Cellulose Derived Graphene/Polyaniline Nanocomposite Anode for Energy Generation and Bioremediation of Toxic Metals via Benthic Microbial Fuel Cells

Abstract

Benthic microbial fuel cells (BMFCs) are considered to be one of the eco-friendly bioelectrochemical cell approaches nowadays. The utilization of waste materials in BMFCs is to generate energy and concurrently bioremediate the toxic metals from synthetic wastewater, which is an ideal approach. The use of novel electrode material and natural organic waste material as substrates can minimize the present challenges of the BMFCs. The present study is focused on cellulosic derived graphene-polyaniline (GO-PANI) composite anode fabrication in order to improve the electron transfer rate. Several electrochemical and physicochemical techniques are used to characterize the performance of anodes in BMFCs. The maximum current density during polarization behavior was found to be 87.71 mA/m2 in the presence of the GO-PANI anode with sweet potato as an organic substrate in BMFCs, while the GO-PANI offered 15.13 mA/m2 current density under the close circuit conditions in the presence of 1000 Ω external resistance. The modified graphene anode showed four times higher performance than the unmodified anode. Similarly, the remediation efficiency of GO-PANI was 65.51% for Cd (II) and 60.33% for Pb (II), which is also higher than the unmodified graphene anode. Furthermore, multiple parameters (pH, temperature, organic substrate) were optimized to validate the efficiency of the fabricated anode in different environmental atmospheres via BMFCs. In order to ensure the practice of BMFCs at industrial level, some present challenges and future perspectives are also considered briefly.

Bioelectricity Production from Blueberry Waste

“…They suggest the observed decrease in voltage values was due to a decrease in microbial activity [24]. Yaqoob et al (2021) reported that the observed decrease in voltage generation was a consequence of a limited supply of organic substrate, which was only enough to achieve a trend of voltage generation for a 25-day period. This was followed by a decrease in the carbohydrate content for oxidation as well as bacterial activity [23].…”

“…According to Harshitha et al, (2019), the potential output depends on the growth rate of microorganisms, which depends on factors such as temperature and nutrients supplied [21]. The quick generation of potential could be explained by the swift adhesion of microorganisms to the anode electrode for biofilm formation [22] and to the oxidation of organic waste due to the bacterial community present in the MFC [23]. On the other hand, the observed decrease in voltage after the eighth day can be attributed to the combination of different events.…”

“…Yaqoob et al (2021) reported that the observed decrease in voltage generation was a consequence of a limited supply of organic substrate, which was only enough to achieve a trend of voltage generation for a 25-day period. This was followed by a decrease in the carbohydrate content for oxidation as well as bacterial activity [23]. In Figure 2b, the values of electric current generation observed during the whole monitoring period are shown.…”

Microbial Fuel Cell: Recent Developments in Organic Substrate Use and Bacterial Electrode Interaction

“…One of the most crucial aspects of MFC is the substrates used due to their effect on the generation of electricity [22,23]. Various substrates can be utilized in the MFC technology to facilitate energy generation, either pure substances or complex mixture from organic materials present in wastewater.…”

“…Among various types of conductive polymers, the most commonly used for anode electrode modification is polyaniline (PANI) [82]. It has been reported that densities of current could be improved by using PANI polymers that had been modified, such as fluorinated PANI [23] and mixture of PANI/titanium dioxide [83]. Another suitable material for anode electrode is the composite of CNTs with polyaniline [84].…”