摘要
钝化修复被广泛用于重金属污染土壤,但是长期环境老化作用对土壤重金属活性的影响仍不明确。本研究结合当地气象资料,设计了一种耦合酸雨-干湿-冻融的老化方法,通过滴定曲线法和化学分析方法考察5年的环境老化对生物炭(Biochar,BC)、生物质灰(Biomass ash,BA)、羟基磷灰石(Hydroxyapatite,HA)和石灰(Lime,LI)改良土壤的酸缓冲能力(acid buffering capacity,pHBC)及有效态镉(Cadmium,Cd)的影响。结果表明:①各改良材料均能显著增加土壤pH,且老化过程中土壤pH表现为HA≈LI>BA>BC>CK,但是老化5年后土壤pH较老化1年后降低0.03~0.34个单位。②老化5年后,BC、BA、HA和LI使土壤pHBC分别较CK提高15.05%、30.97%、62.08%和17.22%,但是基于滴定曲线法得到的pHBC在不同老化年限下呈现较大的波动,无法准确反映其动态变化规律。利用可视化的箱形-小提琴图可以更精准地评价土壤酸缓冲性能随老化年限的动态变化,不同老化年限下土壤酸缓冲性能(pH变化中位数)总体上表现为HA>LI>BA>BC>CK。③老化前,BC、BA、HA和LI的添加使土壤有效态Cd含量较CK分别降低25.17%、42.19%、99.29%和96.01%。老化5年后有效态Cd含量较老化1年后分别增加9.36%、25.33%、2847.15%和486.93%,且不同老化年限下有效态Cd含量表现为HA<LI<BA<BC<CK。研究显示,盐基离子的淋失和环境老化导致的酸化是引起土壤酸缓冲性能降低和有效态Cd含量增加的主要原因;尽管HA处理下土壤有效态Cd含量最低,但是其成本远高于其他材料。综合考虑改良材料的成本及其对土壤酸缓冲性能提升和有效态Cd含量的降低效果,LI在Cd污染土壤的钝化修复中具有较好的应用潜力。
Passivation remediation is widely used for treating heavy metal contaminated soil,but the long-term effects of environmental aging on soil heavy metal availability is still unclear.In this study,an aging method combining acid rain,drying,freezing,and thawing cycles was developed based on local meteorological conditions.The effects of biochar(BC),biomass ash(BA),hydroxyapatite(HA),and lime(LI)on soil acid buffering capacity(pHBC)and available cadmium(Cd)were investigated during the five year aging using titration curves and chemical analyses.The results showed that:(1)The addition of amendments significantly increased the soil pH,and they followed the order of HA≈LI>BA>BC>CK.However,after five years of aging,soil pH decreased by 0.03-0.34 units compared with values measured after one year of aging.(2)After five year aging,soil pHBC in the BC,BA,HA,and LI treatments increased by 15.05%,30.97%,62.08%,and 17.22%,respectively,relative to the control.However,pHBC values obtained from titration curves fluctuated considerably in the aging process and did not accurately reflect the dynamic changes in soil pHBC.In contrast,the visual box-violin diagram can accurately evaluate the dynamic changes of soil buffering capacity with aging years,and they(median pH changes)followed the order of HA>LI>BA>BC>CK.(3)The addition of BC,BA,HA and LI significantly decreased the available Cd by 25.17%,42.19%,99.29%,and 96.01%,respectively,compared with the control soil before aging.After aging for five years,the available Cd in BC,BA,HA,and LI were increased by 9.36%,25.33%,2847.15%,and 486.93%compared with that after one-year aging,respectively;and they followed the order of HA<LI<BA<BC<CK during the aging process.This study indicated that the leaching of base ions and the pH decrease caused by the aging were the main reasons for the decrease of acid buffering performance and the increase of available Cd in soil.Although available Cd in HA was the lowest in soil,its remediation cost was higher than other amendments.Considering the cost of amendments and their effects on the increase of acid buffering performance and the decrease of soil available Cd,LI has good application potential in passivation remediation of Cd-contaminated soil.
作者
崔红标
汪奇辉
王昱茗
杨义
周静
周俊
CUI Hongbiao;WANG Qihui;WANG Yuming;YANG Yi;ZHOU Jing;ZHOU Jun(School of Earth and Environment,Anhui University of Science and Technology,Anhui 232001,China;Jiangxi Jiedi Environmental Governance Ecological Technology Co.Ltd.,Jiangxi 335000,China;Institute of Soil Science,Chinese Academy of Sciences,Nanjing 211135,China)
出处
《环境科学研究》
北大核心
2026年第2期417-426,共10页
Research of Environmental Sciences
基金
安徽省自然科学基金面上项目(No.2208085MD87)
鹰潭市科技计划项目(No.202412-48928)。
关键词
老化
钝化
土壤
酸缓冲性能
有效态Cd
aging
immobilization
soil
acid buffering performance
available cadmium
