P.L de Bruyn

Bio: P.L de Bruyn is an academic researcher from Utrecht University. The author has contributed to research in topics: Precipitation (chemistry) & Supersaturation. The author has an hindex of 25, co-authored 43 publications receiving 2891 citations.

Hydrolysis-precipitation studies of aluminum (III) solutions. 2. A kinetic study and model

Abstract: The hydrolysis-precipitation process of Al(OH)3 from acidified aluminum nitrate and chloride solutions was studied with a homogeneous alkali injection technique. In these studies the total Al(III) concentration (CAl) varied from 5 × 10−5 to 0.5 M, the ionic strength from about 10−4 (no added salt) to 2.8 M; and the temperature from 25 to 90°C. Continuous and discontinuous kinetic experiments with both alkali and acid suggest that different processes occur below and above an OH/Al ratio = 2.5 in solutions with cAl3+ > 5 × 10−4 M. At very low concentration the reaction proceeds solely via monomeric species. Light scattering measurements are used to determine the average degree of polymerization, Nz. It is observed that over the range 0 < OH/Al < 2.5 the average degree of polymerization changes in the order 0 < Nz < 15. The reactivity of these polynuclear complexes with acid suggests that the hydroxyl ions form bridges between the Al3+ cations up to an OH/Al ratio of 2.5. A model, which is based upon the structure of the solid, is postulated for the hydrolysis process. This model appears to be in qualitative agreement with experiment.

Study and Interpretation of the Chemical Characteristics of Natural Water

Abstract: The chemical composition of natural water is derived from many different sources of solutes, including gases and aerosols from the atmosphere, weathering and erosion of rocks and soil, solution or precipitation reactions occurring below the land surface, and cultural effects resulting from human activities. Broad interrelationships among these processes and their effects can be discerned by application of principles of chemical thermodynamics. Some of the processes of solution or precipitation of minerals can be closely evaluated by means of principles of chemical equilibrium, including the law of mass action and the Nernst equation. Other processes are irreversible and require consideration of reaction mechanisms and rates. The chemical composition of the crustal rocks of the Earth and the composition of the ocean and the atmosphere are significant in evaluating sources of solutes in natural freshwater. The ways in which solutes are taken up or precipitated and the amounts present in solution are influenced by many environmental factors, especially climate, structure and position of rock strata, and biochemical effects associated with life cycles of plants and animals, both microscopic and macroscopic. Taken together and in application with the further influence of the general circulation of all water in the hydrologic cycle, the chemical principles and environmental factors form a basis for the developing science of natural-water chemistry. Fundamental data used in the determination of water quality are obtained by the chemical analysis of water samples in the laboratory or onsite sensing of chemical properties in the field. Sampling is complicated by changes in the composition of moving water and by the effects of particulate suspended material. Some constituents are unstable and require onsite determination or sample preservation. Most of the constituents determined are reported in gravimetric units, usually milligrams per liter or milliequivalents

Catalytic ozonation and methods of enhancing molecular ozone reactions in water treatment

Abstract: This paper presents a review of catalytic ozonation and methods of enhancing molecular ozone reactions in water treatment. It is also an attempt to propose general ideas about mechanisms governing catalytic ozone reactions. Catalytic ozonation is a new means of contaminants removal from drinking water and wastewater. Its application is mainly limited to laboratory use. However, due to successful results further investigation is to be carried out. The majority of models proposed represent more of a speculative approach to the problem than a hypothesis based on experimental data. It is therefore useful to provide a summary of the accomplishments concerning catalytic ozonation and methods of enhancing molecular ozone reactions that were published so far. A survey of the application of several homo- and heterogeneous catalysts, their activity and the parameters influencing the efficiency of catalytic systems is presented here as a short overview, the aim of which is to raise awareness of possible new approaches to water purification.