as poly(5-bromoindole), poly(5-cyanoindole), poly(5-nitroindole), poly(5-methylindole), proved polymerization of high-quality polyindoles, which were electrosynthesized from middle strong Lewis acid boron trifluoride diethyl etherate (BFEE) and its mixed electrolytes with additional diethyl ether, occurred at 2,3-position. The elongation of the conjugation length made the chemical shift of all the protons of polyindoles to lower field in comparison with those of monomers.