峨眉山大火成岩省的风化碳汇效应:玄武岩粉末水-岩反应实验研究  

Weathering carbon storage in Emeishan large igneous province:Experimental study on water-rock reaction of basalt powder

作　　者：任俊童 杨江海[1] 程亮 刘澳 张晓容 REN Juntong;YANG Jianghai;CHENG Liang;LIU Ao;ZHANG Xiaorong(School of Earth Sciences,China University of Geosciences(Wuhan),Wuhan,Hubei 430074,China;Gansu Geological Prospecting Tianshui Mineral Exploration Institute,Tianshui,Gansu 741024,China)

机构地区：[1]中国地质大学(武汉)地球科学学院,湖北武汉430074 [2]甘肃省有色金属地质勘查局天水矿产勘查院,甘肃天水741024

出　　处：《地质学报》2023年第9期3087-3100,共14页Acta Geologica Sinica

基　　金：国家自然科学基金项目(编号42122015);中国地质大学(武汉)2021~2022学年度教学实验室开放基金项目联合资助的成果。

摘　　要：在实现“双碳”目标背景下,有效的碳封存技术成为近年来学界关注的焦点。在众多碳封存技术中,基于玄武岩粉末的增强风化碳汇技术具有较强的成本优势,同时也对促进作物生长、改善粮食产量具有积极作用。流域研究揭示玄武岩风化具有非常高的速率,但与玄武岩粉末增强风化碳汇技术在时间尺度和反应条件上存在较大差异。中国西南地区广泛分布有峨眉山玄武岩,其在喷发之后的快速化学风化被认为是晚二叠世冰川活动的驱动机制,有可能成为增强风化碳汇技术的基础原料。为深入理解峨眉山玄武岩的风化碳汇效应,增进对玄武岩增强风化碳汇技术的认识,本文利用不同粒径玄武岩粉末和天然雨水及河水开展了水岩反应实验研究。结果显示,雨水与玄武岩粉末经历720 h常温条件的封闭反应后,其pH值接近河水的pH值,且Na+、K^(+)、Ca^(2+)、Mg^(2+)等离子浓度显著升高,其活动性和溶出速率受所在岩石结构、矿物组成、元素赋存状态、溶液饱和状态等因素共同影响与控制。玄武岩粉末与雨水的反应实验中Si元素的溶出速率最快,为4.36×10^(-12)mol/m^(2)/s,Ca^(2+)和Mg^(2+)的最大浸出速率分别为1.36×10^(-12)mol/m^(2)/s和0.91×10^(-12)mol/m^(2)/s;同时,反应溶液HCO_(3)^(-)浓度快速升高,在720 h左右达到最大浓度,表明了溶液中溶解的CO_(2)快速转变为HCO3-,而随后HCO_(3)^(-)浓度趋于降低,PHREEQC模拟结果显示Ca-Mg碳酸盐矿物达到饱和状态。初步的反应实验研究表明,峨眉山玄武岩风化具有重要的碳汇效应,可应用于增强风化碳汇技术进行地表碳封存。Against the background of realizing the goal of“carbon peaking and carbon neutrality”,effective carbon storage technology has become the focus of research in recent years.Among many carbon storage technologies,enhanced weathering carbon sequestration technology based on basalt powder has advantage of low cost,but also plays a positive role in promoting crop growth and improving grain yield.The catchment study reveals that basalt has a very high rate of weathering,but there are great differences in time scale and reaction conditions in the basalt powder enhanced weathering carbon sink technology.The rapid chemical weathering of the Emei volcanic basalts,which are widely distributed in southwest China,is considered to be the driving mechanism of the glacial activity at the end of the Permian,and may be used as the basic material for enhancing weathering carbon storage technology.In order to further understand the weathering carbon sequestration effect of Emeishan basalts and improve the understanding of enhanced basalt weathering carbon sequestration technology,the water-rock reaction experiments were carried out by using basalt powder with different particle sizes,natural rainwater and river water.The results show that the pH value of experiment between rainwater and basalt powder is close to that of river water,and the concentrations of Na^(+),K^(+),Ca^(2+)and Mg^(2+)are significantly increased.The activity and dissolution rate of rainwater and basalt powder are affected and controlled by rock structure,mineral composition,occurrence state of elements and saturation state of solution.In the reaction experiment between basalt powder and rainwater,Si element dissolution rate is the fastest,which is 4.36×10^(-12) mol/m^(2)/s.The maximum leaching rates of Ca^(2+)and Mg^(2+)are 1.36×10^(-12) mol/m^(2)/s and 0.91×10^(-12) mol/m^(2)/s,respectively.At the same time,the concentration of HCO3-in the reaction solution increased rapidly and reached the maximum concentration at about 720 h.The dissolved CO_(2) in the s

关 键 词：玄武岩 化学风化 碳封存 增强风化 反应实验 

分 类 号：P512.1[天文地球—地质学] P588.145