# Adsorption of Coxsackievirus in Sediments: Influencing Factors, Kinetics, and Isotherm Modeling
## 1 Introduction
Empirical scrutiny has uncovered correlations between virus adsorption onto sediment surfaces and a range of factors, including microbial and sediment typologies, sediment particle size, adsorption duration, adsorption temperature, pH values, ion concentrations, and solid-liquid ratios [27; 28]. The ionizable amino acid composition of the protein coat in most viruses makes them sensitive to environmental pH, which in turn affects their ionization and influences their adsorption and desorption behavior on particle surfaces. Numerous equilibrium experiments consistently demonstrate a decreasing trend in virus adsorption onto particles as pH increases [29; 30; 31]. [PERSON], [PERSON] [32] discovered that in sandy soil, dissolved soil organic matter competes with MS-2 for binding sites and can modify the surface charges of sorption sites. This can suppress the salinity effect on MS-2 sorption, but high salinity levels can overcome this suppression and result in MS-2 sorption on reversible sites in sandy soil. However, current research commonly employs bacteriophages (such as MS2, PRDI) as proxies for pathogenic viruses, with limited consideration given to real viruses [33; 34; 35]. Yet, significant distinctions exist in terms of morphology, activity, and physicochemical properties between bacteriophages and viruses [36]. Studies have demonstrated that bacteriophage indicators or substitutes are often absent or lack a direct correlation with enteric viruses [37]. Using bacteriophages as substitutes may lead to the underestimation of virus occurrence, casting doubt on the reliability of predictive assessments [38; 39]. Meanwhile, when examining the influential factors on virus behavior even with a real virus,experiments often tend to be conducted from a purely biological perspective, overlooking the significance of the groundwater environment [40, 41]. Coxsackievirus, a common enteric virus, serves as a representative in the category of enteric viruses for groundwater transmission. It can result in mild to severe gastrointestinal symptoms, including diarrhea, vomiting, and abdominal pain. The physicochemical attributes of Cossackievirus, including size, morphology, surface charge, capsid conformation, and the arrangement of charged, hydrophilic, and hydrophobic amino acids, play a significant role in the interaction between the virus and the adsorbent material [42]. Therefore, this study aims to investigate the adsorption behavior of Cossackievirus A16 (CA16), the most common strain of cossackievirus associated with mild to severe gastrointestinal symptoms. The research was conducted in a state-of-the-art biosafety level 2 laboratory, strictly adhering to rigorous experimental standards to ensure the accuracy and reliability of the results. Using the standardized batch equilibrium method, the study thoroughly investigated the influence of various factors, including the virus's initial concentration, temperature, sediment particle size, pH value, and presence of humic acid, on its adsorption and adsorption behavior in this study. The main aim was to analyze the adsorption patterns of CA16, observe variations under different influencing factors, and establish quantitative relationships between adsorption and the aforementioned factors. Comparative analysis of different virus models, developed under diverse experimental conditions, was conducted to identify the most suitable model. The findings from this research are significant in two key aspects. Firstly, they contribute to an enhanced understanding of the interactions and behaviors of viruses in groundwater. Secondly, they provide crucial safety evidence for evaluating health risks associated with virus contamination in groundwater.