Synthesis of functionalized biomaterials and its application in the efficient remediation of aquatic environment contaminated with Cr(VI)

Kinetics and Thermodynamic Study on Novel Modified–Mesoporous Silica MCM-41/Polymer Matrix Nanocomposites: Effective Adsorbents for Trace CrVI Removal

“…53−55 At pH greater than 5.5, the dominant species becomes CrO 4 2− in aqueous phase. 56 Consequently, Cr VI ions removal is largely pH-dependent with its adsorption being favored under acidic conditions, which was similarly observed in this work. The effect of the solution pH on the Cr VI removal by m-MCM-41/PMNCs was monitored in the pH range 1.0−8.0 using 0.01 g of the adsorbent and 10 mL of solution containing Cr VI ions (10 mg L −1 ) at 298 K. As shown in Figure 9b, the maximal adsorption is attained at pH = 2.0 for m-MCM/PMMA, m-MCM/PVA, and m-MCM/N6 and at pH = 3.0 for m-MCM/PS, respectively.…”

“…At low pH conditions, the most significant forms of Cr VI are Cr 2 O 7 2– , HCrO 4 – , CrO 4 2– and Cr 3 O 10 2– . Among these oxyanions, HCrO 4 – is the predominant anionic form at pH 2–5, but as the pH increases, it transforms to the other forms such as to forms of CrO 4 2– and Cr 2 O 7 2– . − At pH greater than 5.5, the dominant species becomes CrO 4 2– in aqueous phase . Consequently, Cr VI ions removal is largely pH-dependent with its adsorption being favored under acidic conditions, which was similarly observed in this work.…”

Structural elucidation of hexavalent Cr adsorbed on surfaces and bulks of Fe3O4 and α-FeOOH

“…7,[12][13][14][15][16] Utilization of natural-cationic materials, such as activated carbon, chitosan, chelate resins, and natural zeolites for Cr 6+ adsorption has been widely investigated due to their low cost, feasibility, handling simplicity, and exibility. [17][18][19][20] However, the removal of the adsorbed Cr 6+ species by those adsorbents still needs a further reduction process to complete the Cr disposal.…”

Evaluación De Residuos Agroindustriales Como Biofiltros: Remoción De Cr (Vi) en Efluentes De Curtiembres Sintéticos

“…De ahí, el aumento del riesgo ambiental y a la salud debido a la toxicidad y persistencia de metales pesados tales como Cr (VI), Hg+,Ni 2 O 3 , CuO, Cd, entre otros. [2][3][4][5][6][7][8][9][10][11][12]. En el caso específico del Cr (VI), este se comporta como un elemento tóxico con efectos nocivos, que penetra rápidamente cualquier vía de exposición hasta llegar a los glóbulos rojos, híga-do, bazo, riñón, tejidos blandos y huesos afectando principalmente sistemas digestivo, respiratorio, urinario y la piel [2][3][4][5][6][7][8][9][10][11][12][13].…”

“…La Agencia Internacional de Investigación en Cáncer (IARC por su sigla en inglés) de Estados Unidos, clasifica el cromo hexavalente como un agente potencialmente cancerígeno que modifica el proceso de transcripción del ADN y causa anomalías cromosó-micas [5,14]. Igualmente, la Agencia para Sustancias Tóxicas y Registro de Enfermedades (ATSDR por su sigla en inglés) menciona que dentro de los efectos de exposición prolongada a Cr (VI) en ambientes ocupacionales se incluye cáncer de pulmón, siendo éste la fuente principal del aumento en la tasa de incidencia de esta enfermedad [15].…”