Biological membrane treatment

Jose, H., Gebhardt, W., Moreira, R., et al. (2010). Advanced Oxidation Processes for the Elimination of Drugs Resisting Biological Membrane Treatment, Ozone Science Eng., 32, pp. 305-312. 

The technologies used in the control of gaseous organic compound emissions include destruction methods such as thermal and catalytic incineration and biological gas treatment and recovery methods such as adsorption, absorption, condensation, and membrane separation. The most common control methods are incineration, adsorption, and condensation, as they deal with a wide variety of emissions of organic compounds. The most common types of control equipment are thermal and fixed-bed catalytic incinerators with recuperative heat recovery, fixed-bed adsorbers, and surface condensers. The control efficiencies normally range between 90% and 99%. 

Nakhla, G., Lugowski, A., Patel, J., and Rivest, V., Combined biological and membrane treatment of food-processing wastewater to achieve dry-ditch criteria Pilot and full-scale performance, Bioresource Technology, 97,1-14, 2006. 

The several theoretical and/or simulation methods developed for modelling the solvation phenomena can be applied to the treatment of solvent effects on chemical reactivity. A variety of systems - ranging from small molecules to very large ones, such as biomolecules [236-238], biological membranes [239] and polymers [240] -and problems - mechanism of organic reactions [25, 79, 223, 241-247], chemical reactions in supercritical fluids [216, 248-250], ultrafast spectroscopy [251-255], electrochemical processes [256, 257], proton transfer [74, 75, 231], electron transfer [76, 77, 104, 258-261], charge transfer reactions and complexes [262-264], molecular and ionic spectra and excited states [24, 265-268], solvent-induced polarizability [221, 269], reaction dynamics [28, 78, 270-276], isomerization [110, 277-279], tautomeric equilibrium [280-282], conformational changes [283], dissociation reactions [199, 200, 227], stability [284] - have been treated by these techniques. Some of these... 

A continuing major objective in the search for alternative commercial membranes is stability against active chlorine. Control of biological growth upstream of the membrane appears desirable in most practical water systems. Removal of chlorine prior to membrane treatment is expensive and potentially hazardous should the removal system fail. The polymer chosen for the... 

The study of the ion transfer through artificial liquid membrane systems is important for the elucidation of the ion transfer through biological membranes. In this respect, the Interface between two inmiscible electrolyte solutions (ITIES) constitutes a biomimetic medium suitable for studying several fundamental processes, ranging from biocatalysis to cellular respiration of photosynthesis, and many others [18-22], The first studies of liquid/liquid interfaces (L/L) under the application of an external potential were carried out by Gavach et al. [23], laying the basis for the current electrochemical treatments of ITIES. 

Although whey protein products have several food uses, the lactose contained in the permeate is less valuable, and many plants discharge the permeate to a biological wastewater treatment plant. A few plants recover lactose as dry lactose sugar, as shown in Figure 6.23. Some plants also ferment the lactose concentrate to make ethanol. An introduction to membrane ultrafiltration in cheese production is given by Kosikowski [26],... 

Li H.Q., F. Jiku, and H.F. Schroder. 2000. Assessment of the pollutant elimination efficiency by gas chromatography/mass spectrometry, liquid chromatography-mass spectrometry and—tandem mass spectrometry comparison of conventional and membrane-assisted biological wastewater treatment processes. J. Chromatogr. A 889 155-176. 

There are many studies of the transfer of electrons from enzymes to substrates, across biological membranes, to (or from) electrodes from (or to) substrates, between adsorbed molecular dyes and semiconductor particles, within synthetic films and nano-scale arrays, within molecular wires , and so on. Only a few, general comments will be offered on these topics here. The basic physics of molecular electron transfer does not change with the scale of the system, as long as identifiable molecular moieties are present with at least partly localized electronic configurations. The nature of the properties observed, the experimental probes available, and the level of theoretical treatment that is useful may be very different. Different approaches, different limiting models are used for extended arrays (or lattices) of very strongly coupled moieties. 

The occurrence of cholesterol and related sterols in the membranes of eukaryotic cells has prompted many investigations of the effect of cholesterol on the thermotropic phase behavior of phospholipids (see References 23-25). Studies using calorimetric and other physical techniques have established that cholesterol can have profound effects on the physical properties of phospholipid bilayers and plays an important role in controlling the fluidity of biological membranes. Cholesterol induces an intermediate state in phospholipid molecules with which it interacts and, thus, increases the fluidity of the hydrocarbon chains below and decreases the fluidity above the gel-to-liquid-crystalline phase transition temperature. The reader should consult some recent reviews for a more detailed treatment of cholesterol incorporation on the structure and organization of lipid bilayers (23-25). 

DSC has been used to study the individual protein components of biological membranes of relatively simply protein composition and the interaction of several of these components with lipids and with other proteins. The red blood cell membrane, which has been most intensively studied, exhibits five discrete protein transitions, each of which has been assigned to a specific membrane protein. The response of each of these thermal transitions to variations in temperature and pH as well as to treatment with proteases, phospholipases, specific labelling reagents, and modifiers and inhibitors of selected membrane activities, has provided much useful information on the interactions and functions of these components in the intact erythrocyte membrane (46-49). Similar approaches have been applied to the bovine rod outer segment membrane (50) and to the spinach chloroplast thylakoid membrane (51). 

The first known commercial membrane-based liquid-liquid extraction system involved extraction of by-products from a wastewater stream using an aromatic solvent [102]. Before the membrane system was installed, the entire wastewater stream had to be incinerated leading to high costs for the gas fired incinerator per year. The membrane system lowered the contaminant concentration to adequate levels before the biological wastewater treatment plant, and saved significant operating cost. 

Lesjean B, Rosenberger S, Schrotter J-C, and Recherche A. Membrane-aided biological wastewater treatment—an overview of applied systems. Membr Technol, 2004 2004(8) 5-10. 

Orally administered corticosteroids are effective in the treatment of chronic bronchial asthma. The inhalation route has been widely used in attempts to avoid systemic side-effects, such as adrenal suppression, but evidence suggests that inhaled steroids are absorbed systemically to a significant extent. The respiratory tract epithelium has permeability characteristics similar to those of the classical biological membrane, so lipid-soluble compounds are absorbed more rapidly than lipid-insoluble molecules. Cortisone, hydrocortisone and dexamethasone are absorbed rapidly by a nonsaturable diffusion process from the lung, the half-time of absorption being of the order of 1-1.7 min. Quaternary ammonium compounds, hippurates and mannitol have absorption half-times, in contrast, of between 45 and 70 min. 

The membranes are manufactured from acetylcellulose or, more preferably, polyamide. The technical construction is complicated and made expensive by the large pressure differences and the need for thin membranes. Bundles of coiled thin hollow capillaries (external diameter 0.1 mm, internal diameter 0.04 mm) are, for example, placed in a pressure cylinder (Fig. 1.1-3). The.se capillaries protrude from the ends of the cylinder through plastic sealing layers. Of the (high salt content)-water fed into the cylinder from the other side, 30% passes through the capillary walls into the capillaries and the rest is run off as concentrate and disposed of. An intensive and expensive pretreatment of the feed water is also necessary in addition to the removal of all colloidal and biological impurities, treatment of the feed water is also necessary e.g. by acid addition. The use of feed water from wells in the neighborhood of beaches is particularly favored. 

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