Utilization of carbon nanotubes in hydrogen electrosynthesis from tropical fruit fermentation

ABSTRACT The use of fossil fuels, especially oil and gas, has accelerated in recent years, resulting in the global energy crisis. The fermentative biological process is a sustainable way to produce hydrogen, as it can use as a substrate various types of carbohydrate-rich industrial and household waste such as fruit, minimizing but not completely eliminating the problems caused by improper disposal of this material. From a perspective of energy conservation and use of renewable sources for energy generation, this work aims to contribute to the identification of the use of a currently unused portion of energy, optimizing hydrogen production from a fuel cell. microbial. The main nanomaterial used in electrolysis was carbon nanotubes (CNT) incorporated into carbon felt (CF). Cyclic voltammetry studies were also performed on three electrode systems: vitreous carbon electrode as working electrode, platinum electrode as auxiliary electrode and Ag / AgCl / Cl- as reference electrode. An electrochemical cell formed by two separate compartments was constructed. Before starting the electrolysis experiment, an experimental design was performed using the complete factorial design technique to analyze the influence of the variables selected for this study. The independent variables selected were: Tropical fruit liquor concentration in %v/v, type of working electrode, electrolysis time and pH of the electrolyte medium. The observed variable was the concentration in% v / v of the hydrogen gas obtained in the electrolysis. After the results of the tests, it was concluded that carbon nanotubes can be used as working electrode, presenting success in the hydrogen production process and that the pH of the electrolytic medium has a strong influence on this process. The present work was concluded presenting an alternative way in the production of a renewable energy source.摘要：近年来，化石燃料（尤其是油气）的使用量持续增长，引发了全球能源危机。发酵生物过程是制取氢气的可持续路径，可将各类富含碳水化合物的工业与生活垃圾（如果蔬类废弃物）作为底物，虽能减少此类物料不当处置所引发的问题，但无法完全消除该类弊端。从节能与利用可再生能源发电的视角出发，本研究旨在助力识别当前未被充分利用的能源份额，优化微生物燃料电池的氢气制备工艺。本研究用于电解的核心纳米材料为负载于碳毡（carbon felt, CF）上的碳纳米管（carbon nanotubes, CNT）。此外，针对三电极体系开展了循环伏安法研究：以玻碳电极（vitreous carbon electrode）作为工作电极，铂电极（platinum electrode）作为辅助电极，Ag/AgCl/Cl-作为参比电极。本研究搭建了双室电化学池。在启动电解实验前，本研究采用全因子设计（complete factorial design）技术开展实验设计，以分析选定变量的影响。本次研究选定的自变量包括：热带果酒的体积百分比浓度、工作电极类型、电解时长以及电解质介质的pH值。观测变量为电解过程中产出氢气的体积百分比浓度。试验结果表明，碳纳米管可作为工作电极应用于本体系，氢气制备过程效果良好，且电解质介质的pH值对该过程具有显著影响。本研究最终提出了一种可再生能源制取的替代方案。