Phenol removal from wastewater by adsorption on zeolitic composite.

It is well known that adsorption is an efficient method of removal of various pollutants from wastewater. The present study examines the phenol removal from water by adsorption on a new material, based on zeolitic volcanic tuff. This compound contains zeolitic tuff and cellulose, another known adsorbent, in a mass ratio of 4 to 1. The performances of the new adsorbent composite were compared with those of a widely used adsorbent material, zeolitic volcanic tuff. The adsorbent properties were tested on batch synthetic solutions containing 1-10 mg L(-1) (1-10 ppm) phenol, at room temperature without pH adjustment. The influence of the adsorbent dose, pH and contact time on the removal degree of phenol from water was investigated. The experimental data were modeled using the Langmuir, Freundlich, and Temkin adsorption isotherms. The Langmuir model was found to best represent our data revealing a monolayer adsorption with a maximum adsorption capacity between 0.12 and 0.53 mg g(-1) at 25 °C, for 2.00 g of adsorbent, depending on the initial phenol concentration. The adsorption kinetic study was performed using a pseudo-first- and pseudo-second-order kinetic models illustrating that phenol adsorption on zeolite composite is well described by pseudo-first kinetic equations. Our results indicated that phenol adsorption on the new adsorbent composite is superior to that on the classic zeolite.

Status of the Southern Carpathian forests in the long-term ecological research network.

Air pollution, bulk precipitation, throughfall, soil condition, foliar nutrients, as well as forest health and growth were studied in 2006-2009 in a long-term ecological research (LTER) network in the Bucegi Mountains, Romania. Ozone (O(3)) was high indicating a potential for phytotoxicity. Ammonia (NH(3)) concentrations rose to levels that could contribute to deposition of nutritional nitrogen (N) and could affect biodiversity changes. Higher that 50% contribution of acidic rain (pH < 5.5) contributed to increased acidity of forest soils. Foliar N concentrations for Norway spruce (Picea abies), Silver fir (Abies alba), Scots pine (Pinus sylvestris), and European beech (Fagus sylvatica) were normal, phosphorus (P) was high, while those of potassium (K), magnesium (Mg), and especially of manganese (Mn) were significantly below the typical European or Carpathian region levels. The observed nutritional imbalance could have negative effects on forest trees. Health of forests was moderately affected, with damaged trees (crown defoliation >25%) higher than 30%. The observed crown damage was accompanied by the annual volume losses for the entire research forest area up to 25.4%. High diversity and evenness specific to the stand type's structures and local climate conditions were observed within the herbaceous layer, indicating that biodiversity of the vascular plant communities was not compromised.

Sensitizers on inorganic carriers for decomposition of the chemical warfare agent yperite.

Sulfur-containing compounds, such as mercaptans, alkali sulfides, alkali sulfites, and alkali thiosulfates, are byproducts of industrial processes and pollutants of waste and natural waters. Other sulfur-containing compounds such as yperite are dangerous chemical weapons. Efficient photocatalytic decomposition of these molecules is a process that can find applications in emergency situations or for the controlled destruction of chemical warfare stockpiles. A series of heterogeneous photocatalysts consisting of a metal phthalocyanine or 2,4,6-triphenylpyrylium as photoactive components encapsulated inside the cavities of zeolite Y or the mesoporous channels of MCM-41 or supported on silica or titania-silica was tested for the photocatalytic decomposition of yperite. Two types of photoreactors, either an open reactor naturally aerated or a closed quartz tube with a constant airflow using UV or visible ambient light were used. These tests demonstrated that iron and manganese phthalocyanine and 2,4,6-triphenylpyrylium embedded in NaY or titania-silica can be suitable solid photocatalysts for the degradation of yperite using UV and visible irradiation.