Kinetic, isothermal and thermodynamic studies of Reactive Black 5 removal using rice husk ashes and powdered activated carbon
Luan C. Cavalcante, Karina Querne de Carvalho, Fátima de Jesus Bassetti, Lucila Adriani Coral
Abstract
The study aimed to evaluate the potential of rice husk ashes (RHA) as an adsorbent for removing Reactive Black 5 (RB5) dye from water by comparing its performance to that of a commercial activated carbon (PAC) through kinetic, isotherm, and thermodynamic studies. The optimal results were obtained at pH 2.0 using PAC and RHA dosages of 0.4 and 15 g L−1, respectively. The pseudo-second-order model best described the kinetic data, with equilibrium reaching 40 min for PAC and 120 min for RHA. Langmuir model best-described isotherm data, with a calculated maximum adsorption capacity of 154.17 for PAC and 8.49 mg g−1 for RHA. Although RHA presented less adsorption capacity than PAC, the results suggest this viable and cost-effective adsorbent is an alternative to commercially available activated carbons for RB5 removal.