首页|污染土壤中含锌矿物—溶液之间的同位素平衡分馏效应

污染土壤中含锌矿物—溶液之间的同位素平衡分馏效应

扫码查看
原文链接
  • 国家科技期刊平台
  • NETL
  • NSTL
  • 万方数据
表生环境中,复杂的物理化学过程导致的锌(Zn)同位素分馏严重干扰了污染物的源解析.利用同位素手段示踪重金属污染的前提是精确确定污染土壤中典型含Zn矿物—水溶液之间的Zn同位素分馏系数.该研究基于密度泛函理论的第一性原理计算,探索了水合Zn2+,含Zn层间羟基物矿物、含Zn层状双金属氢氧化物、含Zn三八面体型黏土矿物,和高岭石(010)面及铁锰(氢)氧化物表面吸附态Zn2+的最稳定几何结构,及不同形态Zn与水溶液相的Zn2+之间的同位素平衡分馏系数.结果表明,六配位表面吸附态略微富集64Zn(Δ66/64Zn=-0.29‰～-0.20‰),而四配位表面吸附态富集66Zn(Δ66/64Zn=0.45‰～0.73‰).当Zn转变为更稳定的晶质沉淀物时,次生矿物显著富集66Zn(Δ66/64Zn=0.51‰～1.11‰).基于获得的不同形态Zn与水溶液之间的同位素分馏系数,成功地模拟出平衡分馏和动力学分馏模式下电镀废弃物、铅锌矿石、熔炼烟气和冶金污泥等单一污染源影响下的土壤Zn同位素组成演化趋势,通过对比已知Zn同位素比值甄别出了污染土壤中Zn的主要来源.
Equilibrium Isotope Fractionation Effect between Zn-containing Minerals and Aqueous Solution in Contaminated Soils
Zinc(Zn)isotope fractionation,resulting from multiple physicochemical processes under Earth's surface conditions,confounds the source identification of pollutants.The determination of Zn isotope fractionation factors between typical Zn-containing minerals and aqueous solutions in contaminated soils is crucial to trace Zn sources using isotopic tools.In this study,we used density functional theory based first principles calculations to investigate the most stable geometries of Zn-containing species,including hydrated Zn2+complexes,Zn in hydroxy-interlayered minerals(Zn-HIM),Zn-rich phyllosilicates(Talc),Zn-layered double hydroxide(Zn-LDH),and surface adsorbed Zn2+.Based on these optimized configurations,we calculated the equilibrium isotope fractionation factors between the aforementioned structures and Zn2+in aqueous phases.Our results showed that adsorbed Ⅵ Zn2+is slightly enriched in 64Zn(Δ66/64Zn=-0.29‰～-0.20‰),while adsorbed Ⅳ Zn2+is enriched in 66Zn(Δ66/64Zn=0.45 ‰～0.73‰).Secondary mineral phases are evidently enriched in 66Zn(Δ66/64Zn=0.51‰～1.1 1‰),if Zn transferred to stable crystalline precipitates.Using obtained fractionation factors,we successfully simulated the evolution trends of Zn isotope composition under the influence of single pollution sources(electroplating waste,sphalerite ore,emissions and metallurgical sludge)in equilibrium and Rayleigh fractionation modes.By comparing with available isotope data,these trends facilitate to find out the main source of Zn in contaminated soils.

Zn migration and transformationdensity functional theoryfirst principles calculationsecondary minerals precipitationsurface absorption,pollution source identification

何洪涛、谷一帆、邢乐才、王艳芳、杨阳、蔡兴平、何雨旸

展开 >

河北工程大学地球科学与工程学院,邯郸 056038

河北省资源调查与研究重点实验室,河北工程大学,邯郸 056038

中国科学院地质与地球物理研究所地球与行星物理院重点实验室,北京 100029

Zn迁移转化 密度泛函理论 第一性原理计算 次生矿物结晶 矿物表面吸附 污染源解析

河北省自然科学基金河北省自然科学基金国家自然科学基金国家自然科学基金中国科学院地质地球所重点部署项目资助

D2021402020D20204020044217304142373019IGGCAS-202204

2024

10.16108/j.issn1006-7493.2024006

高校地质学报
南京大学

高校地质学报

CSTPCD北大核心
影响因子：1.243
ISSN：1006-7493
年,卷(期)：2024.30(3)