Introduction The extraction of alumina from bauxite by the Bayer process produces a slurry by-product referred to as ‘bauxite residue’ or ‘red mud’. The liquid component of the slurry is highly alkaline and requires neutralisation to render it environmentally benign. A common practice is neutralisation using Mg rich seawater, which results in the formation of the layered double hydroxide (LDH) ...

Several mesoporous nickel-based catalysts with MgO-Al2O3 as the catalyst support were prepared using a co-precipitation method at a constant pH. The supports were prepared from the decomposition of an Mg-Al hydrotalcite-like structure which had already been prepared with Mg/Al=1. Prior to impregnating 10 wt.% nickel on the supports, the precursor was decomposed at several ...

Hydrotalcite nanoparticles were synthesized by co-precipitation of aqueous Mg(NO(3))(2)·6H(2)O and Al(NO(3))(3)·9H(2)O in the presence of urea and subsequent microwave-hydrothermal treatment. The nanoparticles were activated with saturated aqueous Ca(OH)(2), and used to hydrolyze cellulose. A maximum hydrolysis yield of 47.4% with high glucose selectivity (85.8%) was achieved at 423 K. The nano...

Ahstraet--Hydrotalcite solid solutions were prepared by coprecipitation followed by hydrothermal treatment between 150 ~ and 250~C. Based on the structural formula [Mgl_xAlx(OH)~lX+l(COz)x/2 9 mH20] x-, pure solid solutions were formed in the range Al/(Al + Mg) = 0.2 to 0.33, where m = (1 3x/2). Maximum crystallite size was achieved by hydrothermal treatment between 180 ~ and 200~ with x = 0.33...

The maintenance of waterways generates large amounts of dredged sediments, which are deposited on adjacent land surfaces. These sediments are often rich in metal contaminants and present a risk to the local environment. Understanding how the metals are immobilized at the molecular level is critical for formulating effective metal containment strategies such as phytoremediation. In the present w...

Multicomponent condensation of 1-naphthol, malononitrile, and arylglyoxals in the presence of Mg-Al hydrotalcite under solvent-free MicroWave (MW) conditions gave a new series of 2-amino-4-aroyl-4H-benzo[h]chromene-3-carbonitriles in high yields (70-89%). The structure of all products was elucidated by their...

Rehydration of Mg-Al hydrotalcite in the liquid phase using ultrasounds or a high stirring speed leads to nanoplatelets with surface areas of 400 m(2) g(-1), displaying catalytic activities in aldol condensations up to 8 times higher than the best catalytic system reported in the literature.