Electrochemical ocean iron fertilization and alkalinity enhancement approach toward CO sequestration.

Achieving net-zero emissions by 2050 requires the development of effective negative emission techniques, including ocean-based approaches for CO sequestration. However, the implementation and testing of marine CO removal (mCDR) techniques such as ocean iron fertilization (OIF) or ocean alkalinity enhancement (OAE) face significant challenges. Herein, a novel self-operating electrochemical technology is presented that not only combines OIF and OAE, but also recovers hydrogen gas (H) from seawater, hence offering a promising solution for achieving quantifiable and transparent large-scale mCDR.

Engineering Electrode Polarity for Enhancing In Situ Generation of Hydroxyl Radicals Using Granular Activated Carbon.

Recently, granular activated carbon (GAC) has shown its effectiveness as a cathode material for in situ ROS generation. Here, we present an electrochemically modified GAC cathode using electrode polarity reversal (PR) approach for enhanced HO decomposition via 2-electron oxygen reduction reaction (2e-ORR). The successful GAC modification using PR necessitates tuning of the operational parameters such as frequency, current, and time intervals between the PR cycles.

In-situ groundwater remediation of contaminant mixture of As(III), Cr(VI), and sulfanilamide via electrochemical degradation/transformation using pyrite.

Electrochemical advanced oxidation processes (EAOPs) are effective in removing persistent contaminants from groundwater. However, their practical applicability depends significantly on various site-specific characteristics. Therefore, the primary objective of this investigation was to study the feasibility of EAOPs and pyrite, which is a sulfide mineral, to effectively remove the mixture of arsenic (As (III)), chromium (Cr (VI)), and sulfanilamide in groundwater.

New Insights on Designing the Next-Generation Materials for Electrochemical Synthesis of Reactive Oxidative Species Towards Efficient and Scalable Water Treatment: A Review and Perspectives.

Electrochemical water remediation technologies offer several advantages and flexibility for water treatment and degradation of contaminants. These technologies generate reactive oxidative species (ROS) that degrade pollutants. For the implementation of these technologies at an industrial scale, efficient, scalable, and cost-effective ROS synthesis is necessary to degrade complex pollutant mixtures, treat large amount of contaminated water, and clean water in a reasonable amount of time and cost.

Polarity reversal for enhanced electrochemical synthesis of HO over banana-peel derived biochar cathode for water remediation.

The fabrication of a cost-efficient cathode is critical for in-situ electrochemical generation of hydrogen peroxide (HO) to remove persistent organic pollutants from groundwater. Herein, we tested a stainless-steel (SS) mesh wrapped banana-peel derived biochar (BB) cathode for in-situ HO electrogeneration to degrade bromophenol blue (BPB) and Congo red (CR) dyes. Furthermore, polarity reversal is evaluated for the activation of BB surface via introduction of various oxygen containing functionalities that serve as active sites for the oxygen reduction reaction (ORR) to generate HO.

In-situ hydrogen peroxide formation and persulfate activation over banana peel-derived biochar cathode for electrochemical water treatment in a flow reactor.

Electrochemical advanced oxidation processes (EAOPs) are effective for the removal of organic contaminants from groundwater. The choice of an affordable cathode material that can generate reactive oxygen species (ROS) such as hydrogen peroxide (HO) and hydroxyl radicals (•OH) will increase practicality and cost effectiveness of EAOPs. Carbon enriched biochar (BC), which is derived from pyrolysis of biomass, has emerged as an inexpensive and environmentally-friendly electrocatalyst for removing contaminants from groundwater.

Degradation of Ibuprofen in flow-through system by the Electro-Fenton Process activated by two iron sources.

The electrochemical degradation of ibuprofen (IBP) by electro-Fenton process has been studied in a flow-through system by evaluating the performance of two different iron sources, sacrificial cast iron anode and FeSO salt. The effect of operating conditions, including initial IBP concentration, cast iron anode location, initial FeSO concentration, applied current, the split current on the iron anode, solution pH, and flow rate on the efficacy of the process was evaluated. The sequence of the electrodes significantly influences ibuprofen removal.

Electrogeneration of HO by graphite felt double coated with polytetrafluoroethylene and polydimethylsiloxane.

Efficient and steady electrogeneration of HO is a significant step in the Electro-Fenton water treatment process. This study fabricates a polytetrafluoroethylene (PTFE) coated graphite felt cathode with a polydimethylsiloxane (PDMS) damp-proof coating to generate HO in a flow-through system without an external oxygen supply. We evaluated the effect of PDMS content, current, flow rate, and pH on HO production.

Electrochemical Synthesis of HO for -nitrophenol Degradation Utilizing a Flow-through Three-dimensional Activated Carbon Cathode with Regeneration Capabilities.

The growing ubiquity of recalcitrant organic contaminants in the aqueous environment poses risks to effective and efficient water treatment and reuse. A novel three-dimensional (3D) electrochemical flow-through reactor employing activated carbon (AC) encased in a stainless-steel (SS) mesh as a cathode is proposed for the removal and degradation of a model recalcitrant contaminant -nitrophenol (PNP), a toxic compound that is not easily biodegradable or naturally photolyzed, can accumulate and lead to adverse environmental health outcomes, and is one of the more frequently detected pollutants in the environment. As a stable 3D electrode, granular AC supported by a SS mesh frame as a cathode is hypothesized to 1) electrogenerate HO via a 2-electron oxygen reduction reaction on the AC surface, 2) initiate decomposition of this electrogenerated HO to form hydroxyl radicals on catalytic sites of the AC surface 3) remove PNP molecules from the waste stream via adsorption, and 4) co-locate the PNP contaminant on the carbon surface to allow for oxidation by formed hydroxyl radicals.