Electrocatalytic chloramine removal from water without chemical additives

Overview

This solution addresses the removal of chloramine compounds—monochloramine (NH2Cl), dichloramine (NHCl2), and trichloramine (NCl3)—from drinking water and wastewater without the addition of chemicals. Chloramines form when ammonia is oxidatively chlorinated during water treatment and pose challenges for utilities, including taste and odor issues, disinfectant decay, and toxicity to aquatic life.

The proposed approach uses electrocatalysis to transform chloramines into dinitrogen gas (N2) through controlled oxidation or reduction reactions at electrode surfaces. Because each chloramine species carries a different nitrogen oxidation state (-1, +1, and +3 respectively), the chemistry can be tuned by selecting appropriate electrode materials and operating conditions such as applied current and temperature. The result is a chemical-free, ambient-condition process that converts harmful chloramine residuals into an inert, naturally abundant gas.

This technology is relevant to municipal water utilities, industrial water treatment operators, and drinking water infrastructure providers seeking to reduce chemical inputs, lower operating costs, and meet stricter water quality standards.

Technical specifications

Process mechanism:

• Direct charge-transfer redox reactions occur on the electrode surface, targeting each chloramine species according to its oxidation state
• Indirect transformations mediated by electrogenerated oxidants produced at the electrode surface supplement direct electron transfer
• Oxidation or reduction pathways are selected based on the chloramine species present, enabling flexible operation

Catalyst and operating flexibility:

• Multiple electrode materials will be evaluated to identify those with the highest activity and selectivity for chloramine conversion
• Operational variables such as applied current density and temperature can be adjusted to optimize energy use and removal efficiency
• The process operates under ambient conditions, eliminating the need for heating, UV lamps, or chemical dosing

Demonstrated chemistry foundation:

• The research team has prior experience with electrooxidation of ammonia, hydrogenation of nitrate and nitrite, and electrochemical dehalogenation of organochlorine compounds, establishing a strong basis for chloramine electrochemistry

Technology readiness level

The concept is currently at an early research stage. Chloramine oxidation has previously been shown to be feasible using UV-based and advanced oxidation processes, but electrochemical removal has not yet been demonstrated. Planned validation includes electroanalytical characterization of selected electrode materials followed by bulk electrolysis experiments on individual chloramine compounds and their mixtures in both ultrapure water and real tap water samples. Performance will be benchmarked against UV-based processes using standard engineering figures of merit to assess energy consumption, removal efficiency, and operational practicality.