Biosynthesized silver supported catalysts for disinfection of Escherichia coli and organic pollutant from drinking water Muhammad Bilal a , Salma Khan a , Javed Ali a , Muhammad Ismail a , M.I. Khan a , Abdullah M. Asiri b,c , Sher Bahadar Khan b,c, ⁎ a Department of Chemistry, Kohat University of Science & Technology, Kohat-26000, Khyber Pakhtunkhwa, Pakistan b Center of Excellence for Advanced Materials Research, King Abdulaziz University, P.O. Box 80203, Jeddah 21589, Saudi Arabia c Chemistry Department, Faculty of Science, King Abdulaziz University, P. O. Box 80203, Jeddah 21589, Saudi Arabia abstract article info Article history: Received 23 December 2018 Received in revised form 31 January 2019 Accepted 19 February 2019 Available online 20 February 2019 Presence of Escherichia coli in water is mainly responsible for contamination of drinking water. Currently, organic materials are being used for disinfection of drinking water. However, antimicrobial inorganic materials have more potential due to their thermal resistance, chemical stability, and long lasting action period. In this work sil- ver nanoparticles (AgNPs) were synthesized by chemical and biological methods and then impregnated with dif- ferent support materials including Activated carbon, Zeolite and Magnesium oxide. Formation of nanoparticles was confirmed by UV/visible spectrophotometer due to their surface plasmon resonance, in which AgNPs showed a peak at 445 nm. XRD patterns gave characteristic patterns to AgNPs on support. AgNPs on support ma- terial were further verified by FE-SEM and EDX analyses. AgNPs supported catalysts were more active and all the bacteria were inhibited in drinking water. Beside antibacterial activity, the prepared catalysts shows excellent ac- tivity in the reduction of azo dye methyl orange. Among all, MgO impregnated silver catalysts show an outstand- ing methyl orange reduction with the rate constant of 7.48 × 10 -3 s -1 . So, it indicates that different supported AgNPs have the potential to be used for removal of microbial and organic pollutants from drinking water. © 2019 Elsevier B.V. All rights reserved. Keywords: Biosynthesis Silver nanocatalysts Azo dyes Water purification Escherichia coli 1. Introduction The supply of fresh and clean water is important to protect the com- munity health from different types of diseases. The adverse effects of drinking water and the increasing concerns about contamination of these effects are due to the existence of different pathogens and other industrial wastes. Approximately one billion people are drinking pol- luted water, which causes 2.2 million deaths in world per annum [1]. Water pollution can be caused by chemicals, microbes or by other phys- ical methods. Each type of pollution is a distinct source of health related problems and their consequences. Both chemical and microbiological agents can cause latent health apprehension linked with polluted drink- ing water [2,3]. Microorganisms in water include human pathogens (Shigella spp, Salmonella spp, Escherichia coli (E. coli), Vibrio cholera, Cryptosporidium parvum, rotavirus, Giardia cysts, etc.), free living microbes (Microcystis aeruginosa, Legionella pneumophila, Pseudomonas aeruginosa etc.), nui- sance microbes (sulfur and iron reducing bacteria), and the microbes causing odor and taste problems (Saccamoeba, Vannell and Ripidomyxa) [4]. The presence of fecal pathogens such as E. coli and Enterococci in water are the main indicators of water contamination [5]. WHO has also suggested that drinking water must have ‘zero’ fecal & coliform counts in 100 mL water sample [1]. According to the United Nation, in developing countries over one third of deaths occur because of diarrhea, which are caused by consumption of polluted water [2]. Improper sup- ply of fresh water and sanitation problems in developing countries has led to 800 million cases of diarrhea. The presence of E. coli is the main indicators of diarrhea. The removal of bacteria, especially E. coli from drinking water is of great academic and industrial interest. In order to stop the risk of waterborne diseases disinfection of water is needed. Water disinfection can improve the economic status of the country [6,7]. Currently different techniques and chemicals are used for water dis- infection, including chlorine and its derivatives, ozonation, ultraviolet light, boiling, low frequency ultrasonic irradiation, distillation, reverse osmosis, water sediment filters, activated carbon, solid block, pitcher and faucet-mount filters, ion exchange water softener, and activated alumina [8]. But these agents have some drawbacks towards human health because the addition of these chemicals can result the formation of disinfection byproducts (DBPs). Some DBPs are carcinogenic or muta- genic and are associated with birth defects, adverse pregnancy out- comes, poisoning, cancer, liver, kidney and central nervous system problems [9]. Similarly, conventional water treatment methods like Journal of Molecular Liquids 281 (2019) 295–306 ⁎ Corresponding author at: Chemistry Department, Faculty of Science, King Abdulaziz University, P. O. Box 80203, Jeddah 21589, Saudi Arabia. E-mail address: sbkhan@kau.edu.sa (S.B. Khan). https://doi.org/10.1016/j.molliq.2019.02.087 0167-7322/© 2019 Elsevier B.V. All rights reserved. Contents lists available at ScienceDirect Journal of Molecular Liquids journal homepage: www.elsevier.com/locate/molliq