Activated Hydrotalcites Obtained by Coprecipitation as Photocatalysts for the Degradation of 2,4,6-Trichlorophenol

Abstract

A gallery of hydrotalcite-type mesoporous materials with different Mg/Al molar ratios were synthesized by the coprecipitation method. The materials were activated by heat treatment to test their activity in the photodegradation of 2,4,6-trichlorophenol under UV light irradiation. The physicochemical properties of the different synthesized and activated materials were determined using XRD, physical adsorption/desorption of N2, FTIR, SEM, DTA, and TGA. Their banned band energy was determined by UV-Vis to identify their potential to be used as a semiconductor in catalytic photodegradation processes. The results of photodegradation tests of 2,4,6-trichlorophenol showed that hydrotalcites have a high degradation capacity, up to 100% for the catalyst of Mg/Al ratio = 2, with a high mineralization capacity of 80%. The degradation capacity of most of the catalysts tested is mainly due to the presence of holes and the formation of superoxide free radicals, which are the determining species within the degradation mechanism.

Enhanced Photocatalytic Degradation of Rhodamine-B under Led Light Using CuZnAl Hydrotalcite Synthesized by Co-Precipitation Technique

“…The ratio of Zn and Al atoms in H was closed to a 2:1 ratio. It was possible to attach the H material with the composition Zn 4 Al 2 CO 3 (OH) 12 •3H 2 O. The actual molar ratio of Cu 2+ and Zn 2+ ions in the CuH-3.0 sample is 5.32:6.86, which is quite similar to the theoretically calculated ratio of Cu 2+ and Zn 2+ to synthesize material.…”

“…Based on the distance values (d) between the layers of the hydrotalcites at the plane of (003) and (110), the a and c parameters were obtained, where the a parameter represents the cation-cation distance in the brucite layer and a = 2.d 110 . The thickness of the brucite layer was characterized by parameter c and the inner layer spacing and was calculated according to the formula c = 3d 003 [3,11,12]. The calculation of parameters a and c shown in Table 1 revealed that they fluctuated in the range from 3.058 to 3.074 Å and from 23.18 to 24.15 Å, respectively.…”

Photocatalytic Degradation of Mixed Dyes in Aqueous Phase by MgAlTi and ZnAlTi Mixed Oxides

“…The precipitate was filtered and washed with hot distilled water (70 °C) up to pH = 7 to remove alkaline metals and un-reacted nitrate ions (6 times). The product was dried at 80 °C for 12 h. The reported procedure [27] was followed to obtain the corresponding MMO: the LDH was calcined at 500 °C for 4 h in an air stream. The resulting sample was labeled as MgAlTiM, where letter M which is the last letter corresponds to the identification of the sample that underwent microwave treatment.…”

“…Many authors have reported that after 500 °C no significant weight loss was observed, which is why this temperature was established as the calcination temperature for the study samples. The maximum loss was obtained at around 40-36%, and it is at this point in which it can be assumed that the mixed metal oxides are formed, since no further loss is observed [27]. The surface areas were calculated using the Brunauer-Emmett-Teller (BET) method, whereas the pore size distribution and pore volume were determined by the Barrett-Joyner-Halenda (BJH) method.…”

Low‐Temperature and Highly Active Nickel Catalyst Based on Hydrotalcite Mg–Al for CO2 Methanation

“…The so-obtained a and c values were close to those previously reported. [30] The crystallite size was estimated according to the Scherrer equation (Equation ( 3)), that is appropriate for crystal sizes from 3 to 200 nm. [31] τ…”