A multipurpose compound for protective coatings

International regulations concerning the protection of both the environment and industrial workers have prompted paint manufacturers and end users to look for suitable replacements for traditional pigments.One of the aims of this investigation was to study the inhibitive properties of ferric benzoate-based paints in simulated marine corrosion condition (3% NaCl solution). Anticorrosive paints containing ferric benzoate were formulated and their performance was evaluated by accelerated (salt fog chamber) and electrochemical (corrosion potential and ionic resistance) tests.In addition, the action of ferric benzoate as a probable antifouling agent was studied through laboratory tests and marine exposure. Ferric benzoate hydrolyzes in seawater producing a pH decrease. In this sense, the effects of the pH and the anion benzoate dissolved in seawater and leached from an antifouling paint were evaluated on Balanus amphitrite nauplii. Although benzoate anion showed an intense narcotic effect on nauplii, the results of this research clearly demonstrated that the antifouling activity is due to the combined action of this anion and the pH decrease, i.e. there exists a synergic effect. Field trials confirmed laboratory assays; paints containing ferric benzoate were effective for inhibiting organism settlement and as corrosion of metal.     

Review: Biodegradation of tributyltins (organotins) by marine bacteria

Many marine bacterial strains have an inherent capability to degrade toxic organotin compounds, especially tributyltins (TBTs), that enter into the environment in the form of insecticides, fungicides and antifouling paints as a result of anthropogenic and industrial activities. Significant degradation of these compounds in the ambient environment may take several years, and it is necessary to consider methods or strategies that can accelerate the degradation process. There have been few demonstrations of biological degradation of these organotin biocides exclusively in laboratory‐scale experiments. Compared with the few bench‐scale degradation processes, there are no reports of field‐scale processes for TBT bioremediation, in spite of its serious environmental threat to non‐target organisms in the aquatic environment. Implementation of field‐scale biodegradation of TBT requires inputs from biology, hydrology, geology, chemistry and civil engineering. A framework is emerging that can be adapted to develop new processes for bioremediation of toxic environmental wastes. In the case of TBT bioremediation, this framework incorporates screening and identification of natural bacterial strains, determination of optimal conditions for growth of isolates and TBT degradation, establishment of new metabolic pathways involved in TBT degradation, identification, localization and cloning of genes involved in degradation and in TBT resistance, development of suitable microbial strains using genetic manipulation techniques for practical applications and optimization of practical engineering processes for bioremediation of organotin‐contaminated sites. The present review mainly addresses the aspect of TBT biodegradation with special reference to environmental sources of TBT, chemical structure and biological activity, resistant and degrading bacterial strains, possible mechanisms of resistance and degradation and the genetic and biochemical basis of TBT degradation and resistance. It also evaluates the feasibility and potential of natural and genetically modified TBT‐degrading bacterial strains in field‐scale experiments to bioremediate TBT‐contaminated marine sites, and makes recommendations for more intensive and focused research in the area of TBT bioremediation mediated by marine bacterial strains. Copyright © 2002 John Wiley & Sons, Ltd.     

无毒海洋防污剂研究进展

综述了无毒海洋防污剂研究进展,从防污活性、机理、特点及应用等方面着手介绍了近年来开发的几种新型无毒天然产物防污剂和人工合成防污剂,并就其发展前景进行了展望;指出开发研制无毒海洋防污剂是海洋防污技术的发展方向之一.     

Analytical methods for the determination of common booster biocides in marine samples

Booster biocides are organic compounds that are added to antifouling copper-based paints to improve their efficacy. Due to their widespread use, they are common pollutants of marine ecosystems. Some of these compounds show acute and chronic toxic effects in non-targeted organisms at concentrations as low as ng L⁻¹. The determination of these compounds is therefore important, and for some, which are prioritized in the EU water framework directive, a necessity.     

Research on tributyltin in Australian estuaries

Tributyltin (TBT) from marine antifouling paints has been shown to have a major impact on the oyster industry in eastern Australia. Current research projects are examining the impact of TBT on Australian estuaries, assessing the response of sensitive biota to recently imposed bans and determining whether a continuing use of TBT on large vessels is an environmental concern.     

Influence of manufacturing parameters on development of contraceptive steroid loaded injectable microspheres

The main objective of this work was to develop a system consisting of polymeric microspheres loaded with steroid drugs. The drugs were encapsulated using biodegradable poly(lactide-co-glycolide) (PLG) and poly(epsilon-caprolactone) (PCL) by double emulsion solvent evaporation method. The lipophilic drugs, levonorgestrel and ethinylestradiol were made soluble by adding ethanol/water mixture. The effects of parameters like polymer concentration and stabilizer concentration were studied on the size, size distribution, surface properties and loading efficiencies of microspheres. The formulated microspheres were smooth, spherical and uniform in shape and size. Fourier transformed infrared spectroscopy and differential scanning calorimetry studies seemed to confirm the absence of chemical interaction between the drugs and the polymers, while the drugs were dispersed in the polymer. The increase in polymer concentrations increased the size as well as the loading efficiency of microspheres. Data obtained in this study demonstrated that the PLG/PCL microspheres may be a suitable polymeric carrier for long acting injectable drug delivery.     

Novel marine antifouling coatings inspired by corals

Biofouling is a major problem facing the marine industry. Since toxic antifouling coatings were banned globally due to their negative impacts on the marine environment, the development of environmental-friendly and efficient antifouling coatings has been identified as a pressing need. As an alternative, the antifouling coatings inspired by corals have attracted a great deal of attention over these years. within the marine environment, corals have evolved an excellent antifouling capability. There are five major antifouling strategies applied by corals, including natural antifoulants, foul release effect, sloughing effect, soft tentacles, and fluorescence effect. In this paper, a brief review is conducted to introduce the antifouling coatings inspired by the five strategies. Moreover, a discussion is conducted about the existing problems with the five strategies and the direction of their further development is indicated.     

Environmental aspects of tributyltin

The tributyltin species, the active ingredient in some antifouling paint formulations, is perhaps the most acutely toxic chemical to aquatic organisms ever deliberately introduced to water. It has been demonstrated to have an adverse effect on shellfish in France and England, and as a consequence the use of tributyltin-containing antifouling paints has been restricted in these countries. Other countries have banned the use of tributyltin-containing antifouling paints or are contemplating restrictions. This article reviews such environmental aspects of tributyltin as methods of analysis, toxicity, environmental occurrence, persistence and fate. Tributyltin concentrations in many locations may be high enough to cause chronic toxicity or harmful effects in some aquatic organisms, and in some locations the tributyltin concentrations may be high enough to be acutely toxic to some organisms. Biological degradation of tributyltin in water and sediment appears to be the most important factor limiting the persistence of tributyltin in aquatic environments. To some degree, then, the persistence of tributyltin in aquatic environments depends upon the nature of the ecosystem. Tributyltin exhibits low-to-medium persistence in water and moderate persistence in sediment. A summary is given of the regulatory status of tributyltin in some countries, and recommendations are made for further research.     

Structures and antifouling properties of low surface energy non-toxic antifouling coatings modified by nano-SiO_2 powder

Antifouling coatings are used to improve the speed and energy efficiency of ships by preventing or- ganisms, such as barnacles and weed, building up on the underwater hull and helping the ships movement through the water. Typically, marine coatings are tributyltin self-polishing copolymer paints containing toxic molecules called biocides. They have been the most successful in combating bio- fouling on ships, but their widespread use has caused severe pollution in the marine ecosystem. The low surface energy marine coating is an entirely non-toxic alternative, which reduces the adhesion strength of marine organisms, facilitating their hydrodynamic removal at high speeds. In this paper, the novel low surface energy non-toxic marine antifouling coatings were prepared with modified acrylic resin, nano-SiO2, and other pigments. The effects of nano-SiO2 on the surface structure and elastic modulus of coating films have been studied, and the seawater test has been carried out in the Dalian Bay. The results showed that micro-nano layered structures on the coating films and the lowest surface energy and elastic modulus could be obtained when an appropriate mass ratio of resin, nano-SiO2, and other pigments in coatings approached. The seawater exposure test has shown that the lower the sur- face energy and elastic modulus of coatings are, the less the marine biofouling adheres on the coating films.     

Structures and antifouling properties of low surface energy non-toxic antifouling coatings modified by nano-SiO<Subscript>2</Subscript> powder

Antifouling coatings are used to improve the speed and energy efficiency of ships by preventing organisms, such as barnacles and weed, building up on the underwater hull and helping the ships movement through the water. Typically, marine coatings are tributyltin self-polishing copolymer paints containing toxic molecules called biocides. They have been the most successful in combating biofouling on ships, but their widespread use has caused severe pollution in the marine ecosystem. The low surface energy marine coating is an entirely non-toxic alternative, which reduces the adhesion strength of marine organisms, facilitating their hydrodynamic removal at high speeds. In this paper, the novel low surface energy non-toxic marine antifouling coatings were prepared with modified acrylic resin, nano-SiO₂, and other pigments. The effects of nano-SiO₂ on the surface structure and elastic modulus of coating films have been studied, and the seawater test has been carried out in the Dalian Bay. The results showed that micro-nano layered structures on the coating films and the lowest surface energy and elastic modulus could be obtained when an appropriate mass ratio of resin, nano-SiO₂, and other pigments in coatings approached. The seawater exposure test has shown that the lower the surface energy and elastic modulus of coatings are, the less the marine biofouling adheres on the coating films. Supported by High-Tech Research and Development Program of China (Grant No. 2004AA001520)     

Determination of traces of five antifouling agents in water by gas chromatography with positive/negative chemical ionisation and tandem mass spectrometric detection.

A highly selective and sensitive gas chromatography-mass spectrometry methodology has been developed for the determination of five antifouling compounds, currently licensed for use in marine antifouling paints. The procedure uses an ion trap mass spectrometer provided with an external ion source that allows the combined use, in the same analysis, of positive (PCI) and negative (NCI) chemical ionisation and tandem mass spectrometric fragmentation (MS-MS). Ionisation and fragmentation processes were optimised individually for each compound, thus, permitting maximum sensitivity and selectivity to be obtained. A complete validation study, including those aspects that affect both correct quantification and unequivocal confirmation, demonstrated the good performance of the proposed method. Detection limits obtained were lower than 0.005 microg l(-1), except for Irgarol 1051 (0.050 microg l(-1)). The method was applied to real seawater samples from different     

Solar light-driven photocatalytic production of hypochlorous acid over Pt/WO3 in seawater for marine antifouling

The hypochlorous acid (HCIO) was synthesized from seawater by the Pt/WO₃ photocatalyst under visible-light irradiation. The effect of WO₃ morphology and Pt loading on the performance of the composite photocatalyst for the production of HCIO has been studied in detail. The study found that among the series of materials, hollow WO₃ microspheres with a diameter of about 3 μm loaded with 1.0 wt% Pt have the best HCIO production performance. Over it, 14.52 μM of HClO (1.24 mg/L of free chlorine) was accumulated in 0.5 M NaCl solution after 2 h of visible-light photoirradiation. What is more, the concentration of HClO can reach 4.34 μM (0.354 mg/L free chlorine) in natural seawater for 1 h using this Pt/WO₃ photocatalyst. Under visible-light irradiation, the Pt/WO₃ photocatalyst has a good broad-spectrum antibacterial activity and the activity of inhibiting marine fouling algae. The Pt/WO₃ photocatalyst has high stability and reusability. All these characteristics are conducive to the application in the field of marine antifouling. Moreover, the photocatalytic reaction mechanism was evaluated by studying the photoelectrochemical properties of Pt/WO₃/FTO. This research provides a new strategy for replacing the traditional electrolytic marine antifouling system with the visible-light-catalyzed HClO production system.

     

Alternative antifouling biocides

In response to increasing scientific evidence on the toxicity and occurrence of organotin residues from antifouling paints in the aquatic environment, the use of triorganotin antifouling products was banned on boats of less than 25 m length in many countries during 1987. The use of tributyltin (TBT) products on small boats was superseded by products based on copper, containing organic booster biocides to improve the efficacy of the formulation. Available information and evidence on the occurrence, fate and toxicity of these biocides is reviewed. It is concluded that increased copper concentrations in the aquatic environment, due to the increased use of copper‐based antifoulants, do not have significant effects on marine ecosystems. However, lack of validated analytical methods, limited monitoring data, and very little information about the fate and toxicity of the booster biocides in the aquatic environment, make accurate risk assessments in relation to these compounds difficult. Copyright © 1999 John Wiley & Sons, Ltd.     

The effects of short‐term changes in environmental parameters on the release of biocides from antifouling coatings: cuprous oxide and tributyltin

Current and forthcoming UK and European legislation requires environmental risk assessment of antifouling paints. For assessments to be carried out successfully, the leaching rate of biocides from antifouling paints should be determined. Current methods for the measurement of biocide leach rate have been shown to be very susceptible to changes in parameters such as pH, salinity and temperature. Using apparatus designed to simulate environmental conditions the effect of short‐term changes in salinity, pH, temperature, suspended particulate matter and simulated vessel speed on cuprous oxide and tributyltin (TBT) leaching from self‐polishing antifouling paint was investigated. No effect on copper leaching was observed over a wide range of environmentally relevant conditions, whilst vessel speed was the only parameter found to influence TBT release rates significantly. It is suggested that the decrease observed may be due to the formation of a boundary layer which slows down the release of TBT from the paint surface. The environmental authenticity of this observation and its possible implications for the environmental risk assessment of TBT are discussed. Copyright © 1999 Crown Copyright.     

口服聚酯聚醚疫苗蛋白微球的制备研究

采用本体聚合法合成不同聚醚含量的聚酯聚醚嵌段共聚物聚 ＤＬ 乳酸 聚乙二醇（Ｐｏｌｙ ＤＬ ｌａｃｔｉｄｅ ｂ ｐｏｌｙｅｔｈｙｌｅｎｅｇｌｙｃｏｌ,ＰＥＬＡ）．ＰＥＬＡ及ＰＬＡ包裹人血清白蛋白（ＨＳＡ）微球采用溶剂挥发法双乳液体系（Ｗ１／Ｏ／Ｗ２）制备．微球球形规整,粒径集中在０５～５０μｍ．用ＣＢＢ法检测微球中蛋白含量,蛋白包裹量达２５％,包裹效率近８０％．从双乳液体系中界面张力角度考察了聚合物囊材的性质、稳定剂的种类及Ｗ１／Ｏ的稳定性等对微球粒径及蛋白包裹量的影响．微球体外释放结果表明ＰＥＬＡ蛋白微球的突释现象不明显,释放速度较为恒定．     

水性防污涂料的研究进展

海洋污损生物是海洋资源开发首先要面对的问题。防污涂料是防除海洋污损生物的关键材料。传统的防污涂料虽然发展成熟,但以油性溶剂为介质,存在挥发性有机物(VOC)排放过高、环境污染严重的问题。不释放VOC的水性涂料符合绿色无污染的环保要求,是防污材料领域研究的热点。本文对最重要的四种水性防污涂料(污损释放型水性低表面能防污涂料、自抛光型水性防污涂料、污损阻抗型水凝胶海洋防污涂料、强碱释放型水性硅酸盐防污涂料)从防污机理、制备方法和存在的问题等几个方面进行了综述,并对水性防污涂料的发展趋势进行了展望。     

In vitro and in vivo characterization of huperzine a loaded microspheres made from end-group uncapped poly(d,l-lactide acid) and poly(d,l-lactide-co-glycolide acid)

The purpose of this work was to develop biodegradable microspheres for long term delivery of a potent acetyl cholinesterase inhibitor, huperzine A (Hup-A), which is of interest in the palliative treatment of Alzheimer's disease. Microspheres were successfully prepared with specifically end-group uncapped poly(d,l-lactide acid) and poly(d,l-lactide-co-glycolide acid) using a simple o/w solvent evaporation method. The morphology, particle size and size distribution, drug loading capacity, drug entrapment efficiency (EE) and in vitro drug release were studied in detail. It was found that the terminal group and the inherent viscosity (IV) of the polymers played key role in the drug encapsulation: higher EE was achieved with end-group uncapped and low IV polymers. In vitro drug release from microspheres made from the selected three kinds of polymers revealed sustained release of Hup-A without significant burst release. Preliminary pharmacokinetic study following subcutaneous injection of Hup-A loaded microspheres illustrated the sustained release of the drug over 6-8 weeks at clinically relevant doses in vivo. The studies demonstrated the feasibility of long term delivery of Hup-A using biodegradable microspheres.     

氧化亚铜微/纳米结构的形貌可控制备及光催化和防污性能

利用简便易行的液相法,采用葡萄糖为还原剂,通过调整加料方式、反应温度、NaOH用量等条件,实现具有{110}截面八面体、八面体和短足形等形貌的Cu2O微/纳米结构的可控制备,运用透射电子显微镜、扫描电子显微镜、紫外可见分光光度计等对产物进行组成、结构、形貌和光响应的表征,对Cu2O的形貌结构和生长机理进行研究。对比和优化了具有不同形貌的Cu2O微/纳米结构对甲基橙染料的光催化性能。将不同形貌的微/纳米Cu2O作为防污剂复配的自抛光防污涂料,涂层磨蚀率、接触角与实海挂板实验证明该涂料具有良好的防污性能。     

氧化亚铜微/纳米结构的形貌可控制备及光催化和防污性能

利用简便易行的液相法,采用葡萄糖为还原剂,通过调整加料方式、反应温度、NaOH用量等条件,实现具有{110}截面八面体、八面体和短足形等形貌的Cu₂O微/纳米结构的可控制备,运用透射电子显微镜、扫描电子显微镜、紫外可见分光光度计等对产物进行组成、结构、形貌和光响应的表征,对Cu₂O的形貌结构和生长机理进行研究。对比和优化了具有不同形貌的Cu₂O微/纳米结构对甲基橙染料的光催化性能。将不同形貌的微/纳米Cu₂O作为防污剂复配的自抛光防污涂料,涂层磨蚀率、接触角与实海挂板实验证明该涂料具有良好的防污性能。