Effective levofloxacin adsorption and removal from aqueous solution onto tea waste biochar; synthesis, characterization, adsorption studies, and optimization by Box–Behnken design and its antibacterial activity

ABSTRACT

Research efforts are focusing on investigating cost-effective and ecologically friendly ways to create nanoparticles as a result of promising developments in green technology (NPs). This experiment focused on the effectiveness of using biochar (TWB) made from coffee waste to extract levofloxacin (LEV) from water. The conclusive results of the trials showed that TWB is an effective adsorbent for removing LEV from liquid solutions. The TWB produced through biological processes underwent comprehensive analysis using techniques such as X-ray diffractometry (XRD), scanning electron microscopy (SEM), Brunauer–Emmett–Teller surface area measurement (BET), X-ray photoelectron spectroscopy (XPS), and Fourier transform infrared (FTIR) spectroscopy. The bioengineered TWB’s exceptional crystalline properties, which closely resemble the monoclinic structure of bulk TWB, were confirmed by the XRD analysis. Based on the scanning electron microscopy (SEM) data, the synthesis of TWB Nanoparticles resulted in the formation of spherical particles with an approximate diameter of 40 nm, accompanied by a substantial surface area of 285.55 m²/g. The Pseudo-Second-Order model, which best captured Levofloxacin’s adsorption characteristics, was evaluated on the TWB, and the results showed that external mass transfer was the main determinant of response rate. It was also found that the adsorption process was endothermic and spontaneous. The system was optimized using the Box–Behnken design (BBD) methodology. The achieved removal capacity of 1119.19 mg/g utilizing the tested adsorbent was determined to be reasonable when compared to the performance of other previously used adsorbents when evaluating the effectiveness of eliminating LEV. The process of LEV adsorption onto TWB involves a number of different mechanisms, such as ion exchange, π-π interactions, electrostatic pore filling, and hydrogen bonding. Following extensive testing in connection with a real-world sample, the adsorbent demonstrated remarkable efficacy, and it maintained good performance even after undergoing three further regeneration cycles. By adjusting the annealing temperature, we controlled the synthesis of TWB nanoparticles across a range of sizes in order to maximize their antibacterial capabilities. This research utilized a pair of Gram-positive bacteria (Staphylococcus aureus and Bacillus subtilis) and a pair of Gram-negative bacteria (Pseudomonas aeruginosa and Escherichia coli) to evaluate the antibacterial efficacy of TWB.

Highlights

• Green synthesis of biochar via using tea waste.

• Adsorption studies of harmful pesticides Levofloxacin (LEV).

• The adsorbents exhibited good reusability for four adsorption/desorption cycles.

• Adsorption fit with pseudo second order kinetics and Langmuir isotherm model.

• The adsorption fitted to pseudo-second-order kinetically.

• This system will provide helpful guidance for coloured effluent treatment.

• Optimized the results by using Box-Behnken design.

GRAPHICAL ABSTRACT

KEYWORDS:

• TWB
• LEV
• Box-Behnken design
• adsorption isotherm
• antibacterial activity

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

The author(s) reported there is no funding associated with the work featured in this article.