NSF-BSF Application: Selective Electrosorption for Boron Removal and Recovery from Seawater

农业灌溉是美国最大的用水者，约占全国清洁水消耗量的80%。海水淡化是一种抗旱技术，可以满足农业和其他用途日益增长的用水需求。目前，海水反渗透（SWRO）是最好的商业化海水淡化技术。然而，由于去除硼的能力有限，淡化海水不能直接用于灌溉。这是由于商业SWRO膜的硼保留能力的限制。硼对植物生长有不利影响，当灌溉用水中硼含量超过0.3 mg/L时，会损害苹果、柑橘、葡萄和其他作物。因此，商业SWRO工厂必须使用额外的纯化步骤以将硼浓度降低至可接受的浓度。这大大增加了能源消耗和将淡化水用于农业的成本。拟议的研究将通过开发一种基于电吸附的新型选择性分离技术来解决与硼去除相关的低效率问题。这种新技术将是无化学品的，节能的，并且能够回收高纯度的硼流用于有益的用途。该项目的成功完成将推动下一代可持续SWRO工厂的发展，为社会带来巨大的潜在效益。该项目将通过为耶鲁大学的研究生和本科生提供研究培训来造福社会。此外，调查员将促进多样性，并通过参与耶鲁大学的K-12外展活动，加强代表性不足的群体在科学和工程方面的参与。SWRO脱盐中一个关键且尚未解决的挑战是产生适合灌溉的渗透水流，而无需额外且昂贵的净化来去除植物毒性元素，如硼。该项目的总体目标是开发一种创新的直流电吸附工艺，用于海水淡化中的硼去除和回收。为了实现这一目标，PI建议围绕以下任务进行综合实验和建模项目：1）使用硼螯合树脂作为构建块制造超选择性正电极（阳极）; 2）对制造的电极进行选择性硼去除和回收的性能测试; 3）阐明选择性硼电吸附的机制; 4）评估电化学反应对电极的长期稳定性和硼选择性的影响;和5）评估和模拟组合的SWRO-电吸附过程的能量消耗和硼选择性。拟议的工作将是第一个研究使用无化学品方法从海水中选择性去除和回收硼的工作。这项研究的成功完成有可能通过开发一种更节能和可持续的海水淡化厂硼去除和回收工艺来改变海水淡化。该奖项反映了NSF的法定使命，并被认为值得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来支持。

Agricultural irrigation is the largest user of water in the United States, accounting for approximately 80 percent of the Nation’s clean water consumption. Seawater desalination is a drought-proof technology that can address growing demands for water in agriculture and other uses. At present, seawater reverse osmosis (SWRO) is the best available commercially available desalination technology. However, the desalinated seawater cannot be used directly in irrigation due to the limited ability to remove boron. This results from limitations on the boron retention capability of commercial SWRO membranes. Boron adversely impacts plant growth and damages apple, citrus, grapes, and other crops when water containing more than 0.3 mg/L of boron is used in irrigation. Thus, commercial SWRO plants must use an additional purification step to reduce boron concentration to acceptable concentrations. This greatly increases the energy consumption and costs of using desalinated water for agriculture. The proposed research will address the inefficiencies associated with boron removal through the development of a novel selective separation technology based on electrosorption. This new technology will be chemical-free, energy efficient, and capable of recovering a high purity boron stream for beneficial uses. Successful completion of this project will advance the development of the next generation of sustainable SWRO plants, with great potential benefit to society. The project will fruther benefit society by providing research training to graduate and undergraduate students at Yale University. Also, the investigator will promote diversity and enhance the involvement of under-represented groups in science and engineering through engagement in Yale's K-12 outreach activities. A critical and unresolved challenge in SWRO desalination is to produce a permeate water stream suitable for irrigation without additional and costly purification to remove plant-toxic elements such as boron. The overall goal of this project is to develop an innovative flow-through electrosorption process for boron removal and recovery in seawater desalination. To achieve this goal, the PI proposes to carry out an integrated experimental and modeling project structured around the following tasks: 1) fabrication of an ultra-selective positive electrode (anode) using boron-chelating resins as building blocks; 2) performance testing of the fabricated electrodes for selective boron removal and recovery; 3) elucidation of the mechanisms underlying selective boron electrosorption; 4) assessment of the impact of electrochemical reactions on the long-term stability and boron selectivity of the electrodes; and 5) evaluation and modeling of the energy consumption and boron selectivity of the combined SWRO-electrosorption process. The proposed work would be the first to study boron-selective removal and recovery from seawater using a chemical-free method. The successful completion of this research has potential to transform desalination through the development of a more energy efficient and sustainable boron removal and recovery process from SWRO plants.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.