ABSTRACT
Development of crystalline porous materials for selective CO2 adsorption and storage is in high demand to boost the carbon capture and storage (CCS) technology. In this regard, we have developed a ß-keto enamine-based covalent organic framework (VM-COF) via the Schiff base polycondensation technique. The as-synthesized VM-COF exhibited excellent thermal and chemical stability along with a very high surface area (1258 m2 g-1) and a high CO2 adsorption capacity (3.58 mmol g-1) at room temperature (298 K). The CO2/CH4 and CO2/H2 selectivities by the IAST method were calculated to be 10.9 and 881.7, respectively, which were further experimentally supported by breakthrough analysis. Moreover, theoretical investigations revealed that the carbonyl-rich sites in a polymeric backbone have higher CO2 binding affinity along with very high binding energy (-39.44 KJ mol-1) compared to other aromatic carbon-rich sites. Intrigued by the best CO2 adsorption capacity and high CO2 selectivity, we have utilized the VM-COF for biogas purification produced by the biofermentation of municipal waste. Compared with the commercially available activated carbon, VM-COF exhibited much better purification ability. This opens up a new opportunity for the creation of functionalized nanoporous materials for the large-scale purification of waste-generated biogases to address the challenges associated with energy and the environment.
ABSTRACT
Internal resistance is one of the limiting factors for power production in microbial fuel cells (MFC). To overcome this, current study designed polyaniline functionalized activated carbon (PANi-FAC) composite as capacitive anode with strategic electrocatalytic capability, and was comparatively assessed with SSM-PANi and bare SSM as anodes in three double chambered MFCs respectively. Power output and COD removal efficiency of PANi-FAC coated on stainless steel mesh (SSM-PANi/FAC) is superior (322 mW/m2; 87.6%) in comparison to SSM-PANi (273 mW/m2; 62.4%) and bare SSM (169 mW/m2; 54%). In addition, maximum specific capacitance of hybrid electrodes is relatively high with SSM-PANi/FAC (360.84 F/g) than SSM-PANi anode (128.26 F/g). Nyquist impedance plots showed less charge-transfer resistance (Rct) with SSM-PANi/FAC (29.9 Ω) than SSM-PANi (206.8 Ω) and SSM anodes (678 Ω). Study infers that, development of electrochemical double layer capacitance makes SSM-PANi/FAC, a potential capacitive anode for augmenting bio-electrocatalytic activity and reducing Ohmic losses.
Subject(s)
Bioelectric Energy Sources , Aniline Compounds , Charcoal , ElectrodesABSTRACT
Anode with good electrocatalytic capabilities is more specifically required to reduce the ohimic losses during microbial fuel cell (MFC) operation. Highly conductive polymers viz., Polyaniline (PANi) and Polyaniline/Carbon nanotube (PANi/CNT) composite were prepared by in situ oxidative chemical polymerization method. Anodes were fabricated independently by coating PANi and CNT/PANi composites on the surface of SSM. The fabricated electrodes were evaluated as anode against stainless steel mess (SSM) as cathode during MFC operation. Maximum bioelectricity generation was observed in SSM-PANi/CNT-anode with power density of 48â¯mW/m2 and COD removal efficiency of 80% compared with SSM-PANi-anode (38â¯mW/m2; 65%) and SSM-anode (28â¯mW/m2; 58%). Bioelectrochemical characterization of the electrode materials using cyclic voltammetry and electrochemical impedance spectroscopy showed high electrocatalytic activity of PANi/CNT composite electrode. The study concluded the efficiency of PANi/CNT composite electrodes as bioanode in operation of MFCs towards achieving increased bioelectricity production along with wastewater treatment.
