Development of high quality Fe_3O_4/rGO composited electrode for low energy water treatment

Electrochemical water treatment is an attractive technology for water desalination and softening due to its low energy consumption. Especially, capacitive Deionization(CDI) is promising as a future technology for water treatment. Graphene(rGO) has been intensively studied for CDI electrode because of its advantages such as excellent electrical conductivity and high specific surface area. However, its 2D dimensional structure with small specific capacitance, high resistance between layers and hydrophobicity degrades ion adsorption efficiency. In this work, we successfully prepared uniformly dispersed Fe3O4/rGO nanocomposite by simple thermal reactions and applied it as effective electrodes for CDI. Iron oxides play a role in uniting graphene sheets, and specific capacitance and wettability of electrodes are improved significantly;hence CDI performances are enhanced. The hardness removal of Fe3O4/rGO nanocomposite electrodes can reach 4.3 mg/g at applied voltage of 1.5V, which is 3 times higher than that of separate r GO electrodes.Thus this material is a promising candidate for water softening technology.

Recent advances in the electrochemical oxidation water treatment: Spotlight on byproduct control

Electrochemical oxidation(EO)is a promising technique for decentralized wastewater treatment,owing to its modular design,high efficiency,and ease of automation and transportation.The catalytic destruction of recalcitrant,non-biodegradable pollutants(per-and poly-fluoroalkyl substances(PFAS),pharmaceuticals,and personal care products(PPCPs),pesticides,etc.)is an appropriate niche for EO.EO can be more effective than homogeneous advanced oxidation processes for the degradation of recalcitrant chemicals inert to radical-mediated oxidation,because the potential of the anode can be made much higher than that of hydroxyl radicals(EOH=2.7 V vs.NHE),forcing the direct transfer of electrons from pollutants to electrodes.Unfortunately,at such high anodic potential,chloride ions,which are ubiquitous in natural water systems,will be readily oxidized to chlorine and perchlorate.Perchlorate is a to-be-regulated byproduct,and chlorine can react with matrix organics to produce organic halogen compounds.In the past ten years,novel electrode materials and processes have been developed.However,spotlights were rarely focused on the control of byproduct formation during EO processes in a real-world context.When we use EO techniques to eliminate target contaminants with concentrations atμg/L-levels,byproducts at mg/L-levels might be produced.Is it a good trade-oft?.Is it possible to inhibit byproduct formation without compromising the performance of EO?In this minireview,we will summarize the recent advances and provide perspectives to address the above questions.