摘要
获取廉价、易得且环境友好的高效修复药剂是Cr(Ⅵ)污染土壤修复的重要工作之一.基于室内模拟培养试验,研究了陈皮添加量和土壤中Cr(Ⅵ)初始浓度对Cr(Ⅵ)去除过程的影响,通过Illumina NovaSeq高通量测序技术和X射线近边吸收光谱(XANES)等方法初步探讨了陈皮修复Cr(Ⅵ)污染土壤的机理.结果表明:当土壤中Cr(Ⅵ)初始浓度为(1 600.13±298.11) mg/kg、Cr(Ⅵ)浸出浓度为(143.20±13.5) mg/L、陈皮添加量为5%时,培养30 d后,土壤中Cr(Ⅵ)浓度及其浸出浓度分别降至(10.07±2.98)mg/kg和(1.02±0.30) mg/L,去除率分别达到99.37%和99.29%.土壤中Cr(Ⅵ)的去除效率随陈皮添加量的增加而增大,随Cr(Ⅵ)初始浓度的增加而减小,且添加陈皮后土壤中的Cr(Ⅵ)转化为生物有效性较低的Cr(Ⅲ).此外,陈皮的添加丰富了土壤细菌的营养底物,缓解了Cr(Ⅵ)对细菌生长的抑制作用.土壤中放线菌门(Actinobacteria)为最优菌门,微杆菌属(Microbacterium)、土壤球菌属(Agrococcus)、链球菌属(Streptococcus)和链霉菌属(Streptomyces) 4种Cr(Ⅵ)还原菌不同程度富集.研究显示,陈皮能在较短时间内有效降低污染土壤中Cr(Ⅵ)浓度及其浸出浓度,并影响了污染土壤中细菌群落结构及其组成;陈皮去除土壤中Cr(Ⅵ)的机制可能是其在土壤中水解的小分子有机物直接将Cr(Ⅵ)还原为Cr(Ⅲ),以及作为碳源驱动Cr(Ⅵ)还原菌的富集进而间接降低Cr(Ⅵ)的毒性.
The search for inexpensive, high volume, easily accessible and environmentally friendly efficient remediation agents is one of the important tasks for the remediation of Cr(Ⅵ)-contaminated soil. Based on indoor simulated incubation experiments, the effects of tangerine peel addition and the initial concentration of Cr(Ⅵ) in soil on the removal process of Cr(Ⅵ) were studied, and the mechanism of tangerine peel remediation of Cr(Ⅵ)-contaminated soil was explored by Illumina NovaSeq high-throughput sequencing technology and X-ray near edge absorption spectroscopy(XANES). When the initial concentration of Cr(Ⅵ) in soil was(1600.13±298.11) mg/kg, the leaching concentration of Cr(Ⅵ) was(143.20±13.5) mg/L. After 5% of tangerine peel was added for 30 d, the content of Cr(Ⅵ) and its leaching concentration in soil decreased to(10.07±2.98) mg/kg and(1.02±0.30) mg/L, respectively, and the removal rates reached 99.37%and 99.29%, respectively. The results showed that the removal efficiency of Cr(Ⅵ) in soil increased with the increase of tangerine peel addition and decreased with the increase of the initial concentration of Cr(Ⅵ), the Cr(Ⅵ) in soil was converted to the Cr(Ⅲ) after the addition of tangerine peel. Furthermore, the addition of tangerine peel enriched the nutrient substrate for soil bacteria and alleviated the inhibitory effect of Cr(Ⅵ) on bacterial growth. The soil was enriched with four Cr(Ⅵ)-reducing bacteria, namely, Microbacterium,Agrococcus, Streptococcus and Streptomyces, in different degrees, with Actinobacteria as the optimal phylum. The study showed that tangerine peel could effectively reduce the concentration of Cr(Ⅵ) and its leaching concentration within a short period of time, and it affected the structure and composition of bacterial communities in the contaminated soil. The mechanism of Cr(Ⅵ) reduction in the soil by tangerine peel may be:(1) direct reduction of Cr(Ⅵ) to Cr(Ⅲ) through small molecule organic matter hydrolyzed in the soil;(2) indirect reduction of Cr(Ⅵ) toxicity by driving the enrichment of Cr(Ⅵ)-reducing bacteria as a carbon source.
作者
刘增俊
许贺峰
郭彦旭
樊艳玲
LIU Zengjun;XU Hefeng;GUO Yanxu;FAN Yanling(Beijing Municipal Research Institute of Eco-Environmental Protection,Beijing 100037,China;China Tobacco Sichuan Industrial Co.,Ltd.,Chengdu 610101,China)
出处
《环境科学研究》
CAS
CSCD
北大核心
2023年第1期128-138,共11页
Research of Environmental Sciences
基金
国家重点研发计划项目(No.2018YFC1801405)。