Reactive dyes adsorption by chestnut shells coated with nanoparticles of zinc oxide: Characterization, isotherm and kinetic studies

This investigation employed a new adsorbent composed of chestnut shell powder and covered with ZnO nanoparticles.Coated chestnut shell (CCS) was examined to assess the adsorption of Reactive Blue-19 Dye and Red Reactive-2 from a water-based mixture.Considerable increases in the capability of adsorption of the chestnut shell were recognized following the coating of the powder particles with ZnO nanoparticles.The adsorbent was analyzed using surface area analysis, FTIR, SEM, and XRD to verify its structural and morphological properties.Batch adsorption Research was done to ascertain the optimum Situations, including the solution pH, adsorbent dosage, contact period, speed of shaking, and initial dye concentration, all conducted at room temperature, which is 25 °C.Both the Freundlich and Langmuir isotherm models were used to describe the equilibrium information on adsorption.As a result revealed that the process of adsorption followed Langmuir's isotherm model, using correlation values (R²) of 0.9886 for Reactive Red-2 and 0.9955 for Reactive Blue-19, demonstrating monolayer adsorption onto a uniform surface.The greatest CCS adsorption capacity was observed for Reactive Blue-19 (172.413mg/g), followed by Reactive Red-2 (114.942mg/g).Kinetic information was correlated using both pseudo-first-order and pseudo-second-order models.The findings demonstrated that the model of pseudo-second order gave greater results compared to the pseudo-first order model, considering correlation coefficients (R²) of 0.9951 for Reactive Red-2 and 0.9975for Reactive Blue-19, demonstrating that the process of chemisorption step that limits the rate of adsorption mechanism.Thus, these results show that CCS is among the best and most efficient adsorbents for getting rid of wastewater tainted with reactive dye residues.