生态与农村环境学报 ›› 2018, Vol. 34 ›› Issue (4): 363-370.doi: 10.11934/j.issn.1673-4831.2018.04.010

• 污染控制与修复 • 上一篇    下一篇

动植物来源生物炭对水体中Cd2+的吸附特性

申磊1,2, 荆延德1,2, 孙小银1,2, 郝郝1,2, 曹永强1,2   

  1. 1. 山东省高校南四湖湿地生态与环境保护重点实验室, 山东 济宁 273165;
    2. 曲阜师范大学地理与旅游学院, 山东 日照 276826
  • 收稿日期:2017-08-18 出版日期:2018-04-25 发布日期:2018-04-17
  • 通讯作者: 荆延德 E-mail:jingyande@163.com
  • 作者简介:申磊(1992-),男,山东日照人,硕士生,主要研究方向为生物炭对水/土体系中重金属的固定与去除。E-mail:shen961617375@163.com
  • 基金资助:

    国家自然科学基金(41471389);山东省自然科学基金(ZR2013DM005)

Cd2+ Adsorption Characteristics of Animal-Waste-and-Plant-Derived Biochars in Water

SHEN Lei1,2, JING Yan-de1,2, SUN Xiao-yin1,2, HAO Hao1,2, CAO Yong-qiang1,2   

  1. 1. Key Laboratory of Nansihu Lake Wetland Ecological and Environmental Protection in Universities of Shandong, Jining 273165, China;
    2. College of Geography and Tourism, Qufu Normal University, Rizhao 276826, China
  • Received:2017-08-18 Online:2018-04-25 Published:2018-04-17

摘要:

以动植物来源(鸡粪便和小麦秸秆)的生物质为原料,在350和650℃条件下慢速热解制备生物炭并表征其理化性质,采用批量吸附试验研究不同吸附时间、溶液pH值和Cd2+浓度条件下生物炭对Cd2+的吸附特性。结果表明,随着热解温度升高,生物炭的pH值和灰分含量升高,芳香性和疏水性增强,极性减弱。相同热解温度条件下,动物来源的鸡粪炭pH值和灰分含量比植物来源的小麦秸秆炭高,芳香结构更完备。生物炭对Cd2+的吸附动力学过程均符合准二级动力学模型(R2>0.99),吸附在12 h时达到平衡,吸附过程均由外部液膜扩散、表面吸附和颗粒内扩散共同控制,且后者是主要限速步骤。随着溶液pH值的升高(2.0~6.0),生物炭对Cd2+的吸附量均逐渐增加。Langmuir模型能很好地描述植物来源的小麦秸秆炭对Cd2+的吸附行为(R2为0.970 3~0.981 5),Freundlich模型更适用于动物来源的鸡粪炭(R2为0.971 7~0.976 9),动物来源的鸡粪炭对Cd2+的吸附效果优于植物来源的小麦秸秆炭。阳离子-π作用和沉淀作用是650℃生物炭吸附Cd2+的主要机制。

关键词: 动物粪便, 作物秸秆, 生物炭, Cd2+吸附

Abstract:

Four types of biochars were prepared out of chicken droppings or wheat straw through pyrolysis at 350 or 650℃ separately and analyzed for physic-chemical properties. Batch sorption tests were conducted to explore Cd2+ adsorption characteristics of the biochars relative to duration of the adsorption, pH of the solution, and Cd2+ concentration in the solution. Results show that the higher the temperature of pyrolysis, the higher the pH, ash content, aromaticity and hydrophobicity and the lower the polarity of the biochar. Under the same temperature in pyrolysis, the chicken manure derived biochar was higher in pH and ash contents than the plant-derived one, and more complete in aromatic structure. The Cd2+ sorption kinetics of the biochars well fitted the pseudo second order kinetic model (R2>0.99), and the adsorption reached equilibrium in 12 h. And the sorption processes were controlled jointly by external liquid film diffusion, surface adsorption and intraparticle diffusion, and the latter was found to be the main rate-controlling step. With pH in the solution rising from 2.0 to 6.0, Cd2+ adsorption rate of the biochars gradually increased, and peaked at pH 6.0. The Langmuir model can be used to describe Cd2+ adsorption isotherm of the plant-derived biochars (R2, 0.970 3~0.981 5), whereas the Freundlich model was better at describing the chicken-manue-derived biochars (R2, 0.971 7~0.976 9). The chicken manure-derived biochars are superior to the plant-derived biochars in Cd2+ adsorption. Cation-π action and precipitation were the two main mechanisms for biochars pyrolyzed at 650℃ adsorbing Cd2+.

Key words: animal manure, crop straw, biochar, Cd2+ adsorption

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