Adsorptive removal of azithromycin from aqueous solutions using raw and saponin-modified nano diatomite

Abstract

This study aims to investigate the performance and mechanism of raw (R-ND) and saponin-modified nano diatomite (M-ND) in the removal of azithromycin from aqueous solutions. Adsorbent characterization was performed using X-ray fluorescence, Brunauer–Emmett–Teller (BET), scanning electron spectroscopy, dynamic light scattering and energy-dispersive X-ray analyses. It was shown that the specific surface area of R-ND was 119.5 m2/g, 14-fold higher than that for raw diatomite, and for M-ND it was 90.1 m2/g. Various adsorption conditions, i.e. adsorbent dosage, pH, initial concentration and contact time were investigated. According to the results, despite reducing the specific surface area by 25%, modification of nano diatomite by saponin markedly enhanced its performance in the removal of azithromycin. The maximum adsorption capacity of R-ND and M-ND in the removal of azithromycin was 68 and 91.7 mg/g, respectively. Fourier transform infrared spectroscopy results revealed that azithromycin was adsorbed by O-H groups on the diatomite surface. Weber–Morris intra-particle diffusion (IPD) model suggested that while IPD is not the rate-controlling step in high concentrations of azithromycin, it is the only step that controls the rate of adsorption in low concentrations. In comparison to R-ND, M-ND showed a higher efficiency in the removal of azithromycin and, therefore, it can be used as a promising low-cost adsorbent to remove azithromycin from aqueous solutions.

Environmentally azithromycin pharmaceutical wastewater management and synergetic biocompatible approaches of loaded azithromycin@hematite nanoparticles

“…The D–R isothermal model also was tested and provided us with the average adsorption energy for each Azr molecule adsorbed using α-HNPs “free energy (E D )”. It was found to be 156.5; since the higher value of E D is greater than 80; it is indicating that the adsorption can be expressed as a chemisorption type 26 .…”

“…pH (zero-point charge) of α-HNPs was found to be 5.2 as previously determined 29 so, at lower pH of 5.2; the surface of α-HNPs will be protonated and become positively charged in nature. On the other hand, at pH higher than 5.2; deprotonation of the surface of α-HNPs became negatively charged so, more electrostatic attraction force will be obtained between Azr molecules and the α-HNPs surface 26 .…”

“…This means that at this pH range the removal efficiency is not pH-dependent which is agreed with previously reported work by Siavash et al . 26 which may be attributed to electrostatic repulsion force between the Azr and α-HNPs surface. An observable increment in the removal % of the Azr with about 13% at solution pH 6.0 corresponded to an adsorption capacity of 34.6 mg/g.…”

A critical review on environmental presence of pharmaceutical drugs tested for the covid-19 treatment

“… Drugs Treatment technologies Operational conditions Efficiency of removal * Reference Azithromycin Photocatalytic degradation 30 mg of Ag@Bi 4 O 5 I 2 /SPION/Calg 98.4% A. Kumar et al (2021a , 2021b ) Xe lamp 300W 90 min of reaction 5 mg og ZrO 2 /Ag@TiO 2 90% Naraginti et al (2019) Xe lamp 250W 8 hours of reaction 1000 mg of GO@Fe 3 O 4 /ZnO/SnO 2 90.06% Sayadi et al (2019) UV-C lamp 6W 120 min Membrane bioreactor Pilot plant (anaerobic MBR, 100 PE) 25% Göbel et al (2007) hydraulic retention time 13 hours solid retention time 16 ± 2 d, 33 ± 3 d or 60 – 80 d Adsorption Saponin-modified nano diatomite 99.8% Davoodi et al (2019) 1 g L -1 ; pH 9; 25 °C; agitation 450 rpm 60 min FAU-type zeolites 10 mg L -1 of adsorbent; pH 6,5 30 min 79% de Sousa et al (2018) Nanofiltration Composite polyamide membrane pH 5; 25 °C; 8 bar 120 min 99% …”

A Fast Adsorption of Azithromycin on Waste-Product-Derived Graphene Oxide Induced by H-Bonding and Electrostatic Interactions

“…Excessive use of antibiotics can result in pollution of drinking water, surface/ground water, and even the ecosystem and aquatic environment . Even in low amounts, antibiotics have huge negative impacts on the environment like high toxicity of algae and bacteria and bacterial resistance, inhibiting biological processes in waste water treatment and decreasing the rate of degradation of organic compounds. , Southeast Asia is regarded to have the highest risk of antibiotics among all the regions. Antimicrobials are widely available as over-the-counter drugs in many of these countries; Bangladesh is one of them. , Thus, the removal of widespread antibiotics has become a crucial issue.…”