Department of Computer Engineering, Modeling, Electronics and Systems (D.I.M.E.S.), Laboratory of Transport Phenomena and Biotechnology , University of Calabria , Ponte P. Bucci, cubo 39/c , 87036 Rende , Cosenza , Italy.
Institute on Membrane Technology , ITM-CNR , Ponte P. Bucci, cubo 17/c , 87036 Rende , Cosenza , Italy.
J Chem Inf Model. 2018 Sep 24;58(9):1815-1827. doi: 10.1021/acs.jcim.8b00298. Epub 2018 Sep 6.
In the present paper, an improved multiscale modeling aimed at describing membrane fouling in the UltraFiltration (UF) process was proposed. Some of the authors of this work previously published a multiscale approach to simulate ultrafiltration of Bovine Serum Albumin (BSA) aqueous solutions. However, the noncovalent interactions between proteins and the membrane surface were not taken into account in the previous formulation. Herein, the proteins-surface interactions were accurately computed by first-principle-based calculations considering also the effect of pH. Both the effective surface of polysulfone (PSU) and the first layer of proteins adsorbed on the membrane surface were accurately modeled. Different from the previous work, the equilibrium distance between proteins was calculated and imposed as lower bound to the protein-protein distances in the compact deposit accumulated on the membrane surface. The computed BSA surface charges were used to estimate the protein potential and the charge density, both necessary to formulate a forces balance at microscopic scale. The protein surface potential was compared with Z-potential measurements of BSA aqueous solution, and a remarkable agreement was found. Finally, the overall additional resistance, as due to both the compact and loose layers of the deposit, was computed, thus allowing the final transition to a macroscopic scale, where an unsteady-state mass transfer model was formulated to describe the behavior of a typical dead-end UF process. A good agreement between simulated and experimental permeate flux decays was observed.
在本文中，提出了一种改进的多尺度模型，旨在描述超滤（UF）过程中的膜污染。本文的部分作者之前发表了一种多尺度方法来模拟牛血清白蛋白（BSA）水溶液的超滤。然而，在之前的配方中，没有考虑蛋白质与膜表面之间的非共价相互作用。在这里，通过基于第一性原理的计算考虑 pH 效应来精确计算蛋白质-表面相互作用。准确地模拟了聚砜（PSU）的有效表面和吸附在膜表面上的第一层蛋白质。与之前的工作不同，计算了蛋白质之间的平衡距离，并将其作为膜表面上累积的致密沉积物中蛋白质-蛋白质距离的下限。计算出的 BSA 表面电荷用于估计蛋白质势和电荷密度，这两者都是在微观尺度上形成力平衡所必需的。将蛋白质表面电势与 BSA 水溶液的 Zeta 电势测量值进行了比较，发现两者吻合得很好。最后，计算了由于沉积物的致密层和疏松层而导致的总附加阻力，从而可以最终过渡到宏观尺度，在宏观尺度上，建立了一个非稳态传质模型来描述典型的死端 UF 过程的行为。观察到模拟和实验渗透通量衰减之间的良好一致性。
