Sorptive removal of salicylic acid and ibuprofen from aqueous solutions using pine wood fast pyrolysis biochar
Sorptive removal of salicylic acid and ibuprofen from aqueous solutions using pine wood fast pyrolysis biochar
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DOI：
10.1016/j.cej.2014.12.006
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发表时间：
2015-04-01
影响因子：
15.1
通讯作者：
Mlsna, Todd
中科院分区：
文献类型：
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作者：
Essandoh, Matthew;Kunwar, Bidhya;Mlsna, Todd
在698 K条件下，在螺旋进料反应器中停留20-30 s，制备松木生物炭作为三维吸附剂，用于去除水溶液中的水杨酸和布洛芬。通过红外光谱、扫描电镜、透射电镜、表面积测定和零点电荷测量对该生物炭进行了表征。在pH值为2 ~ 10，吸附质浓度为25 ~ 100 mg/L，温度为298 ~ 318 K的条件下进行了批量吸附研究。两种吸附剂在低pH值时的吸附量最高，随pH值的增加而下降，然后随pH值的增加而第二次增加。随后在高pH下进一步下降。吸附物的共轭酸碱平衡以及酚羟基和羧酸生物炭位点随pH的变化主导了这一机制。吸附遵循准二级动力学。使用Freundlich， Langmuir, Redlich-Peterson, Toth， Sips和Radke-Prausnitz等温吸附模型对298 ~ 318 K的吸附进行了评估。对水杨酸和布洛芬的Langmuir吸附量分别为22.70和10.74 mg/g。这种低表面积松木生物炭（1.35 m(2)/g）比每单位测量表面积的商业活性炭能吸附更多的吸附物。甲醇汽提对废生物炭的水杨酸和布洛芬的解吸率分别为93%和88%，经过4次满容量平衡循环后，水杨酸和布洛芬的初始吸附量分别为76%和72%。(C) 2014 Elsevier B.V.版权所有
Pine wood biochar, prepared at 698 K with a residence time of 20-30 s in an auger-fed reactor, was used as a 3-dimensional adsorbent to remove salicylic acid and ibuprofen from aqueous solutions. This biochar was characterized by FT-IR spectroscopy, scanning electron microscopy, transmission electron microscopy, surface area determination, and zero point charge measurements. Batch sorption studies were carried out at pH values from 2 to 10, adsorbate concentrations from 25 to 100 mg/L and temperatures from 298 to 318 K. The adsorption of both adsorbates was highest at low pH values, dropped as pH increased and then exhibited a second increase related to the pKa of these carboxylic acid adsorbates. This was followed by a further drop at high pH. Conjugate acid/base equilibria of the adsorbates and the phenolic hydroxyl and carboxylic acid biochar sites versus pH dominated the mechanism. Sorption followed pseudo-second order kinetics. Sorption was evaluated from 298 to 318 K using the Freundlich, Langmuir, Redlich-Peterson, Toth, Sips, and Radke-Prausnitz adsorption isotherm models. Langmuir adsorption capacities for both salicylic acid and ibuprofen were 22.70 and 10.74 mg/g, respectively. This low surface area pinewood biochar (1.35 m(2)/g) can adsorb far more adsorbate compared to commercial activated carbons per unit of measured surface area. Methanol stripping achieved 93% and 88% desorption of salicylic acid and ibuprofen, respectively, from the spent biochar, and 76% and 72% of the initial salicylic acid and ibuprofen adsorption capacity, respectively, remained after four full capacity equilibrium recycles. (C) 2014 Elsevier B.V. All rights reserved.