Adsorption of Reactive Red 120 dye from simulated wastewater using rice straw charcoal: isotherm and kinetic studies

ABSTRACT This study investigated the performance of rice straw charcoal (RSC) for removing reactive red 120 (RR 120) dye from aqueous solutions and industrial wastewater. This study was conducted using batch adsorption procedures with the influence of various operating factors such as contact time (1–210 min), pH (3–11), adsorbent dosage (1–20 g/L), and initial dye concentration (5–70 mg/L). The highest removal efficiency of RR 120 was achieved by RSC (95%) at given experimental conditions: 5 mg/L of dye solution, pH 3, adsorbent dosage 10 g/L, and 120 min equilibrium contact time. Scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR) characterize the prepared RSC. The adsorption process for RSC is better suited to the Langmuir than to another isotherm model due to its higher R2 value. The highest adsorption capability for RSC was 4.43 mg/g. The pseudo-second-order kinetic model fit better than the pseudo-first-order model. In conclusion, the findings indicate that rice straw charcoal (RSC) serves as an environmentally friendly and economical adsorbent for effectively eliminating RR 120 dye from both aqueous solutions and industrial wastewater.