Obtaining adsorbent from biomass and investigation of its efficiency in dye removal

In this study, the reed plant (Phragmites australis) collected from the Kızılırmak delta as agricultural biomass was used for the production of activated carbon. Two different methods were tried for the production of activated carbon. In the first method, the reed plant was activated with NaOH and subjected to carbonization (SAK). In the second method, mesoporous activated carbon was attempted to be obtained through NaOH activation of hydrochar obtained from the hydrothermal carbonization of reed (HTC). The dye removal capacities of the prepared activated carbons from aqueous solutions were investigated by taking the Telon Red adsorption model. The structure of the produced activated carbons was investigated by SEM analysis technique. It was determined that NaOH activation improved the porosity and surface functionality of the hydrochar. In this study, the reed and NaOH ratio of 1:3 was used for both carbonization and hydrothermal carbonization processes. Adsorption studies were carried out on Telon Red removal from synthetic wastewater using the prepared activated carbon samples under the same experimental conditions to make a comparison, while adsorption studies were also carried out with commercial activated carbon (TAK). The effects of initial concentration (50-1000 mg/L), contact time (5-180 min), pH (3-11), adsorbent dose (0.1-0.6 g/L), and temperature (20-60°C) parameters on the adsorption process were investigated. In kinetic adsorption studies, the pseudo-second-order model described the best kinetic data, and the Langmuir isotherm model provided the most relevant result in the adsorption isotherm. It was observed that activated carbons produced by the hydrothermal carbonization method (HTC) had the highest dye adsorption capacity. Activated carbons obtained by carbonization and hydrothermal carbonization methods have hydrophilic properties and contain highly reactive functional groups, making them suitable for obtaining efficient adsorbents in wastewater treatment.