The adsorption of partially hydrolyzed polyacrylamide (HPAM) on quartz plays a key role in solid-liquid separation processes that seek to recover water for processing. In this work, computational molecular dynamics is used to study the water-quartz interface in the presence of HPAM under conditions of high salt and wide pH range. The salts used are mostly those of seawater. Small water-structure maker cations are preferentially adsorbed onto the polymer rather than onto the quartz surfaces. In freshwater, the adsorption of HPAM on quartz is reduced to very few contacts, however in saltwater the adsorption contacts of HPAM increase although decrease with surface charge, mainly due to electrostatic repulsion. In the presence of monovalent cations and for any surface charge on the quartz, above the isoelectric point, the adsorption contacts of HPAM decreases as the cation size increases, which is expected considering that smaller cations are more effective in neutralizing both quartz and HPAM. The results show that the adsorption of HPAM occurs exclusively via salt bridges. One way of describing the conformation of an HPAM chain adsorbed onto quartz is to reduce it to the skeleton of carbon atoms of the polymer chain and then determine the fraction of these atoms in loops, trains, and tails. In general, the adsorption contacts of HPAM are few, the carbon fractions in trains and loops are tiny, and therefore most of the carbon atoms in HPAM remain in long tails ready to get entangled with other tails thus favoring the flocculation process. The results are expected to contribute to sustainable water management through the right choice of flocculant based on molecular aspects.

石英上部分水解的聚丙烯酰胺（HPAM）的吸附在固液分离过程中起着关键作用，该过程试图回收水进行加工。在这项工作中，计算分子动力学用于研究高盐和宽pH范围条件下HPAM存在下的水-石英界面。所用盐主要是海水盐。小型水结构助剂阳离子优先吸附在聚合物上，而不是石英表面上。在淡水中，HPAM在石英上的吸附减少到很少的接触，但是在盐水中，HPAM的吸附接触增加，尽管随着表面电荷的增加而减少，这主要是由于静电排斥。在存在单价阳离子的情况下，对于石英上等电点之上的任何表面电荷，HPAM的吸附接触随着阳离子尺寸的增加而减少，考虑到较小的阳离子在中和石英和HPAM方面更有效，因此可以预期。结果表明，HPAM的吸附仅通过盐桥发生。描述吸附在石英上的HPAM链构象的一种方法是将其还原为聚合物链碳原子的骨架，然后确定这些原子在环，链和尾部中所占的比例。通常，HPAM的吸附接触很少，链和环中的碳部分很小，因此HPAM中的大多数碳原子留在长尾巴中，准备与其他尾巴缠结，从而有利于絮凝过程。