Imre Czinkota

Adsorption of propisochlor on soils and soil components equation for multi-step isotherms

Static equilibrium measurements were performed for the study of propisochlor on three different kinds of soils at pH = 7.0 at 25 degrees C. The concentration of herbicide was changed from 30 to 300 mumol/l. The obtained two-step adsorption isotherms cannot be evaluated by using the Freundlich or Langmuir equations. New equation has been derived by making use of the usual mass balance and equilibrium relationships of the adsorption and by considering the possibility of the formation of associates of the hydrophobic solute molecules. The characteristic model parameters of each step of the adsorption isotherm were estimated for the studied systems by a non-linear least square regression. The calculated curves fit well to the experimentally obtained two-step isotherms and the parameters of the model can be used for the characterization of the pesticide-soil interactions and consequently the mobility of the propisochlor in soil/water systems.

New geothermal well-completion and rework technology by laser

Our research team has developed a new well completion and rework technology involving lasers. The system is made up of a high-power laser generator and a custom-designed directional laser drilling head. The laser head is attached to a coiled tubing unit to maximize production and to carry out special downhole tasks. In this phase of the development effort, laser technology is particularly well suited to cost-efficiently drill short laterals from existing wells in a single work phase, drilling through the casing and cement as well as the formation. The technology, which is an extended perforation solution, enables a more intensive interaction with the downhole environment and supports cutting edge subsurface engineering scenarios such as barite removal. Laser-induced heat treatment appears to be a suitable alternative to effectively remove the almost immovable deposits and scales from thermal water-well pipes.

Pesticide-Soil Interaction

Modern pesticides have to fulfill two requirements: they have to control weeds, pests, diseases, etc. while not to load the environment. These agents should put out their plant protective effect before their degradation. It results in an apparent contradiction because the stable chemicals are able to become environmental contaminants concentrated mostly in the soil. The retention of the pesticides in the soil is important otherwise they can reach the groundwater by leaching. It means that the vertical mobility of these compounds is strongly correlated with their adsorption behavior. If we want to predict the leachability of a pesticide the first step is the investigation of its chemical stability under the given conditions (soil type, pH etc). It is followed by the second step being the study of its adsorption on the soil.

Titrálásos módszer talajok redox pufferkapacitásának meghatározására

A talajok redox pufferkepessegenek meresere kidolgoztunk egy olyan titralasos modszert, mellyel a szakirodalomban szereplő redox vizsgalati modszerek hatranyai kikuszobolhetők. A meres soran nem az aktualis redoxpotencialt merjuk, hanem oxidalo vagy redukalo szeres titralassal folyamatosan valtoztatjuk a minta oxidacios allapotat, ezzel gyakorlatilag kikuszoboljuk a mintavetel es a mintatarolas jelentős redox allapotot befolyasolo hibait. A pH es Eh keresztkolcsonhatas kikuszobolese erdekeben parhuzamosan merjuk a rendszer pH-jat es Eh-jat es a szakirodalombol ismert korrekciokat a kiertekelő szoftver automatikusan elvegzi. A teljesen automatizalt meres soran pufferkapacitas erteknek a rendszer titralasi atcsapasi pontjat, vagyis az inflexios pontot vettuk figyelembe, melyet a derivalt gorbe maximuma alapjan keresett meg a program. A modszert szamos magyarorszagi talajmintan alkalmaztuk, elterő adagolasi időkkel, es az eredmenyekből a redoxtulajdonsagokat okozo folyamatok kinetikajara is kovetkeztethettun...