引用本文:
【打印本页】   【HTML】   【下载PDF全文】   查看/发表评论  【EndNote】   【RefMan】   【BibTex】
过刊浏览    高级检索
本文已被:浏览 111次   下载 0  
分享到: 微信 更多
水稻秸秆生物炭中铜和镉的形态分布及释放特性
沈露露, 范玉超, 张雪, 王秋雅, 胡龙龙, 李辉婷, 崔红标
安徽理工大学
摘要:
由于目前缺乏对生物质原料来源的管控办法,极有可能用产自受污染农田土壤的秸秆制备出具有高重金属含量的生物炭,因此,研究生物炭中重金属的形态分布及其释放特性对于防控生物炭应用产生的环境风险具有重要意义。基于此,该研究采集九牛岗污染区和红壤站清洁区种植的水稻秸秆制备生物炭,制备的生物炭分别以九牛岗生物炭和红壤站生物炭表示,分析两种生物炭中w(Cu)、w(Cd)及其化学形态分布,考察不同固液比及pH对生物炭中Cu、Cd浸出的影响。结果表明:九牛岗生物炭Cu、Cd的总量(以w计)分别为119.99、3.83 mg/kg,显著高于红壤站生物炭(19.50、0.96 mg/kg)。尽管九牛岗生物炭中w(酸溶态Cu)、w(酸溶态Cd)显著高于红壤站生物炭,但形态占比上,九牛岗生物炭中Cu、Cd主要为相对稳定态(可氧化态和残渣态),二者占比分别为80.3%、76.7%,高于红壤站生物炭(二者占比分别为53.2%、48.0%)。高固液比和低pH可有效增加两种生物炭中Cu、Cd的浸出毒性,其中,九牛岗生物炭在固液比为1:20和1:60下,浸出液中ρ(Cu)、ρ(Cd)均超过GB/T 14848—2017《地下水质量标准》中Ⅱ类限值。动力学及累积释放试验表明,两种生物炭中的部分Cu、Cd可在短时间内迅速释放而后逐渐平稳并有上升趋势,且九牛岗生物炭Cu、Cd释放量显著高于红壤站生物炭。研究显示,来自污染区水稻秸秆生物炭中的Cu、Cd活性显著高于清洁区生物炭,具有更高的环境风险。
关键词:  生物炭  重金属  化学形态  释放  环境风险
DOI:
分类号:
基金项目:国家自然科学基金项目(面上项目,重点项目,重大项目)
The chemical fractions and release characteristics of Cu and Cd from biochar derived from rice straw
,et al
Abstract:
Since the lack of regulations for the resources of biomass raw materials, some crop straw grew in contaminated farmlands may be used to produce biochar with high content of heavy metals. Therefore, it is of great significance to study the chemical forms and release characteristics of endogenous heavy metals in biochar and it benefits for the decrease of environmental risks due to the unreasonable biochar applications. In the study, rice straws grew in a contaminated soil (Jiuniu Village; JN) and a clean soil (Hongrang Stations; HR) were produced into biochar, named with JN biochar and HR biochar respectively. The chemical fractions of Cu and Cd in biochar were analyzed by BCR sequential extraction, and the effects of solid liquid ratio and pH on the release of Cu and Cd were investigated as well. Results showed that the concentrations of Cu and Cd in JN biochar were 119.99 mg/kg and 3.83 mg/kg, respectively, which were significantly higher than those of HR biochar (19.50 mg/kg and 0.96 mg/kg). Although the acid soluble content of copper and cadmium in JN biochar was higher than HR biochar, but the ratios of stable state (oxidable and residual forms) to total Cu and Cd in JN biochar (Cu 80.3%, Cd 76.7%) were higher than those of HR biochar (Cu 53.2%, Cd 48.0%). The high solid-liquid ratio and lower solution pH increased the leaching toxicity of Cu and Cd in biochar. Especially for JN biochar at solid-to-liquid ratios of 1:20 and 1:60, concentrations of Cu and Cd in leachate are higher than the limit of the Grade II of “Quality standard for groundwater” (GB/T14848—2017). Dynamics and cumulative-release experiments showed that Cu and Cd in both biochars can be released rapidly in a short time and then gradually increased, and the release amounts of Cu and Cd in JN biochar were higher than that of HR biochar. The study suggested that the availability and environmental risk of Cu and Cd in rice straw biochar from the contaminated soil were higher compared with the biochars from clean soil.
Key words:  biochar  heavy metals  chemical form  release  environmental risk