Efficient Hydrogen Generation and Total Nitrogen Removal for Urine Treatment in a Neutral Solution Based on a Self-Driving Nano Photoelectrocatalytic System
Pengbo Wang,
Jinhua Li,
Yang Xu,
Changhui Zhou,
Yan Zhang,
Lina Zha,
Bo Zhang,
Jing Bai,
Baoxue Zhou
Affiliations
Pengbo Wang
Key Laboratory of Thin Film and Microfabrication Technology (Ministry of Education), School of Environmental Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, China
Jinhua Li
Key Laboratory of Thin Film and Microfabrication Technology (Ministry of Education), School of Environmental Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, China
Yang Xu
Key Laboratory of Thin Film and Microfabrication Technology (Ministry of Education), School of Environmental Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, China
Changhui Zhou
Key Laboratory of Thin Film and Microfabrication Technology (Ministry of Education), School of Environmental Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, China
Yan Zhang
Key Laboratory of Thin Film and Microfabrication Technology (Ministry of Education), School of Environmental Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, China
Lina Zha
Key Laboratory of Thin Film and Microfabrication Technology (Ministry of Education), School of Environmental Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, China
Bo Zhang
Key Laboratory of Thin Film and Microfabrication Technology (Ministry of Education), School of Environmental Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, China
Jing Bai
Key Laboratory of Thin Film and Microfabrication Technology (Ministry of Education), School of Environmental Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, China
Baoxue Zhou
Key Laboratory of Thin Film and Microfabrication Technology (Ministry of Education), School of Environmental Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, China
Urine is the main source of nitrogen pollution, while urea is a hydrogen-enriched carrier that has been ignored. Decomposition of urea to H2 and N2 is of great significance. Unfortunately, direct urea oxidation suffers from sluggish kinetics, and needs strong alkaline condition. Herein, we developed a self-driving nano photoelectrocatalytic (PEC) system to efficiently produce hydrogen and remove total nitrogen (TN) for urine treatment under neutral pH conditions. TiO2/WO3 nanosheets were used as photoanode to generate chlorine radicals (Cl•) to convert urea-nitrogen to N2, which can promote hydrogen generation, due to the kinetic advantage of Cl−/Cl• cyclic catalysis. Copper nanowire electrodes (Cu NWs/CF) were employed as the cathode to produce hydrogen and simultaneously eliminate the over-oxidized nitrate-nitrogen. The self-driving was achieved based on a self-bias photoanode, consisting of confronted TiO2/WO3 nanosheets and a rear Si photovoltaic cell (Si PVC). The experiment results showed that hydrogen generation with Cl• is 2.03 times higher than in urine treatment without Cl•, generating hydrogen at 66.71 μmol h−1. At the same time, this system achieved a decomposition rate of 98.33% for urea in 2 h, with a reaction rate constant of 0.0359 min−1. The removal rate of total nitrogen and total organic carbon (TOC) reached 75.3% and 48.4% in 2 h, respectively. This study proposes an efficient and potential urine treatment and energy recovery method in neutral solution.
