Bioelectrochemical system for generating electrical energy from formic acid under natural field conditions

Abstract

Micro-bioenergy system for generating electrical energy from formic acid, comprising at least one capillary tube with a semipermeable membrane for drawing in formic acid from an ant nest, a micropump for transferring the acid into a reaction cell, a reaction cell with magnesium and copper electrodes for electrochemical conversion, an energy storage device for intermediate storage of the generated energy, and a housing for integrating and protecting the components.

Description

1. Technical field

[0001] The invention relates to a microelectrochemical bioenergy system for generating electrical energy from formic acid produced by the natural behavior of living ant colonies. The system combines aspects of bioelectricity, microfluidics, sensor technology, environmental engineering, and self-sufficient energy supply. It is particularly suitable for field applications (e.g., nature conservation, environmental monitoring) and for the ecological charging of miniature batteries. 2. State of the art

[0002] The use of galvanic cells and microfluidic technology for energy generation from chemical reactions is well-established. The utilization of biological reactants such as formic acid has also been described in the literature. Systems for energy generation using micro fuel cells and enzyme systems exist. However, no device is currently known that utilizes the natural secretion of formic acid by living ants for continuous energy generation and simultaneous storage. In particular, a system with targeted ant stimulation, integrated capillary membrane technology, real-time sensors, modular energy buffering, and environmentally friendly battery charging is lacking. 3. Object of the invention

[0003] The aim of the invention is to provide an autonomous, environmentally friendly energy system that: • utilizes the production of formic acid through the natural behavior of the ant colony, • efficiently collects and electrochemically converts the acid, • maximizes efficiency and biocompatibility using sensors and vibration modules, • stores the energy it generates and releases it as needed, • additionally collects the formic acid in a reservoir and uses it to charge miniature batteries, • integrates seamlessly into the ant nest. 4. Summary of the invention

[0004] The mobile bioenergy system comprises the following core elements: 4.1 Capillary lines with membrane filters for selective absorption and transfer of formic acid. 4.2 Micropumps for metered delivery of the acid into the reaction cell. 4.3 A reaction chamber with metal electrodes (Mg and Cu) in which the electrochemical reaction takes place: Mg + 2 HCOOH + Mg 2+ + 2 HCOO - + H2↑ 4.4 Sensor modules (temperature, humidity, pressure, vibration) with control electronics for system control. 4.5 Vibration module for targeted stimulation of ants to secrete acid. 4.6 Energy storage (supercapacitor / micro battery) with intelligent circuitry for energy output. 4.7 A biocompatible, modular housing for different climate conditions and nest shapes. 4.8 A collection container for the accumulation of formic acid for later use in miniature batteries. 5. Detailed Designs 5.1 Capillary Tubes & Membranes

[0005] Flexible, chemically resistant polymer conduits (e.g. PTFE) with semipermeable membranes for the selective absorption of liquids. 5.2 Pump system

[0006] Capillary or electromagnetically operated, with a check valve to prevent backflow. 5.3 Reaction cell

[0007] Two electrodes (anode: Mg, cathode: Cu) in direct contact with the electrolyte. The design prevents short circuits and the introduction of foreign substances. 5.4 Sensors & Control

[0008] Temperature, humidity, pressure, and vibration sensors control pump cycles and the vibration module. A microcontroller regulates energy output. 5.5 Vibration module

[0009] It generates periodic vibrations in the area of ​​the capillary tips to activate defense reactions. 5.6 Energy buffering and release

[0010] The energy generated is stored in a capacitor and released to end devices as needed. Circuits regulate voltage and charge protection. 5.7 Housing

[0011] Weatherproof, biocompatible plastic housing (e.g. PLA), protects electronics and prevents nesting material from entering. 5.8 Acid storage & battery charging

[0012] Separate collection container made of chemically resistant material for storing formic acid. Dosing system directs acid into a secondary fuel cell for charging miniature batteries (e.g., for watches, glasses, cameras, medical instruments).

[0013] Charging a miniature 50 mAh battery requires approximately 0.3–0.4 g of formic acid, based on an energy efficiency of about 40%. A colony of 50,000 individuals can therefore supply over 100 such batteries per day. 6. Advantages and applications • Provision of renewable electrical energy directly at the deployment site • Low maintenance and high self-sufficiency • Minimally invasive integration into the ant nest • Ecological production and charging of miniature batteries • Use as a sustainable field sensor, eco-lamp, data logger or teaching unit 7. Agricultural benefits of ant fields • The invention enables the integration of ant colonies into agricultural ecosystems, utilizing the natural production of formic acid for energy generation. Through targeted habitat design (“ant fields”), areas can be created that are both ecologically and energetically productive. The energy generated can be used to power sensors for soil moisture, temperature, or pest monitoring. Additionally, formic acid can be collected as a biological by-product and used to charge miniature batteries for agricultural equipment (e.g. GPS trackers, microvalves, environmental loggers). The combination of natural biodiversity and technological use represents a new form of sustainable agriculture. 8. Additional medical and functional uses

[0014] Besides its use for energy production, the collected formic acid offers further applications in the medical and functional fields: • Antibacterial effect: Formic acid possesses strong bactericidal properties and can be used for the local disinfection of surfaces, instruments, or skin areas. This is particularly relevant for mobile medical units or field surgery. • Homeopathic and naturopathic treatments: In naturopathy, formic acid is used as a regulatory agent, particularly for rheumatic complaints, skin irritations, and allergic reactions. Controlled collection allows for standardized dosing for therapeutic purposes. • Sterilization of micro-instruments: The acid can be used for cleaning and sterilizing microsurgical instruments, e.g. in mobile operating systems or during minimally invasive procedures. • Treatment of skin changes: In controlled concentrations, formic acid can be used to remove warts or to treat localized skin lesions. • Integration into medical devices: The energy and / or acid obtained can be used to power portable medical devices such as sensors, pumps, or diagnostic units.

[0015] This additional use expands the ecological and functional value of the system and enables its use in medically relevant scenarios, especially in resource-poor or mobile environments. Description Fig. 2 Legend Designation Function / Description 1 Ant colony (natural habitat) Source of formic acid through natural processes 2 Capillary tube system with membrane filters Absorption and transport of formic acid from the nest area 3 Micropump with check valve Metered delivery of the acid into the reaction cell 4 Reaction cell with metal electrodes (Mg / Cu) Site of the electrochemical reaction of formic acid 5 Sensor module (temperature, humidity, pressure, vibration) Monitoring of environmental conditions and control of system processes 6 Vibration module Stimulation of ants to promote acid secretion 7 Collection container for formic acid Storing the excess acid for later use 8 Secondary fuel cell Energy recovery from stored acid for charging miniature batteries 9 Energy storage (supercapacitor / micro battery) Intermediate storage and demand-based release of the generated energy 10 Charging control module Protection and regulation during battery charging 11 Biocompatible housing Protection of the electronics and integration into various nest shapes and floor types 12 Miniature battery (e.g. for watch, sensor, camera) Target device for the stored energy 13 Medical Application Unit Use of the acid for disinfection, sterilization or naturopathic treatment 14 Agricultural sensor (optional) Use in an agricultural context for environmental monitoring

Claims

[1] Micro-bioenergy system for generating electrical energy from formic acid, comprising at least one capillary tube with a semipermeable membrane for drawing in formic acid from an ant nest, a micropump for transferring the acid into a reaction cell, a reaction cell with magnesium and copper electrodes for electrochemical conversion, an energy storage device for intermediate storage of the generated energy, and a housing for integrating and protecting the components. [2] System according to claim 1, wherein the micropump is operated capillary- or electromagnetically and has a check valve. [3] System according to claim 1, wherein the reaction cell performs the electrochemical reaction Mg + 2 HCOOH → Mg 2+ + 2 HCOO - + uses H2. [4] System according to claim 1, additionally equipped with a vibration module for targeted stimulation of the ants to promote acid secretion and at least one sensor module for measuring environmental parameters such as temperature, humidity, pressure or vibration. [5] System according to claim 4, wherein the sensor data are used to control the pump cycles and energy output. [6] System according to one of the preceding claims, wherein the generated electrical energy is stored in a capacitor and released when required to supply a consumer, in particular an LED display or a sensor. [7] System according to claim 6, wherein the energy storage device is a supercapacitor or microaccumulator. [8] System according to one of the preceding claims, additionally comprising a collection container for accumulating formic acid for time-delayed use. [9] System according to claim 8, wherein the stored formic acid is used to charge miniature batteries. [10] System according to one of the preceding claims, wherein the formic acid is used medically, in particular for local disinfection, sterilization of micro-instruments or as a natural remedy. [11] System according to one of the preceding claims, integrated into agricultural ecosystems as an ‘ant field’ for supplying sensors, environmental loggers or microvalves. [12] System according to one of the preceding claims, modular in design and expandable by additional capillary lines, sensor modules or energy storage devices.

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