1. 2. Thanks to this reviewer for the comment. Common waterborne viruses include Shigella, Vibrio cholerae, Poliovirus, adenovirus, and coxsackie virus, with sizes of 26 nm, 27 nm, 30 nm, 90 nm, and 30 nm, respectively [1-5]. The molecular weights of PPCPs are generally less than 1000 Da (about 1-2 nm), obviously smaller than the virus. The molecular weight cut off of UF membranes was an average 100 000 Da in this work, which was similar to the virus but larger than the PPCPs molecules. Karthik K, Dhanuskodi S, Gobinath C, et al. Multifunctional properties of microwave assisted CdO–NiO–ZnO mixed metal oxide nanocomposite: enhanced photocatalytic and antibacterial activities [J]. Journal of Materials Science: Materials in Electronics, 2018, 29(7): 5459-71. Song S, Liu Z, Zhou J, et al. An adjuvant compound that enhances immunogenicity at fractional doses of the Sabin-inactivated poliovirus vaccine (sIPV) with a long duration of protection in a rat model [J]. Journal of Medical Virology, 2019, 91(1): 14-21. Kim K, Choi J-W, Ma K, et al. Nanoisland-Based Random Activation of Fluorescence for Visualizing Endocytotic Internalization of Adenovirus [J]. Small, 2010, 6(12): 1293-9. Dourmashkin R R, Mccall S A, Dourmashkin N, et al. Virus-like particles and enterovirus antigen found in the brainstem neurons of Parkinson's disease [J]. F1000Res, 2018, 7: 302-. Tamano K, Aizawa S-I, Katayama E, et al. Supramolecular structure of the Shigella type III secretion machinery: the needle part is changeable in length and essential for delivery of effectors [J]. The EMBO Journal, 2000, 19(15): 3876-87.
Line 46-52: & line 84-85 “Ultrafiltration (UF) as an emerging alternative technology to conventional water treatment processes, has been widely used to remove pollutants such as particles, colloids, bacteria, and viruses, thus reducing the risk of water-borne diseases [10]. Size exclusion is considered the primary removal mechanism for the UF. However, in the case of the PPCPs with a small molecular weight (typically < 600 Da), UF membranes also cannot effectively reject these PPCPs, but nanofiltration and reverse osmosis are able to remove these PPCPs based on the thin-film composite”. Sorry, but I don't see why UF can reject viruses and bacteria but not PPCPs. Is it true that the molecular weight of viruses and bacteria is more than that of PPCPs? Please elaborate.