Synthesis, characterization and adsorption properties of sewage sludge derived biochar modified with eggshell

Sewage sludge-derived biochar (SDB) in recent times has increasingly been applied in the decontamination of effluents from households and industries due to its adsorptive properties. The SDB adsorbent is composed of a highly porous structure, and it contains multiple functional groups and exchangeable cations. However, it has been reported that the SDB texture could be improved to obtain large amounts of adsorption sites. In this work, the SDB material was treated using eggshell to obtain a novel adsorbent, namely eggshell-modified sludge-derived biochar (EMBC). The EMBC composite was characterized by scanning electron microscopy (SEM), Fourier-transform infrared (FTIR) spectroscopy, and X-Ray diffraction (XRD) spectroscopy. It was demonstrated that the Brunauer-Emmett-Teller (BET) surface area and pore-distribution properties of EMBC were enhanced compared to the unmodified SDB. Moreover, the chemical composition of EMBC was strongly associated with the proliferation of carbonate minerals, amine, and oxygen-containing functional groups such as C-O, C=O, - OH, and -COOH. EMBC was highly porous, containing rough surface and significant amounts of vacant sites. The Barrett-Joyner-Halenda model revealed that the pore sizes of EMBC were well distributed. Based on the results mentioned above, EMBC could be employed as a promising, low-cost, and alternative adsorbent material for the elimination of various pollutants from aqueous solutions; and that will be the focus of our future works.