(6jm) Acoustic Cavitation Induced Chemical Functionalization of Biochar: A Feasible Strategy for Effective Removal of Heavy Metals

• Bioenergy and Biofuels (Biodiesel and Biochar)
• Activation of Carbonaceous Graphitic Structures
• Wastewater Treatment
• CO₂ Capture
• Sono-Physics (acoustic-based bio-processes)
• Computational Fluid Dynamic (CFD) simulation
• Techno Economic Analysis (TEA)

Teaching Interests: All Chemical Engineering Courses

Abstract

The Sustainable Energy and Environment Group (SEEG) of the University of Mississippi (UM) has discovered the synergisms of activating biochar (BC) by acoustics which include disarrangement and exfoliation of BC’s graphitic structure, mineral leaching, significant increase in BC’s internal surface area and porosity, as well as creation of new and opening the blocked mesopores. Acoustic treatment of biochar in water with dissolved CO₂ also created induced surface functional groups that enhance the adsorption capacity. Accordingly, the main objective of a series of our researches is to enhance and specify the adsorption capacity of biochar through integrated structural acoustic modification with chemical functionalization. These synergisms can result in the development of advanced activated carbon (AC) for adsorption of air and water pollutants, as traditional physical and chemical activations require very high temperatures in the activation process. However, the developed acoustic activation method is conducted at ambient temperature and pressure for a very short duration (~30 sec) which requires about 1,135 kcal / kg of activated BC produced.

In order to increase the surface functionality of raw biochar, the synergism of acoustic activation was enhanced by different chemical treatments and functionalization, which include both alkaline (using KOH) and acidic (H₃PO₄ or HNO₃) treatments followed by amination. The effect of ultrasound structural modification on biochar magnetization was also assessed since magnetization usually reduces the biochar adsorption capacity significantly. The activated biochars were used to remove nickel and lead ions, which are a common problem in old water systems. The experimental results demonstrated that the metal adsorption removal of the modified ultrasonic-chemically functionalized biochars is far higher than that of raw biochar. In most cases, the modified biochars had a faster adsorption rate as well. Moreover, the synergism created by the combined effect of ultrasound and chemical functionalization resulted in a higher metal retention capacity with no leaching of adsorbed metals during adsorption with long durations. It can be concluded that the integrated acoustic and chemical functionalization provides an efficacious and economical method which led to an adsorbent with high surface functionality and adsorption capacity as the activation is conducted at low temperatures that requires much lower energy than traditional activations.