elena preda - Academia.edu (original) (raw)
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Papers by elena preda
Environmental Science and Pollution Research, 2013
It is well known that adsorption is an efficient method of removal of various pollutants from was... more 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.
Environmental Engineering and Management Journal, 2018
In this study, the concentrations of 15 phenol derivatives were analyzed from the phreatic and gr... more In this study, the concentrations of 15 phenol derivatives were analyzed from the phreatic and groundwater wells surrounding a decommissioned chemical factory in a village from the western part of Romania. An UPLC-MS method was used to assess the concentrations of the chemical target compounds in the water samples. The most frequent compounds were 4-chlorophenol, 4-tertoctylphenol and 4-nonylphenol, being detected in 17 of the 19 sampling sites, while the least frequent compound was 2,4,6trichlorophenol, that was found in only 7 samples. The highest mean concentration was obtained for bisphenol A (47.54 ngꞏmL-1), while 2,4-dinitrophenol was found with the lowest mean concentration (9.38 ngꞏmL-1). The most contaminated water samples were found in the monitoring wells placed downstream of the factory. With the exception of the samples taken from the municipal drinking water system, the samples from phreatic water wells contained the target phenol derivatives, at various concentrations. Although the platform has ceased completely, the hazard caused by decades of continuous phenolic pollutant leakage is still significant to the present day.
Environmental Science and Pollution Research, 2013
It is well known that adsorption is an efficient method of removal of various pollutants from was... more 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.
Environmental Engineering and Management Journal, 2018
In this study, the concentrations of 15 phenol derivatives were analyzed from the phreatic and gr... more In this study, the concentrations of 15 phenol derivatives were analyzed from the phreatic and groundwater wells surrounding a decommissioned chemical factory in a village from the western part of Romania. An UPLC-MS method was used to assess the concentrations of the chemical target compounds in the water samples. The most frequent compounds were 4-chlorophenol, 4-tertoctylphenol and 4-nonylphenol, being detected in 17 of the 19 sampling sites, while the least frequent compound was 2,4,6trichlorophenol, that was found in only 7 samples. The highest mean concentration was obtained for bisphenol A (47.54 ngꞏmL-1), while 2,4-dinitrophenol was found with the lowest mean concentration (9.38 ngꞏmL-1). The most contaminated water samples were found in the monitoring wells placed downstream of the factory. With the exception of the samples taken from the municipal drinking water system, the samples from phreatic water wells contained the target phenol derivatives, at various concentrations. Although the platform has ceased completely, the hazard caused by decades of continuous phenolic pollutant leakage is still significant to the present day.