杨婷婷, 黄艳艳, 柳维扬, 张婧旻, 杨红竹, 李建宏, 林清火. 三种改性小麦秸秆生物炭表征及其对Cu2+的吸附性能[J]. 农业工程学报, 2023, 39(8): 222-230. DOI: 10.11975/j.issn.1002-6819.202210107
    引用本文: 杨婷婷, 黄艳艳, 柳维扬, 张婧旻, 杨红竹, 李建宏, 林清火. 三种改性小麦秸秆生物炭表征及其对Cu2+的吸附性能[J]. 农业工程学报, 2023, 39(8): 222-230. DOI: 10.11975/j.issn.1002-6819.202210107
    YANG Tingting, HUANG Yanyan, LIU Weiyang, ZHANG Jingmin, YANG Hongzhu, LI Jianhong, LIN Qinghuo. Characterization of three kinds of modified wheat straw derived biochars and their sorption capacity for Cu2+[J]. Transactions of the Chinese Society of Agricultural Engineering (Transactions of the CSAE), 2023, 39(8): 222-230. DOI: 10.11975/j.issn.1002-6819.202210107
    Citation: YANG Tingting, HUANG Yanyan, LIU Weiyang, ZHANG Jingmin, YANG Hongzhu, LI Jianhong, LIN Qinghuo. Characterization of three kinds of modified wheat straw derived biochars and their sorption capacity for Cu2+[J]. Transactions of the Chinese Society of Agricultural Engineering (Transactions of the CSAE), 2023, 39(8): 222-230. DOI: 10.11975/j.issn.1002-6819.202210107

    三种改性小麦秸秆生物炭表征及其对Cu2+的吸附性能

    Characterization of three kinds of modified wheat straw derived biochars and their sorption capacity for Cu2+

    • 摘要: 为研究改性生物炭在水溶液中对Cu2+的吸附性能,利用硅酸钠溶液、氯化镁溶液、过氧化氢溶液制备了3种不同改性小麦秸秆生物炭,通过使用扫描电镜-X射线能量色散光谱(scanning electron microscopy combined with energy dispersive X-ray spectroscopy,SEM-EDS)和傅里叶红外光谱(Fourier infrared spectroscopy,FTIR)等技术对改性前后的生物炭进行表征分析,探究其表面形貌、官能团等性质变化。硅酸钠改性生物炭(sodium silicate modified biochar,SBC)的比表面积与孔容最大,分别为43.69 m2/g、5.30 cm3/g,比未改性生物炭(biochar,BC)(6.02 m2/g、1.40 cm3/g)分别增加了6.25、2.79倍。由SEM-EDS结果表明,改性生物炭均出现C元素质量分数下降、O元素质量分数增加的现象,其中,SBC的C元素和O元素质量分数变化最大,且SBC和氯化镁改性生物炭(magnesium chloride modified biochar,MBC)上负载了大量含Si和Mg的颗粒。FTIR结果表明,改性处理均能增强官能团的峰值,硅酸钠改性增强程度最大。另外,过氧化氢改性生物炭(hydrogen peroxide modified biochar,HBC)、BC、MBC 和SBC对Cu2+的吸附动力学过程更符合准一级动力学模型,BC、MBC、SBC对Cu2+的等温吸附过程更符合Langmuir模型,HBC对Cu2+的等温吸附过程更符合Freundlich模型。分析吸附模型参数可知,改性生物炭MBC、SBC和HBC中,SBC对Cu2+的吸附能力更强,其理论吸附量可以达到230.20 mg/g,该结果可为改性生物炭对Cu2+污染水体的治理提供理论依据。

       

      Abstract: Abstract: Copper pollution has posed a serious threat to the ecologic environment in recent years, particularly for concealment, accumulation, and irreversibility. Fortunately, biochar can serve as a new adsorption material, due to the available raw materials, environmentally friendly, and excellent adsorption performance. However, it is still limited to the effect of pristine biochar on heavy metal pollution in the water environment. The modified biochars have been prepared to improve the adsorption capacity, where the different elements can be loaded onto the pristine biochar. Among them, impregnation is one of the main approaches to modified biochars. In this study, three kinds of chemically modified wheat straw-derived biochar were prepared as the adsorbents for the remediation of Cu2+ pollution in soils and waters. A systematic investigation was implemented to determine the performance of these biochars on Cu2+ sorption in an aqueous solution. The wheat straw-derived biochar was modified with sodium silicate, magnesium chloride, and hydrogen peroxide solution. Scanning electron microscopy (SEM) combined with energy dispersive X-ray spectroscopy (EDS), and Fourier infrared spectroscopy (FTIR) was used to characterize the surface morphology and functional groups on the biochars before and after modification. The sorption kinetic and isotherm models were selected to explore the sorption characteristics of biochars for Cu2+ in the aqueous solution. The result showed that the sodium silicate-modified biochar (SBC) shared the largest specific surface area and micropore volume of 43.69 m2/g and 5.30 cm3/g, respectively, which increased by 6.25 and 2.79 times, compared with the unmodified biochar (6.02 m2/g and 1.40 cm3/g). The SEM-EDS showed that there was a decrease in the elemental C content in the modified biochars of SBC, whereas, an increase was observed in the elemental O content, with the largest changes in the elemental C and O content. By contrast, the Si and Mg-containing particles were loaded on the SBC surface and magnesium chloride-modified biochar (MBC). The FTIR showed that the peak value of functional groups was enhanced after modification. But there was a small enhancement degree of hydrogen peroxide modification, while the large one was in the SBC and MBC. In addition, the pseudo-first-order model was established to express the sorption kinetics of Cu2+ on the BC, MBC, SBC, and hydrogen peroxide-modified biochar (HBC). Moreover, the Langmuir model was fitted for the sorption isotherms of Cu2+ on the unmodified biochar, MBC, and SBC, whereas, the Freundlich model was for the Cu2+ on the HBC. The sorption model parameters demonstrated that the SBC shared the stronger sorption capacity for Cu2+ with a theoretical sorption amount of 230.20 mg/g, compared with the MBC, SBC, and HBC. The findings can provide a theoretical basis for the treatment of Cu2+ contaminated water using modified biochars.

       

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