Rice Husk Biochar as a Sustainable Adsorbent for Tetracycline Removal from Aqueous Solution by Using Taguchi Design Approach

Vásquez Llanos S.A.; Sausa Burga L.L.; Guevara Fernández D.N.; Sánchez Purihuaman M.N.; Scheineder S.H.; Carreño-Farfan C.R.; Vivas-Cuellar M.C.; Sipion K.R.; Medina Collana J.T.; Barturén Quispe A.P. · Journal of Ecological Engineering (2025) · DOI: 10.12911/22998993/205417

Resumen

Tetracycline removal was evaluated in an aqueous solution with rice husk biochar using the Taguchi design with signal-to-noise ratio (S/N) under the ‘Larger is better’ condition. Carbonized biochar samples were prepared at 500, 625, and 750 °C (RHB500, RHB625, and RHB750, respectively) for 1 h. The variables investigated included carbonization temperature, contact time (1, 2.5, and 4 h), and biochar dosage (1, 10, and 20 g/L) at a controlled pH of 3. The results showed that the biochar yield decreased with a nonlinear trend from 39.60% to 29.36%, while the surface area of the BET increased from 12.75 to 231.04 m2/g with increasing carbonization temperature from 500 to 750 °C. The adsorption capacity of rice husk biochar was optimal at 750 °C, a contact time of 4 hours, and a biochar dosage of 20 g/L, achieving a 100% removal efficiency. Optimized conditions allowed 99.51% removal of pure tetracycline (50 mg/L) and 100% removal in a solution containing tap water and medical grade tetracycline. Kinetic analysis indicated that the adsorption process followed a pseudo-second order model, while the equilibrium data were best described by the Langmuir isotherm, with a maximum adsorption capacity of 6.009 mg/g at 25 °C. This suggests that the interaction between biochar and tetracycline is dominated by monolayer chemical reactions on homogeneous surfaces. These results underscore that RHB750 is an efficient, cost-effective, and easily accessible adsorbent and represents a viable and sustainable solution for the treatment of antibiotic contaminated water. © (2025), Journal of Ecological Engineering

Instituciones: Universidad Nacional de Ingeniería; Universidad Nacional Pedro Ruiz Gallo; Universidad Tecnológica del Perú; Universidad Nacional del Callao