Investigation of the use of nitrogen-loaded biochar/chitosan composites for adsorption of organic dyes from waste waters

The aim of this study is to investigate the usability of composites prepared by crosslinking 3 different biochars prepared by pyrolysis of oak sawdust and a suitable nitrogen source [ammonium nitrate and urea] with chitosan as an adsorbent in removing dye from aqueous solution. To determine the adsorption capacities of the adsorbents prepared for this purpose; Test solutions to be used in adsorption studies were prepared by diluting the methylene blue stock solution with a concentration of 1000 mg/L with distilled water to the desired concentration. In batch equilibrium adsorption studies, the effects of two different adsorption parameters such as pH [6-12] and contact time [up to 240 minutes] on the nitrogen-loaded biochar and chitosan-prepared composites of the dyestuff solution were investigated. After the adsorption was completed, the amount of dyestuff remaining in the solution phase was measured at a wavelength of 640 nm using a UV-visible spectrophotometer and the amount of dyestuff adhered to the surface of the adsorbents was calculated. The structure and surface images of the prepared nitrogen-loaded biochars and the composites obtained using chitosan were examined using FT-IR and SEM devices. Adsorption parameters were calculated based on the data obtained as a result of adsorption, adapted to the Freundlich and Langmuir isotherm models. In the study, it was found that the dye adsorption was compatible with the Freundhlich isotherm. The results showed that the prepared adsorbents were good adsorbents for the dyestuff at appropriate pH and contact time.