Numerical Modeling of Kinetics of Heavy Metal Sorption From Polluted Water

Abstract

Water protection is one of the most important priorities of environmental protection. It is necessary to reduce pollution of wastewater in order to reduce pollution of drinking-water and water pools. One of the most dangerous wastewater pollutants are heavy metals (HM). They have a negative influence on people and aquatic water systems. The paper analyses possibilities of the sorption method application for heavy metal elimination from wastewater. Experimental investigation of HM sorption from water and numerical modeling usage possibilities for prognosis of the HM sorption kinetic process was carried out as well as experimental study of HM elimination efficiency dependence on sorption time of HM from wastewater, when using sorbents. Two pseudo kinetic models, i e the pseudo first-and second-order models, were developed on the basis of experimental investigation. These models were applied in numerical modeling in the computer program PHOENICS. The results of the computer program PHOENICS and those of experimental investigation describing HM sorption from water were compared. After comparing the two pseudo models, it is determined that the pseudo second-order model suits better for HM sorption.

Evaluation of the autochthonous free-floating macrophyte Salvinia biloba Raddi for use in the phytoremediation of water contaminated with lead

“…Pseudo-second order kinetics model has been extensively used to describe the sorption of divalent metal ions onto highly heterogeneous surfaces [26]. Most adsorption systems follow this model in which chemisorption took place during the adsorption process [27].…”

Investigation of kinetics of Cr(VI)–fired brick clay interaction

“…When pollutants such as pigments, dyes, metal ions, acids and bases are released to natural waters, the aquatic ecological system breaks down as a result of decreased dissolved oxygen levels and increased amounts of toxic substances. One of the most hazardous water pollutants are the group of heavy metals, such as Pb, Cd, Cr, Sn and Cu [1][2][3]. Among many studies, much attention has been paid on water pollution due to chromium species as they are heavily used in the industrial sector.…”

ESTUDIO DE LA BIOSORCIÓN DE Cd (II) Y Pb (II) USANDO COMO ADSORBENTE Nostoc sphaericum Vaucher

“…La isoterma de Freundlich tuvo un valor n de 0,297; se dice que, cuando las isotermas son cóncavas hacia el eje de las abscisas, n < 1 la isoterma de Freundlich es favorable 11 ; así mismo, la constante de afinidad (K) fue de La tabla 2 muestra que, la cinética de biosorción de Cd (II) sigue un modelo matemático de pseudo segundo orden, ya que resultó significativo (p<0,05) y tuvo un alto R 2 . Este modelo ha sido reportado como dominante en los procesos de adsorción de metales, obteniendo buen ajuste (R 2 = 99%) para Cd (II) utilizando resinas 12 . La reacción de segundo orden indica que entran dos reactantes para dar un producto 13 , lo que probablemente ocurre con el Nostoc como adsorbente y el Cd (II) como adsorbato, que se unen para dar un producto en donde la superficie del Nostoc contendría Cd (II) biosorbido.…”

“…Se observa que, en el análisis de varianza ningún modelo de isoterma se ajusta a los datos de Cd (II) (p>0,05). Se evaluaron el modelo de Elovich, que es utilizado para describir la cinética de adsorción de sistemas inorgánicos como es el caso del Cd (II), y el modelo de pseudo segundo orden, que representa la quimiosorción o adsorción química debido a la formación de enlaces químicos (interacciones fuertes) entre el adsorbente y el adsorbato en una monocapa en la superficie12 . En la figura 3, la ecuación de Elovich tuvo un R 2 de 70,91%; los resultados de la pendiente y la intersección con la ordenada se utilizaron para determinar los valores de las Análisis de varianza de modelos de isotermas de biosorción de Cd (II).…”