Seepma Sergěj Y M H, Kuipers Bonny W M, Wolthers Mariette
Department of Earth Sciences, Utrecht University, Princetonlaan 8A, 3584 CBUtrecht, The Netherlands.
Van 't Hoff Laboratory for Physical and Colloid Chemistry, Debye Institute for Nanomaterials Science, Utrecht University, Padualaan 8, 3584 CHUtrecht, The Netherlands.
ACS Omega. 2023 Jan 30;8(6):5760-5775. doi: 10.1021/acsomega.2c07418. eCollection 2023 Feb 14.
The impact of solution stoichiometry, upon formation of BaSO crystals in 0.02 M NaCl suspensions, on the development of particle size was investigated using dynamic light scattering (DLS). Measurements were performed on a set of suspensions prepared with predefined initial supersaturation, based on the quotient of the constituent ion activity product {Ba}{SO } over the solubility product (Ω = {Ba}{SO }/ = 100, 500, or 1000-11,000 in steps of 1000), and ion activity solution stoichiometries ( = {Ba}:{SO } = 0.01, 0.1, 1, 10 and 100), at circumneutral pH of 5.5-6.0, and ambient temperature and pressure. DLS showed that for batch experiments, crystal formation with varying was best investigated at an initial Ω of 1000 and using the forward detection angle. At this Ω and set of , the average apparent hydrodynamic particle size of the largest population present in all suspensions increased from ∼200 to ∼700 nm within 10-15 min and was independently confirmed by transmission electron microscopy (TEM) imaging. Additional DLS measurements conducted at the same conditions in flow confirmed that the BaSO formation kinetics were very fast for our specifically chosen conditions. The DLS flow measurements, monitoring the first minute of BaSO formation, showed strong signs of aggregation of prenucleation clusters forming particles with a size in the range of 200-300 nm for every . The estimated initial bulk growth rates from batch DLS results show that BaSO crystals formed fastest at near-stoichiometric conditions and more slowly at nonstoichiometric conditions. Moreover, at extreme SO-limiting conditions, barite formation was slower compared to Ba-limiting conditions. Our results show that DLS can be used to investigate nucleation and growth at carefully selected experimental and analytical conditions. The combined DLS and TEM results imply that BaSO formation is influenced by solution stoichiometry and may aid to optimize antiscalant efficiency and regulate BaSO (scale) formation processes.
利用动态光散射（DLS）研究了溶液化学计量比对0.02M NaCl悬浮液中硫酸钡（BaSO）晶体形成以及粒径发展的影响。基于组成离子活度积{Ba}{SO}与溶度积（Ω = {Ba}{SO}/ = 100、500或1000 - 11000，步长为1000）的商，以及离子活度溶液化学计量比（ = {Ba}:{SO} = 0.01、0.1、1、10和100），在pH为5.5 - 6.0的中性环境、环境温度和压力下，对一组具有预定义初始过饱和度的悬浮液进行了测量。DLS表明，对于批次实验，在初始Ω为1000并使用前向检测角的情况下，研究不同时的晶体形成效果最佳。在此Ω和值组下，所有悬浮液中最大群体的平均表观流体动力学粒径在10 - 15分钟内从约200nm增加到约700nm，并通过透射电子显微镜（TEM）成像得到独立证实。在相同流动条件下进行的额外DLS测量证实，对于我们特别选择的条件，BaSO的形成动力学非常快。DLS流动测量监测了BaSO形成的第一分钟，结果显示对于每种，均有强烈迹象表明预成核聚集体聚集形成粒径在200 - 300nm范围内的颗粒。从批次DLS结果估计的初始整体生长速率表明，BaSO晶体在接近化学计量比的条件下形成最快，在非化学计量比条件下形成较慢。此外，在极端的SO限制条件下，重晶石的形成比Ba限制条件下更慢。我们的结果表明，DLS可用于在精心选择的实验和分析条件下研究成核和生长。DLS和TEM的综合结果表明，BaSO的形成受溶液化学计量比影响，可能有助于优化阻垢剂效率并调节BaSO（垢）的形成过程。
