Molecular Dynamics Study on the Adsorption of UO22+ from an Aqueous Phase: Effect of Grafting Dibenzo Crown Ether and Dicyclohexano Crown Ether on the Polystyrene Surface,Journal of Chemical & Engineering Data

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Molecular Dynamics Study on the Adsorption of UO22+ from an Aqueous Phase: Effect of Grafting Dibenzo Crown Ether and Dicyclohexano Crown Ether on the Polystyrene Surface
Journal of Chemical & Engineering Data ( IF 2.0 ) Pub Date : 2019-08-05 , DOI: 10.1021/acs.jced.9b00462
Praveenkumar Sappidi ₁ , Jayant K. Singh ₁

Affiliation

Atomistic molecular dynamics (MD) simulations are performed in order to understand the adsorption behavior of UO₂²⁺ ions from an aqueous medium. The dibenzo crown ether (DBCE) and dicyclo hexano crown ether (DCHCE) grafted on the polystyrene surface is used as the adsorbent. We investigated the role of grafting density ρ_s (mol/nm²) of DBCE and DCHCE on the adsorption behavior with increasing UO₂²⁺ ion concentration C_s (M). The amount of adsorption (q_e) (mg/g) increases with an increase in UO₂²⁺ salt concentration and follows the Langmuir adsorption isotherm model. The maximum amount of adsorption (q_max) (mg/g) increases with increasing grafting density for both DBCE and DCHCE. The DCHCE shows higher q_max values compared to DBCE over the entire range of ρ_s: 0.25 mol/nm² < ρ_s < 2.07 mol/nm². Overall, q_max show a 5-fold increase for DBCE and DCHCE with an increase in ρ_s from 0.25 mol/nm² to 2.07 mol/nm². The optimum ρ_s for the maximum adsorption is found to be 1.25 mol/nm² for both DBCE and DCHCE. The dynamical behavior of the adsorbed UO₂²⁺ is also investigated by calculating the self-diffusion coefficient (D) and mean residence time (τ). The D value decreases by ∼47% for DBCE and ∼61% for DCHCE, for the entire range of ρ_s, with an increase in C_s. Similarly, the τ value shows more than a 5-fold increase irrespective of grafting densities for both DBCE and DCHCE with increasing C_s. In the end, we investigate the UO₂²⁺ binding structure with DBCE and DCHCE. The potential of mean force (PMF) analysis shows a favorable free-energy for the binding of UO₂²⁺ to DCHCE compared to DBCE.

中文翻译：

水相吸附UO22 +的分子动力学研究：接枝二苯并冠醚和二环己酮冠醚在聚苯乙烯表面的影响

进行原子分子动力学（MD）模拟，以了解UO ₂²⁺离子从水性介质中的吸附行为。接枝在聚苯乙烯表面的二苯并冠醚（DBCE）和二环己酮冠醚（DCHCE）被用作吸附剂。我们研究了接枝密度ρ的作用_小号（摩尔/纳米²随UO）DBCE和DCHCE对吸附行为₂²⁺离子浓度Ç_小号（M）。吸附量（q _e）（mg / g）随着UO ₂^2+的增加而增加盐浓度并遵循Langmuir吸附等温线模型。DBCE和DCHCE的最大吸附量（q _max）（mg / g）随着接枝密度的增加而增加。所述DCHCE显示出较高的q_最大值超过ρ的整个范围相比DBCE_小号：0.25摩尔/纳米² <ρ_小号<2.07摩尔/纳米²。总体而言，q_最大值示出了用于DBCE和DCHCE随着一个5倍的增加在ρ _š从0.25摩尔/纳米²至2.07摩尔/纳米²。最佳ρ_小号为最大吸附被发现是1.25摩尔/纳米²对于DBCE和DCHCE。还通过计算自扩散系数（D）和平均停留时间（τ）来研究吸附的UO ₂²⁺的动力学行为。的d值由~47％为DBCE和DCHCE ~61％减小，为ρ的整个范围_小号，与增加Ç_小号。类似地，τ值显示出比不论接枝两种DBCE和DCHCE密度随着增加的5倍的增加更Ç_小号。最后，我们研究了DBCE和DCHCE的UO ₂²⁺结合结构。平均力（PMF）分析的潜力显示了结合UO ₂的有利自由能²⁺到DCHCE相比DBCE。

更新日期：2019-08-05

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