Chromium desalinization using novel chitosan functionalized iron oxide- biochar composites: Analysis, synthesis, characterization and adsorption performance

In the study, chitosan functionalized iron oxide incorporated with peanut shell biomass was prepared for potential adsorption of chromium (VI) from an aqueous media. The prepared material was characterized by modern spectroscopic methods for confirming the successful embedding. The adsorption experiments were conducted in batch systems. The experimental data showed robust removal of chromium supported by kinetic and equilibrium studies. The sorption data exhibited a strong agreement with the pseudo-second-order kinetics model, further confirming conformity with the Langmuir isotherm model. Adsorption studies were taken to find the effects of pH and time, reusability, ionic strength and presence of coexisting ions. The maximum sorption capacity was achieved as 14.28 mg g-1 at pH 4 and the optimum contact time was 40 minutes. The background electrolytes have much less effect on uptake efficiency and this green adsorbent can be utilized for up to four cycles.  Additionally, a systematic approach was employed to ensure the precision and accuracy of the spectroscopic method. Calibration was linear in the range from 0.5 to 6.0 μg L-1  (R2 > 0.99). The limits of detection (LOD) and quantification (LOQ) were 0.65 μg L-1  and 2.16 μg L-1, respectively. The relative standard deviation (RSD) was 7.62 % (n=7).