Mahmoud Mohamed Abdel daiem

Publications (4) See all

• Article: Modeling adsorption rate of organic micropollutants present in landfill leachates onto granular activated carbon.

  Raúl Ocampo-Pérez , Mahmoud M Abdel daiem , José Rivera-Utrilla , José D Méndez-Díaz , Manuel Sánchez-Polo

  [show abstract] [hide abstract]
  ABSTRACT: The overall adsorption rate of single micropollutants present in landfill leachates such as phthalic acid (PA), bisphenol A (BPA), diphenolic acid (DPA), 2,4-dichlorophenoxy-acetic acid (2,4-D), and 4-chloro-2-methylphenoxyacetic acid (MCPA) on two commercial activated carbons was studied. The experimental data obtained were interpreted by using a diffusional model (PVSDM) that considers external mass transport, intraparticle diffusion, and adsorption on an active site. Furthermore, the concentration decay data were interpreted by using kinetics models. Results revealed that PVSDM model satisfactorily fitted the experimental data of adsorption rate on activated carbon. The tortuosity factor of the activated carbons used ranged from 2 to 4. The contribution of pore volume diffusion represented more than 92% of intraparticle diffusion confirming that pore volume diffusion is the controlling mechanism of the overall rate of adsorption and surface diffusion can be neglected. The experimental data were satisfactorily fitted the kinetic models. The second-order kinetic model was better fitted the experimental adsorption data than the first-order model.

  Journal of Colloid and Interface Science07/2012; 385(1):174-82. · 3.07 Impact Factor
• Article: Environmental impact of phthalic acid esters and their removal from water and sediments by different technologies--a review.

  Mahmoud M Abdel daiem , José Rivera-Utrilla , Raúl Ocampo-Pérez , José D Méndez-Díaz , Manuel Sánchez-Polo

  [show abstract] [hide abstract]
  ABSTRACT: This article describes the most recent methods developed to remove phthalic acid esters (PAEs) from water, wastewater, sludge, and soil. In general, PAEs are considered to be endocrine disrupting chemicals (EDCs), whose effects may not appear until long after exposure. There are numerous methods for removing PAEs from the environment, including physical, chemical and biological treatments, advanced oxidation processes and combinations of these techniques. This review largely focuses on the treatment of PAEs in aqueous solutions but also reports on their treatment in soil and sludge, as well as their effects on human health and the environment.

  Journal of Environmental Management07/2012; 109:164-78. · 3.24 Impact Factor
• Article: Role of activated carbon in the photocatalytic degradation of 2,4-dichlorophenoxyacetic acid by the UV/TiO 2 /activated carbon system

  J Rivera-Utrilla , M Sánchez-Polo , M M Abdel daiem , R. Ocampo-Pérez

  [show abstract] [hide abstract]
  ABSTRACT: a b s t r a c t The objective of this study was to photocatalytically degrade the pesticide 2,4-dichlorophenoxyacetic acid (2,4-D) by using the integrated UV/TiO 2 /activated carbon system and to study the degradation kinetics and the role of the chemical and textural properties of activated carbon in this process. Results obtained show that the presence of activated carbon during the catalytic photodegradation (UV/TiO 2) of 2,4-D considerably increases its percentage removal. After 60 min of treatment, the highest percentage 2,4-D degradation is obtained in the presence of the activated carbons with the greatest content of carboxyl groups. In order to determine the role of activated carbon in this process, we determined the adsorptive and photocatalytic contribution (UV/TiO 2) to the overall 2,4-D removal. The total percentage removal by the UV/TiO 2 /activated carbon system is much higher than the value obtained by summing the adsorp-tive and catalytic contributions, mainly when the carbon has an elevated carboxyl group content. No relationship was observed between the textural properties of activated carbons and their synergistic activity; however, the carbons with the greatest carboxyl group content showed the highest synergistic activity. Together with the results of chemical and superficial characterization of the carbon samples after their utilization in the photocatalytic process (UV/TiO 2), these findings demonstrate that the reduc-tion of superficial carboxyl groups to alcohol groups is the main pathway by which activated carbon enhances the additional generation of HO • radicals in the medium. Experiments conducted in the pres-ence of radical scavengers (carbonate ions, sulfate ions, and t-butanol) revealed that H • , e aq − , and HO • species participate in the 2,4-D photodegradation. According to the time course of total organic carbon and toxicity during 2,4-D photodegradation, its complete mineralization is not achieved, and the toxicity of the degradation compounds is lower than that of 2,4-D.

  Applied Catalysis B: Environmental01/2012; 126:100-107.
• Article: Adsorption/bioadsorption of phthalic acid, an organic micropollutant present in landfill leachates, on activated carbons.

  José D Méndez-Díaz , Mahmoud M Abdel daiem , José Rivera-Utrilla , Manuel Sánchez-Polo , Isidora Bautista-Toledo

  [show abstract] [hide 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<surface water≈ultrapure water<wastewater. The effectiveness of PA adsorption was lower in dynamic than in static regime due to the shorter adsorbent-adsorbate contact time in dynamic regime.

  Journal of Colloid and Interface Science12/2011; 369(1):358-65. · 3.07 Impact Factor