Ion Udrea

Evaluation of a novel hybrid inorganic/organic polymer type material in the arsenic removal process from drinking water.

The objective of this paper is the evaluation of a hybrid inorganic/organic polymer type material based on hydrated ferric oxide (HFO), in the adsorption process of arsenic oxyanions from contaminated waters used as drinking water. The study includes rapid small-scale column tests conducted in continuous flow operation in order to assess the arsenic removal capacity in various conditions. Thus it was evaluated the influence of some competing ions like silicate and phosphate on As(V) adsorption and the influence of feed water pH in the removal process of As(V) and As(III) species. Based on the As/pH variation in time at different feed water pH (5, 7 and 9), a possible sorption mechanism that fits the experimental data was suggested. The regeneration and re-use of the hybrid adsorbent was studied in the presence and in the absence of the contaminant ions. The novel hybrid material is very selective towards arsenic oxyanions even though the presence of silica and phosphate reduces the adsorption capacity.

Ozonation of substituted phenols in aqueous solutions over CuO-Al2O3 catalyst

The oxidation of aqueous solutions of substituted phenols, chlorophenols (CPs) and nitrophenols (NPs), at 21±0.5°C and atmospheric pressure, by ozone over a copper–alumina catalyst system was studied. The total disappearance of phenol compounds for 15 to 30 minute reaction times was observed. The presence of the catalyst increased the reaction rate, diminished the ozone consumption and caused an advanced degradation of phenols. A number of six by-products was identified by gas chromatography/mass spectrometry technique (GC/MS), with or without silylation. Based on the experimental data several mechanistic suggestions for the catalytic ozonation are made.

Pollution by Nutrients in the Danube Basin

The assessment of pollution by nutrients in the Danube River has a long-term history at the basin-wide level, especially for estimating the influx of these substances to the Black Sea. The main aim of this chapter is to provide a general overview of the nutrient levels in the Danube Basin based on the data collected in the frame of long-term Trans-National Monitoring Network (TNMN) of the International Commission for the Protection of the Danube River (ICPDR) during 2001–2009. For selected monitoring sections, the dependence of the nutrient concentrations on corresponding daily discharges is also investigated. A comparative view of the surveillance TNMN data and investigative data obtained during the two monitoring programs known as Joint Danube Surveys 1 and 2 (JDS1 and JDS2) is presented. In order to get a general overview of the nutrient levels over the studied period, the temporal trends were analyzed using nonparametric Spearman correlation coefficient before and after removing the impact of the daily discharge on the measured concentration.