Abstract: In this study, hematite dysprosium oxide (Fe2O3–Dy2O3) nanocomposites was generated under laboratory conditions for antibiotic and microorganism removals from the surface water. The effects of increasing nanocomposite concentration, Chloramphenicol (Chloram) antibiotic doses, time and ionic strength levels on the adsorption yields of antibiotic, bacteria (E. coli, Pseudomonas and Salmonella) and virus (Enteric viruses) were investigated. Fe2O3–Dy2O3 (FD) was synthesized via green approach using Syzygium aromaticum bud extract. The formation of Fe2O3–Dy2O3 nanocomposite was confirmed by FTIR, XRD, XPS, FESEM, TEM, VSM, EDX, BET, TGA, and ODRS analyses. A magnetic counterpart Fe2O3–Dy2O3 (c-FD) was obtained via calcinations of FD at 700°C and tested for the Chloram removal performance. BET surface area of the FD and c-FD was found to be 112 and 41 m2/g. Antibiotics have been emerged as an issue high concern due to their potential risk for ecosystem and human health. The detailed kinetic and isotherm modelling showed that the Chloram antibiotic adsorption did not match with the pseudo-second-order and the monolayer pseudo first order adsorption kinetics on the surface of FD and c-FD nanocomposites respectively. With Langmuir and Freundlich adsorption kinetic constants also the Chloram adsorption cannot be defined due to low kinetic constants with low regression coefficients. The removal of Chloram antibiotic in FD and c-FD nanocomposites can be explained with intraparticle diffusion kinetic with high intraparticle diffusion rate constant (Kid) values of 0.982 and 1.98 for 0.001 mg/l Chloram up to 40 mg/l, respectively in both nanocomposites, respectively, with low boundary layer thickness C (0.08 mg/g) values and with high R2 values of 0.999. The maximum removal percentage of Chloram was found to be 99% for FD and 96% for c-FD nanocomposites at an adsorbent dose of 2 mg/l within 15 min for 40 ppm initial concentration of Chloram at an ionic strength of 1.2 M. As the ionic strength was increased from 0.01 M up to 1.2 M, the adsorption efficiencies of Chloram antibiotic increased from 90% and 82% up to 99% and 87%, in FD and c-FD nanocomposites, respectively. The Chloram antibiotic yields at low Chloram concentrations also simulating the surface water doses (0.0001 mg/l, 0.001 and 0.01 mg/l) were 99% at FD nanocomposite.At high Chloram concentrations also (40 mg/l) the Chloram yields also was detected as 99% at FD nanocomposites. The effect of FD and c-FD nanocomposites on bacterial strains (E. coli, Pseudomonas and Salmonella and viruses (Enteric viruses) were found to be high. The removal efficiencies of microorganisms from surface waters using Fe2O3–Dy2O3 nanocomposites are ranked as follows: E. coli > Pseudomonas > Enteric viruses > Salmonella, respectively. The reuse of Fe2O3–Dy2O3 nanocomposite was also investigated. The recyclability of the aforementioned nanoadsorbents showed excellent cycling stability and reuse properties. The operational stability of both nano-adsorbents was revealed by evaluating the Chloram (40 ppm) adsorption after 70 cycle runs. Until 70 cycles the Chloram yields were 99% and 96% at FD and c-FD nanocomposites, respectively. After 70 cycles the Chloram yields decreased slightly to 88% and 80%. This is very advanantageous for further application in water purification and treatment.

Keywords: Adsorption capacity, Antibiotics, Bacteria, Chloramphenicol (Chloram), Hematite dysprosium oxide (Fe2O3–Dy2O3) nanocomposites, Microorganisms, Pathogens, Reuse, Surface water, Virus

Pages: 54-91

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