Effective separation of ciprofloxacin from aqueous solutions using BiOCl/Bi2S3/biochar hybrid structure fabricated via ultrafast solid-state reaction

Abstract Developing a product that serves a dual purpose as an adsorbent/photocatalyst for ecological applications is a compelling study area. This article discusses a facile ultrafast synthesis of BiOCl/Bi 2 S 3 /biochar (BiOCl/Bi 2 S 3 /BC) by solid-state reaction with coupled roles as photocatalyst during sunlight exposure and adsorbent when there is no light. BiOCl/Bi 2 S 3 /BC was characterized by XRD, SEM, EDX, HR-TEM, XPS, FTIR, Raman, and DR/UV–Vis spectroscopy techniques. The adsorption efficiency and its parameters were explored using ciprofloxacin (CPF) as a contaminant model drug in the absence of light irradiation. The coupled role as adsorbent/photocatalyst was considered under direct sunlight irradiation. BiOCl/Bi 2 S 3 /BC 30 achieved removal of 81.25% in the dark and reached 90% during sunlight exposure within 1 h. BiOCl/Bi 2 S 3 /BC 30 exhibited a triplet initial adsorption rate, and doubled rate constant of photocatalysis (11.34 mg g −1 min −1 , 0.642 min −1 ) compared to BiOCl/Bi 2 S 3 (3.88 mg g −1 min −1 , 0.256 min −1 ), respectively, indicating the adsorptive, catalytic, and cocatalytic role of BC. Mechanism studies indicated that BiOCl/Bi 2 S 3 /BC separated CPF by adsorption via electrostatic interaction, π – π conjunction, and hydrogen bonding while the photocatalysis occurred through the S-scheme mechanism where • O 2 − and h + play the predominant role in the photocatalytic degradation. Besides, the BiOCl/Bi 2 S 3 /BC 30 hybrid was stable and revealed acceptable recyclability after four consecutive cycles for CPF removal from their aqueous solutions. This work provided an ultrafast, simple, economical, and efficient strategy for the application of BiOCl/Bi 2 S 3 /BC hybrid structure that has a dual function of adsorption and photocatalysis for the elimination of CPF from water.