Search

• A thorough analysis on variations of CO 2 fluxes and carbon budget was conducted. • Nitrogen and water conditions were primary factors controlling maize seasonal NEE. • NBP for the winter wheat-maize rotation system ranged from -239.1 to 237.0 gCm−2. • Net ecosystem GHG emissions ranged from -39.23 to 325.23 gCm−2 for the wheat system. • Nitrogen and water application should be optimized for climate smart agriculture. Investigating CO 2 fluxes and carbon budget in agro-ecosystems is essential to develop climate smart agriculture. Here, we conducted a thorough analysis on the daily, seasonal and inter-annual variations in CO 2 fluxes and carbon budget in a winter-wheat and summer-maize rotation system in the North China Plain (NCP) to better understand the CO 2 flux exchange and the underlying mechanisms of carbon budget dynamics. During 2003-2010, the inter-annual variability of monthly gross primary productivity was significantly correlated with leaf area index (LAI), temperature and net radiation. The inter-annual variability of monthly ecosystem respiration was significantly correlated with LAI, soil temperature and moisture. Daily and monthly variability in net ecosystem exchange (NEE) was significantly correlated with LAI. At a seasonal scale, soil moisture was one of the primary factors controlling carbon sequestration of wheat system. Nitrogen application rate and water conditions were the primary factors controlling carbon sequestration of maize system. The NEE for winter wheat system, maize system, and winter wheat-maize rotation system in the NCP ranged from -418 to -29, -448 to -119, and -857 to -274 gCm−2, respectively. The net biome productivity (NBP) for winter wheat system, maize system, and winter wheat-maize rotation system in the NCP ranged from -223 to 151, -236 to 94, and -239 to 237 gCm−2, respectively. Taking greenhouse gas (GHG) emissions from irrigation, fertilization, herbicides, fungicide, insecticide, and field operations, the associated net GHG emissions ranged from -39 to 325 gCm−2 for wheat system and -22 to 287 gCm−2 for maize system. Wheat and maize systems in the region were a medium source of GHG emissions in most of years, mainly due to the large application rates of fertilization and irrigation. Our findings gain new insights into the mechanisms underlying the inter-annual variations in CO 2 fluxes and carbon budget, highlighting the optimization of genotype, environment and management interactions to realize climate smart agriculture. [ABSTRACT FROM AUTHOR]

• The main thermodynamic challenges associated with CO 2 transport via pipeline has been analysed. • A critical review of main flow-assurance issues related to CO 2 pipelines has been presented. • The impact of impurities, typology and their concentrations has been included. • Corrosion control strategies and water content limits have been collected through a literature review. • A collection of design parameters useful to technicians and operators has been reported. Environmental issues related to climate change have constantly been increasing in the last years, and global emissions must be managed wisely, adopting the most powerful and effective strategies available. Carbon Capture Utilization and Storage (CCUS) is claimed as a solid climate mitigation strategy for the most challenging emissions and the production of blue hydrogen. The development of an international CO 2 transportation network is considered a necessary cross-cutting topic in the whole Carbon Capture and Storage sector. CO 2 pipeline development is an essential aspect for the realization of most decarbonization CCS projects. Large-scale CCS projects will require the management and transport of CO 2 in the presence of impurities at lower costs than traditional CO 2 pipelines utilized for Enhanced Oil Recovery (EOR). Thus, the accuracy of modelling carbon dioxide in the presence of other components needs to be assessed. Corrosion prediction and control are strongly related to water content and introduces uncertainties in terms of costs and corrosion risks, especially in the presence of other components and possible cross-chemical reactions. In this work, the process and flow assurance challenges related to the design of a CO 2 pipeline have been reviewed in terms of impurities, water content, and corrosion, as well as low-temperature scenarios. The main scope of this paper is to analyse the aspects that can be improved and the ones that need for further research from a thermodynamic point of view. This will help the design of a next generation of CO 2 pipelines with low CAPEX (capital expenditure) and OPEX (operating expense), suitable for large-scale CCS projects and meeting the Paris Agreements. [ABSTRACT FROM AUTHOR]

The mitigation of climate change, abatement of greenhouse gas emissions and thus, fundamentally, the separation of CO 2 from various gas streams are some of the most pressing and multifaceted issues that we face as a society. De-carbonising our entire civilisation will come at a great cost and requires vast amounts of knowledge, initiative and innovation; yet, no matter how much time or money is spent, some sectors simply cannot be de-carbonised without the deployment of carbon capture and storage technologies. The technical challenges associated with the removal of CO 2 are not universal – there exists no single solution. Capturing the CO 2 on solid sorbents has been gaining traction in recent years given its cost-effectiveness as a result of its ease of application, relatively small energy requirements and applicability in a wide range of processes. Even with the myriad materials such as zeolites, carbons, metal organic frameworks, mesoporous silicas and polymers, the challenge to identify a sorbent with optimal capacity, kinetics, selectivity, stability and ultimately, viability, still persists. By tailoring these solid materials through comprehensive campaigns of surface modification, the pitfalls of each can be mollified and the strengths enhanced. This highly specific tailoring must be well informed so as to understand the mechanisms by which the CO 2 is adsorbed, the surface chemistry that has influence on this process, and what methods exist to facilitate the improvement of this. This review endeavours to identify the surface functional groups that interact with the CO 2 molecules during adsorption and the methods by which these functional groups can be introduced. It also provides a comprehensive review of the recent attempts and advancements made within the scientific community in the experimental applications of such methods to enhance CO 2 capture via adsorption processes. The primary search engine employed in this critical review was Scopus. Of the 421 references cited that embody the literature focussed on surface modification for enhancing the selective adsorption of CO 2 , 370 are original research papers, 43 are review articles and 7 are conference proceedings. Image 1 • Critical review of surface modification methods employed to enhance CO 2 adsorption. • Assessment of CO 2 adsorption mechanisms in the context of surface functional groups. • Evaluation of the methods used to introduce functional groups on adsorbent surfaces. • Critical discussion of the reagents used in surface modification of adsorbents. [ABSTRACT FROM AUTHOR]