PDF(Pubmed)
Abstract：
Coastal enhanced weathering (CEW) is a carbon dioxide removal (CDR) approach whereby crushed silicate minerals are spread in coastal zones to be naturally weathered by waves and tidal currents, releasing alkalinity and removing atmospheric carbon dioxide (CO2). Olivine has been proposed as a candidate mineral due to its abundance and high CO2 uptake potential. A life cycle assessment (LCA) of silt-sized (10 μm) olivine revealed that CEW\'s life-cycle carbon emissions and total environmental footprint, i.e., carbon and environmental penalty, amount to around 51 kg CO2eq and 3.2 Ecopoint (Pt) units per tonne of captured atmospheric CO2, respectively, and these will be recaptured within a few months. Smaller particle sizes dissolve and uptake atmospheric CO2 even faster; however, their high carbon and environmental footprints (e.g., 223 kg CO2eq and 10.6 Pt tCO2-1, respectively, for 1 μm olivine), engineering challenges in comminution and transportation, and possible environmental stresses (e.g., airborne and/or silt pollution) might restrict their applicability. Alternatively, larger particle sizes exhibit lower footprints (e.g., 14.2 kg CO2eq tCO2-1 and 1.6 Pt tCO2-1, respectively, for 1000 μm olivine) and could be incorporated in coastal zone management schemes, thus possibly crediting CEW with avoided emissions. However, they dissolve much slower, requiring 5 and 37 years before the 1000 μm olivine becomes carbon and environmental net negative, respectively. The differences between the carbon and environmental penalties highlight the need for using multi-issue life cycle impact assessment methods rather than focusing on carbon balances alone. When CEW\'s full environmental profile was considered, it was identified that fossil fuel-dependent electricity for olivine comminution is the main environmental hotspot, followed by nickel releases, which may have a large impact on marine ecotoxicity. Results were also sensitive to transportation means and distance. Renewable energy and low-nickel olivine can minimize CEW\'s carbon and environmental profile.
摘要：
沿海增强风化（CEW）是一种二氧化碳去除（CDR）方法，其中压碎的硅酸盐矿物散布在沿海地区，以受到波浪和潮流的自然风化，释放碱度和去除大气二氧化碳(CO2)。橄榄石由于其丰富和高CO2吸收潜力而被提议作为候选矿物。淤泥大小(10μm)橄榄石的生命周期评估(LCA)表明，CEW的生命周期碳排放量和总环境足迹，即，碳和环境惩罚，每吨捕获的大气二氧化碳分别约为51千克二氧化碳和3.2生态点(Pt)单位，这些将在几个月内重新夺回。较小的颗粒尺寸溶解和吸收大气中的二氧化碳更快;然而，他们的高碳和环境足迹(例如，分别为223千克CO2eq和10.6千克tCO2-1，对于1μm橄榄石)，粉碎和运输方面的工程挑战，和可能的环境压力(例如，空气和/或淤泥污染)可能会限制它们的适用性。或者，较大的粒径表现出较低的足迹(例如，分别为14.2kgCO2eqtCO2-1和1.6PttCO2-1，对于1000μm橄榄石)，可以纳入沿海地区管理计划，因此，有可能将避免的排放归功于CEW。然而,它们溶解得更慢，在1000μm橄榄石变成碳和环境净负值之前需要5年和37年，分别。碳惩罚和环境惩罚之间的差异凸显了使用多问题生命周期影响评估方法的必要性，而不是仅关注碳平衡。当考虑到CEW的完整环境概况时，已经确定，用于橄榄石粉碎的化石燃料依赖电力是主要的环境热点，其次是镍释放，这可能会对海洋生态毒性产生重大影响。结果对运输方式和距离也很敏感。可再生能源和低镍橄榄石可以最大限度地减少CEW的碳和环境状况。
