Tuerhong Tuerxun, Kuerban Zaituniguli, Abdurahman Maryamgul, Xinbin Cai, Yimingniyazi Amanula
College of Resource and Environmental Sciences, Xinjiang Agricultural University, Urumqi, Xinjiang, People's Republic of China, 830052.
Institute of Cereal Crops, Xinjiang Academy of Agricultural Science Urumqi, Xinjiang, People's Republic of China, 830091.
Environ Sci Pollut Res Int. 2023 Oct;30(48):106460-106479. doi: 10.1007/s11356-023-29833-7. Epub 2023 Sep 20.
To maximize the potential of biomass from invasive plants, waste leaves from Rhus typhina (RT) and Amorpha fruticosa (AF) were used to prepare activated carbons (ACs) for the efficient removal of chromium from wastewater. Six ACs were prepared by CO activation at 850 °C with varying flow rates (500, 1000, and 1500 mL/min) and characterized by yield, pH, N adsorption isotherm, FTIR, SEM, TG, and XPS. The adsorption isotherm and kinetics for chromium removal were analyzed. The outcomes showed that the ACs had mesoporous structures with specific surface areas of 408.05-701.01 m/g and pore volumes of 0.360-0.653 cm/g. The pores are distributed among the agglomerated nanoparticles on the surface of the granules. The existence of two kinds of chromium compounds and two valance states, Cr(III) and Cr(VI), in spent ACs was identified by the FTIR and XPS spectra. The Cr (VI) equilibrium data and adsorption kinetics were well-fit with the Langmuir isotherm (R = 0.936-0.967) and pseudo-second-order kinetic models (R = 0.795-0.937). The maximum Langmuir Cr adsorption capacities of ACRT1.0 and ACAF0.5 were estimated to be 266.54 and 255.21 mg/g at pH = 2.0, respectively. Concentrations of Cr(III) and Cr(VI) in filtrates after equilibrium, combined with XPS and TGA analysis of spent ACs, illustrated that Cr(VI) was converted to the less harmful trivalent chromate Cr(III) during the adsorption processes. Cr(III) and Cr(VI) probably formed compounds with carbon and nitrogen atoms on the surfaces of ACs. ACs with abundant surface N-H groups achieved high Cr adsorption performance. The waste leaves from these invasive plants are suitable for producing cost-effective and efficient ACs for removing Cr (VI) from water by chemical adsorption.
为了最大限度地发挥入侵植物生物质的潜力，利用盐肤木（RT）和紫穗槐（AF）的废弃树叶制备活性炭（ACs），用于高效去除废水中的铬。通过在850℃下以不同流速（500、1000和1500 mL/min）进行CO活化制备了六种ACs，并通过产率、pH值、N吸附等温线、傅里叶变换红外光谱（FTIR）、扫描电子显微镜（SEM）、热重分析（TG）和X射线光电子能谱（XPS）对其进行了表征。分析了铬去除的吸附等温线和动力学。结果表明，ACs具有介孔结构，比表面积为408.05 - 701.01 m/g，孔体积为0.360 - 0.653 cm/g。孔隙分布在颗粒表面的团聚纳米颗粒之间。通过FTIR和XPS光谱确定了废ACs中存在两种铬化合物以及两种价态的铬，即Cr(III)和Cr(VI)。Cr(VI)的平衡数据和吸附动力学与Langmuir等温线（R = 0.936 - 0.967）和伪二级动力学模型（R = 0.795 - 0.937）拟合良好。在pH = 2.0时，ACRT1.0和ACAF0.5的最大Langmuir Cr吸附容量分别估计为266.54和255.21 mg/g。平衡后滤液中Cr(III)和Cr(VI)的浓度，结合废ACs的XPS和TGA分析表明，在吸附过程中Cr(VI)转化为危害较小的三价铬酸盐Cr(III)。Cr(III)和Cr(VI)可能与ACs表面的碳原子和氮原子形成化合物。具有丰富表面N - H基团的ACs具有较高的Cr吸附性能。这些入侵植物的废弃树叶适合生产具有成本效益且高效的ACs，用于通过化学吸附从水中去除Cr(VI)。
