Sign in to use this feature.

Years

Between: -

Subjects

remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline

Journals

Article Types

Countries / Regions

Search Results (14)

Search Parameters:
Keywords = DCOIT

Order results
Result details
Results per page
Select all
Export citation of selected articles as:
12 pages, 2616 KiB  
Article
Microencapsulation Efficiency of DCOIT Biocide in the TPM/SiO2 System and a Study of Their Acute Toxicity
by Assem Issayeva, Saule Aidarova, Galiya Madybekova, Seitzhan Turganbay, Alpamys Babayev, Miras Issakhov, Altynay Sharipova, Reinhard Miller and Botagoz Mutaliyeva
Colloids Interfaces 2025, 9(1), 2; https://doi.org/10.3390/colloids9010002 - 31 Dec 2024
Viewed by 1259
Abstract
Biocides are often used in various industries and applications to control microbial growth and prevent the deterioration of materials, and they often have the ability to target a wide range of microorganisms rather than being specific to one type. They are designed to [...] Read more.
Biocides are often used in various industries and applications to control microbial growth and prevent the deterioration of materials, and they often have the ability to target a wide range of microorganisms rather than being specific to one type. They are designed to be highly effective at killing or inhibiting the growth of microorganisms and some biocides have residual activity, meaning they remain active for a period of time after application, providing longer-term protection. Biocides need to be compatible with the materials and surfaces they are applied to without causing damage or adverse effects, and they should remain stable under various environmental conditions, such as temperature and pH, to maintain their efficacy over time. In this study, microcapsules incorporating the biocide 4,5-dichloro-2-n-octyl-4-isotriazolin-3-one (DCOIT) were synthesized, and their effectiveness was evaluated. The investigation focused on several aspects, including colloidal chemical properties such as interfacial tension at pH values of 3, 7, and 9, as well as the size, ζ-potential, and morphology of the microcapsules. To validate the microcapsule production, elemental analysis was performed, and the effects on wettability and toxicological properties were assessed within the DCOIT + trimethoxysilyl propylmethacrylate/silicon dioxide nanoparticle system. Interfacial tension kinetics were measured using the PAT-1 tensiometer. The microcapsules exhibited an average diameter of 146 ± 1 nm following emulsification, with a ζ-potential of −50.2 ± 1 mV, as determined by the Malvern Zetasizer Nano Z. The morphology of the microcapsules was characterized using the SEM Controller 1550. Elemental composition was analyzed via energy-dispersive X-ray microanalysis (EDAX). The study concluded that the DCOIT biocide, when incorporated in the TPM/SiO2 system, demonstrated non-toxic properties. Full article
Show Figures

Figure 1

14 pages, 507 KiB  
Article
Preliminary Findings on the Bioaccumulation and Marine Trophic Transfer of the Antifouling Biocide DCOIT in Soluble and Nanostructured Forms
by Bruno Galvão de Campos, Denis Moledo de Souza Abessa and Roberto Martins
Sustainability 2024, 16(18), 7996; https://doi.org/10.3390/su16187996 - 13 Sep 2024
Cited by 2 | Viewed by 1762
Abstract
DCOIT (4,5-Dichloro-2-octylisothiazol-3(2H)-one) is a widely used antifouling biocide that emerged after the ban on tributyltin. It has been immobilized in nanostructured silica (SiNC–DCOIT) to reduce its hazard in maritime coatings. This study aimed to compare the bioaccumulation, trophic transfer, and biomagnification of DCOIT [...] Read more.
DCOIT (4,5-Dichloro-2-octylisothiazol-3(2H)-one) is a widely used antifouling biocide that emerged after the ban on tributyltin. It has been immobilized in nanostructured silica (SiNC–DCOIT) to reduce its hazard in maritime coatings. This study aimed to compare the bioaccumulation, trophic transfer, and biomagnification of DCOIT in its soluble and nanostructured forms on mussels Mytilus galloprovincialis, using three different uptake routes: aqueous exposure (i.e., contaminated seawater), dietary exposure (i.e., microalgae Tetraselmis chuii as a contaminated food), and both contaminated food and seawater. DCOIT was determined on water and tissues after 1, 3, and 24 h of uptake and after 72 h of depuration. Briefly, mussels were able to rapidly uptake and metabolize DCOIT and SiNC–DCOIT. Both compounds were non-bioaccumulative, as their bioconcentration and bioaccumulation factor values were lower than 2000. However, the predator–prey biomagnification factors indicated that both forms could be transferred across the trophic web. Therefore, while our findings provide further insight into the environmental risk assessment of DCOIT and SiNC–DCOIT, they do not rule out the possibility of long-term DCOIT bioaccumulation, particularly in areas with constant DCOIT influx. Further studies are thus needed using larger experimental designs and under continuous exposure scenarios to increase the sustainability of the innovative nanomaterial. Full article
Show Figures

Figure 1

16 pages, 3691 KiB  
Review
A Review of Investigations and Applications of Biocides in Nanomaterials and Nanotechnologies
by Assem Issayeva, Altynay Sharipova, Saule Aidarova, Galiya Madybekova, Jaroslav Katona, Seitzhan Turganbay and Reinhard Miller
Colloids Interfaces 2024, 8(3), 31; https://doi.org/10.3390/colloids8030031 - 16 May 2024
Cited by 6 | Viewed by 2825
Abstract
In recent years, the development of nanomaterials with biocidal properties has received considerable attention due to their potential applications in various industries, including food, medicine, and cultural heritage preservation. The growing demand for coatings with antibacterial properties has sparked interest from industrial sectors [...] Read more.
In recent years, the development of nanomaterials with biocidal properties has received considerable attention due to their potential applications in various industries, including food, medicine, and cultural heritage preservation. The growing demand for coatings with antibacterial properties has sparked interest from industrial sectors in exploring the incorporation of biocides into these materials. Coatings are prone to microbial growth, which can cause damage such as cracking, discoloration, and staining. To combat these problems, the integration of biocides into coatings is a crucial strategy. Biocide-embedded nanomaterials offer numerous advantages, including high efficiency in small quantities, ease of application, good chemical stability, low toxicity, and non-bioaccumulation. Encapsulated nanobiocides are particularly attractive to the agro-industry, because they can be less toxic than traditional biocides while still effectively controlling microbial contamination. To fully exploit the benefits of nanobiocides, future research should focus on optimizing their synthesis, formulation, and delivery methods. The purpose of this review is to summarize the current status of biocide nanomaterials, discuss potential future research directions, and highlight research methods, the development of new forms of nanomaterials, and studies of their physico-chemical properties. Biocide nanocapsules of DCOIT (4,5-Dichloro-2-octyl-2H-isothiazol-3-one) are chosen as an example to illustrate the research pathways. Full article
Show Figures

Figure 1

22 pages, 12909 KiB  
Article
Preliminary Study on Microbial Deterioration Control and Effectiveness Evaluation in the Neolithic Prehistoric Archaeological Site of Dadiwan, Northwest China
by Ruihong Xu, Yuxin Chen, Dongpeng He, Guobin Zhang, Qiang Luo, Hongtao Zhan and Fasi Wu
Coatings 2024, 14(1), 100; https://doi.org/10.3390/coatings14010100 - 11 Jan 2024
Cited by 2 | Viewed by 2006
Abstract
Microbial deterioration as one of the widespread problems in archaeological site museums significantly affects their safety and exhibits. This paper systemically investigated the environments and conditions of microbial outbreaks in the Dadiwan No. F901 site museum, which is a representative archaeological site of [...] Read more.
Microbial deterioration as one of the widespread problems in archaeological site museums significantly affects their safety and exhibits. This paper systemically investigated the environments and conditions of microbial outbreaks in the Dadiwan No. F901 site museum, which is a representative archaeological site of prehistoric Yangshao culture. The morphology and harmful characteristics of the outbreak microorganisms were analyzed by microscopic techniques. The ultraviolet resistance of harmful microorganisms was also studied. Combining these findings with the original facilities of the site museum, a scientific and reasonable project was proposed to control and prevent the activity of harmful microorganisms. In addition, a 1% OIT/DCOIT biocide concentration was applied to inhibit microorganism-caused deterioration, in combination with mechanical removal based on laboratory tests and screening in situ. The effectiveness of microbial control was assessed using a portable microscope, ATP bioluminescence assay, and color difference detection. As a long-lasting preventive measure for microbial deterioration, an ultraviolet sterilization system can efficaciously prevent the re-outbreak of microbial deterioration to form a relatively stable dynamic balance for the surroundings of the site. This study is a resultful exploration in terms of microbial control and plays an important role in the sustainable protection of archaeological site museums. Full article
Show Figures

Figure 1

9 pages, 1767 KiB  
Article
Adults of Sun Coral Tubastraea coccinea (Lesson 1829) Are Resistant to New Antifouling Biocides
by Isabela Martins, Kátia Cristina Cruz Capel and Denis Moledo de Souza Abessa
Toxics 2024, 12(1), 44; https://doi.org/10.3390/toxics12010044 - 6 Jan 2024
Viewed by 2210
Abstract
Biocides used in antifouling (AF) paints, such as 4,5-dichlorine-2-n-octyl-4-isothiazole-3-one (DCOIT), can gradually leach into the environment. Some AF compounds can persist in the marine environment and cause harmful effects to non-target organisms. Nanoengineered materials, such as mesoporous silica nanocapsules (SiNCs) containing AF compounds, [...] Read more.
Biocides used in antifouling (AF) paints, such as 4,5-dichlorine-2-n-octyl-4-isothiazole-3-one (DCOIT), can gradually leach into the environment. Some AF compounds can persist in the marine environment and cause harmful effects to non-target organisms. Nanoengineered materials, such as mesoporous silica nanocapsules (SiNCs) containing AF compounds, have been developed to control their release rate and reduce their toxicity to aquatic organisms. This study aimed to evaluate the acute toxicity of new nanoengineered materials, SiNC-DCOIT and a silver-coated form (SiNC-DCOIT-Ag), as well as the free form of DCOIT and empty nanocapsules (SiNCs), on the sun coral Tubastraea coccinea. T. coccinea is an invasive species and can be an alternative test organism for evaluating the risks to native species, as most native corals are currently threatened. The colonies were collected from the Alcatrazes Archipelago, SP, Brazil, and acclimatized to laboratory conditions. They were exposed for 96 h to different concentrations of the tested substances: 3.33, 10, 33, and 100 µg L−1 of free DCOIT; 500, 1000, 2000, and 4000 µg L−1 of SiNC; and 74.1, 222.2, 666.7, and 2000 µg L−1 of SiNC-DCOIT and SiNC-DCOIT-Ag. The test chambers consisted of 500 mL flasks containing the test solutions, and the tests were maintained under constant aeration, a constant temperature of 23 ± 2 °C, and photoperiod of 12 h:12 h (light/dark). At the end of the experiments, no lethal effect was observed; however, some sublethal effects were noticeable, such as the exposure of the skeleton in most of the concentrations and replicates, except for the controls, and embrittlement at higher concentrations. Adults of T. coccinea were considered slightly sensitive to the tested substances. This resistance may indicate a greater capacity for proliferation in the species, which is favored in substrates containing antifouling paints, to the detriment of the native species. Full article
(This article belongs to the Special Issue Toxicity of Contaminants on Aquatic Organisms II)
Show Figures

Figure 1

11 pages, 1125 KiB  
Article
Characterization and Behaviour of Silica Engineered Nanocontainers in Low and High Ionic Strength Media
by Violeta Ferreira, Joana Figueiredo, Roberto Martins, Alesia Sushkova, Frederico Maia, Ricardo Calado, João Tedim and Susana Loureiro
Nanomaterials 2023, 13(11), 1738; https://doi.org/10.3390/nano13111738 - 26 May 2023
Cited by 2 | Viewed by 1941
Abstract
Mesoporous silica engineered nanomaterials are of interest to the industry due to their drug-carrier ability. Advances in coating technology include using mesoporous silica nanocontainers (SiNC) loaded with organic molecules as additives in protective coatings. The SiNC loaded with the biocide 4,5-dichloro-2-octyl-4-isothiazolin-3-one (DCOIT), i.e., [...] Read more.
Mesoporous silica engineered nanomaterials are of interest to the industry due to their drug-carrier ability. Advances in coating technology include using mesoporous silica nanocontainers (SiNC) loaded with organic molecules as additives in protective coatings. The SiNC loaded with the biocide 4,5-dichloro-2-octyl-4-isothiazolin-3-one (DCOIT), i.e., SiNC-DCOIT, is proposed as an additive for antifouling marine paints. As the instability of nanomaterials in ionic-rich media has been reported and related to shifting key properties and its environmental fate, this study aims at understanding the behaviour of SiNC and SiNC-DCOIT in aqueous media with distinct ionic strengths. Both nanomaterials were dispersed in (i) low- (ultrapure water—UP) and (ii) high- ionic strength media—artificial seawater (ASW) and f/2 medium enriched in ASW (f/2 medium). The morphology, size and zeta potential (ζP) of both engineering nanomaterials were evaluated at different timepoints and concentrations. Results showed that both nanomaterials were unstable in aqueous suspensions, with the initial ζP values in UP below −30 mV and the particle size varying from 148 to 235 nm and 153 to 173 nm for SiNC and SiNC-DCOIT, respectively. In UP, aggregation occurs over time, regardless of the concentration. Additionally, the formation of larger complexes was associated with modifications in the ζP values towards the threshold of stable nanoparticles. In ASW, SiNC and SiNC-DCOIT formed aggregates (<300 nm) independently of the time or concentration, while larger and heterogeneous nanostructures (>300 nm) were detected in the f/2 medium. The pattern of aggregation detected may increase engineering nanomaterial sedimentation rates and enhance the risks towards dwelling organisms. Full article
Show Figures

Graphical abstract

16 pages, 1538 KiB  
Article
Marine Hazard Assessment of Soluble and Nanostructured Forms of the Booster Biocide DCOIT in Tropical Waters
by Fernando Perina, Cristiane Ottoni, Juliana Santos, Vithória Santos, Mariana Silva, Bruno Campos, Mayana Fontes, Debora Santana, Frederico Maia, Denis Abessa and Roberto Martins
Water 2023, 15(6), 1185; https://doi.org/10.3390/w15061185 - 18 Mar 2023
Cited by 4 | Viewed by 2410
Abstract
The encapsulation of antifouling compounds, such as DCOIT (4,5-Dichloro-2-octylisothiazol-3(2H)-one), in mesoporous silica nanocapsules (SiNC) has recently been demonstrated to be an eco-friendly alternative to decrease biocide toxicity towards marine non-target species. However, the lack of information on the chronic effects of such nanomaterials [...] Read more.
The encapsulation of antifouling compounds, such as DCOIT (4,5-Dichloro-2-octylisothiazol-3(2H)-one), in mesoporous silica nanocapsules (SiNC) has recently been demonstrated to be an eco-friendly alternative to decrease biocide toxicity towards marine non-target species. However, the lack of information on the chronic effects of such nanomaterials on non-target tropical species is critical for a more comprehensive environmental risk assessment. Thus, the present study aimed to assess the chronic toxicity and hazard of the soluble and encapsulated forms of DCOIT on neotropical marine species. Chronic tests were conducted with six ecologically relevant species. No effect concentration (NOEC) values were combined with NOEC values reported for tropical species to assess the hazard using the probabilistic approach to derive each predicted no effect concentration (PNEC). The SiNC-DCOIT was three- to ten-fold less toxic than soluble DCOIT. Probabilistic-based PNECs were set at 0.0001 and 0.0097 µg DCOIT L−1 for the biocide soluble and nanostructured forms, respectively. The immobilization of DCOIT into SiNC led to an 84-fold hazard decrease, confirming that the encapsulation of DCOIT into SiNC is a promising eco-friendly alternative technique, even in a chronic exposure scenario. Therefore, the present study will contribute to better management of the environmental risk of such innovative products in the tropical marine environment. Full article
Show Figures

Figure 1

13 pages, 2923 KiB  
Article
Analysis of NMR Spectra of Submicro-Containers with Biocide DCOIT
by Saule B. Aidarova, Assem B. Issayeva, Altynay A. Sharipova, Dmitry O. Grigoriev, Reinhard Miller, Tulegen M. Seilkhanov, Alpamys A. Babayev and Miras O. Issakhov
Colloids Interfaces 2020, 4(4), 56; https://doi.org/10.3390/colloids4040056 - 9 Dec 2020
Cited by 4 | Viewed by 2949
Abstract
Nowadays, the search for and development of new forms of materials with biocides is an actual problem of the modern science of nanosized materials due to the problem of microbiological contamination, which can be solved by using nanocontainers carrying biocides. Depending on the [...] Read more.
Nowadays, the search for and development of new forms of materials with biocides is an actual problem of the modern science of nanosized materials due to the problem of microbiological contamination, which can be solved by using nanocontainers carrying biocides. Depending on the morphology of the nanocontainers and the filled active agents, it is possible to create coatings with specially designed self-healing functionality or multifunctional properties. The purpose of this work was to produce submicro-containers (SMCs) with a shell of SiO2 nanoparticles and a core of polymerized 3-(trimethoxysilyl) propyl methacrylate filled with 5-dichloro-2-n-octyl-4-isothiazolin-3-one (DCOIT) in an oil in water (O/W) emulsion. The chemical nature of the individual components of the system and nano-capsules were investigated using NMR spectroscopy. The size and zeta potential of the SMCs were measured by a dynamic light scattering method (d = 170–180 nm, polydispersity index PDI = 0.125 and zeta-potential = 55 mV), the morphology of their outer surface was determined using SEM. The results of NMR analysis showed that during the addition of the biocide into the SMCs, its chemical structure is retained, as is its activity. Minor changes in the chemical shifts of the 1H NMR spectra of the SMCs with DCOIT, as well as of the biocide itself, confirm the inclusion of DCOIT inside the SMCs. Full article
Show Figures

Figure 1

12 pages, 1021 KiB  
Article
Can Encapsulation of the Biocide DCOIT Affect the Anti-Fouling Efficacy and Toxicity on Tropical Bivalves?
by Juliana Vitoria Nicolau dos Santos, Roberto Martins, Mayana Karoline Fontes, Bruno Galvão de Campos, Mariana Bruni Marques do Prado e Silva, Frederico Maia, Denis Moledo de Souza Abessa and Fernando Cesar Perina
Appl. Sci. 2020, 10(23), 8579; https://doi.org/10.3390/app10238579 - 30 Nov 2020
Cited by 21 | Viewed by 4133
Abstract
The encapsulation of the biocide DCOIT in mesoporous silica nanocapsules (SiNC) has been applied to reduce the leaching rate and the associated environmental impacts of coatings containing this biocide. This research aimed to evaluate the effects of DCOIT in both free and nanostructured [...] Read more.
The encapsulation of the biocide DCOIT in mesoporous silica nanocapsules (SiNC) has been applied to reduce the leaching rate and the associated environmental impacts of coatings containing this biocide. This research aimed to evaluate the effects of DCOIT in both free and nanostructured forms (DCOIT vs. SiNC-DCOIT, respectively) and the unloaded SiNC on different life stages of the bivalve Perna perna: (a) gametes (fertilization success), (b) embryos (larval development), and (c) juveniles mussels (byssus threads production and air survival after 72 h of aqueous exposure). The effects on fertilization success showed high toxicity of DCOIT (40 min-EC50 = 0.063 μg L−1), followed by SiNC-DCOIT (8.6 μg L−1) and SiNC (161 μg L−1). The estimated 48 h-EC50 of SiNC, DCOIT and SiNC-DCOIT on larval development were 39.8, 12.4 and 6.8 μg L−1, respectively. The estimated 72 h-EC50 for byssus thread production were 96.1 and 305.5 µg L−1, for free DCOIT and SiNC-DCOIT, respectively. Air survival was significantly reduced only for mussels exposed to free DCOIT. Compared to its free form, SiNC-DCOIT presented a balanced alternative between efficacy and toxicity, inhibiting efficiently the development of the target stage (larvae that is prone to settle) and satisfactorily preventing the juvenile attachment. Full article
Show Figures

Figure 1

12 pages, 4142 KiB  
Article
Development of Marine Antifouling Epoxy Coating Enhanced with Clay Nanotubes
by Ye Fu, Wencai Wang, Liqun Zhang, Vladimir Vinokurov, Anna Stavitskaya and Yuri Lvov
Materials 2019, 12(24), 4195; https://doi.org/10.3390/ma12244195 - 13 Dec 2019
Cited by 27 | Viewed by 4586
Abstract
An antifouling epoxy resin doped with natural clay nanotubes that are loaded with biocide or silver allowed extended protection against the proliferation of marine microorganisms. Compared to the 2–3 months of protection with antifoulant dichlorooctylisothiazolone (DCOIT) directly admixed into epoxy resin, the DCOIT [...] Read more.
An antifouling epoxy resin doped with natural clay nanotubes that are loaded with biocide or silver allowed extended protection against the proliferation of marine microorganisms. Compared to the 2–3 months of protection with antifoulant dichlorooctylisothiazolone (DCOIT) directly admixed into epoxy resin, the DCOIT release time of the halloysite formulations was extended to 12 months by incorporating biocide-loaded nanoclay in the polymer matrix. The protective properties of the epoxy-halloysite nanocomposites showed much less adhesion and proliferation of marine bacteria Vibrio natriegens on the resin surface after a two-month exposure to seawater than the coating formulations directly doped with non-encapsulated DCOIT. The coating formulation protection efficiency was further confirmed by twelve-month shallow field tests in the South China Sea. Replacing 2 wt.% biocide in the traditional formula with DCOIT-loaded natural environmentally friendly halloysite clay drastically improved the antifouling properties of the epoxy coating, promising scalable applications in protective marine coating. The antifouling property of epoxy resin was enhanced with silver particles synthesized on halloysite nanotubes. A natural mixture of MnO particles and halloysite could also be used as a nonbiocide additive to marine coating. The short-term White Sea water test of epoxy coating with 5% of Ag-halloysite composite of MnO-halloysite natural mixture showed no visible fouling. Full article
(This article belongs to the Special Issue Hybrid and Composite Coatings and Thin Films)
Show Figures

Graphical abstract

15 pages, 4835 KiB  
Article
Simultaneous Quantitative Analysis of Six Isothiazolinones in Water-Based Adhesive Used for Food Contact Materials by High-Performance Liquid Chromatography–Tandem Mass Spectrometry (HPLC–MS/MS)
by Huaining Zhong, Zicheng Li, Sheng Chen, Ying Zeng, Jianguo Zheng, You Zeng and Dan Li
Molecules 2019, 24(21), 3894; https://doi.org/10.3390/molecules24213894 - 29 Oct 2019
Cited by 22 | Viewed by 6071
Abstract
In this study, a target analytical approach using high-performance liquid chromatography–tandem mass spectrometry (HPLC–MS/MS) was developed to simultaneously determine six isothiazolinones containing 2-Methylisothiazol-3(2H)-one (MI), 5-Chloro-2-methyl-4-isothiazolin-3-one (CMI), 1,2-benzisothiazolin-3-one (BIT), 2-Octyl-3(2H)-isothiazolinone (OIT), Dichlorooctylisothiazolinone (DCOIT), and 2-methyl-1,2-benzisothiazolin-3-one (MBIT) in water-based adhesive used for food contact materials. [...] Read more.
In this study, a target analytical approach using high-performance liquid chromatography–tandem mass spectrometry (HPLC–MS/MS) was developed to simultaneously determine six isothiazolinones containing 2-Methylisothiazol-3(2H)-one (MI), 5-Chloro-2-methyl-4-isothiazolin-3-one (CMI), 1,2-benzisothiazolin-3-one (BIT), 2-Octyl-3(2H)-isothiazolinone (OIT), Dichlorooctylisothiazolinone (DCOIT), and 2-methyl-1,2-benzisothiazolin-3-one (MBIT) in water-based adhesive used for food contact materials. The main factors affecting extraction efficiency such as extraction method, extraction time, extraction solvent, and solid–liquid ratio have been evaluated by using real adhesive samples. Multiple-reaction monitoring (MRM) was used for the qualitative and quantitative analyses of targeted isothiazolinones. This method was demonstrated as an effective and reliable technique for detecting multiple isothiazolinones with satisfactory recoveries (81.5~107.3%), and the limits of detection (LOD) and quantification (LOQ) were obtained at a low level. This method was validated and applied to the determination of six isothiazolinones in commercial water-based adhesives. The present results revealed that these adhesives contained a combination of isothiazolinones (BIT, MI, CMI, and MBIT) with the concentration ranging from 2.27 to 123.5 mg/kg. To our knowledge, it is the first time it has been reported that MBIT was detected in water-based adhesives used for food contact materials, which requires a further investigation for its migration to food and the risk to human health. Full article
(This article belongs to the Special Issue Food Packaging Materials)
Show Figures

Figure 1

14 pages, 2756 KiB  
Article
Effects of Various Antifouling Coatings and Fouling on Marine Sonar Performance
by Bradley Donnelly, Ian Bedwell, Jim Dimas, Andrew Scardino, Youhong Tang and Karl Sammut
Polymers 2019, 11(4), 663; https://doi.org/10.3390/polym11040663 - 11 Apr 2019
Cited by 22 | Viewed by 4442
Abstract
There is a rising imperative to increase the operational availability of maritime vessels by extending the time between full docking cycles. To achieve operational efficacy, maritime vessels must remain clear of biological growth. Such growth can cause significant increases in frictional drag, thereby [...] Read more.
There is a rising imperative to increase the operational availability of maritime vessels by extending the time between full docking cycles. To achieve operational efficacy, maritime vessels must remain clear of biological growth. Such growth can cause significant increases in frictional drag, thereby reducing speed, range and fuel efficiency and decreasing the sensitivity of acoustic sensors. The impact that various stages of fouling have on acoustic equipment is unclear. It is also unclear to what extent antifouling techniques interfere with the transmission of acoustic signals. In this study, to examine this effect, neoprene samples were coated with three antifouling coatings, namely, Intersmooth 7460HS, HempaGuard X7 and Hempasil X3. Other neoprene samples were left uncoated but were imbedded with the biocide, 4,5-dichloro-2-octyl-4-isothiazolin-3-one (DCOIT) during the mixing and curing process. Uncoated nitrile samples that had varying levels of fouling from immersion in Port Phillip Bay, Australia, for 92, 156 and 239 days were also extracted. The acoustic properties of these samples were measured using an acoustic insertion loss test and compared to uncoated neoprene or nitrile to ascertain the acoustic effects of the applications of antifouling coatings as well as the fouling growth itself. A T-peel test was performed on all coated samples in an attempt to understand the adhesive properties of the coatings when applied to neoprene. It was found that the application of antifouling coatings had little effect on the transmission characteristics of the neoprene with approximately 1 dB loss. The embedment of DCOIT, however, has a chance of causing aeration in the neoprene, which can heavily hamper transmission. An assessment of the effect of the fouling growth found that light and medium fouling levels produced little transmission loss, whereas more extreme fouling lead to a 9 dB transmission loss. The adhesion properties of the coatings were investigated but not fully ascertained as tensile yielding occurred before peeling. However, various failure modes are presented and discussed in this study. Full article
(This article belongs to the Special Issue Marine Polymeric Materials and Biomimetics)
Show Figures

Figure 1

13 pages, 2569 KiB  
Article
Synthesis of Submicrocontainers with “Green” Biocide and Study of Their Antimicrobial Activity
by Saule B. Aidarova, Altynay A. Sharipova, Assem B. Issayeva, Botagoz Zh. Mutaliyeva, Aiym B. Tleuova, Dmitry O. Grigoriev, Dariga Kudasova, Madina Dzhakasheva and Reinhard Miller
Colloids Interfaces 2018, 2(4), 67; https://doi.org/10.3390/colloids2040067 - 3 Dec 2018
Cited by 11 | Viewed by 4047
Abstract
The synthesis and properties of submicrocontainers with a shell of nanoparticles of silicon dioxide and a core of polymerized 3-(Trimethoxysilyl) propyl methacrylate loaded with 5-Dichloro-2-n-octyl-4-isothiazolin-3-one (DCOIT) are considered. The resulting containers were characterized by scanning electron microscopy SEM, laser correlation spectroscopy and thermogravimetric [...] Read more.
The synthesis and properties of submicrocontainers with a shell of nanoparticles of silicon dioxide and a core of polymerized 3-(Trimethoxysilyl) propyl methacrylate loaded with 5-Dichloro-2-n-octyl-4-isothiazolin-3-one (DCOIT) are considered. The resulting containers were characterized by scanning electron microscopy SEM, laser correlation spectroscopy and thermogravimetric analysis. The obtained submicrocontainers show low polydispersity with a small increase in size in comparison with the initial droplet size of the Pickering emulsion. The Zeta potential of the final containers was sufficiently negative at pH7 to be stable. The maximum release of encapsulated biocide was observed over approximately 24–27 h with a lease of about 78% of the encapsulated biocide during 3.5 h. The effectiveness of the encapsulated biocide by the Pickering emulsion technique was studied by tests on the growth rate of a microfungi colony (Aspergillus niger, Aspergillus awamori) and the growth rate of the bacteria Bacillus cereus. The test shows that the submicrocontainers of DCOIT facilitate a growth inhibition of 70% against 52% for the free biocide after 5 days; this is due to the fact that free biocide loses its activity promptly, while the encapsulated biocide is released gradually, and thus retains its effectivity for a longer time. Full article
Show Figures

Graphical abstract

20 pages, 144 KiB  
Review
Risks of Using Antifouling Biocides in Aquaculture
by Francisco Antonio Guardiola, Alberto Cuesta, José Meseguer and Maria Angeles Esteban
Int. J. Mol. Sci. 2012, 13(2), 1541-1560; https://doi.org/10.3390/ijms13021541 - 2 Feb 2012
Cited by 208 | Viewed by 15569
Abstract
Biocides are chemical substances that can deter or kill the microorganisms responsible for biofouling. The rapid expansion of the aquaculture industry is having a significant impact on the marine ecosystems. As the industry expands, it requires the use of more drugs, disinfectants and [...] Read more.
Biocides are chemical substances that can deter or kill the microorganisms responsible for biofouling. The rapid expansion of the aquaculture industry is having a significant impact on the marine ecosystems. As the industry expands, it requires the use of more drugs, disinfectants and antifoulant compounds (biocides) to eliminate the microorganisms in the aquaculture facilities. The use of biocides in the aquatic environment, however, has proved to be harmful as it has toxic effects on the marine environment. Organic booster biocides were recently introduced as alternatives to the organotin compounds found in antifouling products after restrictions were imposed on the use of tributyltin (TBT). The replacement products are generally based on copper metal oxides and organic biocides. The biocides that are most commonly used in antifouling paints include chlorothalonil, dichlofluanid, DCOIT (4,5-dichloro-2-n-octyl-4-isothiazolin-3-one, Sea-nine 211®), Diuron, Irgarol 1051, TCMS pyridine (2,3,3,6-tetrachloro-4-methylsulfonyl pyridine), zinc pyrithione and Zineb. There are two types of risks associated with the use of biocides in aquaculture: (i) predators and humans may ingest the fish and shellfish that have accumulated in these contaminants and (ii) the development of antibiotic resistance in bacteria. This paper provides an overview of the effects of antifouling (AF) biocides on aquatic organisms. It also provides some insights into the effects and risks of these compounds on non-target organisms. Full article
Show Figures

Back to TopTop