In wastewater treatment, antifouling coatings for fiberglass purification tanks require multiple surface properties to withstand complex operating conditions. The primary characteristic is low surface energy, the core foundation of antifouling performance. Low surface energy coatings reduce the contact area between harmful wastewater substances (such as microorganisms and chemical deposits) and the tank surface, thereby reducing adhesion strength. For example, fluoropolymer or silicone-modified resin coatings, through molecular structure engineering, achieve significantly lower surface tension than conventional materials, making it difficult for contaminants to form a stable adhesion layer. In fiberglass purification tank applications at municipal wastewater treatment plants, such coatings can reduce biofouling deposition by over 60%.
Chemical resistance is another key characteristic of antifouling coatings. Wastewater treatment environments often contain acidic, alkaline, or chlorinated media, and traditional coatings are susceptible to chemical attack, leading to swelling and blistering. High-performance epoxy vinyl ester resin coatings, by incorporating a bisphenol A or novolac epoxy backbone, form a dense, three-dimensional cross-linked network, effectively blocking the penetration of corrosive ions. In chemical wastewater treatment, this type of coating maintains stable performance within a pH range of 2-12, extending its service life by 2-3 times compared to conventional coatings.
Surface smoothness directly impacts dirt removal efficiency. Surfaces with microscopic roughness exceeding 0.5μm are prone to fouling. However, coatings modified with nano-scale fillers (such as fumed silica) can reduce surface roughness to below 0.1μm. This ultra-smooth surface not only reduces initial adhesion but also lowers water flow resistance, reducing energy consumption during dynamic cleaning by 30%. Applications at a petroleum refining company have shown that using a nanocomposite coating on a fiberglass purification tank increases suspended solids removal by 25% at the same backwash intensity.
Wear resistance is crucial for long-term fiberglass purification tank operation. Solid particles in wastewater (such as grit and metal oxides) can micro-cut the coating under the influence of the fluid. Polyurethane coatings reinforced with ceramic particles, through a hard phase dispersion reinforcement mechanism, can increase the coating hardness to over 6H while maintaining an elongation at break exceeding 20%. This combination of rigidity and flexibility reduces mass loss by 80% compared to conventional coatings when subjected to a 5N abrasion test, significantly extending maintenance cycles.
UV aging resistance is essential for outdoor fiberglass purification tanks. UV rays can break down the coating's molecular chains, leading to problems like powdering and cracking. Light-stabilized coatings infused with nano-titanium dioxide convert UV rays into harmless heat through photocatalysis. The resulting super-hydrophilic surface reduces dust adhesion. In actual testing at a wastewater treatment plant in a tropical region, this coating maintained a gloss retention rate of over 90% after three years of outdoor exposure, far exceeding the 60% achieved by conventional coatings.
Thermal stability ensures the coating's reliability under fluctuating temperatures. Wastewater treatment processes may involve high-temperature steam sterilization or low-temperature environments, requiring the coating to withstand temperatures between -40°C and 120°C without embrittlement or softening. Silicone-modified acrylic coatings, by incorporating flexible siloxane segments, can lower the glass transition temperature to -50°C while maintaining short-term heat resistance above 150°C, meeting the demands of extreme operating conditions.
Environmental compatibility is a key development direction for modern wastewater treatment coatings. Waterborne epoxy coatings, which use water as a dispersion medium, reduce VOC emissions by 90% compared to solvent-based coatings and contain no heavy metal additives. A food processing wastewater treatment project employed a bio-based epoxy coating that not only met drinking water contact standards but also passed biodegradability testing, achieving full lifecycle environmental friendliness. These characteristics are becoming a key consideration in coating selection amidst increasingly stringent environmental regulations.
