In the present study the main aim was to fabricate the nanofiber polymeric membrane with improved surface properties for application as an antifouling microfiltration membrane in wastewater treatment. The improved nanofiber microfiltration membranes were electrospun from the polyacrylonitrile solutions containing 0.5 to 5 w/w% boehmite nanoparticles. Embedding the hydrophilic boehmite nanoparticles increased the surface hydrophilicity and antifouling properties of the membrane. Among the prepared nanofiber microfiltration membranes, the 3 w/w% boehmites embedded polyacrylonitrile nanofiber membrane (MD) was selected as the membrane with optimum antifouling properties and permeate flux. Concerning the results obtained, our prepared antifouling nanofiber membrane can be efficiently used for wastewater treatment applications.

In this study, the polyethersulfone (PES) membranes were established by surface modification using C, N codoped-TiO2/WO3 (LTW) photocatalytic nanocomposite to amelioration of the membrane performance in terms of antifouling and self-cleaning properties. The nanocomposite membranes were characterized by ATR-FTIR, SEM, AFM, and water contact angle (WCA). The photocatalytic membranes' performance was evaluated using assessment of the pure water flux (PWF), antifouling behavior, photoactivity, and long-term filtration. The membrane modification improved morphology and hydrophilicity of the membranes surface, contributing to the enhanced permeability (PWF of 49.65 kg/m2.h), and substantial antifouling property (FRR of 96.96 %) as well as photoactivity (94.36 % dye removal) of the optimal photocatalytic membrane (M3 membrane). The long-term filtration of the optimal membrane represented its high performance and noteworthy antifouling resistance.

In the marine environment, biofouling phenomenon is referred to as the undesired colonization of marine organisms on anthropogenic surfaces that are immersed into the seawater. To deter the unwanted biofouling, it is common to coat the immersed surfaces with a layer of antifouling paint, which will release antifouling biocide in a controlled manner to form a protective film against nearby biofoulers. The purpose of this study is to review the studies done in this field, especially in the direction of sustainable environmental protection and marine organisms. The research method included searching for articles in Google Scholar using antifouling, biocides and related keywords. The results showed that all biocides used in commercial antifouling paints detrimental the environment and non-target marine organisms. In general, by knowing the fate and pollution caused by biocides in the marine environment, appropriate measures can be taken to protect marine natural resources. It is hoped that in the near future, foul-release coatings will replace today's coatings and paints as biocide-free and environmentally safe coatings.

Antifouling paints are applied to prevent the growth of marine biofouling. In Indonesia, that paint is widely used for ship which commonly used copper-based biocide. In fact, there is no or little comprehesive studies on antifouling paint in Indonesia compared to other tropical countries. In this study, the evaluation of the performance for antifouling paint was carried out where anticorrosion  paint and bare steel were also studied as references. The measurement of corrosion rate on steel was conducted by weight loss method. The panels containing specimens were exposure up to 1-month for immersion in different depth of sea up to 3 meters. Seawater parameters consisting of temperature, pH, salinity, conductivity and dissolved oxygen were measured as well as coating properties. The results showed both surfaces of anticorrosion paint and steel specimens covered by biofouling, but not on antifouling paint. There also is not much different in antifouling paint properties before and after exposure in various depth of sea. The reduction of thickness for antifouling paint is apparently predominant to be affected by sea current. The magnitude of corrosion rate on bare steel is almost the same in different depth of sea which took place due to the effect of dissolved oxygen and biofouling. In the future, the comparison of the paints perfomance all local regions is necessary to be conducted in all local regions of the Indonesia.

Development of natural and environmentally friendly antifouling agents is a suitable alternative to solve the global marine fouling problem. In the current study, antibacterial, anti-micro algal, anti-barnacle and antifouling activity of non-polar, semi-polar and polar extracts from three parts of the sea cucumber, Stichopus herrmanni, body (i.e. body wall, digestive tract and respiratory tree) were studied. The inhibitory activity assay of n-hexan, ethyl acetate and methanol extracts were evaluated against five bacterial strains, two microalgae species and barnacle larvae. In order to investigate the antifouling performance, the extracts were added to a resin epoxy coats and exposed in the sea water for the duration of three months. Based on Results, the ethyl acetate extract of the body wall with the lowest MIC against S. aureus (0.500 mg/ml) and I. galbana (0.125 mg/ml), and the lowest LC50 against barnacle larvae (0.061 mg/ml), showed the best inhibitory activity. After three months treatment, the coated panels containing 4% extract of ethyl acetate from body wall had the lowest final weight (189.67 ± 5.51 g) and lowest fouling cover percentage (74.76%) among all the panels (P<0.05). Regarding the high antifouling activity of ethyl acetate extract from the body wall of the sea cucumber S. herrmanni, it is recommended as a potential natural alternative for the antifouling coats.

Polyethersulfone membrane modification by placing hydrophilic nanoparticles in the membrane matrix can improve antifouling ability. In this study, the Fe3O4 nanoparticles were modified by immobilizing SiO2, KCC-1, GMSI, and Carnosine. After surface modification, the nanoparticles were brought into polyether sulfone-based nanofiltration membranes to improve the membrane permeability, separation efficiency, and antifouling ability. The effect of nanoparticles on membrane structure and its performance was investigated using Field Emission Scanning Electron Microscopy (FE-SEM), Atomic Force Microscopy (AFM), water contact angle, mean pore size and porosity measurements, pure water flux, and wastewater treatment, as well as antifouling ability. Based on the results, increasing the concentration of nanoparticles from 0 to 0.1 wt% developed the membranes to a more porous structure in the sub-layer, higher thickness, increased pure water flux, higher hydrophilicity, and fouling resistance. Consequently, the membrane with 0.1 wt% of nanoparticles endorsed a decreasing contact angle from 76 ±1 to 60.3±0.2, increasing pure water flux from 50.96 L/m2h to 93.42 L/m2h at a pressure of 9 bar, and a relatively high flux recovery ratio of 95.5%. Thus, a considerable performance of the prepared membrane was established in treating the oily wastewater contaminants.

The use of natural antifouling agents is a new and suitable approach to solve the worldwide biofouling problem. In this study, anti-micro algal and antifouling activity of a series of n-hexane, ethyl acetate and methanol extracts from four sections of sea cucumber Holothuria leucospilota (body wall, gonad, digestive tract and respiratory tree) were investigated. Anti-microalgal assay against two microalgae species Chlorella vulgaris and Isochrysis galbana was conducted to determine the minimum inhibitory concentration (MIC) for each extract. The best extracts were added to resin epoxy and applied on fiberglass panels (10×10cm). All panels were immersed in the Persian Gulf (Bandar-e-Gorzeh) for three months. Results indicated that ethyl acetate extract of the body wall had the best inhibitory activity against I. galbana, with MIC of 0.062 mg/mL. Based on field results, the panel coated with 4% ethyl acetate extract from body wall added to resin epoxy had the lowest final weight (123.33±8.32g) and lowest fouling cover percentage (57.8%) among all panels after three months‏ (P<0.05). Regarding the high antifouling activity of ethyl acetate extract from the body wall of sea cucumber H. leucospilota, its use as a potential alternative to commercial biocides in antifouling coats is suggestable.

Regarding the negative impacts of using toxic antifouling paints to solve the problem of biofouling, the development of non-toxic paints from natural products and their application in marine industries has gain importance. In the present study, the antifouling properties of Zataria multiflora essential oil in antifouling epoxy paint were investigated. Antibiofouling activity of essential oil was proved by antibacterial, antimicroalgal, antibarnacel and antiartemia activities. The minimum inhibitory concentration was 0.125 and 0.250 mg/L against two bacteria Staphylococcus aureus and Escherichia coli, respectively. According to antimicroalgal adherence assay, essential oil had inhibited the average specific growth rate of Isochrysis galbana with effective concentration of 52.186±17.67mg/L and LC50 was 8.720±1.28 and 35.210±2.37mg/L against antibarnacel and antiartemia, respectively. The essential oil was added to epoxy paint and coated on the fiberglass panel exposed to seawater for three months. At the end of the first and second months, the coated panels containing 3% essential oil had the lowest weight (78.81±22.2 and 178.44±6.58 g, respectively) and lowest fouling cover percentage (63.52±1.92% and 92.05±3.34%, respectively) (P<0.05). Results showed that the effectiveness of antifouling activity of Z. multiflora essential oil depends on the amount of essential oil in the paint and its wash rate in seawater.

Replacing toxic antifouling paints with coatings that have no effect on the marine environment is an important issue. Phenazine 1-carboxylic acid (PCA) is one of the effective antibiotics, which can be used as antifouling agent in marine coatings to prevent attachment of marine species on ship hulls. In this study, Phenazine 1-carboxylic acid (PCA) as an antibacterial agent which produced by Pseudomonas Aeruginosa MUT.3 was investigated. PCA extraction process was optimized using Response Surface Methodology (RSM). Results showed that at 30 min mixing time, 150% of solvent and using ethyl acetate as solvent are considered the optimum levels and factors in phenazine 1-carboxylic acid production which produced by P. aeruginosa MUT.3. In the present paper, the optimization of extraction process suggested as an effective way to increase the production in biological processes in which the extraction of PCA increased by 34% compared to previous reports.

Nowadays, speed in high speed crafts is of particular importance. Creation in of moss on the hull is one of the factors slowing down the vessel. Among the methods of removing moss, Painting hull is the most effective and the cheapest method among other methods used to remove moss. Antifouling paints, were introduced to the market from the early 20th century among them TBT- SPC Free and tin-free glossy paints has been highly regarded (in terms of quality and economical). This sample of the paints, reduces friction force between water and draught, as well as reducing the surface roughness resulting in less fuel consumption and an increase in speed of the vessel. However, they are rarely used for the vessels, due to environmental pollution this article is about the maintenance of the hull against seaweeds using antifouling paints.