高铁酸钾改性生物炭的制备及其对水体中Cd(Ⅱ)的吸附特性

Preparation of K_(2)FeO_(4) Modified Biochar and Its Adsorption Characteristics for Cd(Ⅱ)in Aqueous Solution

随着工业化的发展,金属铬Cd(Ⅱ)的过量排放将对人类和环境造成巨大的危害。以花生壳为原料制备生物炭,并用高铁酸钾(K_(2)FeO_(4))对其进行改性,制备了磁性吸附剂(Fe-BC)用于吸附并降低水体中的Cd(II)。实验探究了吸附时间、溶液pH、Cd(II)质量浓度和生物炭添加量对吸附效果的影响。研究发现,当溶液pH为6、吸附饱和时间为2 h、饱和Cd(II)质量浓度为300 mg·L^(−1)、吸附剂添加量为4.0 g·L^(−1)时,Cd(II)最大吸附量可达到153.28 mg·g^(−1)。较高的pH值会导致Cd(II)以沉淀的形式析出。同时,多种表征手段表明,改性剂K_(2)FeO_(4)改善了生物炭表面的孔径结构,增加了生物炭表面C=C、C=O和−OH官能团的数量,FTIR还证明了吸附过程中官能团与Cd(II)发生络合作用,从而有效提高吸附效率。Fe-BC在第4次脱附-吸附实验中对Cd(II)的吸附量达79.38 mg·g^(−1),该生物炭具有良好的重复利用性能。为了进一步研究该生物炭的吸附性能,对该吸附过程进行了吸附动力学和吸附等温线的研究,结果表明Fe-BC生物炭对Cd(II)的吸附属于单层表面的吸附,以化学吸附为主、物理吸附为辅。综上所述,Fe-BC生物炭材料制备简单、经济环保,具有吸附速率快、吸附容量大、吸附效率高、化学稳定性好的优点,能够有效降低水体中Cd(II)含量,降低其生态风险,为废弃生物质资源化以及水体污染治理提供了参考。

With the development of industrialization, excessive emission of chromium Cd(Ⅱ) will cause great harm to humans and the environment. in this paper, peanut shell biochar modified with potassium ferrite was used to study the adsorption behavior for Cd(Ⅱ) removal. The effects of reaction time, solution pH, Cd(Ⅱ) concentration and biochar addition on adsorption capacity were explored. It was found when the optimal pH of the solution was 6, the adsorption saturation time was 2 h, the saturated Cd(Ⅱ) concentration was 300 mg·L;and the biochar addition amount was 4.0 g·L;, the maximum adsorption amount was 153.28 mg·g;. Higher pH values would cause Cd(Ⅱ) to precipitate out in the form of precipitation. At the same time, a variety of characterization methods showed that the K;FeO;improved the pore structure of the biochar and increased the numbers of C=C, C=O and-OH functional groups. FTIR also proved that the functional group complexed with Cd(Ⅱ) during the adsorption process, and improved the adsorption efficiency. The reusability study showed that the adsorption capacity of Cd(Ⅱ) in the fourth desorption-adsorption experiment reached 79.38 mg·g;, which indicated the biochar had good reuse performance. In order to further study the adsorption performance of the biochar, the adsorption kinetics and adsorption isotherm of the adsorption process were tested. The results showed that the adsorption of Fe-BC biochar to Cd(Ⅱ) was a single-layer surface adsorption, with chemical adsorption as the main and physical adsorption as a supplement. Fe-BC biochar modified by potassium ferrite is an environmentally friendly and efficient heavy metal adsorbent.It can effectively reduce the Cd(Ⅱ) content in the water and the ecological environment. This research provides a reference for the recycling of waste biomass and water pollution control.