RUI: Elucidating interlayer chemistry for design of novel, nontoxic organoclays for contaminant remediation

化学系的环境化学科学项目将资助米德尔伯里学院的Molly Constanza-Robinson教授阐明有机粘土的化学，并将这一认识应用于设计和表征新型、无毒的有机粘土，以有效修复污染物。潜在的有害化学物质，包括杀虫剂和药品，经常在处理后的废水、接受水的溪流、地下水和饮用水井中被检测到。使用改性粘土矿物(有机粘土)作为吸附剂是去除环境水体中有害污染物的一种有前途的方法，但根本问题仍然存在。该研究小组使用光谱技术研究有机粘土层间化学环境的细节，以了解粘土的分子水平属性如何影响其吸附效率。除了发展促进人类和环境健康的基础知识和社会利益外，该项目还通过相关的基于课程的实验室项目支持对不同群体的环境化学研究的本科生和额外学生的培训和指导。用长链烷基铵阳离子表面活性剂改性的蒙脱石粘土已被广泛研究，并显示出有效地吸附水中的石油碳氢化合物、酚、硝基和氯代芳烃以及其他有机污染物的能力。虽然关于有机粘土的层间污染物吸收已知很多，但尚未回答的问题阻碍了有机粘土用于污染物修复的优化。此外，有机粘土中使用的传统表面活性剂的潜在毒性还没有得到解决。利用多种光谱技术、吸附等温线和其他表征工具，本项目研究了控制有机粘土层间化学环境的因素，包括其大小、结晶度和水化作用，以及这些特性如何影响有机粘土的吸附效率。这一见解随后被应用于新型、有效和无毒的有机粘土的设计和表征。

With this award, the Environmental Chemical Sciences Program of the Division of Chemistry is funding Professor Molly Constanza-Robinson of Middlebury College to clarify the chemistry of organoclays and apply this understanding to the design and characterization of novel, nontoxic organoclays for effective contaminant remediation. Potentially harmful chemicals, including pesticides and pharmaceuticals, are routinely detected in treated wastewater, receiving streams, groundwater, and drinking water wells. Using modified clay mineral (organoclays) as an adsorbent represents a promising approach for removing harmful contaminants from environmental waters, but fundamental questions remain. This research team uses spectroscopic techniques to study the details of the organoclay interlayer chemical environment to understand how the molecular-level properties of the clay influence its sorption efficiency. In addition to developing fundamental knowledge and the societal benefit of promoting human and environmental health, this project supports the training and mentoring of a diverse group of undergraduates in interdisciplinary environmental chemical research and additional students through an associated course-based laboratory project.Montmorillonite clay modified with long-chain alkyl-ammonium cationic surfactants has been extensively studied and demonstrates the ability to effectively sorb petroleum hydrocarbons, phenols, nitro- and chloro-substituted aromatics, and other organic pollutants from water. Although much is known about contaminant uptake into the interlayer of organoclays, unanswered questions hinder optimization of the organoclays for use in contaminant remediation. Moreover, the potential toxicity of conventional surfactants used in organoclays has not been addressed. Using multiple spectroscopic techniques, sorption isotherms, and additional characterization tools, this project investigates factors that govern the organoclay interlayer chemical environment, including its size, crystallinity, and hydration, and how these properties influence the sorption efficiency of the organoclays. This insight is then applied to the design and characterization of novel, effective, and non-toxic organoclays.