Cai Yuhang, Long Xiangxing, Luo Yi-Hao, Zhou Chen, Rittmann Bruce E
Biodesign Swette Center for Environmental Biotechnology, Arizona State University, Tempe, AZ 85287-5701, United States; College of Power and Energy Engineering, Harbin Engineering University, Harbin 150001, PR China.
Biodesign Swette Center for Environmental Biotechnology, Arizona State University, Tempe, AZ 85287-5701, United States; Nanosystems Engineering Research Center for Nanotechnology-Enabled Water Treatment, School of Sustainable Engineering and the Built Environment, Arizona State University, Tempe, AZ 85287-3005, United States.
Water Res. 2021 Mar 15;192:116841. doi: 10.1016/j.watres.2021.116841. Epub 2021 Jan 15.
Trichloroacetic acid (TCAA) is a common disinfection byproduct (DBP) produced during chlorine disinfection. With the outbreak of the Coronavirus Disease 2019 (COVID-19) pandemic, the use of chlorine disinfection has increased, raising the already substantial risks of DBP exposure. While a number of methods are able to remove TCAA, their application for continuous treatment is limited due to their complexity and expensive or hazardous inputs. We investigated a novel system that employs palladium (Pd) nanoparticles (PdNPs) for catalytic reductive dechlorination of TCAA. H was delivered directly to PdNPs in situ coated on the surface of bubble-free hollow-fiber gas-transfer membranes. The H-based membrane Pd film reactor (H-MPfR) achieved a high catalyst-specific TCAA reduction rate, 32 L/g-Pd/min, a value similar to the rate of using homogeneously suspended PdNP, but orders of magnitude higher than with other immobilized PdNP systems. In batch tests, over 99% removal of 1 mM TCAA was achieved in 180 min with strong product selectivity (≥ 93%) to acetic acid. During 50 days of continuous operation, over 99% of 1 mg/L influent TCAA was removed, again with acetic acid as the major product (≥ 94%). We identified the reaction pathways and their kinetics for TCAA reductive dechlorination with PdNPs using direct delivery of H. Sustained continuous TCAA removal, high selectivity to acetic acid, and minimal loss of PdNPs support that the H-MPfR is a promising catalytic reactor to remove chlorinated DBPs in practice.
三氯乙酸（TCAA）是氯消毒过程中产生的一种常见消毒副产物（DBP）。随着2019年冠状病毒病（COVID-19）大流行的爆发，氯消毒的使用增加，这使得原本就很高的DBP暴露风险进一步提高。虽然有多种方法能够去除TCAA，但由于其复杂性以及昂贵或危险的投入，它们在连续处理中的应用受到限制。我们研究了一种新型系统，该系统采用钯（Pd）纳米颗粒（PdNPs）对TCAA进行催化还原脱氯。氢气直接原位输送到涂覆在无泡中空纤维气体传输膜表面的PdNPs上。基于氢气的膜钯膜反应器（H-MPfR）实现了高催化剂特异性TCAA还原速率，为32 L/g-Pd/min，该值与使用均匀悬浮的PdNP的速率相似，但比其他固定化PdNP系统高出几个数量级。在分批试验中，1 mM的TCAA在180分钟内去除率超过99%，对乙酸具有很强的产物选择性（≥93%）。在连续运行50天期间，1 mg/L进水TCAA的去除率超过99%，同样以乙酸作为主要产物（≥94%）。我们确定了使用直接输送氢气的PdNPs对TCAA进行还原脱氯的反应途径及其动力学。持续连续去除TCAA、对乙酸的高选择性以及PdNPs的最小损失表明，H-MPfR是一种在实际中去除氯化DBPs的有前景的催化反应器。
