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Abstract: As an important part of dissolved organic matter (DOM), low molecular weight organic acids (LOAs) may play a key role in the process for DOM stabilizing carbon nanomaterials (e.g. C60) suspensions in aquatic environment. In addition, both LOAs and C60 have been detected in the troposphere and therefore have a chance to interact with each other in the gaseous phase. However, the mechanism for LOAs–C60 interactions and their environmental implications need further investigations. In this study, molecular dynamics (MD) simulation was employed to investigate the interactions between both neutral and ionic LOAs with C60 in vacuum and water. The results showed that the adsorptions of all LOAs on C60 in energy are favorable, and the aromatic acids have stronger interactions with C60 than the aliphatic acids in vacuum and water. The interaction energies (E int) of the LOA anions with C60 were weaker than those of their corresponding neutral LOA molecules. The models were also developed to predict and interpret E int based on the results from MD simulations. Dispersion, induction and hydrophobic interactions were found to be the dominating factor in E int. These findings indicate that cost-efficient MD simulation can be employed as an important tool to predict the adsorption behavior of LOAs on carbon nanomaterials. [Copyright &y& Elsevier]

As a widely produced and used antibiotic, tetracycline (TC) has been frequently found in rivers, soil and drinking water. In this study, the degradation of TC was investigated by UV/Fe 3+ /persulfate (PS) coupled process. The degradation behavior was well fitted with pseudo-first-order model. Hydroxyl radicals (·OH), sulfate radicals (SO 4 - ·) and superoxide radical (O 2 - ·) were identified as the primary reactive oxygen species (ROS) in UV/Fe 3+ /PS process, the contribution to TC degradation were found to be 41.94%, 33.94% and 17.44% at pH 3.0, respectively. Fe(IV) generated from the system also played a crucial role in TC removal. The effects of process parameters (PS/Fe 3+ dosages, pH, humic acid, Cl - , HCO 3 - , NO 3 - and CO 3 2- ) on degradation were investigated. It was found that the degradation of TC was highly pH-dependent, and the optimal performance was obtained at pH 3.0. Except for Cl - , the presence of HA, HCO 3 - , NO 3 - and CO 3 2- inhibited TC degradation. The possible transformation pathway involving the hydroxylation, N-demethylation, hydrogenation and dehydroxylation was proposed. Furthermore, the toxicity and mutagenicity of TC and transformation products (TPs) were estimated using ECOSAR and TEST softwares, demonstrating that the toxicity level of most TPs was lower/equal to their precursors. The evaluation of DBPs showed that UV/Fe 3+ /PS process could reduce the potential of DBPs formation, especially for TCAA and TCM. Microbial community composition was analyzed by 16 S rDNA sequencing, and the relative abundance of ARG-carrying opportunistic pathogens was significantly declined after UV/Fe 3+ /PS treatment. In general, this study provides an economical, efficient and safe strategy for TC removal., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier Ltd. All rights reserved.)