Biologically hard

Of interest is the relative composition of the LABs, particularly the different amount of 2-phenyl isomer and of nonlinear alkylates, given in Table 8. Branched alkylbenzene (BAB) formed by the AlCl3-catalyzed reaction between propylene, condensed to its tetramer, and benzene are less biodegradable and are termed biologically hard. LABs have to a large extent replaced BABs in the domestic markets because of their improved biodegradability. 

Biological pump The transport of chemicals in the ocean as a result of incorporation into biological hard and soft parts, followed by pelagic sedimentation into the deep sea. 

Newesely, H. Conditions for the existence of octacalcium phosphate, withlockit and carbonate apatite. A contribution to the crystal chemistry of biological hard substances. Dtsch. zahnarztl. Ztschr. 20, 754-766 (1965). 

The basic factor for a surfactant to be classified as biologically hard substance is its low adsorptive capacity due to which the required sludge adaptation and the stationary state are reached only after 15-20 and more days. Biologically soft surfactants easily adsorb on activated sludge, and their adaptation is reached in a shorter period of time (2 to 4 days). 

Lipid content In biological hard tissues, lipids have been reported to be mineral nucleators [24-26]. As is the case with proteoglycans, their content is rather easily established in Raman spectra through the integrated area of the characteristic band at 1298cm [27]. 

Uses Biological hard surf, cleaner, odor eliminator, sanitizer for bathroom fixtures, sinks, toilets, drain lines, septic systems, waste treatment facilities Features Degrades residual organics environmentally friendly effective on mold and mildew... 

Currey, J. D. (1996). Biocomposites micromechanics of biological hard tissues. Current Opinion in Solid State Materials Science, 1, 440-445. 

In order to ensure that reproducible results are obtained in different laboratories, only a small amount of a polyvalent bacteria suspension which has not been preadapted (for example discharge from an aerobic treatment plant, in most cases a municipal treatment plant) is used for inocculation. To check the system, a biologically hard standard (tetrapropylenebenzenesulfonate) and a biologically soft standard (MARLON A , a linear alkylbenzenesulfonate) of known degradation behaviour are tested in parallel with each test series. The maximum duration of a test is 19 years. 

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