### Nanotechnology in Wastewater Treatment  
Different treatment techniques can effectively remove pollutants, chemicals, and pathogens. Traditional water treatment involves various methods such as filtration, coagulation, and flocculation for gathering and removing impurities, sedimentation, and disinfection using processes like chlorination, UV irradiation, and ozonation [7]. In addition, advanced techniques such as reverse osmosis removal, ion exchange, and desalination are used to treat wastewater. The development of nanoscience and nanotechnology offers a promising solution to the drawbacks associated with conventional water treatment [8,9]. Particles with diameters smaller than 100 nm are called nanoparticles (NPs). Nanomaterials, including NPs, with their unique properties, such as high adsorption capacity, catalytic activity, and reactivity, have gained attention for their effectiveness in water and wastewater treatment [10,11]. Recent advancements in nanomaterials, including nano photocatalysts, nanomembranes, and nano sorbents, provide diverse tools in the field of water treatment [12]. Therefore, nanotechnology serves not only as a catalyst for advancing the field but also introduces innovative pathways to enhance pollutant removal efficiency [13]. Adsorption is a fundamental physical technique used to remove pollutants from the environment that depends on the active involvement of nanomaterials. This method has several advantages compared to other mentioned methods, which are explained in Table 1.  
NPs play an important role in nanotechnology for water treatment, offering innovative solutions to address water pollution challenges [14]. The integration of traditional and modern approaches highlights the dynamic nature of research and development in water treatment [15]. This collaboration addresses the increasing need for sustainable, durable, and effective water treatment solutions [16]. The NPs have been classified into two important categories: carbon nanoparticles (CNPs) and metal-oxide nanoparticles (MONPs), as shown in Figure 1.  
Several review papers have been recently published regarding the role of nanomaterials in water treatment [17,18,19,20,21,12], the application of CNPs in water treatment [6,22,23], and the role of MONPs in water treatment [10,24]. Therefore, the efficiency of different types of CNPs and MONPs in wastewater treatment and their synthesis methods in recently published studies have been reviewed and discussed. In this review, the selection of studies  
\begin{table}
\begin{tabular}{c c c c} \hline \hline
**Method** & **Types of Pollutants** & **Pros** & **Cons** \\ \hline \multirow{3}{*}{adsorption} & Organic & Low cost & Selective removal \\  & Inorganic (heavy metals, elements) & Easy operation & Adsorbent fouling \\  & Microbes & High efficiency & Disposal issues \\ \hline \multirow{3}{*}{Photocatalysis} & \multirow{3}{*}{Organic} & No secondary pollution & High energy required \\  & & Complete & Slow reaction rate \\  & & degradation of pollutants & High \\ \hline \multirow{3}{*}{Nanomembrane} & Microbes & Fewer chemicals & High cost and high energy \\  & Particulates & High efficiency & needed \\ \cline{1-1}  & Organic & Low waste & Waste generation \\ \cline{1-1}  & Inorganic & generation & Selective removal \\ \hline \multirow{3}{*}{Disinfection} & \multirow{3}{*}{Microbes} & Low cost & High level of toxicity \\ \cline{1-1}  & & Low cost & generation \\ \cline{1-1}  & & Environmentally friendly & Potential taste and odor \\ \cline{1-1}  & & Limited scalability \\ \hline \hline \end{tabular}
\end{table}
Table 1: Different nanotechnology methods for water treatment.  
was based on their main scope and the year (about 130 studies have been published within 2020-2024). In the end, 70 papers were selected and analyzed in detail, and their results have been summarized.