生物炭负载纳米零价铁复合材料对土壤中Pb(ii)的去除机制

Removal mechanism of Pb(ii) from soil by biochar-supported nanoscale zero-valent iron composite materials.

作者信息

Wei Shuxian, Du Gang, Li Canhua, Zhang Lanyue, Li Jiamao, Mao Aiqin, He Chuan

机构信息

School of Metallurgical Engineering, Anhui University of Technology Ma'anshan Anhui 243002 China

Anhui Province Key Laboratory of Metallurgical Engineering & Resources Recycling Ma'anshan Anhui 243002 China.

出版信息

RSC Adv. 2024 Jun 6;14(26):18148-18160. doi: 10.1039/d4ra03357d.

Abstract

As an adsorbent, biochar has a highly porous structure and strong adsorption capacity, and can effectively purify the environment. In response to the increasingly serious problem of heavy metal pollution in water, this study used nano zero valent iron and rice husk biochar to prepare a new type of magnetic sheet-like biochar loaded nano zero valent iron (BC-nZVI) composite material through rheological phase reaction, showing remarkable advantages such as low cost, easy preparation, and superior environmental remediation effect. The physical and chemical properties and structure of the material were extensively characterized using various methods such as HRTEM, XPS, FESEM, EDS, XRD, FTIR, and RAMAN. Concurrently, batch experiments were undertaken to assess the removal efficiency of Pb(ii) by BC-nZVI, with investigations into the influence of pH value, temperature, soil water ratio, and initial concentration of heavy metal ion solution on its removal efficiency. The results indicate that the removal of Pb(ii) by BC-nZVI reaches an equilibrium state after around 120 minutes. Under the conditions of pH 6, temperature 20 °C, soil water ratio 1 : 5, and BC-nZVI dosage of 1 g L, BC-nZVI can reduce the Pb(ii) content in wastewater with an initial concentration of 30 mg L to trace levels, and the treatment time is about 120 minutes. The analysis of adsorption kinetics and isotherms indicates that the adsorption process of Pb(ii) by BC-nZVI adheres to the quasi-second-order kinetic model and Langmuir model, suggesting a chemical adsorption process. Thermodynamic findings reveal that the adsorption of Pb(ii) by BC-nZVI is spontaneous. Furthermore, BC-nZVI primarily accumulates Pb(ii) through adsorption co-precipitation. BC-nZVI serves as an eco-friendly, cost-effective, and highly efficient adsorbent, showing promising capabilities in mitigating Pb(ii) heavy metal pollution. Its recoverability and reusability facilitated by an external magnetic field make it advantageous for remediating and treating lead-contaminated sites.

摘要

作为一种吸附剂,生物炭具有高度多孔的结构和强大的吸附能力,能够有效净化环境。针对日益严重的水体重金属污染问题,本研究采用纳米零价铁和稻壳生物炭,通过流变相反应制备了一种新型的磁性片状生物炭负载纳米零价铁(BC-nZVI)复合材料,该材料具有成本低、易于制备以及环境修复效果优异等显著优势。利用高分辨透射电子显微镜(HRTEM)、X射线光电子能谱(XPS)、场发射扫描电子显微镜(FESEM)、能谱仪(EDS)、X射线衍射仪(XRD)、傅里叶变换红外光谱仪(FTIR)和拉曼光谱仪(RAMAN)等多种方法对该材料的物理化学性质和结构进行了广泛表征。同时,进行了批量实验以评估BC-nZVI对Pb(ii)的去除效率,并研究了pH值、温度、水土比和重金属离子溶液初始浓度对其去除效率的影响。结果表明,BC-nZVI对Pb(ii)的去除在约120分钟后达到平衡状态。在pH值为6、温度为20℃、水土比为1∶5且BC-nZVI投加量为1 g/L的条件下,BC-nZVI能够将初始浓度为30 mg/L的废水中的Pb(ii)含量降低至痕量水平,处理时间约为120分钟。吸附动力学和等温线分析表明,BC-nZVI对Pb(ii)的吸附过程符合准二级动力学模型和朗缪尔模型,表明这是一个化学吸附过程。热力学研究结果表明,BC-nZVI对Pb(ii)的吸附是自发的。此外,BC-nZVI主要通过吸附共沉淀作用积累Pb(ii)。BC-nZVI是一种环保、经济高效的吸附剂,在减轻Pb(ii)重金属污染方面展现出了良好的能力。其在外加磁场作用下的可回收性和可重复使用性使其在修复和处理铅污染场地方面具有优势。

https://cdn.ncbi.nlm.nih.gov/pmc/blobs/14b3/11155265/c96b3ed3f6a1/d4ra03357d-f1.jpg

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