Synergetic antibacterial activity of reduced graphene oxide and boron doped diamond anode in three dimensional electrochemical oxidation system

At a Glance

Metadata	Details
Publication Date	2015-05-21
Journal	Scientific Reports
Authors	Xiujuan Qi, Ting Wang, Yujiao Long, Jinren Ni
Institutions	Peking University
Citations	33
Analysis	Full AI Review Included

Technical Documentation: Synergetic Antibacterial Activity of BDD-rGO Anodes

Documentation Generated by 6CCVD Technical Engineering Team based on analysis of “Synergetic antibacterial activity of reduced graphene oxide and boron doped diamond anode in three dimensional electrochemical oxidation system.”

Executive Summary

This research validates the superior performance of Boron-Doped Diamond (BDD) anodes when integrated with reduced Graphene Oxide (rGO) in a three-dimensional (3D) electrochemical oxidation (EChO) system for water disinfection. This synergistic approach offers dramatically enhanced bacterial inactivation rates, demonstrating BDD’s strength as the premier anode material for advanced water treatment applications.

100% Inactivation Enhancement: The BDD-rGO system achieved a 100% improvement in E. coli inactivation efficiency compared to using BDD alone.
Rapid Disinfection: The optimized BDD-rGO system achieved a <7 log inactivation of E. coli (from an initial 10⁷ CFU/ml concentration) in only 25 minutes.
Dual Mechanism Synergy: Antibacterial activity is driven by the BDD-generated electric field accelerating bacterial migration toward rGO nanosheets for physical cell disruption, coupled with BDD’s intrinsic ability to chemically oxidize bacteria via hydroxyl radical (•OH) generation.
Enhanced Radical Production: The integration of rGO led to a 25% promotion in hydroxyl radical production compared to BDD used in isolation, resulting from the delayed recombination of electron-hole pairs.
Sustained Performance: The system exhibited a capacitance effect, maintaining significant antibacterial performance (4.5 log inactivation) for 15 minutes even after power cut-off.
Material Requirements: Success hinges on the consistent quality and high electrochemical stability of the Boron-Doped Diamond (BDD) anode material.

Technical Specifications

Parameter	Value	Unit	Context
Anode Material	Boron-Doped Diamond (BDD)	Material	Primary electrochemical oxidation surface
Cathode Material	Stainless Steel	Material	Counter electrode
Anode Geometric Area	4	cm²	Electrode dimensions used in batch tests
Electrode Gap	1	cm	Distance between anode and cathode
Max E. coli Inactivation	<7	log (N/N₀)	Achieved in BDD-rGO system
Optimized Inactivation Time	25	minutes	Time to achieve 7 log kill
Optimized Current Density	15	mA cm^-2	Optimal performance parameter
Hydroxyl Radical Production	25	% Increase	BDD-rGO vs. BDD alone
Initial E. coli Concentration	10⁷	CFU/ml	Indicator microorganism concentration
Electrolyte Concentration	0.05	M	Na₂SO₄ electrolyte (Optimized)
Optimized rGO Concentration	1	µg ml^-1	Optimal concentration of reduced graphene oxide
rGO Reduction Temperature	95	°C	Constant temperature for GO reduction process

Key Methodologies

The study utilized galvanostatic batch electrochemical experiments to assess synergistic disinfection performance. The core components and operational methods employed were:

Electrode Fabrication: BDD anodes (4 cm²) and stainless steel cathodes (4 cm²) were set up in a 400 ml beaker with a 1 cm electrode gap. The system operated under DC power, maintaining galvanostatic control.
rGO Nanosheet Synthesis: Graphite Oxide (GO) was prepared using a modified Hummer’s method. GO dispersion was reduced chemically using hydrazine solution (50%w/w) and ammonia solution (25%w/w), and heated in an oil bath at 95 °C for 1 hour to yield rGO nanosheet dispersion.
Microorganism Preparation: E. coli C3000 was cultured at 37 °C, centrifuged at 6000 rpm, and washed to remove nutrients. The E. coli suspension was subsequently standardized to an initial concentration of 10⁷ CFU/ml in the Na₂SO₄ electrolyte.
Electrochemical Disinfection: Experiments were run in a 250 ml electrolytic solution, stirred continuously, typically at 15 mA cm^-2 current density.
Reaction Quenching: Samples withdrawn at time intervals were immediately mixed with 10 mM sodium thiosulfate (Na₂S₂O₃) to scavenge residual hydroxyl radicals and terminate the oxidation reaction before colony counting.
Membrane Damage Analysis: Cell permeability and membrane stress were evaluated using ONPG (o-nitrophenyl-β-D-galactopyranoside) hydrolysis assays and K⁺ leakage measurements via Flame Atomic Absorption Spectrometer (FAAS).

6CCVD Solutions & Capabilities

The successful implementation of this high-efficiency 3D EChO system relies on the availability of highly stable, high-performance BDD materials. 6CCVD is an expert MPCVD diamond manufacturer, perfectly positioned to supply the materials required to replicate, optimize, and scale this advanced disinfection technology.

Applicable Materials

To achieve the superior disinfection rates demonstrated in this paper, researchers require BDD electrodes optimized for high hydroxyl radical generation and stability.

Research Requirement	6CCVD Material Recommendation	Material Benefits
High-Efficiency Anode	Boron-Doped Diamond (BDD)	Highest chemical stability, widest potential window, maximum •OH generation efficiency compared to conventional materials (Ti/RuO₂, Pt). Custom doping levels available to optimize conductivity (Ω).
Standard BDD Anodes	Polycrystalline BDD Wafers	Thickness range: 0.1 µm - 500 µm. Available in plates/wafers up to 125mm in size, enabling industrial scaling far beyond the 4 cm² used in the paper.
Stability & Purity	Optical Grade SCD or PCD Substrates	Used for backing and support layers, available up to 10 mm thickness for robust, long-lasting electrochemical systems.

Customization Potential

The experiment utilized precisely cut 4 cm² electrodes. 6CCVD offers full customization required for research and subsequent industrial scale-up:

Custom Dimensions and Shaping: We provide advanced laser cutting services to produce complex geometries or specific electrode sizes (like the 4 cm² used here) with sub-micron precision. We can supply inch-size wafers (up to 125mm) for pilot plant scale-up.
Tailored Metalization: For robust electrical contact, we offer in-house metalization services, including deposition of standard contacts such as Au, Pt, Pd, Ti, W, and Cu, ensuring low-resistance connections for high current density operation (up to 20 mA cm^-2 demonstrated).
Surface Finish Optimization: While this study focused on 3D structure synergy (BDD + rGO), we offer high-quality polishing services (Ra < 1nm for SCD, < 5nm for inch-size PCD), important for applications where smoothness minimizes fouling.

Engineering Support

This research highlights complex synergistic effects driven by charge transfer, electric fields, and radical chemistry. 6CCVD’s in-house PhD team can assist researchers and technical engineers with material selection and integration for similar advanced electrochemical oxidation projects. We offer consultative support on:

Optimizing BDD doping profiles for maximum hydroxyl radical yield.
Designing electrode geometries for flow systems and maximizing mass transfer kinetics.
Selecting appropriate metalization stacks for long-term stability in highly oxidative environments.

For custom specifications or material consultation, visit 6ccvd.com or contact our engineering team directly. We offer global shipping (DDU default, DDP available) to ensure fast delivery to research facilities worldwide.

Tech Support

Original Source

DOI: https://doi.org/10.1038/srep10388