Biosynthesis of SiO2 nanoparticles using extract of Nerium oleander leaves for the removal of tetracycline antibiotic

Abstract

Tetracycline (TC) is one of the antibiotics that is found in wastewaters. TC is toxic, carcinogenic, and teratogenic. In this study, the tetracycline was removed from water by adsorption using dioxide silicon nanoparticles (SiO₂ NPs) biosynthesized from the extract of Nerium oleander leaves. These nanoparticles were characterized using SEM-EDX, BET-BJH, FTIR-ATR, TEM, and XRD. The influences of various factors such as pH solution, SiO₂ NPs dose, adsorption process time, initial TC concentration, and ionic strength on adsorption behaviour of TC onto SiO₂ NPs were investigated. TC adsorption on SiO₂ NPs could be well described in the pseudo-second-order kinetic model and followed the Langmuir isotherm model with a maximum adsorption capacity was 552.48 mg/g. At optimal conditions, the experimental adsorption results indicated that the SiO₂ NPs adsorbed 98.62% of TC. The removal of TC using SiO₂ NPs was 99.56% at conditions (SiO₂ NPs dose = 0.25 g/L, C₀ = 25 mg/L, and t = 40 min) based on Box-Behnken design (BBD) combined with response surface methodology (RSM) modelling. Electrostatic interaction governs the adsorption mechanism is attributed. The reusability of SiO₂ NPs was tested, and the performance adsorption was 85.36% after the five cycles. The synthesized SiO₂ NPs as promising adsorbent has a potential application for antibiotics removal from wastewaters.

Keywords: Adsorption and optimization; Chemical engineering; Green synthesis; Nerium oleander leaves Extract; SiO(2) nanoparticles; Tetracycline.