Carbon dioxide (CO2) capture and utilization technologies: New developments toward net-zero emissions and climate-change mitigation Basiru O. Yusuf, Abdulrahman A. Abdulrasheed, Hambali U. Hambali, Afeez Gbadamosi, Adeyinka S. Yusuff, Funsho Afolabi, Mansur Aliyu, Saheed A. Ganiyu Carbon Capture Science and Technology, 2026 • Integrated assessment of CO 2 capture and utilization technologies was conducted • Advances in solid sorbents and solvents for efficient CO 2 capture was elucidated • Comparative analysis of catalytic and non-catalytic CO 2 utilization routes was analyzed • Techno-economic barriers and scale-up challenges for CCU deployment was probed. • Future directions toward scalable and integrated CCU systems were proffered The accelerating rise in anthropogenic carbon dioxide (CO 2 ) emissions poses a critical threat to global climate stability, necessitating scalable and technologically robust mitigation strategies. Carbon capture and utilization (CCU) have emerged as a key approach for reducing emissions while simultaneously transforming CO 2 into fuels, chemicals, and value-added products. This review provides a comprehensive and integrated assessment of recent advances in CO 2 capture technologies, advanced capture materials, and utilization pathways, with emphasis on their combined role in influencing conversion efficiency, material performance, and system-level techno-economic outcomes to support net-zero and circular-carbon objectives. Contemporary capture approaches, including pre-combustion, post-combustion, oxy-fuel combustion, and direct air capture, are critically examined alongside emerging materials such as functionalized carbons, graphene-based composites, zeolites, metal–organic frameworks, and hybrid sorbent–catalyst systems. The review further evaluates state-of-the-art CO 2 utilization routes, including dry reforming of methane, bi- and oxy-reforming, CO 2 -assisted dehydrogenation, and catalytic hydrogenation to fuels and chemicals, highlighting how material and capture performance directly affect conversion efficiency and process integration. In addition, this review incorporates a dedicated techno-economic assessment (TEA) of CCU technologies, critically evaluating capital and operating costs, energy requirements, process efficiency, scalability, and market competitiveness across major capture and utilization pathways. Key scientific, technological, and economic barriers hindering large-scale CCU deployment are identified, including capture–conversion coupling, energy intensity, catalyst durability, and the interdependence of material selection and process performance. Finally, future research directions are outlined to accelerate the transition of CCU from laboratory-scale innovations to commercially viable, integrated carbon management solutions. By synthesizing advances in CO 2 capture, utilization, and techno-economic performance within a unified framework, this work provides strategic insights for advancing CCU as a practical pathway for emissions reduction and sustainable chemical production.
Evaluation of the structural and crystalline properties of hybrid biochar derived from co-carbonized polyethylene and soybean pod waste Hambali Umar Hambali, Micheal Kehinde Temitope, Motunrayo Adejoke Olowookere, Mubarak A. Amoloye, Kingsley O. Iwuozor, Ebuka Chizitere Emenike, Kayode Peter Odimayomi, Adewale George Adeniyi Biofuels, 2026 The accumulation of plastic waste, which is non-biodegradable, along with various agricultural wastes, such as soybean pods, which are often dumped in an open field, poses a major concern for humans and the environment due to the increase in greenhouse gases and ineffective waste management. The co-carbonization of these wastes to produce hybrid biochar, a valuable product, is therefore a viable method toward a more sustainable future. The structural and crystalline properties of biochar (SBP) and hybrid biochar (SBPP) were evaluated in this study. SBP was produced by carbonizing soybean pod waste in a 48.5 cm high top-lit updraft gasifier reactor, and SBPP was made by co-carbonizing polyethylene and soybean pod waste (1:15) in a 53 cm high top-lit updraft gasifier reactor, and both biochars were characterized. A yield of 27.85% and 25.87% was obtained for SBP and SBPP, respectively. The SEM-EDX results revealed that SBP had a repeating pattern with a regular surface and 55% carbon composition, whereas SBPP had a heterogeneous surface with a 71% carbon composition. BET results showed surface areas of 285.021 m²/g for SBP and 352.490 m²/g for SBPP. FTIR analysis confirmed hydroxyl, carboxyl, and aliphatic groups. XRD analysis revealed crystalline materials, with enhancements attributed to plastic waste.
Production and characterization of sunflower stalk biochar and ash: a study on batch versus semi-batch gasifier systems Adewale George Adeniyi, Taiwo Temitayo Micheal, Ebuka Chizitere Emenike, Omar H. Abd-Elkader, Kingsley O. Iwuozor, Hamad A. Al-Lohedan, Hambali Umar Hambali, Abdelrahman O. Ezzat, Toheeb Adeeyo, Mubarak A. Amoloye, Ifeoluwa Peter Oyekunle International Journal of Chemical Reactor Engineering, 2025 This study is the first to compare batch and semi-batch gasifier systems for turning sunflower stalks into useful products, filling an important gap in our understanding of gasification technologies that use biomass fuel. This study investigated the production and characterization of biochar and ash derived from sunflower stalks using batch and semi-batch gasifiers. The conversion process, lasting 90 min, employed the top-lit updraft mechanism to generate sunflower stalk ash and biochar under both systems. The yields of batch-based samples were 34.60 % for biochar (BSB) and 19.40 % for ash (BSA), while semi-batch samples yielded 20.80 % (SSA) and 18.55 % (SSB). Elemental analysis revealed significant carbon enrichment from 44.2 % in raw feedstock to 85.4 % in semi-batch biochar, representing a 93 % increase in carbon concentration. The biochar produced in the batch gasifier exhibited a surface area of 364.127 m2/g, compared to 392.508 m2/g for the semi-batch gasifier biochar, as determined by BET analysis. Scanning Electron Microscopy (SEM) revealed a more porous structure in the semi-batch biochar. Fourier Transform Infrared Spectroscopy (FTIR) analysis identified both similarities and differences in the functional groups between the biochar and ash samples from both systems. Thermogravimetric analysis (TGA/DTA) showed a higher mass loss in the semi-batch ash (SSA) compared to the batch sample (BSA), indicating greater thermal stability in the batch biochar. These findings showed the potential of sunflower stalk biochar and ash for diverse applications such as soil improvement, pollutant removal, and energy conversion, while also providing insights into optimizing carbonization processes for enhanced material properties.
Dual-phase valorization of chicken feathers and Delonix regia biomass into biochar and pozzolan using a top-lit updraft gasifier Tunmise Latifat Adewoye, Stephen Emmanuel Sunday, Ebuka Chizitere Emenike, Kingsley O. Iwuozor, Emmanuel Baba, Hambali Umar Hambali, Harvis Bamidele Saka, Mubarak A. Amoloye, Adewale George Adeniyi Biofuels, 2025 The increasing accumulation of biomass residues presents significant environmental challenges and demands sustainable valorization approaches. This study explores the dual-phase conversion of chicken feathers and Delonix regia biomass into biochar and pozzolan. Using top-lit updraft gasifier, chicken feathers and Delonix regia biomass were co-gasified to produce biochar and pozzolan. Biochar yields were 41.6%, 52%, and 37.1% for samples derived from 25 g of chicken feathers and 50 g of Delonix regia, 50 g of chicken feathers and 50 g of Delonix regia, and 50 g of Delonix regia alone, respectively, at a maximum temperature of 450 °C for 130 min. The biochar samples exhibited mesoporous structures with surface areas of 262.189, 329.460, and 381.154 m2/g, respectively. Pozzolan analysis revealed functional groups such as Si-O-Si, Si(Al)–O, and CO32-, indicating the presence of aluminosilicates, cristobalite, calcite, and mullite phases. SEM micrographs showed irregular pore networks in both biochar and pozzolan, while thermal analysis confirmed higher stability in pozzolan derived from chicken feathers and Delonix regia. The results shows the potential of these materials as eco-friendly additives in cement, heterogeneous catalysts, and pollutant remediation systems, contributing to sustainable construction practices and agricultural innovations. This approach demonstrates an efficient pathway for converting waste into high-value products while advancing circular economy goals.
Characterization of groundnut shell biochar produced with different stainless steel combustion compartment volumes Oluwatoyin Rhoda Ayanwusi, Sulyman A. Abdulkareem, Taiwo Temitayo Michael, Kingsley O. Iwuozor, Ebuka Chizitere Emenike, Hambali Umar Hambali, Adewale George Adeniyi Biofuels Bioproducts and Biorefining, 2024 Biochar, a solid material derived from a thermochemical process, has received significant attention due to its usefulness in various sectors. Previous studies have been conducted to improve the properties and quality of this material by altering the thermochemical processes, treating the feedstock, hybridizing the feedstock, and so forth, but little has been done on the effect of varying the reactor's configuration. This research aims to study the effect of varying the stainless‐steel‐based combustion compartment volume of a biomass‐fueled top‐lit updraft gasifier on the groundnut shell biochar. The biochar yields for reactors ranged from 34.9% to 51.2%. The sample produced in the smallest combustion compartment volume showed the highest carbon content, according to energy dispersive X‐ray spectroscopy (EDX) analysis. Potassium, another major element, decreased as the combustion compartment was reduced. Scanning electron microscopy (SEM) analysis revealed that the biochar samples produced had an irregular shape and rough surfaces, and reducing the combustion compartment volume resulted in larger particles on the surface. Fourier transform infrared (FTIR) spectroscopy analysis showed similarities and differences in peaks observed for all the samples. The biochar samples produced can find applications in wastewater treatment, energy conversion and storage, and soil amendment, and the findings contribute to the design and optimization of biomass‐based gasifiers.
A Review on CO2 Capture over Novel Adsorbents: Progress in Robust Zeolite Adsorbent Development H. U. Hambali, T. Jimoh, T. L. Peng, A. A. Umar, B. T. Mutiullah, J. A. Okolie Nigerian Journal of Technological Development, 2024 Indubitably, the combustion of fossils fuels has really hampered the preservation of the environment as it raises the content of CO2 in the atmosphere which consequentially results in global warming. Adsorption process remains the popular technique owing to its cost-effectiveness, faster reaction rates and flexible design. This review detailed the research progress in preparation of modified zeolite-based and novel adsorbents towards enhanced CO2 capture. In addition, the review presents an overview on available techniques of capturing CO2 and mechanism of reaction. Large surface area, distinctive mechanical characteristics and uniform dispersion of the exchangeable cations in the porous framework is prerequisite for high adsorption capacity and stability over zeolite materials. Novel nanostructured and polymeric zeolite composite materials seem promising because they offer solutions to energy-related problems while also contributing to environmental preservation. It is anticipated that this review could offer a conclusive roadmap in the pursuit of a cost-effective, industrially potent adsorbent suited for enhance CO2 capture.
Hydrothermic Reduction of Rutile-Ilmenite Mineral Producing an Oxyhydride η-Ti2FeO0.2H2.8: Towards In-Situ Hydrogen Production and Storage I. A. Mohammed, S. I. Mustapha, F. A. Aderibigbe, H. U. Hambali, A. M. Afolabi, K. B. Muritala, U. M. Aliyu Nigerian Journal of Technological Development, 2024 As an alternative to the physical storage of hydrogen as compressed gas or liquid hydrogen requiring high-pressure tanks and cryogenic temperatures, the material-based storage of hydrogen in solids involves hydrogen uptake and release from the surface of adsorbents or within interstitials of hydrides. We report a hydrothermic reduction of rutile-ilmenite mineral into hydrogen-rich fibrous products, η-Ti2FeO0.2H2.8, in an ethanol-water system at 120°C for 4 hrs. As part of a project to generate hydrogen from water-ethanol system using advanced catalysts containing graphene oxide (GO) as carbon source, a system of 62.5 μg graphene oxide per g of rutile-ilmenite mineral was employed in a concentration of 50 mg/mL of ethanol-water solution. As well as in the original mineral, XRD of thermal annealed mineral between 500 and 800°C showed no hydride or phase change in rutile-ilmenite. With hydrothermal treatment of GO/rutile-ilmenite (50 mg/mL) in ethanol-water (1:1 v/v) at 120°C, a hydrogen-rich ferrotitanium hydride phase was formed, and there was a change in morphology from plate-like and granular particles into fibrous structures. Like the release of hydrogen by its ‘carriers’ (e.g., CaH2, NH4BH4, NaBH4, NH3, formic acid), it is anticipated that hydrogen was generated from the ethanol-water system in-situ, which reduced the rutile-ilmenite mineral into a hydride. EDX results showed that the reduction affected specifically the oxides of Fe and aluminosilicates in the mineral. The study demonstrated a possibility of in-situ hydrogen generation and storage via low-temperature graphene oxide hydrothermic reduction of rutile-ilmenite mineral in an ethanol-water system.
