UTILIZING IMMOBILIZED BIOCATALYSTS ON ACTIVATED CARBON BLACK ADSORBENTS FOR CARBON DIOXIDE CAPTURE FROM SIMULATED AMBIENT AIR UNDER A pH SWING ADSORPTION PROCESS

Open Access
Author:
Cuesta, Antonio Rafael
Graduate Program:
Energy and Mineral Engineering
Degree:
Master of Science
Document Type:
Master Thesis
Date of Defense:
April 28, 2017
Committee Members:
  • Dr. Chunshan Song, Thesis Advisor
Keywords:
  • CO2 Capture
  • Ambient Air Capture
  • CO2 Adsorbent
  • Swing Adsorption
  • pH Swing Adsorption
  • Activated Carbon Adsorbent
  • Immobilized Carbonic Anhydrase
  • Nitrogen Enriched Carbon Adsorbent
  • Potassium Enriched Carbon Adsorbent
  • Biocatalyst CO2 Gas Hydration
  • CCUS
  • Carbon Capture
Abstract:
Adsorbent-based carbon capture is only feasible if adsorption-desorption cycles are both fully regenerating and economical. A potentially energy-saving and regenerating pH swing system is currently utilized by biocatalysts. The main objective is to develop, test and analyze a synthetic pH Swing Adsorption (pHSA) system as well as a pHSA compatible solid adsorbent to capture CO2 from a simulated ambient air gas stream. Furthermore, comparing its performance to other CO2 sorbent systems is necessary to determine the feasibility of pHSA implementation. The lead developed adsorbent is a carbon black co-activated with potassium carbonate and nitrogenous copolymer that is impregnated with immobilized bovine carbonic anhydrase and thereby deemed “BCA/KN-CB”. BCA/KN-CB has preliminarily demonstrated both a competitive CO2 adsorption capacity and a limited regenerative ability under experimental pHSA conditions. In addition, BCA-based adsorbents achieved higher adsorption capacities than non-BCA adsorbent counterparts. BCA-based adsorbents displayed better regenerative stability when the adsorbent was chemically activated with K2CO3. The point of zero charge of adsorbents BCA/KN-CB and KN-CB showed change between pHSA steps and came close to returning to the initial point of zero charge after one pHSA cycle. While the cost of the biocatalyst easily makes its use for CO2 capture impractical, the operational and remaining material costs are competitive to MSA and TSA solid adsorbent systems. The scientific contribution of the thesis is the concept of a pH swing adsorption/biocatalytic adsorbent system that can effectively operate under ambient conditions and has competitive CO2 adsorption capacities compared against other swing adsorption CO2 capture systems.