# Adsorption of Coxsackievirus in Sediments: Influencing Factors, Kinetics, and Isotherm Modeling
## 1 Introduction  
Groundwater plays a critical role in maintaining an ecosystem balance and promoting the sustainable advancement of human society, particularly in regions facing rapid economic and population growth [1]. In recent years, there has been a growing focus on groundwater pollution caused by viruses [2; 3; 4]. The origins of bacteria and viruses in groundwater primarily stem from sources such as domestic sewage, hospital wastewater, and leachate from waste. Undisinfected sewage carries a substantial load of bacteria and viruses, leading to the biological contamination of groundwater through infiltration during sewage irrigation and seepage pits reaching the vadose zone and saturated water zone. It affects millions of people globally each year, standing as a major contributor to healthissues worldwide [5; 6; 7]. Cases involving viruses have become increasingly prevalent and widespread [1]. Among the viruses leading to water contamination, the presence of enteric viruses is responsible for considerable mortality worldwide, with frequent reports of outbreaks linked to contaminated drinking water sources, especially in developing countries [8; 9; 10; 11; 12]. The prevalence and extensive distribution of enteric viral infections have led to significant research attention on attenuating viruses in sediments [13; 14]. Among them, cosrackioviruses are common among enteroviruses that can survive in the aquatic environment for weeks to months and migrate in groundwater systems [15; 16]. Enteric viruses can cause a range of illnesses and are associated with symptoms such as gastroenteritis, respiratory problems, conjunctivitis, hepatitis, central nervous system infections, and muscular syndromes. Infected individuals can excrete a large number of virus particles in their stool, typically between \(10^{5}\) and \(10^{11}\) virus particles per gram. Consequently, wastewater that contains fecal matter can have high concentrations of enteric viruses. While wastewater treatment systems can remove around 20-80% of these viruses, a significant viral load is still released into the environment through effluent discharge. This can result in the spread of viruses in groundwater, estuarine water, seawater, and rivers. It is important to note that the concentration of enteric viruses in water can vary based on factors such as season, prevalence of viral infections, and the type of pollution sources [17]. The attenuation of viral particles in groundwater is mainly controlled by two processes: inactivation and adsorption aggregation [18; 19]. These mechanisms actively contribute to reducing the concentration of infectious virus in the aqueous phase [20]. Generally, the inactivation and adsorption of viruses in groundwater are considered separate phenomena [21]. Within a few hours, viral inactivation can be reasonably overlooked, with existing reports suggesting that it has reached or been presumed to have achieved equilibrium adsorption [22]. When examining virus adsorption, the influence of inactivation is typically disregarded due to its occurrence within a relatively short time span of hours [23]. Conversely, when studying virus inactivation, adsorption phenomena are considered inconsequential as virus viability is monitored over the course of several days or months [24]. Hence, acquiring a thorough comprehension of the adsorption behavior exhibited by viruses in groundwater is essential to ensure the preservation of water quality and overall safety. The adsorption of viruses onto suspended particles predominantly depends on the interplay between the surface structures and chemical compositions of both the adsorbent and adsorbate [25]. Attaining maximum virus adsorption onto clay materials can happen instantaneously or may take several minutes, or even hours [26].