Investigation of Hydronium Diffusion in Poly(vinyl alcohol) Hydrogels: A Critical First Step to Describe Acid Transport for Encapsulated Bioremediation
Investigation of Hydronium Diffusion in Poly(vinyl alcohol) Hydrogels: A Critical First Step to Describe Acid Transport for Encapsulated Bioremediation
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DOI：
10.1021/acsestengg.2c00107
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发表时间：
2022-09
期刊：
影响因子：
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通讯作者：
Carson J. Silsby;Jonathan R. Counts;Thomas A. Christensen;M. Roll;K. Waynant;J. Moberly
中科院分区：
文献类型：
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作者：
Carson J. Silsby;Jonathan R. Counts;Thomas A. Christensen;M. Roll;K. Waynant;J. Moberly
氯代脂肪族烃污染含水层的生物修复可能因污染物浓度高和修复过程中产生的酸而受到阻碍。将微生物封装在水凝胶中可以提供一个保护性的、可调节的环境，使其免受抑制化合物的影响;然而，目前制定成功的封装系统的方法依赖于试错法而不是工程方法，因为缺乏关于传质系数的基本信息。为了解决这一知识差距，水合氢离子通过两种常用的水凝胶材料，聚（乙烯醇）和海藻酸，在两种固化方法（化学和低温）的传质速率进行了测量。研究了水凝胶交联条件、聚合物组成和溶剂离子强度的变化，以了解各自如何影响水合氢离子扩散率。三因素方差分析表明，离子强度、膜类型和交联方法显著（p< 0.001）影响水合氢离子传质的变化。水合氢离子的扩散增加与离子强度，相反的是在只有水（无聚合物）的解决方案中观察到的。与离子强度增加的水合氢离子扩散相关的共同发生机制包括水凝胶基质内的水分数增加和水凝胶收缩。在这项研究中测定的扩散速率提供了第一个主要的设计信息，以进一步优化生物修复封装水凝胶。
Bioremediation of chlorinated aliphatic hydrocarbon-contaminated aquifers can be hindered by high contaminant concentrations and acids generated during remediation. Encapsulating microbes in hydrogels may provide a protective, tunable environment from inhibiting compounds; however, current approaches to formulate successful encapsulated systems rely on trial and error rather than engineering approaches because fundamental information on mass-transfer coefficients is lacking. To address this knowledge gap, hydronium ion mass-transfer rates through two commonly used hydrogel materials, poly(vinyl alcohol) and alginic acid, under two solidification methods (chemical and cryogenic) were measured. Variations in hydrogel crosslinking conditions, polymer composition, and solvent ionic strength were investigated to understand how each influenced hydronium ion diffusivity. A three-way ANOVA indicated that the ionic strength, membrane type, and crosslinking method significantly (p< 0.001) contributed to changes in hydronium ion mass transfer. Hydronium ion diffusion increased with ionic strength, counter to what is observed in aqueous-only (no polymer) solutions. Co-occurring mechanisms correlated to increased hydronium ion diffusion with ionic strength included an increased water fraction within hydrogel matrices and hydrogel contraction. Measured diffusion rates determined in this study provide first principal design information to further optimize encapsulating hydrogels for bioremediation.