Electrochemical Co-Production of Ammonia and Biodegradable Polymer Monomer Glycolic Acid via the Co-Electrolysis of Nitrate Wastewater and Waste Plastic
Tianlun Ren, Zhongyao Duan, Huizhen Wang, Hongjie Yu, Kai Deng, Ziqiang Wang, Hongjing Wang, Liang Wang, You Xu
Abstract
Electrochemical reformation of nitrate wastewater and poly(ethylene terephthalate) (PET) plastic waste into ammonia (NH 3 ) and fine chemicals is a sustainable strategy for waste resource utilization. Herein, a co-production system of ammonia and glycolic acid (GA, degradable polymer monomer) is constructed by coupling nitrate reduction and ethylene glycol (EG, in PET hydrolysate) oxidation. Low-crystalline CoOOH (LC-CoOOH/CF) and Pd nanothorns (Pd NTs/NF) grown in situ on the metal foam substrates are employed as cathode and anode, respectively. The high density of amorphous regions in LC-CoOOH/CF enables enhanced nitrate adsorption and provides abundant active sites, ultimately leading to an ammonia Faradic efficiency (FE) of 97.38 ± 1.0% at −0.25 V vs reversible hydrogen electrode (RHE). Meanwhile, the unique nanothorn morphology endows the Pd NTs/NF with a high-curvature tip, triggering a tip effect (TE) to promote the highly selective oxidation of EG to GA. Furthermore, in the two-electrode coupling system, the co-production of NH 3 and GA is operated at a low energy consumption (onset voltage: 0.5 V), much lower than the traditional nitrate electrolysis process (1.4 V). This study provides a method for the resource utilization of nitrate wastewater and PET plastic waste to co-produce NH 3 and value-added chemicals.