Flower‐like bismuth oxyiodide (BiOI) hierarchical microspheres were synthesized successfully at room temperature in the presence of ethylene glycol and KI as solvent and iodide source, respectively and applied for the photocatalytic degradation of levofloxacin from aqueous media under visible light irradiation. Optimal conditions for the synthesis and photocatalytic processes were obtained by using the response surface methodology (RSM) combined with central composite design (CCD). Based on the CCD, the quadratic model represents the relationship between the following factors: reactant concentration (0.009–0.116 mol/L), percentage of ethylene glycol (15%–85%) for synthesis processes and contact time (12–108 min), BiOI dosage (0.05–2.45 g/L), and initial concentration (1.1–5.9 mg/L) for photocatalytic processes. The obtained BiOI structures were characterized by scanning electron microscopy (SEM), nitrogen adsorption (BET), X‐ray diffraction (XRD), and UV–Vis absorption spectroscopy. The results show that the proposed quadratic model in accordance with the experiment results in an R2 value and lack of fit F‐values of 0.9987 and 2.79 for synthesis processes, and 0.9977 and 3.06 for photocatalytic processes. It was observed that ethylene glycol not only acted as a solvent but was also a soft temple for the fabrication of flower‐like BiOI hierarchical microspheres. The optimum conditions of reactant concentration and percentage of ethylene glycol for synthesis processes were obtained at 0.063 mol/L and 85%, respectively. Additionally, under visible light irradiation, the synthesized flower‐like BiOI hierarchical microspheres can remove levofloxacin up to 99%. The optimum conditions of contact time, BiOI dosage, and levofloxacin initial concentration for photocatalytic processes were obtained at 90 min, 2 g/L, and 2 mg/L, respectively.

Bismuth Oxyiodide (BiOI) hierarchical structures were fabricated from the solution route at room temperature (BiOI-R) and solvothermal synthesis (BiOI-S) in the presence of KI and ethylene glycol to improve the photocatalytic and adsorption ability for the removal of ciprofloxacin from the aqueous environment. In this study, BiOI was characterized by using X-ray diffraction (XRD), scanning electron microscopy (SEM), N2 adsorption-desorption isotherm (BET), UV-Vis absorption spectroscopy, and pH of the point of zero charge (pHpzc). It was observed that the BiOI-S has better adsorption and photocatalysis capacity as a result of having more surface area, higher light absorption ability, and lower band-gap energy than the BiOI-R. The response surface methodology was applied to optimize the conditions of contact time, BiOI dosage, ciprofloxacin initial concentration, and pH for ciprofloxacin adsorption and photocatalytic processes using BiOI-S. The results show that the optimum conditions of ciprofloxacin removal processes obtained as contact time of 90 min, BiOI-S dosage of 2 g/L, and initial ciprofloxacin concentration of 2 mg/L, solution pH of 4.5 for adsorption processes. Meanwhile BiOI-S dosage of 1.5 g/L, initial ciprofloxacin concentration of 3.5 mg/L, and contact time of 108 min were the best condition for photocatalytic degradation. Additionally, the adsorption isotherm and kinetic studies fitted the Freundlich isotherm and pseudo-second-order model, respectively. The ciprofloxacin adsorption capacity value for BiOI-S of 3.799 mg/g was obtained and photocatalytic degradation of ciprofloxacin by BiOI-S followed the pseudo-first-order rate reaction based on Langmuir-Hinshelwood kinetics.

Bismuth oxyiodide (BiOI) hierarchical structures were fabricated by the solution route at room temperature (BiOI‐R) and solvothermal synthesis (BiOI‐S) in the presence of KI and ethylene glycol to improve the photocatalytic and adsorption ability for the removal of ciprofloxacin from the aqueous environment. BiOI was characterized by X‐ray diffraction, scanning electron microscopy, N2 adsorption‐desorption isotherm, UV‐Vis absorption spectroscopy, and pH of the point of zero charge. It was observed that BiOI‐S has better adsorption and photocatalysis capacity as a result of having higher surface area, higher light absorption ability, and lower band‐gap energy than BiOI‐R. BiOI‐S exhibited good ciprofloxacin adsorption and photocatalytic degradation under visible‐light irradiation. Adsorption isotherm and kinetic studies fitted the Langmuir and Freundlich isotherm and pseudo‐second‐order models respectively. The photocatalytic degradation of ciprofloxacin by BiOI‐S followed a pseudo‐first‐order reaction based on Langmuir‐Hinshelwood kinetics.