Abstract:
To address the issues of water environment pollution caused by the azo dye Congo Red (CR), such as the easy agglomeration, difficult separation, poor regenerability of existing CR adsorbent materials, and the limited adsorption performance of single metal oxides, ZnO/MgO composite nanofibers were prepared via electrospinning technology. The morphological characteristics and structure of the composite fibers were systematically analyzed using characterization techniques including SEM, XRD, BET, and FT-IR. Through adsorption experiments, the effects of various factors on the CR adsorption behavior were comprehensively investigated, such as the mass ratio of metal salts, calcination temperature, solution pH value, and initial CR concentration. The results show that when the mass ratio of magnesium-zinc metal salts is 3∶1 and the calcination temperature is 500℃, the prepared ZnO/MgO composite fibers exhibit the maximum adsorption capacity under the condition of pH=3. The adsorption behavior of the composite fibers for CR conforms to the pseudo-second-order kinetic model and Langmuir isotherm model, with the adsorption mechanism mainly manifested as chemical adsorption and monolayer molecular adsorption. Thermodynamic studies confirm that the adsorption process is a spontaneous reaction with entropy increase and endothermic characteristics; after 5 adsorption-desorption cycles, the removal rate of CR remains above 85%, indicating good regenerability and practical application value.