Development of Hybrid Materials Based on Ionic Liquids and Activated Carbon for the Removal of CO2 and H2S from Biogas

• Grant number: 25/04416-4
• Support Opportunities: Scholarships in Brazil - Doctorate
• Start date: May 01, 2025
• End date: April 30, 2029
• Field of knowledge: Engineering - Chemical Engineering - Chemical Process Industries
• Principal Investigator: Luis Alberto Follegatti Romero
• Grantee: Hilman Ibnu Mahdi - Dave Ronel
• Host Institution: Núcleo Interdisciplinar de Planejamento Energético (NIPE). Universidade Estadual de Campinas (UNICAMP). Campinas , SP, Brazil
• Associated research grant: 24/01112-1 - São Paulo Center for Biogas and Bioproducts Studies, AP.CCD

Abstract

The growing interest in sustainable energy production has driven research into biogas, a renewable alternative obtained from the anaerobic decomposition of organic waste. Commonly, biogas consists of 60 to 70% methane and 30 to 40% carbon dioxide (CO¿), followed by hydrogen sulfide (H¿S), carbon monoxide, and other components. It is well known that CO¿ and H¿S are highly toxic, poisonous, and corrosive gases. However, the presence of these impurities reduces energy efficiency and can cause corrosion in equipment. Thus, developing efficient purification processes for biogas.This project proposes the synthesis and characterization of innovative hybrid materials based on the combination of ionic liquids (ILs) and activated carbon (AC) to enhance the selective removal of contaminants from biogas. To remove CO¿ and H¿S, it may be necessary to develop these hybrid materials using a combination of ionic liquids [Bmim]Cl- and [Bmim][NTf¿] and activated carbon, which acts as an adsorbent for undesirable gases. AC will be produced through the pyrolysis process at a temperature range of 600 to 1200°C for a period of 30 to 90 minutes, using various types of biomass and insects, such as coffee waste, coconut husks, sugarcane bagasse, microalgae, pumpkin seeds, mealworm larvae (YML), and black soldier fly larvae (BSFL). The produced AC will be diluted in an IL solution composed of different mass concentrations and subsequently impregnated via an ultrasonic system, resulting in a new hybrid adsorbent. The research will be conducted in three main stages: (i) synthesis and modification of ionic liquids with different cations and anions to enhance selectivity in capturing H¿S and CO¿; (ii) impregnation of ILs into activated carbon and characterization of the resulting hybrid materials using techniques such as Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM), nitrogen adsorption/desorption analysis (BET), thermogravimetric analysis (TGA-DTG), and energy-dispersive X-ray spectroscopy (SEM-EDX); and (iii) performance tests of the materials in biogas purification, evaluating adsorption efficiency under different temperature, pressure, and gas composition conditions.The prepared hybrid adsorbent will be applied in an adsorption system under atmospheric temperature and pressure, with CO¿ and H¿S gases supplied to the system. The adsorption process will be carried out for an estimated period, with the process time and outlet concentrations recorded at short time intervals until breakthrough and saturation points are reached. Some of the operational variables studied include different pyrolysis temperatures (600 - 1200°C), pyrolysis times (30 - 90 min), impregnation durations (10 - 30 min), types of raw materials (biomass, residues, microalgae, and insects), IL mass concentrations (25 - 100% relative to AC mass), and adsorption times. The final produced gas will be analyzed for CO¿ and H¿S concentrations in ppm, and adsorption capacity will be calculated. The developed hybrid materials are expected to exhibit a high capacity for the selective capture of H¿S and CO¿, promoting efficient biogas purification and expanding its applications as a clean energy source. The results will contribute to advancing knowledge in the field of adsorbent materials and gas separation while encouraging the implementation of more sustainable technologies in the biogas industry. Thus, the project proposes an innovative approach to biogas purification, combining the benefits of ionic liquids and activated carbon to develop high-performance adsorbent materials, aligning with sustainability and energy efficiency demands.