About

Sergio Capareda is a professor in the Department of Biological and Agricultural Engineering at Texas A&M University. He holds a B.S. in Agricultural Engineering from the University of the Philippines, an M.E. in Energy Technology from the Asian Institute of Technology, and a Ph.D. in Agricultural Engineering from Texas A&M University. His areas of expertise include fluidized bed pyrolysis and gasification of biomass, biofuels and biopower production including biomass characterization, high value chemicals and materials from biomass, biochar and graphene research, GHG and RVOC emissions measurements, engine dynamometer testing, and process design and development. Professor Capareda has received numerous awards for his contributions, including the 2018 ASABE Superior Paper Award, the 2017 ASABE Outstanding Leadership in Energy System’s Renewable Power Generation Committee, and the 2016 Charles H. Barklay Jr. ’45 Fellow for Engineering Outstanding Contributions. His research focuses on sustainable biomass utilization and renewable energy systems, contributing significantly to the fields of biological and agricultural engineering.

Research topics

• Political Science
• Chemistry
• Nuclear chemistry
• Computer Science
• Organic chemistry
• Chromatography
• Economics
• Environmental economics
• Geography
• Marketing
• Materials science
• Business
• Inorganic chemistry
• Agronomy

Selected publications

• Ocean Thermal Energy Conversion (OTEC) Systems

  2026-01-19

  book-chapter1st authorCorresponding
  PublisherDOI

• Introduction to Renewable Energy

  2026-01-19

  book-chapter1st authorCorresponding
  PublisherDOI

• Sustainability and Cost of Renewables

  2026-01-19

  book-chapter1st authorCorresponding
  PublisherDOI

• Laboratory-Based Estimation of Ammonia-Derived Secondary PM2.5 for Air Quality Assessment of Concentrated Animal Feeding Operations

  Air · 2026-04-12

  articleOpen accessSenior author

  Ammonia (NH3) emissions from concentrated animal feeding operations (CAFOs) are recognized contributors to secondary fine particulate matter (PM2.5) formation, yet empirically derived secondary PM2.5 emission factors applicable to livestock operations remain limited. This study investigated NH3-derived secondary PM2.5 formation under controlled laboratory conditions using a PTFE flow reactor in which NH3 was reacted with sulfur dioxide (SO2) across ammonia-rich NH3:SO2 ratios, with and without zero air. The resulting aerosols were characterized using gravimetric analysis, elemental analysis, Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM/EDS), and particle size distribution (PSD) measurements. The recovered particles were dominated by inorganic ammonium–sulfur species, with FTIR and elemental trends indicating sulfite-related intermediates under no-zero-air conditions and more oxidized ammonium–sulfur products under oxygenated conditions. Accounting for both filter-collected and wall-deposited particles, unit particulate emission factors normalized to ammonia input were derived. Size-based apportionment using PSD data indicated that approximately 76.6% of the recovered particulate mass was within the PM2.5 size range. Scaling the experimentally derived unit emission factors using literature-based ammonia emission rates yielded an estimated secondary PM2.5 emission factor of 0.351 ± 0.084 g PM2.5 per animal head per day for cattle feedlots, corresponding to approximately 3–4% of reported total PM2.5 emissions. Because the experimental system isolates NH3–SO2 interactions under idealized conditions and does not represent full atmospheric chemistry, the derived values should be interpreted as screening-level estimates of NH3-derived secondary PM2.5 formation potential intended to support comparative air quality assessments of CAFOs rather than direct predictions of ambient PM2.5 concentrations.

  PublisherOA PDFDOI

• Cold Fusion and Gravitational Energy

  2026-01-19

  book-chapter1st authorCorresponding
  PublisherDOI

• Intelligent Valorization: integrating AI, imaging, and sustainability for Next-Generation biofuel systems

  Global Energy Interconnection · 2026-03-01 · 1 citations

  articleOpen accessSenior author
  PublisherDOI

• Co-pyrolyzed and valorized municipal solid wastes and coconut husks into biochar adsorbing methylene blue in aqueous solution

  Sustainable Chemistry for the Environment · 2025-08-18 · 1 citations

  articleOpen access

  The adsorption potential of biochar derived from municipal solid waste (MSW) and coconut husk (CH) for methylene blue (MB) removal was investigated in this study. Both produced biochars exhibited a pH PZC of 8.5 with no observed significant compositional changes (consistent with literature values). The integration of CH in the co-pyrolysis process altered the surface morphology of MSW-BC. Moreover, the post-adsorption images indicated MB deposition on the biochar surfaces. The MCH-BC had 559 m² g -1 specific surface area and about 29 mg g -1 adsorption capacity, and practically indicated superior adsorbent quality than MSW-BC (with corresponding lower values). Furthermore, the adsorption behaviors suggested that the phenomena were (1) potentially influenced by chemisorption from kinetic studies, (2) best fitted the Freundlich isotherm model, denoting a heterogeneous adsorption mechanism, and (3) endothermic and spontaneous from the thermodynamic analysis. The proposed adsorption mechanism was feasibly dominated by physisorption, as indicated by low ΔG° values (-1.234 kJ mol⁻¹ to -4.531 kJ mol⁻¹) and functional groups, likely facilitating hydrogen bonding, which perhaps followed by initially identified chemisorption from kinetic studies. Finally, the study highlighted the potential of co-pyrolyzed MSW and CH biochar as a competitive low-energy synthesis, producing an adsorbent for MB removal. • Valorized MSW and CH by co-pyrolysis into biochar improved adsorption properties. • MCH-BC synthesis yielded a practically competitive adsorption capacity, 29 mg g -1 . • The proposed mechanism involves physisorption, feasibly followed by chemisorption. • MCH-BC is regarded as a competitive MB adsorbent with lower energy requirements.

  PublisherDOI

• Activated Carbon Production from Jatropha Pyrolysis Biochar

  Journal of Korea Society of Waste Management · 2025-02-28

  article
  PublisherDOI

• RSM-CCD modeled and enhanced liquid hydrocarbon from Scedemus obliquus oil by Ni-functionalized and pyrolyzed rice husk: Relative diesel and gasoline content responses

  Fuel · 2025-03-03 · 4 citations

  article
  PublisherDOI

• Continuously Stirred Reactor Pyrolyzed Oil Assessment as an Alternative Fuel from Plastic and Tire Waste Feedstock: Leveraging Towards Circular Economy

  SSRN Electronic Journal · 2025-01-01

  preprintOpen accessSenior author
  PublisherDOI

Frequent coauthors

• C. B. Parnell

  43 shared

• Bryan Shaw

  Georgetown University Medical Center

  26 shared

• Hyungseok Nam

  24 shared

• Ronald E. Lacey

  23 shared

• Saqib Mukhtar

  23 shared

• Amado L. Maglinao

  18 shared

• William B. Faulkner

  17 shared

• Jr. .

  15 shared

Education

• B.S., Agricultural Engineering

  University of the Philippines

  1982

• Other, Energy Technology

  Asian Institute of Technology

  1985

• Ph.D., Agricultural Engineering

  Texas A&M University

  1990

Awards & honors

• 2018 ASABE Superior Paper Award, 2018 ASABE International Me…
• 2017 ASABE Outstanding Leadership in Energy System’s Renewab…
• 2017 USAID-STRIDE Visiting Professorship Award at Mariano Ma…
• 2016 Charles H. Barklay Jr. ’45 Fellow for Engineering Outst…
• 2015 Texas A&M AgriLife Research Vice Chancellors Award in E…