THE EFFECTS OF TANNIC ACID ON THE EFFECTIVENESS OF EGG FERTILIZATION AND REMOVING CARP EGG ADHESIVENESS

Egg adhesiveness is one of the major problems in carp artificial breeding. The appropriate elimination of egg adhesiveness impacts the effectiveness of the breeding. This article discusses two used methods of carp egg adhesiveness removal: tannic acid+water and milk+water+salt solutions. Milk, water and salt solution was based on the following proportions: 1 litre of milk + 7 litres of water +50g of NaCl. Adhesiveness is removed from fertilized eggs in bowls by mixing them with geese feathers for no shorter than 60 minutes. The tannic acid solution was prepared by mixing 7 grams of tannic acid powder with 5 litres of water. 1 litre of solution is immediately poured into a bowl with fertilized eggs. Adhesiveness is removed from fertilized eggs in bowls by intensively mixing them for 10 minutes. After fertilization and removal of adhesiveness, the eggs were transferred into Weiss jars. The results showed that during the process of incubation, 3.7 million eggs were fertilized; out of them 1.6 million were rid of adhesiveness by milk solution, 2.1 – by tannic solution. It is plausible that unfavourable environmental conditions influenced the low egg vitality. 750 000 (47%) carp larvae hatched from milk solution treated eggs, while 800 000 (38%) of larvae hatched from the eggs treated with tannic solution.

Effects of UV Radiation and pH of Tannic Acid Solution in the Synthesis of Silver Nanoparticles

The reductions of silver nitrate by tannic acid at various pH with and without UV radiation at room temperature were done in order to study the effects of UV radiation and pH of tannic acid solution in the synthesis of silver nanoparticles. The results from UV-Visible spectroscopy, dynamic light scattering method and transmission electron microscopy indicated that using UV radiation resulted in silver nanoparticles with smaller particles and narrower size distribution at every pH. The results also revealed that smallest particles without agglomeration were obtained when alkali condition was applied. Therefore, the suitable condition for synthesizing silver nanoparticles in this research was to use UV radiation and tannic acid solution having pH of 8.0.

Degradation of Tannic Acid Using TiO2 Nanotubes as Electrocatalyst

Structured TiO2 nanotubes were grown on 2 mm thick titanium sheet by anodization of titanium in ethylene glycol medium containing 0.025 M NaF. The morphology of TiO2 nanotubes (TNT) was characterized using field emission scanning electron microscope. The potential of TNT as anode and also as photocatalyst for the degradation of tannic acid was studied. The mineralization of tannic acid was measured in terms Total Organic Carbon (TOC). Only 50% of TOC could be removed by exposing the tannic acid solution to UV-radiation (photolysis), whereas it was improved to 70% by electrooxidation (EO) using TNT as anode. Maximum degradation of 83% was achieved when electrooxidation was conducted under the influence of UV-radiation (photoelectrocatalytic process (PEC)). Among the electrolytes tried, Na2SO4 was observed to be very effective for the degradation of tannic acid. The kinetics of tannic acid degradation by photoelectrocatalytic process was found to follow zero-order rate expression.

Phosphorus and organic matter removal from synthetic wastewater using alum and aluminum hydroxide

At present, chemical processes are widely used to remove phosphorus and organic matter from water or wastewater either as the only advanced treatment method or as a pre-treatment stage to biological treatment, and aluminium salts have been traditionally used as coagulants. In the present study removal of orthophosphate or dissolved organic matter with the use of two aluminium sources: alum [Al2(SO4)3•18H2O] and aluminium hydroxide [Al(OH)3(s)] is examined for the wastewater treatment process. Amorphous aluminium hydroxide was chosen because it is the hydrolyzed (olated) product of alum and an important adsorbent of inorganic and organic substances in soils since bayerite, gibbsite and boehmite contain a large portion of aluminium hydroxides. Laboratory jar test studies were carried out using either an orthophosphate solution (10 mg l-1) or a tannic acid solution (50 mgC l-1) as simulated wastewater and the effect of parameters such as coagulant dose (up to 15 mg Al l-1 in the case of alum and up to 90 mg Al l-1 in the case of Al(OH)3) and pH (2-12) is investigated. The values of these parameters were based upon measurements on municipal wastewaters from the input of the primary treatment of a wastewater plant in Athens. Orthophosphates have been chosen as a P surrogate as they are the major portion of the total P found in wastewater and tannic acid solution was used as a surrogate for soluble organic matter. It was proven that alum is much more efficient in phosphorus and tannic acid removal than aluminium hydroxide. The optimal pH values are 5-6 in both cases, alum and aluminium hydroxide, although alum is efficient in a wider pH range (4-7) and a mechanism was proposed to interpret these results. In pH values less than 6 the mechanism proposed was chemical bonding between Al species and tannic acid or phosphates creating insoluble complexes while in bigger pH values (6-8) adsorption on solid Al(OH)3. Freundlich isotherm was proven to fit satisfactorily the experimental data for aluminium hydroxide and orthophosphate at 250C suggesting heterogeneous sorption, with KF and N values 49,1 and 0,19 respectively. The findings of this work may not only contribute to a better understanding of the chemistry of chemical wastewater treatment and therefore to an improvement of the process but also on phosphorus and organics fixation in soils that contain a large portion of aluminium hydroxides.