# Micro-Nanobubble Technology in Surface Cleaning and Defouling
## 4 Biofouling Mitigation and Advanced Cleaning Technologies
### Sustainable Cleaning Techniques  
Sustainable cleaning methods that utilize NBs and ROS have become popular and are eco-friendly for removing pollutants and biofilms from various surfaces [109]. In addition to lowering the dependency on harsh chemicals and decreasing environmental effects, these techniques integrate cutting-edge techniques to improve the cleaning efficiency [25]. [PERSON] et al. [68] examined the effectiveness of air bubbles in cleaning contaminated surfaces, paying particular attention to the inclination angles for optimal sanitation, especially for agricultural products. Bubbles worked best at an inclination angle of about 22\({}^{\circ}\) (or \(\pi/8\)), according to experiments performed on surfaces coated with either a protein solution or a bacterial biofilm. The findings suggested that the angle of inclination was more important than the surface wettability for achieving efficient cleaning. Considering that the cleaning performance was influenced by the balance between the sliding speed and film thickness, a numerical analysis of the bubble impact verified that the maximum shear force occurred at this angle. According to the research, biomedical devices and delicate surfaces such as fruits and vegetables may benefit from this environmentally friendly cleaning technique. Future studies should examine how the bubble size and dynamics affect curved surfaces to improve cleaning efficacy. [PERSON] et al. [109] discussed a new technique for cleaning the ceramic membranes used in drinking water treatment that utilizes ozone and MNBs (O\({}_{3}\)-MNBs) to increase the cleaning effectiveness. In this study, tyrosine-like proteins and soluble microbial byproducts were identified as the primary causes of membrane fouling. These factors were strongly correlated with the levels of dissolved organic carbon. At a low ozone dosage of 10 mg/L, O\({}_{3}\)-MNBs showed better cleaning performance than conventional sodium hypochlorite, achieving a cleaning efficiency of 86.72% as opposed to 66.91% with conventional ozone. By increasing the hydrophilia and porosity of the fouling layer and reducing the environmental impact of the chemical cleaning agents, the O\({}_{3}\)-MNBs technique successfully eliminated irreversible fouling and restored the membrane flux. The results implied that this novel strategy could greatly enhance ceramic membrane cleaning procedures, especially in industrial settings where biofilms and other contaminants must be removed. [PERSON] et al. [110] discussed the application of ozone NBs (ozone-NBs) as a successful cleaning agent for ceramic membrane fouling, which is a major problem in water treatment, particularly in the dye sector (Figure 17). After a 4 h cleaning procedure, the membrane flux increased from 608 L/h/m\({}^{2}\) to 1050 L/h/m\({}^{2}\), nearly doubling, with a 50% recovery rate. This study introduced a novel ozone-NB generator system. As a result of the cleaning process, the membrane's surface properties showed noticeable changes, such as less foulant buildup and a change in color from dark blue to lighter hues, suggesting less dye fouling. The results were corroborated by a zeta potential of \(-\)20.26 \(\pm\) 0.13 mV, which indicated the presence of negatively charged surfaces. They showed that ROS produced during ozone-NB cavitation were significant contributors to this improvement. According to the study, ozone-NBs greatly improved the ability of the ceramic membranes to remove foulants, underscoring the potential of this cutting-edge and environmentally friendly technology for solving fouling problems in water treatment applications. Furthermore, MNB technology has shown significant potential in various industries such as food, agriculture, and cosmetics. In the food manufacturing industry, both NBs and MBs are utilized to clean and decontaminate surfaces and equipment. Their capacity to enter tiny cracks enables efficient biofilm removal and disinfection, guaranteeing sanitary conditions in processing settings.