Santana Andrea J, dos Santos Walter N L, Silva Laiana O B, das Virgens Cesário F
Departamento de Ciências Exatas e da Terra, Universidade do Estado da Bahia (UNEB), Campus I-Programa de Pós-Graduação em Química Aplicada (PGQA), Rua Silveira Martins, 2555-Bairro Cabula, Salvador-Bahia, 41195-001, Brazil.
Environ Monit Assess. 2016 May;188(5):293. doi: 10.1007/s10661-016-5266-7. Epub 2016 Apr 15.
Mercury is a highly toxic substance that is a health hazard to humans. This study aims to investigate powders obtained from the peel of the fruit of Pachira aquatica Aubl, in its in natura and/or acidified form, as an adsorbent for the removal of mercury ions in aqueous solution. The materials were characterized by Fourier transform infrared spectroscopy and thermogravimetric analysis. The infrared spectra showed bands corresponding to the axial deformation of carbonyls from carboxylic acids, the most important functional group responsible for fixing the metal species to the adsorbent material. The thermograms displayed mass losses related to the decomposition of three major components, i.e., hemicellulose, cellulose, and lignin. The adsorption process was evaluated using cold-vapor atomic fluorescence spectrometry (CV AFS) and cold-vapor atomic absorption spectrometry (CV AAS). Three isotherm models were employed. The adsorption isotherm model, Langmuir-Freundlich, best represented the adsorption process, and the maximum adsorption capacity was predicted to be 0.71 and 0.58 mg g(-1) at 25 °C in nature and acidified, respectively. Adsorption efficiencies were further tested on real aqueous wastewater samples, and removal of Hg(II) was recorded as 69.6 % for biomass acidified and 76.3 % for biomass in nature. Results obtained from sorption experiments on real aqueous wastewater samples revealed that recovery of the target metal ions was very satisfactory. The pseudo-second-order model showed the best correlation to the experimental data. The current findings showed that the investigated materials are potential adsorbents for mercury(II) ion removal in aqueous solution, with acidified P. aquatica Aubl being the most efficient adsorbent.
汞是一种剧毒物质，对人类健康构成危害。本研究旨在调查从水瓜栗果实果皮中获得的天然和/或酸化形式的粉末，作为去除水溶液中汞离子的吸附剂。通过傅里叶变换红外光谱和热重分析对材料进行了表征。红外光谱显示出与羧酸羰基轴向变形相对应的谱带，羧酸是将金属物种固定到吸附材料上的最重要官能团。热重曲线显示了与半纤维素、纤维素和木质素这三种主要成分分解相关的质量损失。使用冷蒸气原子荧光光谱法（CV AFS）和冷蒸气原子吸收光谱法（CV AAS）对吸附过程进行了评估。采用了三种等温线模型。吸附等温线模型Langmuir-Freundlich最能代表吸附过程，预测在25℃时天然和酸化形式的最大吸附容量分别为0.71和0.58 mg g(-1)。在实际含汞废水样品上进一步测试了吸附效率，酸化生物质对Hg(II)的去除率为69.6%，天然生物质的去除率为76.3%。对实际含汞废水样品的吸附实验结果表明，目标金属离子的回收率非常令人满意。准二级模型与实验数据的相关性最好。目前的研究结果表明，所研究的材料是水溶液中去除汞(II)离子的潜在吸附剂，酸化水瓜栗是最有效的吸附剂。
