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 (Pd⁰) nanoparticles (PdNPs) for catalytic reductive dechlorination of TCAA. H₂ was delivered directly to PdNPs in situ coated on the surface of bubble-free hollow-fiber gas-transfer membranes. The H₂-based membrane Pd film reactor (H₂−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 H₂. Sustained continuous TCAA removal, high selectivity to acetic acid, and minimal loss of PdNPs support that the H₂−MPfR is a promising catalytic reactor to remove chlorinated DBPs in practice.

三氯乙酸 (TCAA) 是氯消毒过程中常见的消毒副产物 (DBP)。随着 2019 年冠状病毒病 (COVID-19) 大流行的爆发，氯消毒的使用有所增加，增加了本已相当大的 DBP 暴露风险。虽然许多方法能够去除 TCAA，但由于其复杂性和昂贵或危险的投入，它们在连续处理方面的应用受到限制。我们研究了一种使用钯 (Pd ⁰ ) 纳米粒子 (PdNPs) 进行 TCAA 催化还原脱氯的新型系统。H ₂被直接输送到原位涂覆在无气泡中空纤维气体传输膜表面的 PdNPs 上。H ₂基膜钯膜反应器（H ₂−MPfR) 实现了高催化剂特异性 TCAA 还原率，32 L/g-Pd/min，该值类似于使用均匀悬浮的 PdNP 的速率，但比其他固定化 PdNP 系统高几个数量级。在批量测试中，1 mM TCAA 在 180 分钟内去除率超过 99%，对乙酸的产品选择性很强 (≥ 93%)。在连续运行 50 天的过程中，超过 99% 的 1 mg/L 进水 TCAA 被去除，再次以乙酸作为主要产物 (≥ 94%)。_{我们确定了使用直接输送 H 2}使用 PdNP 进行 TCAA 还原脱氯的反应途径及其动力学。持续的 TCAA 去除、对乙酸的高选择性和 PdNP 的最小损失支持 H ₂−MPfR 是一种很有前途的催化反应器，可在实践中去除氯化 DBP。