Improving Degradation Efficiency of Organic Pollutants through a Self-Powered Alternating Current Electrocoagulation System

Abstract

Although electrocoagulation technology has been widely researched in wastewater treatment, high energy consumption and electrode passivation are still the main challenges for its widespread applications. Here, we propose a self-powered electrocoagulation system based on a triboelectric nanogenerator (TENG) with alternating current (AC) outputs to solve these two issues, and thus enhance the removal efficiency of organic pollutants. Compared with the direct current source, the AC power source can reduce the electrode passivation, produce more aluminum hydroxide compounds after consuming an equal amount of charges, and thus improve the degradation efficiency. Moreover, the removal efficiency can be further enhanced by decreasing the frequency AC, in which a 5.7-fold improvement was achieved at 0.2 Hz compared to DC at 1.8 Hz. Inspired by the low frequency of ocean wave water, we developed a self-powered AC-electrocoagulation system to directly drive the electrocoagulation reaction by harvesting water wave energy, which can effectively remove 94.8% of xylenol orange and 98.8% of water–oil emulsion, and thus completely address the problem of energy consumption. This study further promotes the application of self-powered electrochemical systems in treating environmental pollution.

Recent Advances in Triboelectric Nanogenerators for Marine Exploitation

“…Reproduced with permission. [ 215 ] Copyright 2021, American Chemical Society. d) A efficient water‐oil emulsion separation system by asymmetric alternating current electric field.…”

A flexible and stretchable triboelectric nanogenerator based on a medical conductive hydrogel for biomechanical energy harvesting and electronic switches

“…[14][15][16] A triboelectric nanogenerator (TENG) is considered as an effective tool to convert low-frequency mechanical energy into electrical energy based on the coupling effect of contact electrification and electrostatic induction. 4,[17][18][19][20][21][22][23][24][25] TENGs can effectively harvest many types of low-frequency mechanical energy including human daily activities, wind energy, ocean energy [26][27][28] for energy conversion, self-powered sensors, physiological monitoring, 4,[29][30][31][32] and human-machine interactions. 9,33,34 In order to realize biomechanical energy harvesting and physiological sensing, a wearable TENG requires the features of flexibility, comfortability, and stretchability of both the triboelectric layer and the electrode layer.…”

Output Enhancement of Triboelectric Nanogenerators Based on Hierarchically Regular Cadmium Coordination Polymers for Photocycloaddition

“…To customize the hierarchical frameworks of CPs with the desired dimensions and properties, well-defined and tractable size and shape of building blocks are required to manipulate the intrinsic characteristics of the CPs by molecular encoding. This allows the tailoring of the electronic structure through building blocks with efficient site-to-site charge transport. − Alternatively, this propagation could be adopted to explore charge transport in triboelectric nanogenerators (TENGs), which are a novel type of energy storage and output devices that directly convert various mechanical energies to electricity. − The use of materials with proper molecular or electronic structures to facilitate the ability of gain/loss electrons is conducive to determining the output of TENGs for their wide practical applications in self-powered sensors, wearable devices, supercapacitors, tribo-catalytic, and self-powered electrochemical cathodic protection since their first construction in 2012. − Thus, benefiting from the well-defined platform and unique electronic properties of building blocks in CPs, we attempted to explore the possible utility of building blocks in the hierarchical frameworks of CPs in TENGs and expand the application scope of CP-based TENGs for photocatalysis of organic molecules, especially in selective photocycloaddition organic transformation, which is still in its infancy. − …”