Nanohybrid Layered Double Hydroxides Used to Remove Several Dyes from Water

Abstract

For the preparation and characterization of several layer double hydroxides (LDH) with inorganic interlayer anions (carbonate and nitrate) and nanohybrids, two organo-LDHs were studied in detail. The dodecylbenzene sulfonate (DBS) was used as an organic interlayer anion to modify the hydrophilic nature of the interlayer. The aim of the modification of the layered double hydroxides (LDH) was to change the hydrophilic character of the interlayer to hydrophobic with the purpose of improving its ability to adsorb several (anionic and cationic) dyes from water. These compounds have been used as adsorbents of amaranth (Am), diamine green B (DGB) and brilliant green (BG) dyes. Adsorption tests were conducted using variable pH values, contact times and initial dye concentrations (adsorption isotherms) to identify the optimum conditions for the intended purpose. Adsorbents and adsorption products were characterized by several physicochemical techniques. The results of the adsorption tests showed that the organo-LDH nanohybrids could be efficient adsorbents in the removal of studied dyes from water. Thus, it can be concluded that nanohybrids studied in this work might act as suitable supports in the design of adsorbents for the removal of a wide spectrum of dyes with the aim of reducing the adverse effects on water resources.

LDH-TiO2 Composite for Selenocyanate (SeCN−) Photocatalytic Degradation: Characterization, Treatment Efficiency, Reaction Intermediates and Modeling

“…The basal spacing (d 003 ) of 0.807 nm indicates nitrate in LDH as revealed by the presence of nitrogen in the EDX spectra analysis (Table 3) [49,50]. Moreover, theses cell values along with the sharp XRD peaks in Figure 2A-(b) for LDH (003, 006, 110, and 113) represent a well-crystallized LDH structure [48]. Furthermore, for the LDH-TiO 2 matrix, the respective XRD results (Figure 2A-(c)) show both LDH and TiO 2 peaks that suggests incorporation of TiO 2 into the LDH phase.…”

“…The presence of both rutile and anatase phases is reported to yield better photocatalysis efficiency [47]. Furthermore, the XRD results for the uncalcined LDH (Figure 2A-(b)) indicate a hydrotalcite mass with a rhombohedral structure (3R poly-type) based on the basal (003, 006, 009, 015, and 018), and non-basal (110 and 113) reflections [48,49]. The corresponding cell parameters i.e., a, c, and d 003 for uncalcined LDH were found to be 0.307, 2.407 and 0.807 nm, respectively ((c is equal to ((6d 006 + 3d 003 )/2) and a is equal to 2d 110 ).…”

Empleo de Hidróxidos Dobles Laminares como material adsorbente en el tratamiento de aguas contaminadas por ácido pícrico, experiencia realizada en la UNAH año 2018

“…Con los datos obtenidos en el estudio queda evidenciada la obtención de los HDL reflejadas en la aparición de picos de absorción característicos de estos compuestos intercaladas con aniones carbonatos y sulfatos en los espectros infrarrojos, tal como lo demuestran otros estudios 2,21,22 , siendo ésta la única técnica de caracterización con la que se pudo contar, limitando un poco la investigación, ya que para una confirmación más exacta se hubiera deseado realizar un análisis de difracción de rayos X, tantos de los materiales sintetizados como de los complejos resultantes con el contaminante 23,24 . Con respecto a los resultados de los experimentos de influencia del tiempo de contacto queda demostrado que este tipo de nanopartícula puede utilizarse como un material adsorbente que favorece la descontaminación de aguas residuales que contengan acido pícrico de diferentes lugares o industrias que trabajen con este tipo de compuestos tal es el caso de la Facultad de Química y Farmacia de la Universidad Nacional Autónoma de Honduras o diferentes industrias químicas que utilicen estos compuestos, siendo similares a otros estudios donde demuestran que los HDL favorece la descontaminación de aguas con otro tipo de contaminantes con estructura muy similar al contaminante estudiado 25 , así como el acercamiento de los porcentajes de adsorción de este contaminante en otros tipo de materiales 26 .…”

“…Un problema de gran magnitud es la contaminación ambiental, que es originada por fuentes naturales, así como por las actividades humanas. Los diversos procesos industriales de naturaleza química y el aumento día tras día de la población contribuyen al incremento de contaminación de las fuentes de agua, produciendo un déficit de este preciado recurso 1,2 . La presencia de contaminantes en el agua hace necesario un estricto control y eliminación de los mismos, sobre todo cuando estas van destinadas al consu-mo humano.…”

Size Selectivity of Anionic and Cationic Dyes Using LDH Modified Adsorbent with Low-Cost Rambutan Peel to Hydrochar

“…Currently, many researchers report that there are several methods that have been developed to remove pollutants in wastewater. In general, various methods, physics and biology are used in wastewater treatment, such as electrochemistry, oxidation, biodegradation, chemical chemistry, coagulation, photocatalysis, membrane filtration, flocculation, ion exchange, ozonation, filtration, and adsorption [4,6,11,12]. Among these methods, adsorption is the most appropriate method and has many advantages for removing methylene blue from wastewater.…”