الفهرس 
Fouling and biofoulingOnly 14 pages are availabe for public view
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Abstract
Fouling refers to the accumulation of unwanted materials on solid surfaces, most often in an aquatic environment. The fouling materials consist of either living organisms or non-living substances (inorganic or organic). Marine biofouling organisms (>4000 species) can be divided into two groups (micro and macro fouling organisms). Biofouling is found in almost all circumstances where water based liquids are in contact with other materials. In Industry, important examples include membrane systems, such as membrane bioreactors and reverse osmosis spiral wound membranes cooling water cycles of large industrial equipments and power stations.
Biofouling on ships reduces their speed and maneuverability, causing increased fuel and maintenance costs. On static structures (e.g. buoys, piers, jetties, offshore oil and gas platforms) biofouling can enhance the corrosion of metal by seawater, reducing the metal’s susceptibility to environmental fracture, and increasing the risk of mechanical failure. More seriously, biofouling can be harmful to humans coming in contact like operational and maintenance personnel. Other diseases potentially spread by hull fouling are white spot diseases via barnacles, amoebic gill diseases and bonaiosis.
Antifouling coatings are the most widely accepted method of controlling and preventing biofouling. Efficient antifouling paints are based on copper compounds and booster biocides that when submerged, release toxic compounds causing adverse environmental effects. Organo tin-based paints have been linked to pollution of food webs and are of particular concern to human consumers.
As means of protecting the public health from hazardous caused by leached metals from marine paints to the environment and their accumulation in fishes and other edible marine organisms, 8-hydroxyquinoline (8-HQ) derivatives will be studied to be used as alternative pigments to some toxic metals present in commercial paints.
Five derivatives of 8-hydroxyquinoline were prepared; 8-phenylaminoquinoline (compound I), 8-hydroxyquinoline-4-nitroaniline (compound II), 8-p-methylphenylaminoquinoline (compound III), 8-p-chlorophenylaminoquinoline (compound IV) and 8-p-nnˉ-dimethylphenylketoquinoline (compounds V).
Melting point, percentage yield and the elemental analysis of the prepared compounds were determined. The elemental analysis of the prepared compounds indicates the presence of an ethanol molecule in the proposed structure of both compounds I and III and a water molecule with compound IV.
The structures of the prepared compounds were identified by, mass spectra, UV-visible spectra, 1H NMR spectra and Infra-Red spectra.
The UV-Visible spectrum of 8-HQ in de-ionized distilled water suggests the presence of intra-molecular and intermolecular hydrogen bond with its structure.
The UV-Visible spectra of 10-4 molar aqueous solutions of the prepared compounds in deionized distilled water showed new bands appeared at 260 nm in the spectra of compound I, at 375 nm in compound II, at 260 nm in compound III, 290 nm in compound IV and at 340 nm in compound V which confirm the formation of new compounds. The present of polar solvents interaction (water and / or ethanol) with the prepared compounds, I, III and V are proposed.
UV-Visible spectra of 8-HQ and its five prepared compounds measured in natural seawater reveals the interaction of the prepared compounds with the metal ions in seawater which affect their electronic environments.
The 1HNMR major peaks of 8-HQ and its derivative 8-hydroxyquinoline.4-nitroaniline (compound II) were measured in DMSO-d6. The position of the aromatic and phenolic protons of 8-hydroxyquinoline and compound (II) were assigned. The 1HNMR spectrum of compound (II) confirms its proposed structure.
The infrared absorption bands of 8-hydroxyquinoline indicate its presence mainly in the enol form. IR of the five derivatives; 8-phenylaminoquinoline, 8-hydroxyquinoline-4-nitroaniline, 8-p-methylphenylaminoquinoline, 8-p-chlorophenylaminoquinoline and 8-p-nn—dimethylphenylketoquinoline support their proposed structures due to the presence of –NH band and the bands due to the p- substitutes of -C–NO2, C-CH3 and C–Cl of the phenyl ring. The presence of a medium band appears at 1669 cm-1 assigned to be due to the absorption of carbonyl group confirms the proposed structure of compound V.
With respect to the reaction of 8-hydroxyquinoline with some major ions, four solutions were prepared in the laboratory; soln.1, soln.2, soln.3 and soln.4, the results showed decrease in temperature values than that of 8-HQ solution which indicates that the reaction of 10-3 M aqueous solution of 8-HQ with 10-3 M aqueous solution of both monovalent and divalent metal salts (NaCl, KCl, CaCl2 and MgCl2) are endothermic reactions.
The increase in pH values in the solutions 1, 2 and 3 and 4 could interpret the salt formation in which the OH group of 8-HQ acts as an acid form salts with the metal ions; Na+, K+, Ca++ and Mg++ accompanied by increasing the pH values of the solutions than its value in 8-HQ. Also, The band absorbed at 250 nm in 8 HQ disappeared in the spectrum of the solution 1 (8- HQ with NaCl) and its band at 260 nm disappeared in the spectra of the solutions 2, 3 and 4 (8- HQ with KCl, CaCl2 and MgCl2) suggesting the salts formation of quinolate ion with Na, K, Ca and Mg ions in the aqueous medium.
Anti-microbial activity of 8-hydroxyquinoline and its prepared compounds were tested against B. subtilis EU107759. It is clear that, the maximum inhibitory effect of the solutions of 8-HQ and its prepared compounds against B. subtilis EU107759 were recorded at the maximum concentrations (10-3M) except compound (II) while the minimum inhibitory effect recorded at 10-4 M concentration for all solutions. On the other hand, at 8x10-5 M concentration, 8-HQ and the solutions’ of the five compounds showed no inhibitory effect against B. subtilis EU107759. Also, the activity units of the compounds’ solutions decrease with decreasing their concentrations.