CS240940B1 - Acid-base bio-battery using aquatic plants - Google Patents

Abstract

The algae is an acid-base biobattery using aquatic plants, preferably the green freshwater algae Hydrodictyon reticulatum. The biobattery consists of a glass container, in one part of which there is an illuminated suspension of algae, which alkalize their environment, as an electrolyte, and in the other part there is pond water or an acidic buffer. The electrodes are made of a pH-sensitive material, preferably antimony, tellurium, a lead-tin alloy covered with a layer of manganese dioxide, while the partition is made of a cellulose membrane, or the electrodes are silver chloride or carbon, while the partition is made of a pH-sensitive material, preferably antimony, tellurium, or a lead-tin alloy covered with a layer of manganese dioxide. This is a new method of converting solar energy into electricity, which uses the ability of some algae and possibly higher plants to significantly change the pH of their surroundings, and the difference in pH between the two environments serves as a source of free energy for the biobattery.

Description

BACKGROUND OF THE INVENTION The present invention relates to an acid-base biobaterium utilizing aquatic plants.

It is a new way of converting solar energy into electric energy, which uses the ability of some algae and possibly even higher rotin to significantly change the pH of their surroundings when illuminated by sunlight or other light source} the pH difference between two environments then serves as a source of free energy for biobaterii. Electricity is a by-product of the growth of biomass in aquatic plants.

Biobatteries proposed so far, where bioanode or even biocatode are produced by microorganisms (eg Rhodospirillum rubrum, Proteus vulgaris, Micrococcus cerificans, Escherichia coli, Alcaligenes eutrophus and various cyanobacteria) or algae (Chlorella) are of redox oxidation type (Oisalvo EA, Bioeng. 23, 1159-1164, 1981} Benneto HP, Stirling OL, Tanaka K., Vega CA: Biotechnol. Bioeng., 25, 559-568, 1983} Oelaney.

G.M., Roller S.O., Bennetto H.P., Mason J.R., Stirling, J., Thurston C.F., Charge and Field Effects in Biosystems, eds. Allen M.O. and Usherwood P.N.R., England, 1984, in press; Tanaka K., Bennetto H.P .: ibid. It is an anodic oxidation or cathodic reduction of added organic substrate with the participation of bioelectrochemical transformations caused by a living organism. The actual electrode processes take place on platinum electrodes, the substrate being glucose. The reaction mechanisms at the electrodes have not yet been fully elucidated.

So far, the acid-base principle has not been used in the construction of biobatteries. However, it is known that alkaline algae (Hydrodictyon reticulatum) and filamentous algae (Cladophora glomerata and Rhizoclonium hieroglyphicum) are alkalinized by irradiation with sunlight

- 2 240 940 its environment above pH 10. On the other hand, for example, a larger aquatic duckweed plant (Lemna gibba) causes a slight acidification of its environment (Novinky A, Ullrich-Eberius CI, Luttge U, Planta 149, 321-326, 1980) ).

The acid-base biobattery of the invention comprises a glass container divided into two parts with a positive and a negative electrode. It is an object of the invention that the electrolyte in one part of the container is an illuminated suspension of aquatic plants, preferably algae, which basify their environment, and the other part of the container is pond water or acid buffer and electrodes are pH sensitive material, preferably antimony, tellurium , lead and tin alloys coated with a manganese dioxide layer, wherein the barrier is a cellulose membrane, or the electrodes are argentchloride or carbon, the barrier being a pH sensitive material, preferably antimony, tellurium, a lead-tin alloy coated with a manganese dioxide layer. Zelené a suspension of green freshwater algae Hydrodictyon reticulatum is preferably used as the electrolyte in one part of the container.

An advantage of the acid-base cell of the invention is that it utilizes the growth of Hydrodictyon reticulatum algae in their natural habitat, especially in the waters of our ponds, and no organic substrate need be added to the medium. These algae can be used as biomass * in some fields of agriculture. The basic advantage is the model of using solar energy to generate electric energy.

The connection of two different pH environments by means of pH-sensitive electrodes and a bridge (an optional pH-selective membrane and two electrodes for the current circuit) is a source of electromotive voltage, generally known as the pH-meter principle.

However, glass electrodes, now exclusively used for pH measurement, are completely useless for current collection due to their high ohmic resistance. This does not apply to today's semi-forgotten antim, tellurium, or inert electrodes coated with manganese dioxide (see eg Tomíček 0 ·, Poupě F .:

Coll. Czechoslov. Chem. Comm. 8, 520, 1936i Vinogradovová O.N .: Methods for Determination of Hydrogen Ion Concentration. Natural Science Publishing House, Prague, 1953), whose resistance is much lower.

240 940

Some types of acid-base biobattery according to the present invention are schematically shown in the accompanying drawing, in which Fig. 1 shows an acid-base biobattery according to the present invention comprising an illuminated suspension of Hydrodictyon reticulatum algae in one part and artificial pond water in the other part. the antimony and the membrane separating the acidic and basic media is cellulosic; FIG. 2 is a similar biobattery to that of FIG. 1 except that the baffle with a tellurium rod and the argent chloride electrodes separates the two parts; and FIG. 3 a biobattery according to the invention with a flow arrangement.

Figure 1 shows an acid-base biobattery according to the invention consisting of a glass vial JL divided into two parts by membrane 5, one of which part 3 contains an illuminated suspension of 300 mg algae of Hydrodictyon reticulatum in 10 ml of artificial pond water (1mM potassium chloride KCl). 1 mM sodium chloride NaCl and 0.1 mM calcium chloride (pH = 9.5-10) and the second part 4 contains artificial pond water with pHe5.8.

Both electrodes 2 (positive and negative) are made of pH-selective elements - antimony. The membrane separating the acid and alkaline media is cellulose (Cuprofan).

Figure 2 is a schematic representation of an acid-base biobattery according to the invention similar to Figure 1 except that a solid barrier 7 with a built-in pH-tellurium element 6 is used instead of the membrane 5 to separate both solutions. The current is discharged by the Argentine chloride electrodes 2, which can be easily regenerated by intermittent position change.

The electromotive force of the cells was in both cases from 150 to 180 mV, the current at the maximum power (external resistance close to the internal) was 4.5 to 5.5 * 10 "A.cm" electrode surface, the maximum -7 - 2 the electrode surface was 1.10 W.cm.

A suitable arrangement for constant current collection would be the cultivation of Hydrodictyon reticulatum algae in the flowing artificial pond water, so as to ensure a constant performance under load. This type of acid-base biobattery according to the invention is shown schematically in FIG. 3. the cell is similar to that of FIG. 1 except that the alkalized solution of the illuminated Hydrodictyon reticulatum algae suspension is in another glass container 8,

4 240 940 before the pH-selective electrode 2 is placed. The connection between the container 8 and the electrode part 3 is made by means of a closed tube 9. Also the part 3 is closed by a wolf 10 to prevent contact of the alkalized solution with air carbon dioxide; thus the pH of this solution did not drop.

A prerequisite for practical use is to increase both the voltage and current of the proposed bio-battery. The voltage can be increased by series arrangement of individual biological cells. An increase in power presupposes such a reduction in internal resistance. When replacing pond water with an acid buffer (a solution of 50 ml of 0.2 M potassium chloride KCl and 10.6 ml of 0.2 M hydrochloric acid supplemented to 200 ml of total volume) the resistance decreases significantly and the cell performance is then comparable with the performance of current redox type or non-biological solar cells.

Claims (2)

SUBJECT OF THE INVENTION Acid-base biobattery utilizing aquatic plants comprising a glass vessel divided by a septum into two portions with a positive and a negative electrode and different types of electrolytes, characterized in that the electrolyte in one part (3) of the vessel (1) forms an illuminated suspension of aquatic plants, preferably algae which basify their environment and in the second part (4) of the container (1) is pond water or acid buffer and the electrodes (2) are of a pH sensitive material, preferably antimony, tellurium, lead-tin alloy coated with an oxide layer wherein the baffle (5) is a cellulosic membrane, or the electrodes (2) are argentchloride or carbon, the baffle (5) being a pH sensitive material, preferably antimony, tellurium, or a lead-crime alloy coated with a manganese dioxide layer. 2. Acid-base biobaterial according to claim 1, characterized in that the aquatic plant is green freshwater algae Hydrodictyon reticulatum.