تاريخ النشر الصنف اللغة الصورة الملفات المسموح بها: JPG, PNG | الحد الأعلى 500 كيلوبايت | يجب أن تكون الصورة مربعة أو أفقية الصور الإضافية (حتى 3) — مطلوبة صورة واحدة على الأقل صورة 1 JPG/PNG ≤ 500KB إزالة صورة 2 JPG/PNG ≤ 500KB إزالة صورة 3 JPG/PNG ≤ 500KB إزالة إضافة مرفق إضافةإلغاءWater treatment and purification represent critically important global challenges in achieving Sustainable Development Goal 6 (SDG 6): Clean Water and Sanitation. In recent years, laser technologies have emerged as powerful and efficient tools across multiple stages of water treatment, offering high-efficiency solutions with minimal chemical residues compared to conventional methods. This article reviews the most prominent academic and research-based applications of laser radiation in water purification, with particular emphasis on disinfection, organic contaminant removal, and desalination technologies. ➢ Applications of Lasers in Disinfection and Sterilization Disinfection is a fundamental step in ensuring the safety of drinking water. Laser radiation is used as an intense, highly directed light source to achieve effective sterilization. ∗ Ultraviolet Lasers (UV Lasers) Principle: Short wavelengths within the UVC range (200–280 nm), particularly around 220 nm and 270 nm, are utilized. At these wavelengths, the nucleic acids of microorganisms (such as bacteria and viruses) strongly absorb laser energy. This absorption induces photochemical reactions that alter DNA structure (e.g., formation of thymine dimers), thereby disabling the organism’s ability to reproduce (inactivation). Academic Advantages: Compared with conventional mercury lamps used in UV disinfection, laser systems provide superior precision and beam-focusing efficiency, while significantly reducing the risk of mercury toxicity from water in the event of lamp breakage. ∗ Femtosecond Lasers Recent studies have demonstrated the feasibility of using highly focused femtosecond laser pulses to inhibit bacterial growth, such as Escherichia coli (E. coli), by exposing bacterial cells to controlled laser doses (e.g., at a wavelength of 400 nm). This approach represents a promising, environmentally friendly method for remote disinfection without direct chemical contact. ➢ Lasers in Desalination and Evaporation Laser technologies contribute to the development of innovative and energy-efficient desalination processes. ∗ Laser-Enhanced Solar Evaporation Lasers are used to treat metal surfaces (such as aluminum) to render them super-wicking and highly absorptive of solar energy. Mechanism: Laser-treated panels are positioned at an angle facing the sun, allowing a thin layer of water to be drawn upward along the surface. The modified surface absorbs nearly 100% of incident solar energy, leading to rapid heating and evaporation of surface water while leaving behind salt and contaminants. This method has demonstrated effective removal of common pollutants and heavy metals to safe levels. ∗ Carbon Dioxide (CO₂) Lasers Some studies indicate the potential use of CO₂ lasers to induce localized thermal effects in water that promote evaporation, which could theoretically be exploited in desalination processes. Lasers in the Removal of Chemical and Organic Contaminants ∗ Photocatalysis Lasers facilitate the synthesis of nanoscale photocatalysts (such as titanium dioxide nanoparticles) through techniques such as Pulsed Laser Ablation in Liquids (PLAL). Mechanism: These nanomaterials, when exposed to light (laser or ultraviolet), generate reactive oxygen species (such as hydroxyl radicals, OH) that oxidize and decompose toxic organic compounds, pesticides, and pharmaceutical pollutants into less harmful or harmless products, such as carbon dioxide and water. Decomposition of Recalcitrant Compounds (Phenol Decomposition) Laser-assisted processes have been investigated for the degradation of biologically resistant organic compounds, such as phenol, in industrial wastewater. This research supports conventional biological treatment systems by reducing phenol concentrations to levels that are non-toxic to microorganisms. ➢ Lasers in Water Quality Monitoring and Analysis ∗ Laser-Induced Breakdown Spectroscopy (LIBS) This technique is employed to determine the chemical composition of water and its solid contaminants (such as heavy metals) by directing a high-energy laser pulse at a water sample or sediment. The resulting plasma emission is analyzed to accurately identify elemental constituents, making LIBS a valuable tool for precise environmental monitoring. Conclusion Laser-based applications in water purification represent a rapidly expanding research field with strong potential for delivering sustainable solutions. The academic strength of laser technologies lies in their high precision, reduced reliance on chemical additives in certain applications (such as UVC disinfection and photocatalysis), and energy efficiency in selected processes, including nanostructure-enhanced desalination. Future research directions focus on developing more efficient and reliable solid-state lasers and integrating laser technologies into decentralized, small-scale water treatment systems designed to serve communities lacking extensive infrastructure. References 1. Okuno, M. R. et al., “UV Laser Disinfection of Water: Efficiency and Mechanism against Bacterial Spores,” Water Research, Vol. 210, Issue 4, 2020. 2. Singh, R. K. et al., “The Use of Femtosecond Laser Pulses for Highly Localized Disinfection of Water,” Applied Physics B, Vol. 138, No. 6, 2022. 3. Raghunath, A., & Ghosh, “Comparative Analysis of UVC-LED and Laser Diode Efficiency in Microbial Inactivation,” Environmental Science & Technology Letters, Vol. 10, Issue 1, 2023. Al-Mustaqbal university is the top-ranked among Iraqi universities.