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Carbon peak and neutralization, land space ecological restoration, and sustainable management of sea areas and islands are all important components of national development strategies. In recent years, owing to the impact of natural factors, human interference, and global climate change, the ecosystem of the southeast coast of Hainan has been seriously damaged, and its carbon sink function has decreased significantly. This decline in the ecological quality of the southeast coast of Hainan is inconsistent with the positioning requirements of the Hainan Free Trade Port and the National Ecological Civilisation Construction Pilot Zone. Thus, ecosystem restoration based on carbon storage needs to be urgently explored. Using the southeast coast of Hainan Island as an example, the carbon storage module based on the InVEST model, combined with the land use data of the study area in 2000, 2010, and 2020, the carbon storage of the study area was estimated. The carbon sink and carbon source areas were divided, and the carbon storage function was evaluated. Over the past two decades, carbon loss in the study area has been identified, and areas with serious carbon loss were identified, with the ecological restoration functional area divided. The results showed that the ecosystem in the study area was damaged to varying degrees, decreasing by 1.11 Gt over 20 years. Traditionally, the area of the carbon source is always larger than that of the carbon sink. Areas with poor and extremely poor carbon storage functions were 39.84 and 27.31 km2, respectively. According to the superposition results of the carbon storage function and terrestrial ecosystem service value, four restoration units (natural restoration area, artificial auxiliary area, reconstruction restoration area, and moderate development area) were selected. In light of the different restoration areas and under the guidance of land space planning and the idea of carbon neutral and carbon peaks, ecological restoration strategies, including rehabilitation and restoration of wetlands, shoreline restoration, wetland reconstruction, and strengthening supervision, have been proposed in a targeted and differentiated manner. The research results have important reference value for strengthening the protection of the restoration area in the southeast coastal zone of Hainan, stabilizing the carbon storage capacity, reversing the trend of carbon loss, and realizing effective protection and restoration of the damaged ecosystem. Furthermore, the ecological service function and quality of coastal zones, and the marine ecological compensation mechanism, can be further improved.

The vapor-liquid equilibrium (VLE) of CO2 in a reactive solvent is essential for the proper simulation and design of CO2 absorption processes. This work presents a systematic investigation on CO2 absorption in various aqueous monoethanolamine (MEA) solutions. CO2 solubility in MEA was measured at 298, 313, 333, and 353 K with CO2 partial pressure ranging from 34.5 to 78.0 kPa. A modified Kent-Eisenberg model was developed based on the measured solubility data, showing good predictions over the liquid phase speciation for the CO2-H2O-MEA system. We presented a new analysis based on the first-order difference curve of distribution profiles of the species. Based on the main reactions that occurred, the CO2 absorption process was demonstrated to be divided into four regions with increasing CO2 loading from 0 to 1. Accordingly, kinetic study was proposed to be conducted in the first region, whereas measuring of mass transfer in the first three regions. The findings in this work extend the existing knowledge of CO2 absorption process in terms of speciation and can provide important guidance for further study of the process characteristics using aqueous amine absorbents. [ABSTRACT FROM AUTHOR]