This project targets the elimination of 1,4-dioxane, a water pollutant that resists conventional remediation due to its high solubility and chemical stability. The work introduces a continuous-flow millifluidic photoreactor that selectively removes 1,4-dioxane based on skeletal editing under blue LED irradiation, without requiring chemical oxidants. The process utilizes aryl diazoacetates as carbene precursors to trigger a ring-expansion transformation, converting 1,4-dioxane into water-insoluble 1,4-dioxepanes, enabling physical separation.

 

Process intensification was investigated using Design of Experiments (DoE) and Generalized Linear Modeling (GLM), identifying favorable operating conditions (TF = 0.246 mL/min, FR = 0.2, LED = 100%, [dioxane] = 25.5 g/L, M2 channel), predicting 100% conversion. Experimental trials achieved up to 93% conversion in S3 geometry, exceeding the performance of M2 under comparable conditions. Synergistic non-linear parameter interactions among flow rate, light intensity and reactor geometry were identified through statistical analysis.

Even at low pollutant concentration (1 g/L), high efficiencies were retained 95.15% (M2 meandering channel reactor) and 88.19% (S3 spital channel reactor) demonstrating the potential of this method for trace-level water remediation. The modularity of the flow photoreactor supports easy scaling and coupling with industrial treatment pipelines, positioning it as a promising solution toward UN Sustainable Development Goal (SDG-6): Clean Water and Sanitation.

Funding agency:  FGIR/2023/Proposal/23

Team: Dr. Subhabrata Sen (Principal Investigator), Dr. V. M. Rajesh (Co-PI), from Chemistry and Chemical Engineering