Abstract:

The large amount of CO₂ emitted by the burning of fossil fuels contributes to global climate warming. CO₂ mineralization is one of the most effective technologies for CO₂ terminal emission reduction in recent years. CO₂ mineralization can use natural alkaline minerals or industrial alkaline solid waste for transforming acidic CO₂ gas into carbonate. Despite its promise, many reported CO₂ mineralization methods remain plagued by excessive energy consumption and cost. This study introduces an innovative, environmentally friendly, and energy-efficient air-driven membrane electrolysis technology, tailored for efficient CO₂ mineralization and the production of high-quality porous silica materials. The key advancement of this technology hinges on the simultaneous occurrence of the oxygen reduction reaction (ORR) and the oxygen evolution reaction (OER) at the anode and cathode, respectively, within the electrolytic environment. This unique feature results in low-energy water ionization, generating both alkaline and acidic solutions. Crucially, this developed electrolytic technology demonstrates a substantial reduction in electrolytic voltage, at least 0.5 V lower than conventional electrolytic processes under equivalent current densities. By combining the acidic solution from the anode with a moderately alkaline solution from the cathode to dissolve wollastonite, the resultant mixture yields high-quality porous silica. Subsequently, the filtrate and remaining alkaline solution at the cathode effectively absorb CO₂, yielding calcium carbonate as the mineralization product. This breakthrough technology offers a compelling pathway to efficient CO₂ utilization through mineralization, addressing both environmental concerns and energy efficiency challenges.

Key words: CO₂ capture, electrolysis, silica, electrochemistry, catalyst, CO₂ emission reduction

摘要：

化石燃料燃烧排放的大量CO₂ 造成了全球气候变暖。CO₂矿化是近年来CO₂末端减排最有效的技术之一。CO₂矿化的本质是利用天然碱性矿物或工业碱性固废将酸性CO₂气体转化、固定为碳酸盐的过程，但目前所报道的技术大多仍面临高能耗、高成本的限制。提出一种安全、环保、低能耗的空气驱动的膜电解技术，可在低能耗下促使硅灰石有效矿化CO₂并产优质多孔白炭黑（二氧化硅）产品。核心技术为：电解条件下，阴极氧气还原反应（ORR）与阳极析氧反应（OER）同时进行实现低能耗下水的电离产生碱性和酸性液体。该电解技术比同电流密度下电解水低至少0.5 V的电解电压。电解所得酸性溶液溶解硅灰石后与电解所得碱性溶液混合可得优质多孔二氧化硅，CO₂通入后可被有效吸收并得到矿化产物碳酸钙，实现了高效矿化利用CO₂。

关键词: 二氧化碳捕集, 电解, 二氧化硅, 电化学, 催化剂, 二氧化碳减排