Coelho Juliana A, Azevedo Diana Cristina S DE, Silva Junior Ivanildo JosÉ DA, Capelo-Neto JosÉ
Universidade Federal do Ceara, Departamento de Engenharia Química, Campus do Pici, Bloco 709, Av. Mister Hull, s/n, Pici, 60455-760 Fortaleza, CE, Brazil.
Universidade Federal do Ceará, Departamento de Engenharia Hidráulica e Ambiental, Campus do Pici, Bloco 713, Pici 60455-900 Fortaleza, CE, Brazil.
An Acad Bras Cienc. 2020 Nov 11;92(3):e20190453. doi: 10.1590/0001-3765202020190453. eCollection 2020.
Taste and odor compounds affect drinking water safety perception and may drive consumers to less secure water sources. Adsorption, using powered activated carbon, is the most common method to remove these compounds but greatly increases the amount of sludge generated. Another way of removing taste and odor compounds is to use filters with granular activated carbon (GAC) but little is still known on how to design them. In this work, the homogeneous surface diffusion model (HSDM) was used to model bench-scale kinetic and isotherm experiments and to simulate the removal of geosmin in a full-scale GAC filter. Geosmin adsorption isotherm was best described by the Freundlich model in all used carbons and film resistance (Kf) was more relevant to adsorption kinetics than pore diffusion (Ds). The simulation showed that in a filter with an empty bed contact time of 5 minutes and raw water with geosmin concentrations of 50, 75, and 100 ng.L-1, the effluent would exceed the trash-hold concentration (10 ng.L-1) in 98, 77, and 66 days, respectively, without considering biological removal.
味觉和嗅觉化合物会影响对饮用水安全性的认知，并可能促使消费者转向安全性较低的水源。使用粉末活性炭进行吸附是去除这些化合物的最常用方法，但这会大大增加产生的污泥量。另一种去除味觉和嗅觉化合物的方法是使用颗粒活性炭（GAC）过滤器，但对于如何设计此类过滤器仍知之甚少。在这项工作中，采用均相表面扩散模型（HSDM）对实验室规模的动力学和等温线实验进行建模，并模拟在全尺寸GAC过滤器中去除土臭素的过程。在所有使用的活性炭中，土臭素吸附等温线均最适合用Freundlich模型描述，且膜阻力（Kf）比孔隙扩散（Ds）与吸附动力学的相关性更强。模拟结果表明，在空床接触时间为5分钟且原水中土臭素浓度分别为50、75和100 ng.L-1的过滤器中，若不考虑生物去除作用，出水将分别在98天、77天和66天后超过阈值浓度（10 ng.L-1）。
