Cr(VI) immobilization in mixed (Mg,Al) oxides

Martínez-Gallegos, Sonia; Pfeiffer, Heriberto; Lima, Enrique; Espinosa, M.; Bosch, P.; Bulbulian, S.

doi:10.1016/j.micromeso.2006.03.045

Cited by 19 publications

(13 citation statements)

References 30 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…It is believed this increase in pH helps to reduce hardness parameter. This behavior is important because the HTLCs were thought of only as means for anion exchange [31], but now we can see that it also precipitated cations. The mechanism proposed from these observations is that when HT3015OT comes in contact with the sulfurous water a catalytic activity of dissociation of the water molecules occurs (H + + OH Al OH        formed.…”

Section: Sorption Testmentioning

confidence: 72%

Green Cycle: Sulfate Sorption from Natural Water on Anionic Clay Compound Obtained from Industry Wastewater

Rosano-Ortega¹,

Lebrún²,

Oglesby³

et al. 2013

GSC

View full text Add to dashboard Cite

In this paper we are describing a green cycle process. The first step was a novel hydrotalcite-like compound (HTLC) synthesized by a co-precipitating method, under standard ambient temperature and pressure, using chemical industry wastewater rich in divalent and trivalent cations, activated by a thermal treatment and finally characterized by scanning electron microscopy (SEM), energy dispersive X-ray fluorescence (EDS) and thermogravimetric analysis (TGA). The second step was a series of batch sorption tests performed with this activated HTLC and untreated underground sulfurous water from the state of Puebla, México. The HTLC calcined at 500˚C/3 h exhibited the best sorption ability for ions, demonstrated a decrease of the hardness and sulfate ions to below the regional legal standards for drinking water. Once inactive after being used in water treatment, the sorbed ions were removed by ion exchange in a carbonate-containing solution, resulting in an 80% recycling of the material which upon activation demonstrated a retained capacity for water treatment. This recyclability suggests the exciting possibility of this novel compound as an efficient "green" technology in water treatment processes.

show abstract

Section: Sorption Testmentioning

confidence: 72%

Green Cycle: Sulfate Sorption from Natural Water on Anionic Clay Compound Obtained from Industry Wastewater

Rosano-Ortega¹,

Lebrún²,

Oglesby³

et al. 2013

GSC

View full text Add to dashboard Cite

show abstract

“…The physical properties of the granular LDH used in the column tests of this study were already investigated in our prior work [44,46], which established that the as-obtained, mixed metal oxide material exhibited the cubic periclase structure of a magnesium/aluminum solid solution, which is typically obtained when LDH is calcined at high temperatures to remove interlayer water and anions [47][48][49]. Upon re-introduction of the granules to DI water, the layered double hydroxide structure was successfully recovered [44] in what is known as the "memory effect" of LDHs [38].…”

Section: Physical Properties Of Ldhmentioning

confidence: 99%

Layered Double Hydroxide Sorbents for Removal of Selenium from Power Plant Wastewaters

Chowdhury

Kraetz

et al. 2019

ChemEngineering

View full text Add to dashboard Cite

Selenium is an essential trace element but is increasingly becoming a contaminant of concern in the electric power industry due to the challenges of removing solubilized selenate anions, particularly in the presence of sulfate. In this work, we evaluate granulated layered double hydroxide (LDH) materials as sorbents for selenium removal from wastewaters obtained from a natural gas power plant with the aim to elucidate the effect of competing ions on the sorption capacities for selenium removal. We first present jar test data, followed by small-scale column testing in 0.43 inch (1.1 cm) and 2 inch (5.08 cm) diameter testbed columns for the treatment of as-obtained cooling tower blowdown waters and plant wastewaters. Finally, we present field results from a pilot-scale study evaluating the LDH media for treatment of cooling tower blowdown water. We find that despite the high levels of total dissolved solids and competing sulfate ions, the selenium oxoanions and other regulated metals such as chromium and arsenic are successfully removed using LDH media without needing any pre-treatment or pH adjustment of the wastewater.

show abstract

“…Environmentally hazardous wastewaters from tannery industry 12 are among the most polluted either due to chromium as well as to 13 organic residues [1]. Indeed, the most polluting species are the 14 chromates formed with chromium (VI) and chromium(III) cation.…”

Section: Introductionmentioning

confidence: 99%

“…Furthermore there is a possibility to recover the metal 32 or even the retained chromium to be disposed for some useful 33 application such as catalysis [9,10]. 34 An original and recent approach has been the use of ionic 35 exchangers such as hydrotalcites (HT) [11][12][13][14][15]. Hydrotalcites, also 36 known as layered double hydroxides (LDH), are anionic clays with 37 positively charged octahedral hydroxide layers, which are neutral- where M 2+ and M 3+ are di-and tri-valent cations, respectively, A 41 mÀ is an anion whose charge is mÀ.…”

mentioning

confidence: 99%