Adsorptive Performance of Tobacco Biomass for Copper and COD Removal from Industrial Wastewater

This study investigates the feasibility of utilizing locally sourced Nicotiana tabacum biomass from Adıyaman, Türkiye, as a cost-effective biosorbent for the removal of copper and chemical oxygen demand (COD) from industrial wastewater originating from the Adıyaman Organized Industrial Zone. Batch adsorption experiments were conducted to systematically investigate the influence of solution pH, contact time, and initial metal concentration on adsorption performance. The untreated wastewater exhibited elevated pollution levels, with mean chemical oxygen demand and copper concentrations of 925 ± 391 mg/L and 2.54 ± 0.97 mg/L, respectively. Four tobacco-derived biosorbents (Çelikhan, Ova, Bulam, and Çağlan) were evaluated under optimized experimental conditions (pH ≈ 8.3, 60 min contact time, and a biosorbent dosage of 2.2 g/L). The Çelikhan biosorbent exhibited the highest copper removal efficiency (approximately 83%), whereas chemical oxygen demand removal ranged between 28% and 34%. The adsorption kinetics were well described by the pseudo-second-order model, with coefficients of determination ranging from 0.987 to 1.000. Isotherm analysis further indicated favorable adsorption behavior, with a maximum Langmuir adsorption capacity of 1.867 mg/g. Fourier transform infrared (FT-IR) spectroscopy confirmed the involvement of hydroxyl, carbonyl, and ester functional groups in metal binding. These findings highlight tobacco biomass as a sustainable and cost-effective biosorbent for industrial wastewater treatment. This study presents the first comprehensive evaluation of locally sourced Adıyaman tobacco biomass as a biosorbent for the removal of copper and organic pollutants from real industrial wastewater, integrating kinetic, isotherm, and FT-IR analyses to elucidate the underlying adsorption mechanisms.