Applied Machine Learning for Prediction of CO₂ Adsorption on Biomass Waste-Derived Porous Carbons

Abstract

Biomass waste-derived porous carbons (BWDPCs) are a class of complex materials that are widely used in sustainable waste management and carbon capture. However, their diverse textural properties, the presence of various functional groups, and the varied temperatures and pressures to which they are subjected during CO 2 adsorption make it challenging to understand the underlying mechanism of CO 2 adsorption. Here, we compiled a data set including 527 data points collected from peer-reviewed publications and applied machine learning to systematically map CO 2 adsorption as a function of the textural and compositional properties of BWDPCs and adsorption parameters. Various tree-based models were devised, where the gradient boosting decision trees (GBDTs) had the best predictive performance with R 2 of 0.98 and 0.84 on the training and test data, respectively. Further, the BWDPCs in the compiled data set were classified into regular porous carbons (RPCs) and heteroatom-doped porous carbons (HDPCs), where again the GBDT model had R 2 of 0.99 and 0.98 on the training and 0.86 and 0.79 on the test data for the RPCs and HDPCs, respectively. Feature importance revealed the significance of adsorption parameters, textural properties, and compositional properties in the order of precedence for BWDPC-based CO 2 adsorption, effectively guiding the synthesis of porous carbons for CO 2 adsorption applications.

Efficient N-Doped Porous Carbonaceous CO2 Adsorbents Derived from Commercial Urea-Formaldehyde Resin

“…For this purpose, numerous adsorbents such as porous carbons, ,− zeolites, porous polymers, − covalent organic frameworks (COFs), and metal–organic frameworks (MOFs) , have been widely investigated in the past decades. Among those, porous carbon has been likely the most attractive adsorbent for the CO 2 capture because of its large specific surface area along with tunable pore structure, low density, tailored surface functionalization, strong thermal/chemical stability, and low cost. , Besides, porous carbon is not sensitive to water vapor when compared with different CO 2 -philic adsorbents.…”

“…Among those, porous carbon has been likely the most attractive adsorbent for the CO 2 capture because of its large specific surface area along with tunable pore structure, low density, tailored surface functionalization, strong thermal/chemical stability, and low cost. 20,21 Besides, porous carbon is not sensitive to water vapor when compared with different CO 2 -philic adsorbents.…”

Sustainable Food Waste Management: Synthesizing Engineered Biochar for CO2 Capture

“…Carbon capture and storage (CCS) and greenhouse gas removal (GGR) have been widely considered promising and indispensable routes to meeting global climate change targets − because the concentration of atmospheric CO 2 gas has exceeded 410 ppm and continues to increase . Numerous investigations have been performed to reduce the cost of carbon capture processes (i.e., precombustion, postcombustion, and oxyfuel combustion), owing to the fact that common carbon capture processes constitute up to 50–80% of all CCS cost. , Among all CO 2 capture routes, solid-carbon-based adsorption is one of the most promising and cost-effective routes, ,, owing to its advantages of cost-effectiveness, well-developed pore structures of the adsorbents, low energy requirement for regeneration (e.g., by low-grade renewable solar thermal energy), and excellent cyclic stability. − …”

“…Upcycling biomass waste into value-added engineered biochar for CO 2 capture has recently been proposed as an innovative, sustainable, and low-cost approach, simultaneously mitigating the environmental pollution caused by waste mismanagement and climate change caused by CO 2 emissions. ,, As a typical biomass waste, food waste (FW) has been labeled as one of the priority waste streams globally; mismanagement of FW has led to critical challenges from the environmental protection and economic perspectives. , As summarized in Table , ,− each FW gave a relatively high CO 2 capture capacity at 25 °C (1 bar), which is feasible for practical CO 2 capture. , Furthermore, no clear relationship between CO 2 capture capacity and surface area was observed. ,, In the actual case, the FW is usually a complicated mixture, and it is a challenge to separate one type from the mixture with a simple method. Therefore, upcycling FW into engineered biochar for effective CO 2 capture can serve as a promising route to practical and sustainable FW management.…”

“…Slow pyrolysis is one of the most promising and feasible routes for valorizing FW into carbon materials, owing to its high biochar yields, mild operating conditions, and excellent practical commercial-scale applications . For activation (as listed in Table ), physical or chemical agents are typically applied to improve the pore structure and increase functional groups, which are essential factors in biochar-based CO 2 adsorption processes . For example, KOH chemical activation has been demonstrated to be one of the most effective routes for synthesizing engineered biochar with high CO 2 capture performance. − This is because microporous structures can be well developed during KOH activation, which enhance the textural properties and are beneficial for increasing CO 2 capture capacity. − , …”