Excellence in Research: A Novel High Throughput Forward Osmosis Membrane for Produced Water Treatment

用于页岩气和石油生产的水力压裂操作消耗大量的淡水，最终产生作为副产品的回流水和采出水。这些水大部分通过深井注入处理，如果处理不当，可能造成环境危害。理想情况下，采出水将被处理并排放到环境中。由于采出水中存在高水平的有机污染物和各种盐，因此缺乏用于该应用的有效且成熟的技术。反渗透对于处理采出水是无效的，因为由高盐度引起的渗透压排斥反渗透中使用的液压。正向渗透是一种新兴的技术，由于其是一种自然渗透过程，因此适用于处理采出水。正渗透膜在分离废水中的有机污染物和盐以及处理高盐度采出水方面显示出良好的性能。然而，要将正渗透技术应用于工业规模的采出水处理，必须解决一些技术挑战，包括：（1）可商购的正向渗透膜的相对低的通量，（2）在正向渗透过程中由有机物沉积引起的膜污染，以及（3）当氨-二氧化碳用作正渗透过程中的汲取溶质时，来自膜的水进料侧的氨损失。该项目将开发一种独特的双层正渗透膜，旨在克服这些挑战。计算建模将被应用于描述的机制，通过该机制，通量得到改善，污垢得到缓解。研究和教育将通过教育活动和本科生和研究生的培训相结合。这些活动将通过服务学习教学法为学生成为社区参与学者以及未来的政策制定者做好准备。本研究的目标是在工业水平上有效处理页岩油气采出水。为了实现这一目标，该项目将研究一种新型的高通量正渗透膜设计，该设计针对处理高盐度采出水进行了优化。正向渗透膜将由中间纳米纤维支撑层和在支撑层两侧上的双层外皮组成。支撑层将是含有聚醚酰亚胺和氧化石墨烯的多孔织物。为了减少膜污染并防止来自进料采出水侧的氨损失，膜表层将涂覆有高度亲水性的两性离子聚合物。将膜合成、表征和性能评价与分子动力学模拟相结合，以制造和优化用于使用正渗透工艺的采出水处理的膜。将对开发的采出水处理膜的性能和稳定性进行长期检查，并通过生命周期评估评估新采出水处理工艺的环境和经济影响。该奖项反映了NSF的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Hydraulic fracturing operations for shale gas and oil production consume high volumes of fresh water eventually generating flowback water and produced water as byproducts. Much of this water is disposed of through deep-well injection which, if handled improperly, can cause environmental hazards. Ideally, produced water would instead be treated and discharged to the environment. Due to high levels of organic contaminants and various salts present in produced water, there is a lack of efficient and mature technologies for this application. Reverse osmosis is ineffective for treating produced water because the osmotic pressure caused by the high salinity repels the hydraulic pressure used in reverse osmosis. Forward osmosis is an emerging technology that is suitable for treating produced water since it is a naturally osmotic process. Forward osmosis membranes have shown promising performance for separating organic pollutants and salt from some wastewater and for treating produced water at high salinity. However, to apply forward osmosis technologies to produced water treatment at the industrial scale, there are technical challenges that must be addressed, including: (1) relatively low flux of commercially available forward osmosis membranes, (2) membrane fouling caused by deposition of organic matter during forward osmosis, and (3) ammonia loss from the water feeding side of the membrane when ammonia-carbon dioxide is used as draw solute in the forward osmosis process. The project will develop a unique dual-skinned forward osmosis membrane designed to overcome these challenges. Computational modeling will be applied to describe the mechanisms by which flux is improved and fouling is mitigated. Research and education will be integrated through educational activities and training of undergraduate and graduate students. These activities will prepare students to become community-engaged scholars as well as future policymakers through a service-learning pedagogy.The goal of this research is to make it possible to efficiently treat shale oil and gas produced water at the industrial level. Toward this goal, the project will investigate a novel high throughput forward osmosis membrane design that is optimized for treating high-salinity produced water. The forward osmosis membrane will consist of an intermediate nanofibrous support layer and double ultrathin skins on both sides of the support layer. The support layer will be a porous nanofiber textile containing polyetherimide and graphene oxide. To reduce membrane fouling and to repel ammonia loss from the feeding produced water side, the membrane skins will be coated with zwitterionic polymers, which are highly hydrophilic. Membrane synthesis, characterization, and performance evaluation is integrated with molecular dynamics simulation to fabricate and optimize a membrane for produced water treatment using the forward osmosis process. The performance and stability of the developed membrane for treating produced water will be examined over the long-term, and the environmental and economic impacts of the new produced water treatment process will be evaluated through a life cycle assessment.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.