Synthesis and characterization of a novel benzothiazole functionalized chitosan and its use for effective adsorption of Cu(II)

Contamination of water with the copper(II) ions leads to serious diseases such as liver damage and cancer. This deadly effect prompted us to target the synthesis of a novel functionalized chitosan (Cs-BT) to be used as an adsorbent for removing the copper(II) ions from the aqueous solution. The functionalization was done by introducing benzothiazole moiety into the chitosan (Cs) chain and confirmed by the full disappearance of the NH₂ band in the FT-IR spectrum of the adsorbent. The TGA-DTG analysis revealed that the functionalization reduced the thermal stability of the adsorbent (Cs-BT) as compared with pure chitosan. The adsorption was evidenced by SEM and EDX analysis. The adsorption study demonstrated that the optimal adsorption conditions were 120 min contact time, pH = 6, and initial Cu(II) concentration 200 mg/L. At these conditions, the Cs-BT achieved a maximum copper adsorption capacity of 1439.7 mg/g. Consequently, Cs-BT could be a promising and efficient Cu adsorbent in water treatment. Study the adsorption kinetics and isotherms manifested that the pseudo-first-order was better than pseudo-second-order and Temkin isotherm was better than Langmuir, Freundlich, and Dubinin-Radushkevich for explaining the adsorption process. The calculated thermodynamic parameters implied the spontaneity and the endothermic nature of the adsorption process.

Modeling and optimizing Acid Orange 142 degradation in aqueous solution by non-thermal plasma

The effects of the high voltage electrode material, initial pH of the solution, initial concentration of Fe²⁺, and time of plasma treatment on the efficiency of Acid Orange 142 (AO142) degradation were studied and evaluated. Furthermore, based on the Box-Behnken response surface methodology (BBD-RSM), a model between response (decolorization efficiency %) and influencing factors was proposed to estimate the interactive effects and optimize the process conditions. The proposed model was adequate with an R² of 0.8005 which is in reasonable agreement with the R²_adj of 0.9307. According to the model, the optimum conditions were steel as a high voltage electrode, an initial pH 3.0, an initial Fe²⁺ concentration 0.9 mM, and 20 min time of treatment to obtain a decolorization efficiency of 95.05%. In addition, the analytical results of UV-Vis, FT-IR, TOC and GC-MS indicated the degradation of the dye molecule.