The kinetics of dehydroxylation
have been studied .
temperature of most kaolinites ranges from 498 [degree]C to 605 [degree]C, whereas the dehydroxylation
of dickite and nacrite occurs at 680 [degree]C.
Upon ingestion, polyphenols can be metabolized (deglucosylated, glucuronidated, sulphated, and possibly deesterified) by human enzymes, with additional changes in the gut by (typically, colonic) bacteria, which may hydrolyse glucosides, glucuronides, sulfates, amides, esters, and lactones and further result in ring-fission, in addition to further reduction, decarboxylation, demethylation, and dehydroxylation
, among other reactions [134,136].
Considering that the weight loss due to dehydroxylation
of pure kaolinite is 14% (Eslinger and Peaver, 1988), the calculated kaolinite content in the Nagar Parkar kaolin is 50.
The hump near 300[degrees]C in Figure 3a and near 350[degrees]C in Figure 3b can be assigned to the dehydroxylation
of gibbsite (y-Al(OH)3) present in the dawsonite sample [2, 13].
A high acid content influences the sensory parameters of the wine but also acts as a preservative and stabilizes the wine colour due to the chemical dehydroxylation
of anthocyanins in low pH conditions.
The endothermic and exothermic effects were recorded on the DSC curve and were used to determine the dehydroxylation
temperatures of different clay species.
Metakaolin (MK), which is formed by the dehydroxylation
of kaolin upon heating in the temperature range of 700-800[degrees]C (Moya, 1998), has been successfully used as SCM in concrete because of its high pozzolanic properties (Sabir et al.
This difference is because there are more hydroxyl groups in natural clays, while in calcined clay the dehydroxylation
occurs with the calcination process.
Although the thermal transformation of kaolinite has been investigated for many years, a controversy about the process of dehydroxylation
(elimination of the OH groups from the kaolinite structure) remains.
Increased calcitonin level inhibits renal absorption of calcium and phosphorous, osteoclastic reabsorption of bones and decreases renal dehydroxylation
of vitamin D.
The weight loss which is attributed to adsorbed water molecules, dehydroxylation
reaction and the presence of hydroxyl groups .