• Membrane Journal
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• v.32 no.3
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• pp.181-190
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• 2022

Membrane separation provides various advantages including cost effectiveness and high efficiency over traditional wastewater treatment methods such as flocculation and adsorption. However, the effectiveness of membrane separation greatly declines due to membrane fouling, where pollutants are accumulated on the membrane surface. Among different groups of membranes, ceramic membranes can provide good antifouling properties due to its hydrophilicity and chemical stability. In addition, composite membranes such as graphene oxide modified membranes can help prevent membrane fouling. Recently, hybrid photocatalytic membranes have been proposed as a solution to prevent membrane fouling and provide synergetic effects. Membrane separation can solve the disadvantages of photocatalytic oxidation such as low reutilization rate, while photocatalytic oxidation can help reduce membrane fouling.

• Korean Journal of Environmental Biology
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• v.38 no.2
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• pp.207-215
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• 2020

Toxic assessment of antifouling agents (diuron and irgarol) was conducted using the fertilization and the normal embryogenesis rates of the sea urchin, Mesocentrotus nudus. Bioassessment began with male and female reproductive cell induction. White or cream-colored male gametes(sperm) and yellow or orange-colored female gametes (eggs) were acquired and fully washed, separately. Then, the fertilization and normal embryogenesis rates were measured after 10 min and 48 h of exposure to the toxicants, respectively. The fertilization and embryo development rates were greater than 90% in the control, validating the suitability of both endpoints. The normal embryogenesis rates were significantly decreased with increasing concentrations of diuron and irgarol, but no changes in the fertilization rates were observed in concentrations ranging from 0 to 40 mg L^-1. The EC₅₀ values of diuron and irgarol for the normal embryogenesis rates were 20.07 mg L^-1 and 22.45 mg L^-1, respectively. The no observed effect concentrations (NOEC) were <1.25 mg L^-1 and the lowest observed effect concentrations (LOEC) were 1.25 mg L^-1 and 2.5 mg L^-1, respectively. From these results, concentrations of diuron and irgarol over 1.25 mg L^-1 and 2.5 mg L^-1, respectively, can be considered to have toxic effects on invertebrates, including M. nudus. The ecotoxicological bioassay in this study using the noted fertilization and normal embryogenesis rates of M. nudus can be used as baseline data for the continued establishment of environmental quality standards for the effects of antifouling agents(especially diuron and irgarol) in a marine environment.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.3 no.4
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• pp.249-260
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• 1998

To understand the attachment of micro algae and their subsequent growths on artificial surfaces immersed in seawater, the relationship between attachment of diatoms on the immersed artificial substrates and species pool in the surrounding water was investigated. We used acryl slides for the study of diatom attachment and examined the surrounding water samples collected in Incheon Harbour from July 1995 to February 1997. Variations of species composition and abundances by exposure time in seawater were investigated during the early phase of biofilm formation on various substrates, e.g. glass, acryl, titanium, copper and antifouling paint-treated slides. Immigration rates of diatoms to acryl slides during spring and winter were significantly correlated with the abundance of benthic diatoms in surrounding water ($r^2$=0.78, p<0.01, n=42), suggesting that immigration rates were affected by variations of benthic diatom abundances in surrounding water. Immigration coefficient of monoraphid diatoms was 5 times higher than that of biraphid diatoms, but relative abundance of monoraphid diatoms was 3 times lower than that of biraphid diatoms on acryl slides in spring. In winter, immigration coefficient and relative abundance of centric diatoms were higher compared to other raphe forms. These results suggest that the attachment of diatoms seems to be caused by the abundance and immigration coefficients of benthic diatoms in surrounding water. Pennate diatoms predominantly attached to all artificial surfaces throughout all experimental periods. Interestingly, centric diatoms predominantly attached to all artificial surfaces in winter. Hantzschia virgata, Licmophora abbreviata and Melosira nummuloides appeared dominantly on antifouling paint-treated slides, probably being tolerant of the antifouling paint. During incubations, the abundance of attached diatoms increased exponentially on glass, titanium and acryl slides with exposure time. The maximum abundance was highest on glass slide, followed by acryl, titanium, copper and antifouling paint-treated slides. The growth rates of attached diatom community on all artificial surfaces were higher at temperature of $24-25^{\circ}C$ than that of $2-3^{\circ}C$. The growth rate of attached diatoms on glass slide was generally higher compared to other slides during the study period. Dominant morphotypes of observed species with exposure time in seawater were prostrate form Amphora coffeaeformis, fan shape Synedra tabulata, stalk type Licmophora paradoxa and chain type M. nummuloides. A micro-succession in the attached microalgal community was observed. The composition of dominant species seems to be the result of species-specific response to gradually limited space with development of microalgal film.

• Journal of the korean society of oceanography
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• v.33 no.3
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• pp.64-70
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• 1998

Forty sediment samples from Kyeonggi Bay, Korea were analyzed for butyltins, including tributyltin (TBT), dibutyltin (DBT), and monobutyltin (MBT) to determine their distribution and source in this area. Total butyltin concentrations in Kyeonggi Bay sediments ranged from 0.8 to 297 ng/g dry wt. with a mean value of 38 ng/g. The highest butyltin concentration was found in the innermost site in Incheon Harbor basin. The mouth of Han River had higher butyltin levels in sediments compared to open ocean. Butyltin levels correlated well with organic carbon content of sediment, but the major factor was the distance from the source area where antifouling paints were used for vessels and marine structures. Butyltin concentrations in the study area were lower than those reported for bays in other parts of the world. Considering the high toxic potential and sediment/water partition coefficient of TBT, further studies are needed to assess its biological effect in the marine ecosystem of Kyeonggi Bay.

• Tribology and Lubricants
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• v.29 no.5
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• pp.304-309
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• 2013

Shark skin has functionalities such as self-cleaning and antifouling; it also exhibits excellent drag reduction owing to a hierarchical structure of microgrooves and nanometer-long chain mucus drag reduction interfaces around the shark body. In this study, the wettability of a shark skin surface and its replicas are evaluated. First, a shark skin template is taken from a real shark. Then, shark skin replicas are produced directly from a shark skin template, using a micromolding technique. The quantitative replication precision of the shark skin replicas is evaluated by comparing the geometry of the shark skin template to the replica using 2D surface profiles. Contact angles at the solid-air-water interfaces are evaluated for the shark skin template and its replicas under two conditions: with and without hydrophobic coating. The results show that the microriblets on shark skin improve the hydrophobic feature and play a critical role in self-cleaning.

• Environmental Analysis Health and Toxicology
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• v.15 no.4
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• pp.115-122
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• 2000

Biocides, or non-agricultural pesticides, are a broad class of chemical. They are including biological agents used to disinfect/sanitize, pesticides for non-agricultural use, wood preservatives, antifoulants, etc. Since the early 1980s, many adverse effects of biocides to human health and ecosystem have been found in the world. Especially, antifouling biocide like TBT caused serious toxic effects on the marine organisms. Therefore, OECD began to work on biocides in mid 1996 to help Member countries co-operate in the assessment and registration of these products. EU also announced the Biocidal Products Directive (BPD, 98/8/EC) in 1998 to harmonize regulatory approaches to allow EU countries to conduct evaluations of biocides more efficiently. Korea just start to consider of biocides regulation. Some biocides products are regulated, but not all the biocides which are using in Korea. Therefore, we need to make a appropriate regulation for the all biocides categories. In addition, there are necessary to develop risk assessment tools, to survey the use pattern and amount, to research on the ecosystem contamination by the biocides .

• Proceedings of the Polymer Society of Korea Conference
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• 2006.10a
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• pp.379-379
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• 2006

AcAP was prepared by reacting p-hydroxyacetophenone (HAP) with acryloyl chloride (Ac) in presence of triethylamine (TEA) in MEK at $0^{\circ}C$. The reaction was monitored by TLC and the prepared monomer was characterized by UV, IR, $^{1}H-NMR\;and\;GC-MS$. The homo- [poly (AcAP)] and copolymers [poly (AcAP-co-MMA)] were prepared by solution polymerization at $70^{\circ}C$, in which BPO as initiator. The molecular weight of the polymers was determined by GPC. In order to find out the AF activity of prepared polymers, representatives of marine microfoulers, shipfouling bacteria (B. macroides & P. aeruginosa) and microalgae (A. coffeaeformis & N. incerta) were screened. The results of antibacterial activity and diatom attachment assays revealed potential AF efficiency of these polymers.

• Proceedings of the Polymer Society of Korea Conference
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• 2006.10a
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• pp.381-381
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• 2006

AcDP and AcAP were prepared by the reaction of acryloyl chloride (Ac) with 2,4,4' -trichloro-2' -hydroxydiphenyl ether (DP) and p-hydroxyacetophenone respectively in presence of triethylamine (TEA) in MEK at $0^{\circ}C$. The reaction was monitored by TLC and the prepared monomer was characterized by UV, IR, $1^H-NMR$ and GC-MS. Further, copolymers poly (AcDP-MMA-AcAP) were prepared in different feed ratio of monomers by free radical polymerization at $70^{\circ}C$, in which BPO as initiator and their molecular weight was determined by GPC. The AF activity of prepared polymers was investigated against representatives of marine microfoulers, shipfouling bacteria (B. macroides & P. aeruginosa) and microalgae (A.coffeaeformis & N. incerta). The antibacterial activity and diatom attachment assays showed significant AF potential of these polymers.

• Journal of Environmental Health Sciences
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• v.29 no.3
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• pp.1-8
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• 2003

The development of environmentally nontoxic or non-polluting antifouling additives that can be formulated in practical coating requires assay involving target organisms. Described here are the simple laboratory assays that have been developed using the barnacle, Balanus amphitrite, a common fouling organism found throughout temperate and tropical seas. One of the assays depends on synchronous year-round mass culture, the procedure for which is described, of nauplii larvae and cyprids larvae. The laboratory assays provided quantitative estimates of toxicity and settlement inhibition of the test compounds. Laurinterol (1), isolaurinterol (2), alpysinal (3), and aplysin (4) have been isolated from the Korean red alga Laurencia okamurae. Their structures were identified by spectral data in comparison with the literature data. Compounds 1-4 inhibited larval settlement of the barnacle B. amphitrite with EC$_{50}$ values of 0.18- 36 $\mu\textrm{g}$/ml. Com-pounds 2-4 showed larval toxicity against nauplii of the barnacle B. amphitrite with 5-10 $\mu\textrm{g}$/ml, while laurinterol (1) exhibited no toxicity at even 100 $\mu\textrm{g}$/ml. Therefore, laurinterol was expected as a promising natural antifoulant.t.

• Proceedings of the Korean Society of Toxicology Conference
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• 2003.05a
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• pp.68-69
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• 2003

Tributyltin (TBT) used world-wide in antifouling paints for ships is a widespread environmental pollutant and cause reproductive organs atrophy in rodents. At low doses, antiproliferative modes of action have been shown to be involved, whereas at higher doses apoptosis seems to be the mechanism of toxicity in reproductive organs by TBT. (omitted)