Synthesis and characterization of FSB@Fe3O4 composites and application in removal of indigo carmine dye from industrial wastewaters.

The syntheses and characterization of fish scale biochar magnetic composites (FSB@Fe3O4) and their applications in the removal of indigo carmine dye from effluents are described. Preparation of the fish scale biochar magnetic composites, FSB@400 °C-Fe3O4, FSB@600 °C-Fe3O4, and FSB@800 °C-Fe3O4, was done following the chemical co-precipitation method. The adsorbents were characterized using peak optical absorbance, functional groups, magnetic strength, surface morphology, particle size, elemental compositions, surface charge, surface area, thermal stability, and crystalline phase, using ultraviolet-visible spectroscopy (UV-vis spec), Fourier transform infrared (FTIR) spectroscopy, vibrating sample magnetometry (VSM), transmission electron microscopy/scanning electron microscopy (TEM/SEM), energy dispersive X-ray (EDX), point of zero charge pH (pHpzc), Brunauer-Emmett-Teller (BET), thermo-gravimetric analysis (TGA), and powder x-ray diffraction (PXRD) techniques, correspondingly. The potential of magnetic composites for the abstraction of indigo carmine dye from wastewater was determined as a function of the initial concentration of indigo carmine dye, contact time, dye solution pH, adsorbent dosage, and solution temperature. The results demonstrated that the quantity (q) of indigo carmine dye adsorbed onto magnetic composites improved with a rise in initial dye concentration, adsorbent load, and solution temperature. Conversely, lower quantities of adsorbed dye were recorded at higher pH levels. The data fitted a pseudo-second-order kinetic model. The Langmuir isotherm gave the best fit (Langmuir>Freundlich>Redlich-Peterson>Toth>Hill>Sips>Temkin) suggesting a uniformly monolayer adsorption. Adsorption of environmental wastewater samples revealed that all the adsorbents can be used to effectively treat industrial wastewaters. The recycling data established that the adsorbents could be used for five consecutive cycles without significant loss of adsorption capacities.

Preparation, characterization of fish scales biochar and their applications in the removal of anionic indigo carmine dye from aqueous solutions.

The preparation and applications of Tilapia (Oreochromis niloticus) fish scale biochars (FSB) as an adsorbent in the removal of indigo carmine dye (ICD) from aqueous solutions is described. The biochars were prepared through pyrolysis over a temperature range of 200 °C-800 °C and characterized for surface charge, functional groups, thermal stability, particle size and morphology, elemental composition, crystallinity, and surface area by using pHpzc, Fourier transform infrared (FTIR) spectroscopy, thermo-gravimetric analysis (TGA), transmission electron microscopy/scanning electron microscopy (TEM/SEM), energy dispersive X-ray (EDX) spectroscopy, powder X-ray diffraction (PXRD) and Brunauer-Emmett-Teller (BET) techniques, respectively. Batch experiments were carried out to determine the variation of adsorption process with initial dye concentration, contact time, initial solution pH, adsorbent load, temperature and adsorbent pyrolysis temperature on the removal of the dye. The percentage removal increased with increase in initial dye concentration and adsorbent dosage. A pH of 2 was the most appropriate for the adsorption experiments. The equilibrium data fitted pseudo-first-order kinetics and Freundlich models, while the thermodynamic parameters confirmed that the adsorption process was endothermic.