The Experts below are selected from a list of 441 Experts worldwide ranked by ideXlab platform

Jorge L Gardeatorresdey - One of the best experts on this subject based on the ideXlab platform.

  • potential of agave lechuguilla biomass for cr iii removal from aqueous solutions thermodynamic studies
    Bioresource Technology, 2006
    Co-Authors: J Romerogonzalez, Jose R Peraltavidea, Elena Rodriguez, M Delgado, Jorge L Gardeatorresdey
    Abstract:

    Thermodynamic studies on the Bioadsorption of Cr(III) onto Agave lechuguilla biomass were conduced. The experimental results at different temperatures were modeled using the Langmuir and Freundlich isotherms to obtain the characteristic parameters of each model. Both the Freundlich and Langmuir models were found to represent the Bioadsorption process. The average adsorption capacities calculated from Freundlich (4.7 mg/g) and Langmuir (14.2 mg/g) isotherms showed A. lechuguilla to be an effective biomass in the removal of Cr(III) from an aqueous solution. Thermodynamic parameters (DG 0 , DH 0 and DS 0 ) determined in the temperature range from 10 to 40 C along with the parameters of the Dubinin–Radushkevick equation support the idea that the binding of Cr(III) may be caused by interactions with functional groups such as carboxyl groups located on the outer surface of the cell tissue of the bioadsorbent. 2005 Elsevier Ltd. All rights reserved.

  • determination of thermodynamic parameters of cr vi adsorption from aqueous solution onto agave lechuguilla biomass
    The Journal of Chemical Thermodynamics, 2005
    Co-Authors: J Romerogonzalez, Jose R Peraltavidea, Elena Rodriguez, S L Ramirez, Jorge L Gardeatorresdey
    Abstract:

    The temperature dependence of the Cr(VI) Bioadsorption and its possible reduction to Cr(III) by Agave lechuguilla biomass were studied. The experimental data obtained in batch experiments at different temperatures were fitted to the Langmuir and Freundlich isotherms to obtain the characteristic parameters of each model. The adsorption equilibrium data fitted well with the Freundlich model. The average model parameters calculated from Freundlichs isotherms (adsorption capacity KF =4 AE 10 � 2 mol AE g � 1 and an average adsorption intensity value n = 13.07) showed that A. lechuguilla can be considered as an effective biomaterial for Cr(VI) removal from aqueous solution. Thermodynamic parameters (DG � , DH � , and DS � ) for Cr(VI) adsorption determined in the temper- ature range from (283 to 313) K suggest that a portion of Cr(VI) may be bound to functional groups on the surface of the adsorbent and then reduced to Cr(III). Additionally, the parameters of the Dubinin-Radushkevick equation indicated that the sorption of chromium species onto lechuguilla biomass mainly proceeds through binding surface functional groups. 2004 Elsevier Ltd. All rights reserved.

J Romerogonzalez - One of the best experts on this subject based on the ideXlab platform.

  • potential of agave lechuguilla biomass for cr iii removal from aqueous solutions thermodynamic studies
    Bioresource Technology, 2006
    Co-Authors: J Romerogonzalez, Jose R Peraltavidea, Elena Rodriguez, M Delgado, Jorge L Gardeatorresdey
    Abstract:

    Thermodynamic studies on the Bioadsorption of Cr(III) onto Agave lechuguilla biomass were conduced. The experimental results at different temperatures were modeled using the Langmuir and Freundlich isotherms to obtain the characteristic parameters of each model. Both the Freundlich and Langmuir models were found to represent the Bioadsorption process. The average adsorption capacities calculated from Freundlich (4.7 mg/g) and Langmuir (14.2 mg/g) isotherms showed A. lechuguilla to be an effective biomass in the removal of Cr(III) from an aqueous solution. Thermodynamic parameters (DG 0 , DH 0 and DS 0 ) determined in the temperature range from 10 to 40 C along with the parameters of the Dubinin–Radushkevick equation support the idea that the binding of Cr(III) may be caused by interactions with functional groups such as carboxyl groups located on the outer surface of the cell tissue of the bioadsorbent. 2005 Elsevier Ltd. All rights reserved.

  • determination of thermodynamic parameters of cr vi adsorption from aqueous solution onto agave lechuguilla biomass
    The Journal of Chemical Thermodynamics, 2005
    Co-Authors: J Romerogonzalez, Jose R Peraltavidea, Elena Rodriguez, S L Ramirez, Jorge L Gardeatorresdey
    Abstract:

    The temperature dependence of the Cr(VI) Bioadsorption and its possible reduction to Cr(III) by Agave lechuguilla biomass were studied. The experimental data obtained in batch experiments at different temperatures were fitted to the Langmuir and Freundlich isotherms to obtain the characteristic parameters of each model. The adsorption equilibrium data fitted well with the Freundlich model. The average model parameters calculated from Freundlichs isotherms (adsorption capacity KF =4 AE 10 � 2 mol AE g � 1 and an average adsorption intensity value n = 13.07) showed that A. lechuguilla can be considered as an effective biomaterial for Cr(VI) removal from aqueous solution. Thermodynamic parameters (DG � , DH � , and DS � ) for Cr(VI) adsorption determined in the temper- ature range from (283 to 313) K suggest that a portion of Cr(VI) may be bound to functional groups on the surface of the adsorbent and then reduced to Cr(III). Additionally, the parameters of the Dubinin-Radushkevick equation indicated that the sorption of chromium species onto lechuguilla biomass mainly proceeds through binding surface functional groups. 2004 Elsevier Ltd. All rights reserved.

I Bautistatoledo - One of the best experts on this subject based on the ideXlab platform.

  • adsorption Bioadsorption of phthalic acid an organic micropollutant present in landfill leachates on activated carbons
    Journal of Colloid and Interface Science, 2012
    Co-Authors: J D Mendezdiaz, M Sanchezpolo, J Riverautrilla, Mahmoud Abdel M Daiem, I Bautistatoledo
    Abstract:

    This study investigated the adsorption of phthalic acid (PA) in aqueous phase on two activated carbons with different chemical natures, analyzing the influence of: solution pH, ionic strength, water matrix (ultrapure water, ground water, surface water, and wastewater), the presence of microorganisms in the medium, and the type of regime (static and dynamic). The activated carbons used had a high adsorption capacity (242.9 mg/g and 274.5 mg/g), which is enhanced with their phenolic groups content. The solution pH had a major effect on PA adsorption on activated carbon; this process is favored at acidic pHs. PA adsorption was not affected by the presence of electrolytes (ionic strength) in solution, but was enhanced by the presence of microorganisms (bacteria) due to their adsorption on the carbon, which led up to an increase in the activated carbon surface hydrophobicity. PA removal varies as a function of the water type, increasing in the order: ground waterwastewater. The effectiveness of PA adsorption was lower in dynamic than in static regime due to the shorter adsorbent-adsorbate contact time in dynamic regime.

  • adsorption Bioadsorption of phthalic acid an organic micropollutant present in landfill leachates on activated carbons
    Journal of Colloid and Interface Science, 2012
    Co-Authors: J D Mendezdiaz, M Sanchezpolo, J Riverautrilla, Mahmoud Abdel M Daiem, I Bautistatoledo
    Abstract:

    Abstract This study investigated the adsorption of phthalic acid (PA) in aqueous phase on two activated carbons with different chemical natures, analyzing the influence of: solution pH, ionic strength, water matrix (ultrapure water, ground water, surface water, and wastewater), the presence of microorganisms in the medium, and the type of regime (static and dynamic). The activated carbons used had a high adsorption capacity (242.9 mg/g and 274.5 mg/g), which is enhanced with their phenolic groups content. The solution pH had a major effect on PA adsorption on activated carbon; this process is favored at acidic pHs. PA adsorption was not affected by the presence of electrolytes (ionic strength) in solution, but was enhanced by the presence of microorganisms (bacteria) due to their adsorption on the carbon, which led up to an increase in the activated carbon surface hydrophobicity. PA removal varies as a function of the water type, increasing in the order: ground water

  • removal of nitroimidazole antibiotics from aqueous solution by adsorption Bioadsorption on activated carbon
    Journal of Hazardous Materials, 2009
    Co-Authors: J Riverautrilla, G Pradosjoya, M Sanchezpolo, M A Ferrogarcia, I Bautistatoledo
    Abstract:

    Abstract The objective of the present study was to analyse the behaviour of activated carbon with different chemical and textural properties in nitroimidazole adsorption, also assessing the combined use of microorganisms and activated carbon in the removal of these compounds from waters and the influence of the chemical nature of the solution (pH and ionic strength) on the adsorption process. Results indicate that the adsorption of nitroimidazoles is largely determined by activated carbon chemical properties. Application of the Langmuir equation to the adsorption isotherms showed an elevated adsorption capacity (Xm = 1.04–2.04 mmol/g) for all contaminants studied. Solution pH and electrolyte concentration did not have a major effect on the adsorption of these compounds on activated carbon, confirming that the principal interactions involved in the adsorption of these compounds are non-electrostatic. Nitroimidazoles are not degraded by microorganisms used in the biological stage of a wastewater treatment plant. However, the presence of microorganisms during nitroimidazole adsorption increased their adsorption on the activated carbon, although it weakened interactions between the adsorbate and carbon surface. In dynamic regime, the adsorptive capacity of activated carbon was markedly higher in surface water and groundwater than in urban wastewaters.

J Riverautrilla - One of the best experts on this subject based on the ideXlab platform.

  • removal of the surfactant sodium dodecylbenzenesulfonate from water by processes based on adsorption Bioadsorption and biodegradation
    Journal of Colloid and Interface Science, 2014
    Co-Authors: M I Bautistatoledo, M Sanchezpolo, J Riverautrilla, J D Mendezdiaz, Francisco Carrascomarin
    Abstract:

    Abstract This study analyzed the Bioadsorption/biodegradation kinetics of the surfactant sodium dodecylbenzenesulfonate (SDBS) on commercial activated carbons and on activated carbons prepared in the laboratory by activation of almond shells. The effect of surface oxygen species on these processes was also investigated by using an activated carbon from almond shells oxidized with H2O2 or HNO3. SDBS removal kinetics followed a first-order kinetic model, with rate constants between 1.25 × 10−2 h−1 and 2.14 × 10−2 h−1. The removal rate constants of total organic carbon (TOC) were also determined, obtaining values ranging between 0.51 × 10−2 h−1 and 1.76 × 10−2 h−1. TOC removal rate constants were lower than SDBS removal rate constants, demonstrating that SDBS is also biodegraded during Bioadsorption. Both the inorganic carbon concentration and the colony forming units confirm this biodegradation. The amount of SDBS removed from water varies between 109.0 and 232.3 mg SDBS/g of carbon. When SDBS adsorption on activated carbon is conducted in the presence of bacteria, which is the real situation in water treatment plants, a fraction of bacteria are adsorbed on the surface of activated carbon. A part of the SDBS is removed by adsorption (Bioadsorption) and other part by biodegradation.

  • tetracycline removal from water by adsorption Bioadsorption on activated carbons and sludge derived adsorbents
    Journal of Environmental Management, 2013
    Co-Authors: J Riverautrilla, M Sanchezpolo, C V Gomezpacheco, J J Lopezpenalver, R Ocampoperez
    Abstract:

    The objective of this study was to analyze the behavior of activated carbons with different chemical and textural natures in the adsorption of three tetracyclines (TCs) (tetracycline, oxytetracycline, and chlortetracycline). We also assessed the influence of the solution pH and ionic strength on the adsorption of these compounds and studied their removal by the combined use of microorganisms and activated carbon (Bioadsorption). Sludge-derived materials were also used to remove TC from water. The capacity of these materials to adsorb TC was very high and was much greater than that of commercial activated carbon. This elevated adsorption capacity (512.1–672.0 mg/g) is explained by the high tendency of TC to form complex ions with some of the metal ions present in these materials. The medium pH and presence of electrolytes considerably affected TCs adsorption on commercial activated carbon. These results indicate that electrostatic adsorbent–adsorbate interactions play an important role in TC adsorption processes when conducted at pH values that produce TC deprotonation. The presence of bacteria during the TCs adsorption process decreases their adsorption/Bioadsorption on the commercial activated carbon, weakening interactions between the adsorbate and the microfilm formed on the carbon surface. The adsorptive capacity was considerably lower in dynamic versus static regime, attributable to problems of TC diffusion into carbon pores and the shorter contact time between adsorbate and adsorbent.

  • pharmaceuticals as emerging contaminants and their removal from water a review
    Chemosphere, 2013
    Co-Authors: J Riverautrilla, G Pradosjoya, M Sanchezpolo, M A Ferrogarcia, Raul Ocampoperez
    Abstract:

    The main objective of this study was to conduct an exhaustive review of the literature on the presence of pharmaceutical-derived compounds in water and on their removal. The most representative pharmaceutical families found in water were described and related water pollution issues were analyzed. The performances of different water treatment systems in the removal of pharmaceuticals were also summarized. The water treatment technologies were those based on conventional systems (chlorine, chlorine dioxide, wastewater treatment plants), adsorption/Bioadsorption on activated carbon (from lotus stalks, olive-waste cake, coal, wood, plastic waste, cork powder waste, peach stones, coconut shell, rice husk), and advanced oxidation processes by means of ozonation (O3, O3/H2O2, O3/activated carbon, O3/biological treatment), photooxidation (UV, UV/H2O2, UV/K2S2O8, UV/TiO2, UV/H2O2/TiO2, UV/TiO2/activated carbon, photo-Fenton), radiolysis (e-Beam, 60Co, 137Cs. Additives used: H2O2, SO32-, HCO3-, CH3OH, CO32-, or NO3-), and electrochemical processes (Electrooxidation without and with active chlorine generation). The effect of these treatments on pharmaceutical compounds and the advantages and disadvantages of different methodologies used were described. The most important parameters of the above water treatment systems (experimental conditions, removal yield, pharmaceutical compound mineralization, TOC removal, toxicity evolution) were indicated. The key publications on pharmaceutical removal from water were summarized.

  • adsorption Bioadsorption of phthalic acid an organic micropollutant present in landfill leachates on activated carbons
    Journal of Colloid and Interface Science, 2012
    Co-Authors: J D Mendezdiaz, M Sanchezpolo, J Riverautrilla, Mahmoud Abdel M Daiem, I Bautistatoledo
    Abstract:

    Abstract This study investigated the adsorption of phthalic acid (PA) in aqueous phase on two activated carbons with different chemical natures, analyzing the influence of: solution pH, ionic strength, water matrix (ultrapure water, ground water, surface water, and wastewater), the presence of microorganisms in the medium, and the type of regime (static and dynamic). The activated carbons used had a high adsorption capacity (242.9 mg/g and 274.5 mg/g), which is enhanced with their phenolic groups content. The solution pH had a major effect on PA adsorption on activated carbon; this process is favored at acidic pHs. PA adsorption was not affected by the presence of electrolytes (ionic strength) in solution, but was enhanced by the presence of microorganisms (bacteria) due to their adsorption on the carbon, which led up to an increase in the activated carbon surface hydrophobicity. PA removal varies as a function of the water type, increasing in the order: ground water

  • adsorption Bioadsorption of phthalic acid an organic micropollutant present in landfill leachates on activated carbons
    Journal of Colloid and Interface Science, 2012
    Co-Authors: J D Mendezdiaz, M Sanchezpolo, J Riverautrilla, Mahmoud Abdel M Daiem, I Bautistatoledo
    Abstract:

    This study investigated the adsorption of phthalic acid (PA) in aqueous phase on two activated carbons with different chemical natures, analyzing the influence of: solution pH, ionic strength, water matrix (ultrapure water, ground water, surface water, and wastewater), the presence of microorganisms in the medium, and the type of regime (static and dynamic). The activated carbons used had a high adsorption capacity (242.9 mg/g and 274.5 mg/g), which is enhanced with their phenolic groups content. The solution pH had a major effect on PA adsorption on activated carbon; this process is favored at acidic pHs. PA adsorption was not affected by the presence of electrolytes (ionic strength) in solution, but was enhanced by the presence of microorganisms (bacteria) due to their adsorption on the carbon, which led up to an increase in the activated carbon surface hydrophobicity. PA removal varies as a function of the water type, increasing in the order: ground waterwastewater. The effectiveness of PA adsorption was lower in dynamic than in static regime due to the shorter adsorbent-adsorbate contact time in dynamic regime.

M Sanchezpolo - One of the best experts on this subject based on the ideXlab platform.

  • removal of the surfactant sodium dodecylbenzenesulfonate from water by processes based on adsorption Bioadsorption and biodegradation
    Journal of Colloid and Interface Science, 2014
    Co-Authors: M I Bautistatoledo, M Sanchezpolo, J Riverautrilla, J D Mendezdiaz, Francisco Carrascomarin
    Abstract:

    Abstract This study analyzed the Bioadsorption/biodegradation kinetics of the surfactant sodium dodecylbenzenesulfonate (SDBS) on commercial activated carbons and on activated carbons prepared in the laboratory by activation of almond shells. The effect of surface oxygen species on these processes was also investigated by using an activated carbon from almond shells oxidized with H2O2 or HNO3. SDBS removal kinetics followed a first-order kinetic model, with rate constants between 1.25 × 10−2 h−1 and 2.14 × 10−2 h−1. The removal rate constants of total organic carbon (TOC) were also determined, obtaining values ranging between 0.51 × 10−2 h−1 and 1.76 × 10−2 h−1. TOC removal rate constants were lower than SDBS removal rate constants, demonstrating that SDBS is also biodegraded during Bioadsorption. Both the inorganic carbon concentration and the colony forming units confirm this biodegradation. The amount of SDBS removed from water varies between 109.0 and 232.3 mg SDBS/g of carbon. When SDBS adsorption on activated carbon is conducted in the presence of bacteria, which is the real situation in water treatment plants, a fraction of bacteria are adsorbed on the surface of activated carbon. A part of the SDBS is removed by adsorption (Bioadsorption) and other part by biodegradation.

  • tetracycline removal from water by adsorption Bioadsorption on activated carbons and sludge derived adsorbents
    Journal of Environmental Management, 2013
    Co-Authors: J Riverautrilla, M Sanchezpolo, C V Gomezpacheco, J J Lopezpenalver, R Ocampoperez
    Abstract:

    The objective of this study was to analyze the behavior of activated carbons with different chemical and textural natures in the adsorption of three tetracyclines (TCs) (tetracycline, oxytetracycline, and chlortetracycline). We also assessed the influence of the solution pH and ionic strength on the adsorption of these compounds and studied their removal by the combined use of microorganisms and activated carbon (Bioadsorption). Sludge-derived materials were also used to remove TC from water. The capacity of these materials to adsorb TC was very high and was much greater than that of commercial activated carbon. This elevated adsorption capacity (512.1–672.0 mg/g) is explained by the high tendency of TC to form complex ions with some of the metal ions present in these materials. The medium pH and presence of electrolytes considerably affected TCs adsorption on commercial activated carbon. These results indicate that electrostatic adsorbent–adsorbate interactions play an important role in TC adsorption processes when conducted at pH values that produce TC deprotonation. The presence of bacteria during the TCs adsorption process decreases their adsorption/Bioadsorption on the commercial activated carbon, weakening interactions between the adsorbate and the microfilm formed on the carbon surface. The adsorptive capacity was considerably lower in dynamic versus static regime, attributable to problems of TC diffusion into carbon pores and the shorter contact time between adsorbate and adsorbent.

  • pharmaceuticals as emerging contaminants and their removal from water a review
    Chemosphere, 2013
    Co-Authors: J Riverautrilla, G Pradosjoya, M Sanchezpolo, M A Ferrogarcia, Raul Ocampoperez
    Abstract:

    The main objective of this study was to conduct an exhaustive review of the literature on the presence of pharmaceutical-derived compounds in water and on their removal. The most representative pharmaceutical families found in water were described and related water pollution issues were analyzed. The performances of different water treatment systems in the removal of pharmaceuticals were also summarized. The water treatment technologies were those based on conventional systems (chlorine, chlorine dioxide, wastewater treatment plants), adsorption/Bioadsorption on activated carbon (from lotus stalks, olive-waste cake, coal, wood, plastic waste, cork powder waste, peach stones, coconut shell, rice husk), and advanced oxidation processes by means of ozonation (O3, O3/H2O2, O3/activated carbon, O3/biological treatment), photooxidation (UV, UV/H2O2, UV/K2S2O8, UV/TiO2, UV/H2O2/TiO2, UV/TiO2/activated carbon, photo-Fenton), radiolysis (e-Beam, 60Co, 137Cs. Additives used: H2O2, SO32-, HCO3-, CH3OH, CO32-, or NO3-), and electrochemical processes (Electrooxidation without and with active chlorine generation). The effect of these treatments on pharmaceutical compounds and the advantages and disadvantages of different methodologies used were described. The most important parameters of the above water treatment systems (experimental conditions, removal yield, pharmaceutical compound mineralization, TOC removal, toxicity evolution) were indicated. The key publications on pharmaceutical removal from water were summarized.

  • adsorption Bioadsorption of phthalic acid an organic micropollutant present in landfill leachates on activated carbons
    Journal of Colloid and Interface Science, 2012
    Co-Authors: J D Mendezdiaz, M Sanchezpolo, J Riverautrilla, Mahmoud Abdel M Daiem, I Bautistatoledo
    Abstract:

    Abstract This study investigated the adsorption of phthalic acid (PA) in aqueous phase on two activated carbons with different chemical natures, analyzing the influence of: solution pH, ionic strength, water matrix (ultrapure water, ground water, surface water, and wastewater), the presence of microorganisms in the medium, and the type of regime (static and dynamic). The activated carbons used had a high adsorption capacity (242.9 mg/g and 274.5 mg/g), which is enhanced with their phenolic groups content. The solution pH had a major effect on PA adsorption on activated carbon; this process is favored at acidic pHs. PA adsorption was not affected by the presence of electrolytes (ionic strength) in solution, but was enhanced by the presence of microorganisms (bacteria) due to their adsorption on the carbon, which led up to an increase in the activated carbon surface hydrophobicity. PA removal varies as a function of the water type, increasing in the order: ground water

  • adsorption Bioadsorption of phthalic acid an organic micropollutant present in landfill leachates on activated carbons
    Journal of Colloid and Interface Science, 2012
    Co-Authors: J D Mendezdiaz, M Sanchezpolo, J Riverautrilla, Mahmoud Abdel M Daiem, I Bautistatoledo
    Abstract:

    This study investigated the adsorption of phthalic acid (PA) in aqueous phase on two activated carbons with different chemical natures, analyzing the influence of: solution pH, ionic strength, water matrix (ultrapure water, ground water, surface water, and wastewater), the presence of microorganisms in the medium, and the type of regime (static and dynamic). The activated carbons used had a high adsorption capacity (242.9 mg/g and 274.5 mg/g), which is enhanced with their phenolic groups content. The solution pH had a major effect on PA adsorption on activated carbon; this process is favored at acidic pHs. PA adsorption was not affected by the presence of electrolytes (ionic strength) in solution, but was enhanced by the presence of microorganisms (bacteria) due to their adsorption on the carbon, which led up to an increase in the activated carbon surface hydrophobicity. PA removal varies as a function of the water type, increasing in the order: ground waterwastewater. The effectiveness of PA adsorption was lower in dynamic than in static regime due to the shorter adsorbent-adsorbate contact time in dynamic regime.